Slag supplementing method and slag supplementing device for electroslag fusion welding

Abstract

The invention relates to the technical field of metallurgy, in particular to a slag supplementing method and device for electroslag fusion welding, and the slag supplementing method comprises the steps that S1, working condition parameters of electroslag fusion welding are collected, and the rated electrode melting speed and the rated welding current are determined according to the working condition parameters; s2, the welding current obtained through monitoring is compared with rated welding current, and the first electrode melting speed or the second electrode melting speed is obtained according to the comparison result; s3, the first electrode melting speed or the second electrode melting speed is compared with the rated electrode melting speed, and the third electrode melting speed or the fourth electrode melting speed is obtained according to the comparison result; and S4, the third electrode melting speed or the fourth electrode melting speed is compared with the rated electrode melting speed till the third electrode melting speed or the fourth electrode melting speed is within the normal fluctuation range of the rated electrode melting speed. By means of the slag supplementing method and the slag supplementing device, constant melting speed control over electroslag fusion welding is achieved, the stable molten steel solidification speed is guaranteed, and it is facilitated that the internal mechanical property of a fusion welding part is kept uniform.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a slag filling method and a slag filling device for electroslag fusion welding. Background Art

[0002] With the continuous and in-depth development of my country's industrial modernization, the demand for heavy equipment in all walks of life is increasing, especially in the field of high-end manufacturing, the demand for heavy equipment made of high-quality special steel is more urgent. Among them, the large-scale equipment has become a core concern, which requires the material to not only have excellent properties such as high strength and high toughness, but also meet the manufacturing requirements of large sizes. Therefore, electroslag fusion welding technology came into being. This technology uses plate-type consumable electrodes and an appropriate amount of slag to fuse and weld two or more small-sized electroslag parts under a precisely controlled welding spacing, thereby "joining" them into a large-sized electroslag product. The advantage of this technology is that it not only meets the needs of large-scale production, but also effectively inherits the excellent properties of small-sized electroslag products through the secondary manufacturing process, such as high strength, high toughness, good corrosion resistance and precise size control. In addition, compared with integral forging, electroslag fusion welding technology greatly reduces the generation of metal waste, improves resource utilization, reduces production costs, and also shortens the production cycle and improves production efficiency.

[0003] In the current electroslag fusion welding, during the welding process of the plate consumable electrode and the welded parts, since the two are made of the same material, the slag pool will melt and extend to the inside of the welded parts during welding. As the welding process continues, the horizontal cross-sectional area of ​​the slag pool will gradually increase, while the depth of the slag pool will decrease accordingly, and the shape of the slag pool will gradually change from deep and narrow to shallow and wide. The above-mentioned morphological changes of the slag pool not only increase the risk of the welded parts being melted through in the horizontal direction, but also expand the affected area of ​​the weld, which will lead to deformation of the welded parts and uneven mechanical properties.

[0004] And because the width of the molten welding pool is relatively narrow and the total amount of slag is limited, as the slag pool melts and extends to the inside of the welded parts, its horizontal cross-sectional area continues to increase, while the depth of the slag pool continues to decrease, resulting in the adjustment space of the movement position of the consumable electrode in the slag pool becoming increasingly limited. And because the electroslag fusion welding technology usually adopts the constant power control method, the current fluctuation amplitude in this process is large. This technology changes the resistance value in the closed loop by adjusting the immersion depth of the consumable electrode in the slag pool, and its working principle is similar to that of a sliding rheostat. Therefore, during the fusion welding process, the movement position of the consumable electrode and its immersion depth will also fluctuate greatly. As the electroslag fusion welding proceeds, on the one hand, the slag pool depth continues to decrease, and on the other hand, the electrode immersion depth fluctuates greatly. The combined effect of these two factors will produce a greater risk of short circuit.

[0005] To this end, the present application provides a slag filling method and a slag filling device for electroslag fusion welding. Summary of the invention

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a slag filling method and a slag filling device for electroslag fusion welding, thereby solving the technical problems of deformation and uneven mechanical properties of fusion welding parts, as well as the risk of short circuit caused by the continuous decrease in slag pool depth and large fluctuations in electrode immersion depth during the fusion welding process between the plate-type consumable electrode and the fusion welding parts.

[0007] In order to achieve the above object, the first aspect of the present invention provides a slag filling method for electroslag fusion welding, the slag filling method specifically comprising: S1: Collect the working parameters of electroslag fusion welding, and determine the rated electrode melting speed and rated welding current according to the working parameters; S2: Compare the monitored welding current with the rated welding current. When the welding current is greater than or equal to the rated welding current, the computer automatically controls the electrode lifting device to lift the plate-type consumable electrode, reduce the electrode melting speed, and reduce the welding current. Then the first electrode melting speed is calculated by the automatic weighing device. Record the weight increase of the automatic weighing device per unit time and the weight of the slag added per unit time, and then calculate the first weight increase caused by the drop of metal droplets generated by electrode melting; When the welding current is greater than the rated welding current: ; in, It is the first weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; According to the first weight increase caused by the drop of metal droplets produced by electrode melting per unit time, , calculate the melting rate of the first electrode for: ; in, is the melting rate of the first electrode, in kg / s; It is the first weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; is the unit time, unit s; When the welding current is less than the rated welding current, the automatic computer controls the electrode lifting device to lower the plate-type consumable electrode, increase the electrode melting speed, increase the welding current, and then obtain the second electrode melting speed through the automatic weighing device; When the welding current is less than the rated welding current: ; in, The second weight increase per unit time caused by the falling of metal droplets generated by the melting of the plate consumable electrode, unit: kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; The second weight increase caused by the drop of metal droplets produced by the melting of the plate consumable electrode per unit time is , the melting rate of the second electrode is calculated for: ; in, is the melting rate of the second electrode, in kg / s; The second weight increase per unit time caused by the falling of metal droplets generated by the melting of the plate consumable electrode, unit: kg; is the unit time, unit s.

[0008] S3: comparing the first electrode melting speed or the second electrode melting speed with the rated electrode melting speed. When the first electrode melting speed or the second electrode melting speed is greater than or equal to the preset electrode melting speed, the computer is automatically controlled to close the slag feeder, so that the slag pool depth becomes shallower, the electrode immersion depth is reduced, and the electrode melting speed is further reduced. The third electrode melting speed is obtained by the automatic weighing device. Comparing the first electrode melting speed or the second electrode melting speed with the rated electrode melting speed, and closing the slag feeder when the first electrode melting speed or the second electrode melting speed is greater than or equal to the rated electrode melting speed; ; in, The third weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; ; in, is the melting rate of the third electrode, in kg / s; The third weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; is the unit time, unit s; When the first electrode melting speed or the second electrode melting speed is less than the rated electrode melting speed, the automatic control computer starts the slag feeder to deepen the slag pool and increase the electrode immersion depth, thereby increasing the electrode melting speed, and the fourth electrode melting speed is obtained through the automatic weighing device; When the first electrode melting speed or the second electrode melting speed is less than the rated electrode melting speed, the slag feeder is turned on, and the slag feeding speed is calculated from the difference between the first electrode melting speed or the second electrode melting speed and the rated electrode melting speed: ; in, is the electrode melting speed difference, unit is kg / s; is the rated electrode melting speed, in kg / s; is the melting rate of the first electrode, in kg / s; is the melting rate of the second electrode, in kg / s; ; in, The fourth weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate consumable electrode, in kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; ; in, is the melting rate of the fourth electrode, in kg / s; The fourth weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate consumable electrode, in kg; is the unit time, unit s.

[0009] S4: comparing the melting speed of the third electrode or the melting speed of the fourth electrode with the rated electrode melting speed. When the melting speed of the third electrode or the melting speed of the fourth electrode is within the range of 95% to 105% of the rated electrode melting speed, the melting speed of the third electrode or the melting speed of the fourth electrode is within the normal fluctuation range of the rated electrode melting speed, and the electrode melting speed is constant. When the third electrode melting speed or the fourth electrode melting speed is outside the range of 95% to 105% of the rated electrode melting speed, steps S3 and S4 are repeated until the third electrode melting speed or the fourth electrode melting speed is equal to the rated electrode melting speed, thereby achieving a constant electrode melting speed.

[0010] Step S5 specifically includes: S51: Calculate a preset electrode immersion depth according to a rated electrode melting rate; S511: The latent heat for melting the plate consumable electrode is calculated from the rated electrode melting rate and the latent heat of melting per unit mass of metal: ; in, Q L is the latent heat used to melt the plate consumable electrode, in W; is the rated electrode melting speed, in kg / s; L is the latent heat of fusion per unit mass of metal, in J / kg; S512: Since the temperature inside the plate-type consumable electrode in the width direction is uniformly distributed, the sensible heat inside the plate-type consumable electrode used for heat conduction of the plate-type consumable electrode is: ; in, Q S is the sensible heat used for heat conduction of the plate-type consumable electrode, in W; k m is the thermal conductivity of metal, unit is W / (m·K); l e is the length of the plate consumable electrode, in m; w e is the width of the plate consumable electrode, in m; S513: According to the heat balance relationship, the heat flux between the slag pool and the plate consumable electrode contact surface is equal to the sum of the latent heat used to melt the plate consumable electrode and the sensible heat used to conduct heat to the plate consumable electrode: ; in, Q s-e is the heat flux between the contact surface of the slag pool and the plate-type consumable electrode, in W; Q L is the latent heat used to melt the plate consumable electrode, in W; Q S is the sensible heat used for heat conduction of the plate-type consumable electrode, in W; S514: The contact area between the slag pool and the plate-type consumable electrode is calculated by Fourier's law: ; in, A s-e The contact area between the slag pool and the plate-type consumable electrode, unit: m 2 ; k l is the liquid phase thermal conductivity of the metal, unit is W / (m·K); T 1 is the slag temperature at the contact surface between the slag pool and the plate-type consumable electrode, unit K; T 2 is the metal solidus temperature, unit K; Q s-e is the heat flux between the contact surface of the slag pool and the plate-type consumable electrode, in W; δ is the thickness of the metal liquid film, in mm; S515: The preset electrode immersion depth is calculated based on the contact surface area between the slag pool and the plate-type consumable electrode: ; in, h p is the preset electrode immersion depth, in m; A s-e The contact area between the slag pool and the plate-type consumable electrode, unit: m 2 ; l e is the length of the plate consumable electrode, in m; w e It is the width of the plate consumable electrode, in m.

[0011] S52: The automatic control computer obtains the maximum metal immersion depth based on the current electrode immersion depth, the maximum metal droplet height and the maximum downward movement distance of the plate-type consumable electrode obtained through monitoring and calculation, and then obtains the preset maximum metal immersion depth based on the maximum metal droplet height and the preset electrode immersion depth, and compares the maximum metal immersion depth with the preset maximum metal immersion depth: S521: Record the total weight gain of the automatic weighing device and the total weight gain of the supplementary slag, and then calculate the total weight gain caused by the falling of the metal droplets generated by the melting of the plate-type consumable electrode; ; in, The total weight gain of the automatic weighing device, in kg; It is the total weight increase caused by the falling of molten metal droplets due to electrode melting, in kg; The total weight increase to supplement the slag, in kg; S522: considering the slag density and the metal density, calculating the slag-air interface height increment caused by the total weight increase of the automatic weighing device; ; in, The volume increment caused by the falling of metal droplets and slag filling, unit: m 3 ; It is the total weight increase caused by the falling of molten metal droplets due to the melting of the plate consumable electrode, in kg; The total weight increase to supplement the slag, in kg; ρ m is the metal density, unit is kg / m 3 ; ρ s is the slag density, unit: kg / m 3 ; ; in, It is the increment of slag-air interface height caused by the total weight increase of the automatic weighing device, in m; w z is the width of the fusion welding area, in m; l z is the length of the fusion welding area, in m; S523: Since the slag pool height rises due to the plate-type consumable electrode being immersed in the slag pool, the slag-air interface height is corrected by the electrode immersion depth; ; in, The volume of the plate-type consumable electrode immersed in the slag pool, in m 3 ; h p is the preset electrode immersion depth, in m; l e is the length of the plate consumable electrode, in m; w e is the width of the plate consumable electrode, in m; ; in, It is the increment of slag-air interface height caused by the plate-type consumable electrode being immersed in the slag pool, in m; The volume of the plate-type consumable electrode immersed in the slag pool, in m 3 ; w z is the width of the fusion welding area, in m; l z is the length of the fusion welding area, in m; ; in, is the total increment of the slag-air interface height, in m; It is the increment of slag-air interface height caused by the total weight increase of the automatic weighing device, in m; It is the increment of slag-air interface height caused by the plate-type consumable electrode being immersed in the slag pool, in m; Finally, the initial slag-air interface height is calculated from the initial slag volume, the length of the fusion welding area, and the width of the fusion welding area, and the current slag-air interface height is calculated from the total increment of the slag-air interface height; ; in, h a-s_i is the slag-air interface height, in m; m i_s is the initial mass of the slag, in kg; ρs is the slag density, unit: kg / m 3 ; w z is the width of the fusion welding area, in m; l z is the length of the fusion welding area, in m; is the total increment of the slag-air interface height, in m; S524: During the electroslag fusion welding process, the welding current will fluctuate. The movement position of the plate consumable electrode changes due to the current fluctuation. The change law of the welding current is as follows: ; in, I is the welding current, unit is A; I r is the rated welding current, in A; ω 0 is the angular frequency determined by the operating frequency of the industrial AC power supply, in Hz; θ 0 is the initial phase of rated welding current; ; in, v e is the actual moving speed of the plate-type consumable electrode, in m / s; v 0 is the average moving speed of the plate-type consumable electrode, in m / s; v v is the fluctuating motion speed of the plate-type consumable electrode, in m / s; ω 1 is the angular frequency of the plate-type consumable electrode movement, in Hz; θ 1 is the initial phase of the plate-type consumable electrode movement, which is determined by the actual working conditions and calculated from the data recorded by the electrode lifting device; ; in, S e_d is the maximum downward movement distance of the plate-type consumable electrode, in m; [t 1 ，t 2 ] The time interval of the downward movement speed of the plate-type consumable electrode, unit: s; v e is the actual moving speed of the plate-type consumable electrode, in m / s; S525: Calculate the maximum metal immersion depth, including the current electrode immersion depth h a-s_i -h e_p , Maximum metal droplet height h d And the maximum downward movement distance of the plate consumable electrodeS e_d ; ; in, is the maximum metal immersion depth, in m; h a-s_i -h e_p is the current electrode immersion depth, in m; h e_p is the electrode tip position recorded by the electrode lifting device, in m; h d is the maximum metal droplet height, in m; S e_d is the maximum downward movement distance of the plate-type consumable electrode, in m; ; in, is the maximum metal immersion depth, in m; h p is the preset electrode immersion depth, in m; h d is the maximum metal droplet height, in m; h p + h d ) is the preset maximum metal immersion depth, in m; C is the safety factor; Then, a safety factor is introduced to correct the preset maximum metal immersion depth, and then the maximum metal immersion depth is compared with the preset maximum metal immersion depth.

[0012] When the maximum metal immersion depth is greater than or equal to 110% to 130% of the preset maximum metal immersion depth, the electric limit device is started, and the computer-controlled electrode lifting device is automatically controlled to prevent the plate-type consumable electrode from moving downward, thereby reducing the rated welding current and the rated electrode melting speed. If the electroslag fusion welding of the fusion welding parts is not completed, steps S2 to S5 are repeated until the electroslag fusion welding of the fusion welding parts is completed; When the maximum metal immersion depth is less than 110% to 130% of the preset maximum metal immersion depth, the automatic control computer controls the plate-type consumable electrode to continue to move downward until the electroslag fusion welding of the fusion welding parts is completed.

[0013] The second aspect of the present invention provides a slag filling device, which is applied to the slag filling method of electroslag fusion welding provided in the first aspect, and the slag filling device includes: an automatic weighing device; a fusion welding component, which is placed above the automatic weighing device; a slag pool, which is located between two fusion welding components; an electrode protection cover, which is supported and connected to an external support rod so as to be arranged above the fusion welding component; a slag feeder, which is arranged below the electrode protection cover and connected to the electrode protection cover, and the slag outlet of the slag feeder faces the slag pool; an electrode lifting device, which is supported and connected to an external support rod so as to be arranged above the slag pool; an electrode limiting device, which is arranged below the electrode lifting device and connected to the electrode lifting device; a plate-type consumable electrode, which is arranged below the electrode limiting device and inserted into the slag pool; an automatic control computer, which is arranged outside the automatic weighing device and is electrically connected to the automatic weighing device, the electrode protection cover, the slag feeder, the plate-type consumable electrode, the electrode limiting device, and the electrode lifting device.

[0014] Optionally, a bottom cooling water tank is provided between the automatic weighing device and the fusion welding component, thereby cooling the fusion welding component and the slag pool.

[0015] Optionally, there are multiple slag feeders.

[0016] Optionally, a plurality of slag feeders are evenly spaced and arranged in the circumferential direction of the plate-type consumable electrode.

[0017] The beneficial effects of the present invention are: The present invention provides a slag filling method and a slag filling device for electroslag fusion welding. The automatic control computer adjusts the lifting or lowering of the plate-type consumable electrode to change the electrode immersion depth, so that the welding current is maintained at the rated welding current, thereby obtaining the corresponding electrode melting speed (including the first electrode melting speed, the second electrode melting speed, the third electrode melting speed or the fourth electrode melting speed), and then timely adjusts the slag filling amount of the slag filler to the slag pool or stops the slag filling according to the size relationship or difference between the corresponding electrode melting speed and the rated electrode melting speed, so as to control the electrode immersion depth, maintain the stability of the slag pool depth, and ensure that the electrode melting speed is equal to the rated electrode melting speed when the slag pool temperature is stable. The slag filling method and the slag filling device of the present invention can realize the constant melting speed control of electroslag fusion welding, and the stable electrode melting speed can ensure the stable solidification speed of molten steel, improve the element segregation of elements such as carbon, sulfur, phosphorus and molybdenum in the vertical direction, and improve the uneven distribution of non-metallic inclusions in the vertical direction, which are all conducive to maintaining uniform mechanical properties inside the fusion welding parts and improving their mechanical properties and service life.

[0018] Furthermore, since the electrode melting rate is ensured to be equal to the rated electrode melting rate, that is, constant melting rate control is achieved, the total welding time can be increased or shortened by adjusting the rated electrode melting rate, and the heat transferred from the slag pool to the molten welding part can be regulated, thereby controlling the horizontal melting depth of the cross-section of the molten welding part and the volume of the molten welding affected area, thereby avoiding deformation of the molten welding part due to excessive horizontal melting depth of the cross-section, and making the mechanical properties inside the molten welding part more uniform, thereby ultimately improving the quality of electroslag fusion welding.

[0019] Furthermore, the slag filling method and slag filling device of the present invention can control the slag pool depth by continuous slag filling, adjust the electrode melting rate, increase or shorten the total welding time, and regulate the heat transferred from the slag pool to the molten welding parts, thereby controlling the horizontal melting depth of the cross-section of the molten welding parts to remain stable, breaking through the welding height limitation under the conventional constant power control strategy, and realizing electroslag fusion welding of parts with larger geometric dimensions.

[0020] Furthermore, the slag feeding device sets an electric limit device and cooperates with the automatic weighing device to enable the automatic control computer to obtain the maximum metal immersion depth and the preset maximum metal immersion depth. By comparing the results of the two, it is determined whether to start the electric limit device, and the plate-type consumable electrode is driven to move upward or downward through the electrode lifting device, ensuring the stability of the maximum metal immersion depth. This setting effectively avoids the contact between the plate-type consumable electrode and the metal surface of the slag pool, eliminates the risk of short circuit in the electroslag fusion welding process, and improves the safety of the fusion welding system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic flow diagram of a slag filling method for electroslag fusion welding of the present invention; Figure 2 It is a structural schematic diagram of a slag filling device for electroslag fusion welding according to the present invention; Figure 3 It is a cloud diagram of the numerical simulation calculation of the maximum metal droplet height by ANSYS-Fluent software when the current electrode immersion depth is 0.020m; Figure 4 It is a cloud diagram of the numerical simulation calculation of the maximum metal droplet height by ANSYS-Fluent software when the current electrode immersion depth is 0.030m; Figure 5 This is a cloud diagram of the numerical simulation calculation of the maximum metal droplet height using the ANSYS-Fluent software when the current electrode immersion depth is 0.040 m.

[0022] Explanation of the accompanying reference numerals: 1. Electrode lifting device; 2. Electrode limiting device; 3. Electrode protection cover; 4. Plate-type consumable electrode; 5. Slag feeder; 6. Control valve; 7. Welding components; 8. Slag pool; 9. Automatic weighing device; 10. Industrial AC power supply; 11. Automatic control computer; 12. Bottom cooling water tank; 13. Metal molten pool. DETAILED DESCRIPTION

[0023] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0024] The embodiment of the present invention provides a slag filling method for electroslag fusion welding, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the slag filling method includes: S1: Collect the working parameters of electroslag fusion welding, and determine the rated electrode melting speed and rated welding current according to the working parameters; specifically including material properties, slag parameters and process parameters, see Table 1 for details.

[0025] Table 1 Working parameters of electroslag fusion welding process in this embodiment Working parameters Numeric Material properties (material grade: ZG04Cr13Ni5Mo) <![CDATA[Metal density, kg / m 3 > 7300(1578K) Thermal conductivity of metal, W / m·K 20.38(603K);30.85(1503K)34.21(1713K);35.87(2003K) Metal liquidus / solidus temperature, K 1747 / 1578 Latent heat of fusion per unit mass of metal, J / kg 180000 <![CDATA[Slag parameters (CaF2 - matrix)]]> <![CDATA[The density of slag, kg / m 3 > 2350 Process parameters Length of fusion welding area, m 1 Fusion welding area width, m 0.06 Plate consumable electrode length, m 0.96 Thickness of plate consumable electrode, m 0.02 Rated electrode melting speed, kg / s 0.78304 Initial slag weight, kg 9.9 Initial slag pool height, m 0.07 Rated welding current, A 12000 ; S2: Compare the monitored welding current 12500A with the rated welding current 12000A. If the welding current of 12500A is greater than the rated welding current of 12000A, the automatic control computer 11 controls the electrode lifting device 1 to lift the plate-type consumable electrode 4 by 2mm, so that the electrode melting speed is reduced and the welding current is decreased. Then the first electrode melting speed is calculated by the automatic weighing device 9. The weight increase of the automatic weighing device 9 per unit time and the weight of the supplementary slag obtained by the slag feeder 5 are recorded, and then the first weight increase caused by the falling of the metal droplets generated by the melting of the plate consumable electrode 4 is calculated; because the total working time of the electroslag fusion welding process is short, basically within 1 hour, and the total amount of slag is small, the slag consumption is ignored; and before the start of fusion welding, the crushed and preheated slag is loaded into the slag feeder 5 for use when the slag pool 8 needs to be supplemented.

[0026] When the welding current of 12500A is greater than the rated welding current of 12000A: ; in, The first weight increase per unit time caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, totaling 5 kg; The weight increase of the automatic weighing device 9 per unit time is 5.2 kg in total; The weight of slag added per unit time, a total of 0.2kg; According to the first weight increase caused by the falling of metal droplets due to the melting of the plate-type consumable electrode 4 per unit time, , calculate the melting rate of the first electrode for: ; in, is the melting rate of the first electrode, which is calculated to be 1kg / s; The first weight increase per unit time caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, totaling 5 kg; is the unit time, totaling 5s; When the welding current 11500A is less than the rated welding current 12000A, the automatic control computer 11 controls the electrode lifting device 1 to lower the plate-type consumable electrode 4 by 2mm, the electrode melting speed is increased, the welding current is increased, and then the second electrode melting speed is obtained by the automatic weighing device 9; When the welding current 11500A is less than the rated welding current 12000A: ; in, The second weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, which is 2.5 kg in total; The weight increase of the automatic weighing device 9 per unit time is 2.6 kg in total; The weight of slag added per unit time, a total of 0.1kg; According to the second weight increase caused by the metal droplets falling due to the melting of the plate-type consumable electrode 4 per unit time, , the melting rate of the second electrode is calculated for: ; in, is the melting rate of the second electrode, which is calculated to be 0.5kg / s; The second weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, which is 2.5 kg in total; The unit time is 5s in total.

[0027] S3: Compare the first electrode melting speed or the second electrode melting speed with the rated electrode melting speed of 0.78304 kg / s. When the first electrode melting speed or the second electrode melting speed is greater than or equal to the preset electrode melting speed, the automatic control computer 11 closes the slag feeder 5, so that the depth of the slag pool 8 becomes shallower, the electrode immersion depth is reduced, and then the electrode melting speed is reduced, and the third electrode melting speed is obtained by the automatic weighing device 9; In this embodiment, the first electrode melting rate of 1 kg / s is greater than the rated electrode melting rate of 0.78304 kg / s, so the slag feeder 5 needs to be closed; ; in, The third weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, which is 3.9 kg in total; The weight increase of the automatic weighing device 9 per unit time is 3.9 kg in total; The weight of slag added per unit time, a total of 0kg; ; in, is the melting rate of the third electrode, which is calculated to be 0.78kg / s; The third weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, which is 3.9 kg in total; is the unit time, totaling 5s; When the first electrode melting speed or the second electrode melting speed is less than the rated electrode melting speed of 0.78304 kg / s, the automatic control computer 11 turns on the slag feeder 5, so that the depth of the slag pool 8 becomes deeper, the electrode immersion depth increases, and then the electrode melting speed is increased, and the fourth electrode melting speed is obtained by the automatic weighing device 9; In this embodiment, the second electrode melting speed of 0.5 kg / s is less than the rated electrode melting speed of 0.78304 kg / s. The slag feeder 5 is turned on. The slag feeding speed is calculated by the difference between the first electrode melting speed or the second electrode melting speed and the rated electrode melting speed. The slag feeding speed in this embodiment is determined by the difference between the second electrode melting speed of 0.5 kg / s and the rated electrode melting speed of 0.78304 kg / s, that is, -0.28304 kg / s: ; in, is the electrode melting speed difference, calculated to be -0.28304kg / s; is the rated electrode melting rate, which is 0.78304kg / s; is the second electrode melting rate, which is 0.5 kg / s; the electrode melting rate difference in this embodiment is -0.28304 kg / s, the slag supplement amount is 0.5 kg, and the slag supplement amount is adjusted proportionally for other electrode melting rate difference conditions.

[0028] ; in, The fourth weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, which is 3.8 kg in total; The weight increase of the automatic weighing device 9 per unit time is 4.3 kg in total; The weight of slag added per unit time, 0.5kg; ; in, is the melting rate of the fourth electrode, which is calculated to be 0.76 kg / s; The fourth weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4, which is 3.8 kg in total; The unit time is 5s in total.

[0029] S4: Compare the third electrode melting speed of 0.78kg / s or the fourth electrode melting speed of 0.76kg / s with the rated electrode melting speed of 0.78304kg / s. When the third electrode melting speed or the fourth electrode melting speed is within the range of 95% to 105% of the rated electrode melting speed, the third electrode melting speed or the fourth electrode melting speed is within the normal fluctuation range of the rated electrode melting speed, and the electrode melting speed is constant. When the third electrode melting speed or the fourth electrode melting speed is outside the range of 95% to 105% of the rated electrode melting speed, steps S3 and S4 are repeated until the third electrode melting speed or the fourth electrode melting speed is within the normal fluctuation range of the rated electrode melting speed, thereby achieving a constant electrode melting speed.

[0030] Step S5 specifically includes: S51: Calculate a preset electrode immersion depth according to a rated electrode melting rate; S511: The latent heat for melting the plate-type consumable electrode 4 is calculated from the rated electrode melting rate and the melting latent heat per unit mass of metal: ; in, Q L is the latent heat used to melt the plate consumable electrode, in W; is the rated electrode melting speed, 0.78304kg / s; L is the melting latent heat per unit mass of metal, in J / kg; the rated electrode melting rate in this embodiment is 0.78304 kg / s, and the melting latent heat per unit mass of metal is 180000 J / kg, then the calculation yields Q L It is 140947.2W.

[0031] S512: Since the temperature inside the plate-type consumable electrode 4 in the width direction is uniformly distributed, the sensible heat inside the plate-type consumable electrode 4 used for heat conduction of the plate-type consumable electrode 4 is: ; in, Q S is the sensible heat used for heat conduction of the plate-type consumable electrode 4, in W; k m is the thermal conductivity of metal, unit is W / (m·K); l e The length of the plate-type consumable electrode 4 is 0.96m; w e is the width of the plate-type consumable electrode 4, 0.02m; the thermal conductivity of the metal in this embodiment is 32W / m·K. During the welding process, the temperature gradient of the plate-type consumable electrode 4 in the height direction remains steady, which can be calculated by numerical simulation method. In this embodiment, the temperature gradient is -37606K / m, and the calculation results are Q S It is 23105W.

[0032] S513: According to the heat balance relationship, the heat flux of the contact surface between the slag pool 8 and the plate-type consumable electrode 4 is equal to the sum of the latent heat used to melt the plate-type consumable electrode 4 and the sensible heat used to conduct heat of the plate-type consumable electrode 4: ; in, Q s-e is the heat flux between the contact surface of the slag pool 8 and the plate-type consumable electrode 4, in W; Q L is the latent heat used to melt the plate-type consumable electrode 4, in W; Q S is the sensible heat used for heat conduction of the plate-type consumable electrode 4, in W; Q s-e It is 164052.2W.

[0033] S514: In this embodiment, the temperature of the slag pool 8 is 1830K, the solidus temperature of the metal is 1578K, and the liquid phase thermal conductivity of the metal is 32W / m·K. The contact surface area between the slag pool 8 and the plate-type consumable electrode 4 is calculated by Fourier's law: ; in, A s-e is the contact area between the slag pool 8 and the plate-type consumable electrode 4, in m 2 ; k l is the liquid phase thermal conductivity of the metal, unit is W / (m·K); T1 is the slag temperature at the contact surface between the slag pool 8 and the plate-type consumable electrode 4, in K; T 2 is the metal solidus temperature, unit K; Q s-e is the heat flux between the contact surface of the slag pool 8 and the plate-type consumable electrode 4, in W; δ is the thickness of the metal liquid film, which is 3 mm; A s-e 0.061031m 2 .

[0034] S515: The preset electrode immersion depth is calculated based on the contact area between the slag pool 8 and the plate-type consumable electrode 4: ; in, h p is the preset electrode immersion depth, in m; A s-e is the contact area between the slag pool 8 and the plate-type consumable electrode 4, in m 2 ; l e is the length of the plate-type consumable electrode 4, in m; w e is the width of the plate-type consumable electrode 4, in m. h p It is 0.03m.

[0035] S52: The automatic control computer 11 obtains the maximum metal immersion depth according to the current electrode immersion depth, the maximum metal droplet height and the maximum downward movement distance of the plate-type consumable electrode 4 obtained through monitoring and calculation, and then obtains the preset maximum metal immersion depth according to the maximum metal droplet height and the preset electrode immersion depth, and compares the maximum metal immersion depth with the preset maximum metal immersion depth: S521: recording the total weight gain of the automatic weighing device 9 and the total weight gain of the supplementary slag, and then calculating the total weight gain caused by the falling of the metal droplets generated by the melting of the plate-type consumable electrode 4; ; in, The total weight gain of the automatic weighing device 9 is 10.5 kg; The total weight increase caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4 is 10 kg in total; To supplement the total weight of the slag, a total of 0.5kg; S522: The high-temperature liquid slag and the high-temperature liquid metal are Newtonian fluids that do not dissolve in each other, and the density of the slag is less than that of the metal. Therefore, no matter how the slag pool 8 changes in shape, the slag pool 8 is always located above the metal pool 13 and the liquid surface in contact with the air remains horizontal; considering the density of the slag and the density of the metal, the increment of the slag-air interface height caused by the total weight increase of the automatic weighing device 9 is calculated; ; in, is the volume increment caused by the falling of metal droplets and slag filling, which is calculated to be 0.00158m 3 ; The total weight increase caused by the falling of metal droplets generated by the melting of the plate-type consumable electrode 4 is 10kg; The total weight increase to supplement the slag is 0.5kg; ρ m is the metal density, 7300kg / m 3 ; ρ s is the slag density, 2350kg / m 3 ; ; in, is the increment of the slag-air interface height caused by the total weight increase of the automatic weighing device 9, which is calculated to be 0.02638m; w z is the width of the fusion welding area, 0.06m; l z is the length of the fusion welding area, 1m; S523: Since the height of the slag pool 8 rises due to the immersion of the plate-type consumable electrode 4 into the slag pool 8, the height of the slag-air interface is corrected according to the electrode immersion depth; ; in, is the volume of the plate-type consumable electrode 4 immersed in the slag pool 8, which is calculated to be 0.000286m 3 ; h p is the preset electrode immersion depth, 0.03m; l e The length of the plate-type consumable electrode 4 is 0.96m; w e The width of the plate-type consumable electrode 4 is 0.02m; ; in, is the height increment of the slag-air interface caused by the immersion of the plate-type consumable electrode 4 into the slag pool 8, which is calculated to be 0.00477m; is the volume of the plate-type consumable electrode 4 immersed in the slag pool 8, 0.000286m 3 ; w z is the width of the fusion welding area, 0.06m; l z is the length of the fusion welding area, 1m; ; in, is the total increment of the slag-air interface height, which is calculated to be 0.03115 m; is the increment of the slag-air interface height caused by the total weight increase of the automatic weighing device 9, which is calculated to be 0.02638m; is the height increment of the slag-air interface caused by the immersion of the plate-type consumable electrode 4 into the slag pool 8, which is calculated to be 0.00477m; Finally, the initial slag-air interface height is calculated from the initial slag volume, the length of the fusion welding area, and the width of the fusion welding area, and the current slag-air interface height is calculated from the total increment of the slag-air interface height; ; in, h a-s_i is the slag-air interface height, which is calculated to be 0.101363m; m i_s is the initial mass of the slag, 9.9 kg; ρ s is the slag density, 2350kg / m 3 ; w z is the width of the fusion welding area, 0.06m; l z is the length of the fusion welding area, 1m; is the total increment of the slag-air interface height, which is calculated to be 0.03115 m; S524: During the electroslag fusion welding process, the welding current will fluctuate. The movement position of the plate-type consumable electrode 4 changes due to the current fluctuation. The change rule of the welding current is as follows: ; in, I is the welding current, unit is A; I r is the rated welding current, in A; ω 0 is the angular frequency determined by the working frequency of the industrial AC power supply 10, in Hz; θ0 is the initial phase of the rated welding current; the welding current in this embodiment changes with time, the rated welding current is 12000A, the power supply operating frequency is consistent with the industrial AC frequency, both are 50Hz, then ω 0 is 314.15926, θ 0 is 0; ; in, v e is the actual moving speed of the plate-type consumable electrode 4, in m / s; v 0 is the average moving speed of the plate-type consumable electrode 4, in m / s; v v is the fluctuating motion speed of the plate-type consumable electrode 4, in m / s; ω 1 is the angular frequency of the movement of the plate-type consumable electrode 4, in Hz; θ 1 is the initial phase of the movement of the plate-type consumable electrode 4, which is determined by the actual working conditions and calculated by the data recorded by the electrode lifting device 1; v e 0.09m / s, v 0 is 0.087m / s, v v 0.003m / s, ω 1 is 1Hz, θ 1 is 0.

[0036] ; in, S e_d is the maximum downward movement distance of the plate-type consumable electrode 4, in m; [t 1 ，t 2 ] is the time interval during which the plate-type consumable electrode 4 moves downward, in seconds; v e is the actual moving speed of the plate-type consumable electrode 4, in m / s; S e_d It is 0.005m.

[0037] S525: Because liquid metal is also a good conductor, the maximum metal droplet height must be considered when considering the short circuit risk during electroslag welding. Based on the current electrode immersion depth and the corresponding electrode melting rate, the corresponding maximum metal droplet height is calculated using the numerical simulation software ANSYS-Fluent under the working condition parameters given in Table 1.

[0038] Figure 3This is the ANSYS-Fluent software numerical simulation calculation cloud diagram of the maximum metal droplet height when the current electrode immersion depth is 0.020m. The statistically obtained maximum metal droplet height is 0.013m. Combined with the electrode immersion depth, when the electrode immersion depth is 0.020m, the preset maximum metal immersion depth of the slag feeding device of the electroslag fusion welding is 0.033m, that is, the preset maximum immersion depth of the good conductor including the plate consumable electrode 4 and the metal droplet in the slag pool 8 is 0.033m. This result is used for comparison and judgment with the maximum metal immersion depth in the actual welding process to control the start and stop of the electrode limit device 2.

[0039] Figure 4 This is the cloud diagram of the maximum metal droplet height calculated by ANSYS-Fluent software numerical simulation when the current electrode immersion depth is 0.030m. The statistically obtained maximum metal droplet height is 0.014m, and the preset maximum metal immersion depth is 0.044m. This result is used to compare with the maximum metal immersion depth in the actual welding process to control the start and stop of the electrode limit device 2.

[0040] Figure 5 This is the cloud diagram of the maximum metal droplet height calculated by ANSYS-Fluent software numerical simulation when the current electrode immersion depth is 0.040m. The statistically obtained maximum metal droplet height is 0.017m, and the preset maximum metal immersion depth is 0.057m. This result is used to compare with the maximum metal immersion depth in the actual welding process to control the start and stop of the electrode limit device 2.

[0041] Calculates maximum metal immersion depth, including current electrode immersion depth h a-s_i -h e_p , Maximum metal droplet height h d And the maximum downward movement distance of the plate-type consumable electrode 4 S e_d ; ; in, is the maximum metal immersion depth, in m; h a-s_i -h e_p is the current electrode immersion depth, in m; h e_p is the electrode tip position recorded by the electrode lifting device 1, in m; h d is the maximum metal droplet height, in m; S e_dis the maximum downward movement distance of the plate-type consumable electrode 4, in m; h a-s_i -h e_p is 0.03115m, h d 0.014m, S e_d 0.005m, It is 0.05015m.

[0042] Since the position fluctuation of the plate consumable electrode 4 is inevitable due to feedback control delay and other reasons during the electroslag fusion welding process, in order to ensure the normal progress of the welding process and prevent the electric limit device 2 from being started too frequently, it is necessary to set a safety factor C as a control margin. The safety factor C is set in the range of 1.1 to 1.3. In the actual production process, the safety factor C can be adjusted according to the initial slag amount and the start and stop state of the electric limit device 2. The corrected preset maximum metal immersion depth is compared with the maximum metal immersion depth obtained by monitoring and calculation during the welding process. Make comparisons; When the maximum metal immersion depth is greater than or equal to 110% to 130% of the preset maximum metal immersion depth, the electrode limit device 2 is started, and the automatic control computer 11 controls the electrode lifting device 1 to prevent the plate-type consumable electrode 4 from moving downward, thereby reducing the rated welding current and the rated electrode melting speed. If the fusion welding component 7 has not completed the electroslag fusion welding, steps S2 to S5 are repeated until the fusion welding component 7 completes the electroslag fusion welding. When the maximum metal immersion depth is less than 110%-130% of the preset maximum metal immersion depth, the automatic control computer 11 controls the plate-type consumable electrode 4 to continue to move downward until the electroslag fusion welding of the fusion welding component 7 is completed.

[0043] ; in, is the maximum metal immersion depth, in m; h p is the preset electrode immersion depth, in m; h d is the maximum metal droplet height, in m; h p + h d ) is the preset maximum metal immersion depth, in m; C is the safety factor; C is 1.1, ( h p + h d) is 0.044m, then 0.05015m>0.0484m, the electrode limit device 2 is started to prevent the plate-type consumable electrode 4 from moving downward.

[0044] In the actual process of electroslag fusion welding, it is necessary to repeat multiple steps S2 to S5 until the two fusion welding parts 7 are welded. The specific number of repetitions depends on the actual welding situation and will not be repeated here.

[0045] It can be seen from the above embodiments that: (1) By automatically adjusting the lifting and lowering (e.g., ±2 mm displacement) and slag filling amount of the plate-type consumable electrode 4, the fluctuation of the welding current is controlled within the range of ±4% (e.g., 12500A to 12000A) of the rated value (e.g., 12000A), and the deviation of the electrode melting speed is limited to the range of ±5% (95% to 105% of the rated melting speed of 0.78304kg / s); (2) The electrode immersion depth (e.g., the preset value of 0.03 m) is calculated using the thermal balance relationship, and the maximum metal immersion depth (e.g., 0.05015 m) is dynamically calculated in combination with the safety factor (1.1-1.3). When the maximum metal immersion depth exceeds the safety value (0.0484), the electrode limit device 2 is activated to prevent the plate-type consumable electrode 4 from moving downward, thereby eliminating the risk of short circuit. (3) The slag feeding device of this embodiment adjusts the depth of the slag pool 8, reduces the horizontal extension of the slag pool 8, reduces the horizontal melting depth of the fusion welding component 7, and improves the uniformity of the mechanical properties; (4) In the prior art, constant power control is used, so the inner side of the molten welding part 7 is continuously melted, causing the slag pool 8 to extend to both sides, and the depth of the slag pool 8 decreases. In order to maintain the rated power, the electrode immersion depth needs to be continuously reduced, resulting in a smaller and smaller electrode melting rate. The Joule heat generated in the slag pool 8 is mainly transferred to the molten welding parts 7 on both sides, causing the slag pool 8 to continuously extend to both sides until it melts through the molten welding part 7. Therefore, there is a welding height limit for the electroslag fusion welding under the constant power control strategy, and electroslag fusion welding that exceeds the height limit cannot be performed. The slag filling method of this embodiment can control the depth of the slag pool 8 by continuous slag filling, adjust the electrode melting rate, increase or shorten the total welding time, and regulate the heat transferred from the slag pool 8 to the molten welding part 7, thereby controlling the horizontal melting depth of the cross section of the molten welding part 7 to remain stable. Therefore, it is not limited by constant power, supports electroslag fusion welding of molten welding parts 7 of larger sizes (such as a height of more than 1m), and can be applied to the manufacture of high-precision large electroslag steel components.

[0046] The embodiment of the present invention also provides a slag filling device for electroslag fusion welding, such as Figure 2As shown, the slag feeding device includes: an automatic weighing device 9; a fusion welding component 7, which is placed above the automatic weighing device 9; a slag pool 8, which is located between the two fusion welding components 7; an electrode protection cover 3, which is supported and connected to an external support rod so as to be arranged above the fusion welding component 7; a slag feeder 5, which is arranged below the electrode protection cover 3 and connected to the electrode protection cover 3, and the slag outlet of the slag feeder 5 faces the slag pool 8; an electrode lifting device 1, which is supported and connected to an external support rod so as to be arranged above the slag pool 8; an electric limit device 2, which is arranged below the electrode lifting device 1 and connected to the electrode lifting device 1; a plate-type consumable electrode 4, which is arranged below the electric limit device 2 and inserted into the slag pool 8; an automatic control computer 11, which is arranged outside the automatic weighing device 9 and is electrically connected to the automatic weighing device 9, the electrode protection cover 3, the slag feeder 5, the plate-type consumable electrode 4, the electric limit device 2, and the electrode lifting device 1.

[0047] Exemplarily, the automatic control computer 11 is arranged outside the automatic weighing device 9 and is placed at a position convenient for the operator to operate according to actual needs. It is then electrically connected to the automatic weighing device 9, the electrode protection cover 3, the slag feeder 5, the plate-type consumable electrode 4, the electric limit device 2, and the electrode lifting device 1 through wires, thereby realizing automatic control of the above-mentioned components.

[0048] For example, the plate-type consumable electrode 4 is rigidly connected to the electrode protection cover 3 by clamping or welding. The electrode lifting device 1 is arranged directly above the electrode protection cover 3, and the electrode lifting device 1 and the electrode protection cover 3 can be connected or welded by screws and nuts. The slag feeder 5 and the electrode protection cover 3 are also connected or welded by screws and nuts, which is also a rigid connection.

[0049] Exemplarily, a control valve 6 is provided at the bottom of the slag feeder 5, which is also electrically connected to the automatic control computer 11. When the slag feeder 5 needs to be opened, the automatic control computer 11 opens the control valve 6, thereby realizing slag feeding of the slag feeder 5; when slag feeding is not needed, the automatic control computer 11 closes the control valve 6, thereby realizing stopping the slag feeder 5 from feeding slag.

[0050] In a possible embodiment, Figure 2 As shown, the bottom cooling water tank 12 is arranged between the automatic weighing device 9 and the fusion welding component 7, thereby cooling the fusion welding component 7 and the slag pool 8.

[0051] Exemplarily, the bottom cooling water tank 12 of this embodiment is only placed above the automatic weighing device 9 and below the fusion welding component 7. The bottom cooling water tank 12 is used to cool the slag pool 8 and the fusion welding components 7 on both sides of the slag pool 8, so that the two fusion welding components 7 are accelerated to be welded into a whole of the same material.

[0052] Exemplarily, two ends of the industrial AC power supply 10 are respectively connected to the plate-type consumable electrode 4 and the bottom cooling water tank 12, and the working voltage is adjusted according to the actual requirements of electroslag fusion welding, and the working voltage ranges from 30V to 100V.

[0053] In a possible embodiment, Figure 2 As shown, there are multiple slag feeders 5.

[0054] Exemplarily, in the present embodiment, two slag feeders 5 are provided, and the two slag feeders 5 are symmetrically arranged on both sides of the plate-type consumable electrode 4. The two symmetrically arranged slag feeders 5 can evenly feed the slag pool 8 from both sides of the plate-type consumable electrode 4 when the slag pool 8 needs to be fed with slag, which is conducive to evenly adjusting the depth of the slag pool 8.

[0055] In a possible embodiment, Figure 2 As shown, a plurality of slag feeders 5 are evenly spaced and arranged in the circumferential direction of the plate-type consumable electrode 4 .

[0056] Exemplarily, in the present embodiment, three slag feeders 5 are arranged evenly spaced apart in the circumference of the plate type consumable electrode 4. The three slag feeders 5 arranged in this way can evenly feed the slag pool 8 from both sides of the plate type consumable electrode 4 when the slag pool 8 needs to be fed with slag, which is conducive to evenly adjusting the depth of the slag pool 8.

[0057] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The first feature being "above" or "below" the second feature can mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0058] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A slag filling method for electroslag fusion welding, characterized in that: include: S1: Collect the working parameters of electroslag fusion welding, and determine the rated electrode melting speed and rated welding current according to the working parameters; S2: Compare the monitored welding current with the rated welding current. When the welding current is greater than or equal to the rated welding current, the computer automatically controls the electrode lifting device to lift the plate-type consumable electrode, reduce the electrode melting speed, and reduce the welding current. Then the first electrode melting speed is calculated by the automatic weighing device. When the welding current is less than the rated welding current, the automatic computer controls the electrode lifting device to lower the plate-type consumable electrode, increase the electrode melting speed, increase the welding current, and then obtain the second electrode melting speed through the automatic weighing device; S3: Compare the first electrode melting speed or the second electrode melting speed with the rated electrode melting speed. When the first electrode melting speed or the second electrode melting speed is greater than or equal to the rated electrode melting speed, the computer is automatically controlled to close the slag feeder to make the slag pool shallower and the electrode immersion depth lower, thereby reducing the electrode melting speed, and obtaining the third electrode melting speed through the automatic weighing device; When the first electrode melting speed or the second electrode melting speed is less than the rated electrode melting speed, the automatic control computer starts the slag feeder to deepen the slag pool and increase the electrode immersion depth, thereby increasing the electrode melting speed, and the fourth electrode melting speed is obtained through the automatic weighing device; S4: comparing the melting speed of the third electrode or the melting speed of the fourth electrode with the rated electrode melting speed. When the melting speed of the third electrode or the melting speed of the fourth electrode is within the range of 95% to 105% of the rated electrode melting speed, the melting speed of the third electrode or the melting speed of the fourth electrode is within the normal fluctuation range of the rated electrode melting speed, and the electrode melting speed is constant. When the third electrode melting speed or the fourth electrode melting speed is outside the range of 95% to 105% of the rated electrode melting speed, steps S3 and S4 are repeated until the third electrode melting speed or the fourth electrode melting speed is within the normal fluctuation range of the rated electrode melting speed, thereby achieving a constant electrode melting speed.

2. The slag filling method for electroslag fusion welding according to claim 1, characterized in that: After step S4, step S5 is further provided, and step S5 specifically includes: S51: Calculate a preset electrode immersion depth according to a rated electrode melting rate; S52: The automatic control computer obtains the maximum metal immersion depth based on the current electrode immersion depth, the maximum metal droplet height and the maximum downward movement distance of the plate-type consumable electrode obtained through monitoring and calculation, and then obtains the preset maximum metal immersion depth based on the maximum metal droplet height and the preset electrode immersion depth, and compares the maximum metal immersion depth with the preset maximum metal immersion depth: When the maximum metal immersion depth is greater than or equal to 110% to 130% of the preset maximum metal immersion depth, the electric limit device is started, and the computer-controlled electrode lifting device is automatically controlled to prevent the plate-type consumable electrode from moving downward, thereby reducing the rated welding current and the rated electrode melting speed. If the electroslag fusion welding of the fusion welding parts is not completed, steps S2 to S5 are repeated until the electroslag fusion welding of the fusion welding parts is completed; When the maximum metal immersion depth is less than 110% to 130% of the preset maximum metal immersion depth, the automatic control computer controls the plate-type consumable electrode to continue to move downward until the electroslag fusion welding of the fusion welding parts is completed.

3. The slag filling method for electroslag fusion welding according to claim 2, characterized in that: In step S51, it specifically includes: S511: The latent heat for melting the plate consumable electrode is calculated from the rated electrode melting rate and the latent heat of melting per unit mass of metal: ； in, Q L is the latent heat used to melt the plate consumable electrode, in W; is the rated electrode melting speed, in kg / s; L is the latent heat of fusion per unit mass of metal, in J / kg; S512: Since the temperature inside the plate-type consumable electrode in the thickness direction is uniformly distributed, the sensible heat inside the plate-type consumable electrode used for heat conduction of the plate-type consumable electrode is: ； in, Q S is the sensible heat used for heat conduction of the plate-type consumable electrode, in W; k m is the thermal conductivity of metal, unit is W / (m·K); l e is the length of the plate consumable electrode, in m; w e is the width of the plate consumable electrode, in m; S513: According to the heat balance relationship, the heat flux between the slag pool and the plate consumable electrode contact surface is equal to the sum of the latent heat used to melt the plate consumable electrode and the sensible heat used to conduct heat to the plate consumable electrode: ； in, Q s-e is the heat flux between the contact surface of the slag pool and the plate-type consumable electrode, in W; Q L is the latent heat used to melt the plate consumable electrode, in W; Q S is the sensible heat used for heat conduction of the plate-type consumable electrode, in W; S514: The contact area between the slag pool and the plate-type consumable electrode is calculated by Fourier's law: ； in, A s-e The contact area between the slag pool and the plate-type consumable electrode, unit: m 2 ; k l is the liquid phase thermal conductivity of the metal, unit is W / (m·K); T 1 is the slag temperature at the contact surface between the slag pool and the plate-type consumable electrode, unit K; T 2 is the metal solidus temperature, unit K; Q s-e is the heat flux between the contact surface of the slag pool and the plate-type consumable electrode, in W; δ is the thickness of the metal liquid film, in mm; S515: The preset electrode immersion depth is calculated based on the contact area between the slag pool and the plate-type consumable electrode: ； in, h p is the preset electrode immersion depth, in m; A s-e The contact area between the slag pool and the plate-type consumable electrode, unit: m 2 ; l e is the length of the plate consumable electrode, in m; w e It is the width of the plate consumable electrode, in m.

4. The slag filling method for electroslag fusion welding according to claim 1, characterized in that: In step S2, it specifically includes: Record the weight increase of the automatic weighing device per unit time and the weight of the slag added per unit time, and then calculate the first weight increase caused by the falling of the metal droplets generated by the melting of the plate-type consumable electrode; When the welding current is greater than the rated welding current: ； in, It is the first weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; According to the first weight increase caused by the metal droplets falling due to the melting of the plate consumable electrode per unit time, , calculate the melting rate of the first electrode for: ； in, is the melting rate of the first electrode, in kg / s; It is the first weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; is the unit time, unit s; When the welding current is less than the rated welding current: ； in, The second weight increase per unit time caused by the falling of metal droplets generated by the melting of the plate consumable electrode, unit: kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; The second weight increase caused by the drop of metal droplets produced by the melting of the plate consumable electrode per unit time is , the melting rate of the second electrode is calculated for: ； in, is the melting rate of the second electrode, in kg / s; The second weight increase per unit time caused by the falling of metal droplets generated by the melting of the plate consumable electrode, unit: kg; is the unit time, unit s.

5. The slag filling method for electroslag fusion welding according to claim 1, characterized in that: In step S3, it specifically includes: Comparing the first electrode melting speed or the second electrode melting speed with the rated electrode melting speed, and closing the slag feeder when the first electrode melting speed or the second electrode melting speed is greater than or equal to the rated electrode melting speed; ； in, The third weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; ； in, is the melting rate of the third electrode, in kg / s; The third weight increase caused by the falling of metal droplets due to the melting of the plate consumable electrode per unit time, in kg; is the unit time, unit s; When the first electrode melting speed or the second electrode melting speed is less than the rated electrode melting speed, the slag feeder is turned on, and the slag feeding speed is calculated from the difference between the first electrode melting speed or the second electrode melting speed and the rated electrode melting speed: ； in, is the electrode melting speed difference, unit is kg / s; is the rated electrode melting speed, in kg / s; is the melting rate of the first electrode, in kg / s; is the melting rate of the second electrode, in kg / s; ； in, The fourth weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate consumable electrode, in kg; The weight gain of the automatic weighing device per unit time, in kg; The weight of slag added per unit time, in kg; ； in, is the melting rate of the fourth electrode, in kg / s; The fourth weight increase per unit time is caused by the falling of metal droplets generated by the melting of the plate consumable electrode, in kg; is the unit time, unit s.

6. The slag filling method for electroslag fusion welding according to claim 2, characterized in that: In step S52, it specifically includes: S521: Record the total weight gain of the automatic weighing device and the total weight gain of the supplementary slag, and then calculate the total weight gain caused by the falling of the metal droplets generated by the melting of the plate-type consumable electrode; ； in, The total weight gain of the automatic weighing device, in kg; It is the total weight increase caused by the falling of molten metal droplets due to the melting of the plate consumable electrode, in kg; The total weight increase to supplement the slag, in kg; S522: Considering the slag density and the metal density, the slag-air interface height increment caused by the total weight increase of the automatic weighing device is calculated; ； in, The volume increment caused by the falling of metal droplets and slag filling, unit: m 3 ; It is the total weight increase caused by the falling of molten metal droplets due to the melting of the plate consumable electrode, in kg; The total weight increase to supplement the slag, in kg; ρ m is the metal density, kg / m 3 ; ρ s is the slag density, unit: kg / m 3 ; ； in, The increment of slag-air interface height calculated from the total weight gain of the automatic weighing device, in m; w z is the width of the fusion welding area, in m; l z is the length of the fusion welding area, in m; S523: Since the slag pool height rises due to the plate-type consumable electrode being immersed in the slag pool, the slag-air interface height is corrected by the electrode immersion depth; ； in, The volume of the plate-type consumable electrode immersed in the slag pool, in m 3 ; h p is the preset electrode immersion depth, in m; l e is the length of the plate consumable electrode, in m; w e is the width of the plate consumable electrode, in m; ； in, It is the increment of slag-air interface height caused by the plate-type consumable electrode being immersed in the slag pool, in m; The volume of the plate-type consumable electrode immersed in the slag pool, in m 3 ; w z is the width of the fusion welding area, in m; l z is the length of the fusion welding area, in m; ； in, is the total increment of the slag-air interface height, in m; It is the increment of slag-air interface height caused by the total weight increase of the automatic weighing device, in m; It is the increment of slag-air interface height caused by the plate-type consumable electrode being immersed in the slag pool, in m; Finally, the initial slag-air interface height is calculated from the initial slag volume, the length of the fusion welding area, and the width of the fusion welding area, and the current slag-air interface height is calculated from the total increment of the slag-air interface height; ； in, h a-s_i is the slag-air interface height, in m; m i_s is the initial mass of the slag, in kg; S524: During the electroslag fusion welding process, the welding current will fluctuate. The movement position of the plate consumable electrode changes due to the current fluctuation. The change law of the welding current is as follows: ； in, I is the welding current, unit is A; I r is the rated welding current, in A; ω 0 is the angular frequency determined by the operating frequency of the industrial AC power supply, in Hz; θ 0 is the initial phase of rated welding current; ； in, v e is the actual moving speed of the plate-type consumable electrode, in m / s; v 0 is the average moving speed of the plate-type consumable electrode, in m / s; v v is the fluctuating motion speed of the plate-type consumable electrode, in m / s; ω 1 is the angular frequency of the plate-type consumable electrode movement, in Hz; θ 1 is the initial phase of the plate-type consumable electrode movement, which is determined by the actual working conditions and calculated from the data recorded by the electrode lifting device; ； in, S e_d is the maximum downward movement distance of the plate-type consumable electrode, in meters; [t 1 ，t 2 ] The time interval of the downward movement speed of the plate-type consumable electrode, unit: s; v e is the actual moving speed of the plate-type consumable electrode, in m / s; S525: Calculate the maximum metal immersion depth, including the current electrode immersion depth h a-s_i -h e_p , Maximum metal droplet height h d And the maximum downward movement distance of the plate consumable electrode S e_d ; ； in, is the maximum metal immersion depth, in m; h a-s_i -h e_p is the current electrode immersion depth, in m; h e_p is the electrode tip position recorded by the electrode lifting device, in m; h d is the maximum metal droplet height, in m; S e_d is the maximum downward movement distance of the plate-type consumable electrode, in meters; ； in, is the maximum metal immersion depth, in m; h p is the preset electrode immersion depth, in m; h d is the maximum metal droplet height, in m; h p + h d ) is the preset maximum metal immersion depth, in m; C is the safety factor; Then, a safety factor is introduced to correct the preset maximum metal immersion depth, and then the maximum metal immersion depth is compared with the preset maximum metal immersion depth.

7. A slag filling device, applied to the slag filling method for electroslag fusion welding as claimed in claim 2, characterized in that: The slag feeding device comprises: Automatic weighing device; A fusion welding component is placed above the automatic weighing device; A slag pool, located between the two fusion welding parts; The electrode protection cover is connected to the external support rod to be arranged above the fusion welding component; A slag feeder is arranged below the electrode protection cover and connected to the electrode protection cover, and a slag outlet of the slag feeder faces the slag pool; An electrode lifting device is connected to the external support rod to be arranged above the slag pool; An electrode limiting device is arranged below the electrode lifting device and connected to the electrode lifting device; A plate-type consumable electrode is arranged below the electrode limit device and inserted into the slag pool; The automatic control computer is arranged outside the automatic weighing device and is electrically connected to the automatic weighing device, the electrode protection cover, the slag feeder, the plate-type consumable electrode, the electric limit device, and the electrode lifting device.

8. The slag feeding device according to claim 7, characterized in that: Also includes: The bottom cooling water tank is arranged between the automatic weighing device and the fusion welding component, so as to cool the fusion welding component and the slag pool.

9. The slag feeding device according to claim 7, characterized in that: The number of the slag feeders is multiple.

10. The slag feeding device according to claim 9, characterized in that: A plurality of slag feeders are evenly spaced and arranged in the circumferential direction of the plate-type consumable electrode.

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