Surfacing process and device for charging bell

Abstract

The invention relates to the technical field of surfacing, in particular to a surfacing process and device for a charging bell. According to the surfacing process, the surface of a to-be-surfaced bell is cleaned, the welding starting position is preheated, and the preheating temperature is controlled to be not lower than 120 DEG C, so that intermolecular bonding during welding is promoted, and cracks are prevented from being generated after welding; the fusion zone, the interlayer temperature and the weld fusion ratio are controlled through specific welding current, surfacing voltage and gas flow, and it is guaranteed that in the surfacing process, weld forming is good, and the surface is smooth; multi-layer and multi-pass welding is adopted, so that heat of a molten pool and a heat affected zone is concentrated, the cooling speed after welding is reduced, crystal fusion between welding seams is promoted, and the surface layer does not have fusion defects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surfacing, and relates to surfacing of a bell, in particular to a surfacing process and device for a bell. BACKGROUND

[0002] In the modern industrial field, wear-resistant alloy surfacing technology has been mature at home and abroad, and the use standards and performance requirements of surfacing products in the industry are increasingly standardized. With the continuous advancement of industrial technology towards large-scale and high-efficiency, the requirements for reliability and performance of various mechanical equipment continue to improve. As an important branch of welding technology, the surfacing of wear-resistant alloy on the surface of materials has become a key technical means to improve the performance of products and equipment, prolong the service life, and reduce production costs, with its unique technical advantages.

[0003] Taking the bell / hopper of the top equipment of an iron-making furnace as an example, through in-depth research on the surfacing process, the surfacing of wear-resistant alloy on the surface can not only significantly improve the service life of the bell / hopper, but also form a heterogeneous material surfacing layer organization, so that it has stronger impact resistance and erosion resistance, effectively solves the problem of material wear, and realizes the dual goals of cost reduction and quality improvement.

[0004] However, the traditional surfacing process still has many limitations. Taking the surfacing of a bell with ZG270-500 material as an example, the traditional process needs to preheat the bell as a whole to 300 DEG C, which not only needs large heating equipment, but also has the problems of long preheating time and high cost. In actual operation, due to the complexity of the heating process, it is easy to cause uneven temperature distribution, and then cause defects such as cracks and large hardness differences of the surfacing layer metal, which seriously affects the service performance and life of the product. In the welding operation link, the traditional process usually selects high-chromium surfacing welding material, and relies on 4-8 electric welders to complete the operation in shifts. However, the high-temperature operation environment and continuous arc radiation cause great harm to the physical and mental health of the operators; at the same time, the manual gas shielded welding operation is greatly affected by human factors, and welding defects such as pores and slag are frequent, which seriously restricts the improvement of product quality.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art, provide a surfacing process and device for a bell, which omits the whole preheating process, reduces the number of electric welders, and improves the welding quality while reducing the corresponding cost.

[0007] To achieve the above purpose, the present application provides the following technical solutions:

[0008] On the one hand, the present application provides a surfacing process for a bell, which specifically includes the following steps:

[0009] Step 1, clean the surface of the material bell to be surfacing, and preheat the welding starting point of the material bell;

[0010] Step 2, use gas shielded welding to perform surfacing, the surfacing method adopts multi-layer and multi-pass welding, and the surfacing process parameters are as follows: the surfacing current is 280-400A, the surfacing voltage is 32-38V, and the gas flow is 20-28ml / min;

[0011] Step 3, after the welding is completed and no defects are found after inspection, the material bell is subjected to heat treatment;

[0012] Step 4, the material bell after heat treatment is subjected to machining treatment, and the surfacing of the wear-resistant alloy layer on the surface of the material bell is completed.

[0013] Specifically, in step 1, the cleaning treatment specifically includes the following steps: first, use cotton yarn dipped in kerosene to wipe the surfacing surface, and then use a baking gun (such as a propane baking gun) to dry, repeat the steps twice to ensure the surfacing quality and avoid surfacing defects caused by rust, water and dirt.

[0014] Specifically, in step 1, the preheating temperature is controlled to be not less than 120℃, and the main function of preheating is to promote the intermolecular bonding during welding and prevent cracks after welding.

[0015] Specifically, in step 2, the gas shielded welding uses high-hardness and high-anti-cracking martensitic tool steel gas shielded welding wire material, and the welding bead lap width is 1 / 2 of the current welding bead width.

[0016] Preferably, the diameter of the gas shielded welding wire material is 1.2mm.

[0017] Preferably, the protective gas used in the gas shielded welding is Ar+CO2 mixed gas.

[0018] Specifically, in step 3, the heat treatment adopts annealing furnace for annealing treatment, specifically:

[0019] The temperature in the furnace is increased from room temperature to 100℃, the temperature increasing speed is controlled to be ≤40℃ / h, when the temperature is greater than 100℃, the temperature increasing speed is controlled to be ≤50℃ / h, and after uniform heating to 550℃, the temperature is kept for 5h;

[0020] Then, the temperature is decreased to 300℃ at a decreasing speed of not more than 50℃ / h, and then taken out and air-cooled to room temperature.

[0021] In another aspect, the present application also provides a surfacing device applying the surfacing process as described above, comprising a roller frame arranged at the bottom of a bell, a plurality of welding devices capable of adjusting the angle are uniformly distributed along the circumferential direction of the bell, each of the welding devices is connected with a PLC control box, and the PLC control box is also connected with the roller frame, so that the roller frame rotates forwardly / reversely at a set rotating speed under the control of the PLC control box, and the spiral welding operation from top to bottom is realized under the cooperation of the welding devices.

[0022] Preferably, the welding device comprises a first support rod arranged vertically, a second support rod is hinged on the first support rod, and a MAG gas shielded welding device is mounted on the second support rod.

[0023] Further, the material of the bell is ZG270-500 carbon cast steel.

[0024] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0025] The present application first cleans the surface of the bell to be surfaced, and preheats the welding starting position, so that the preheating temperature is not lower than 120 DEG C, to promote the intermolecular bonding during welding and prevent cracks after welding; the fusion zone, the interlayer temperature and the weld fusion ratio are controlled through specific welding current, surfacing voltage and gas flow, so that the weld is formed well and the surface is smooth during the surfacing process; the multi-layer and multi-pass welding is adopted, so that the heat of the molten pool and the heat affected zone is concentrated, the cooling speed after welding is reduced, and the crystalline fusion between the welds is promoted, and the surface layer does not appear fusion defects. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are incorporated into and form part of the specification, illustrate the principles of the application and, together with the description, serve to explain the application.

[0027] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without any creative labor under the premise of these drawings.

[0028] Figure 1 A surfacing process flow chart for a bell is provided in the present application;

[0029] Figure 2 An assembly structure schematic view of the surfacing device for the bell is provided in the present application, wherein the bell is a sectional view;

[0030] Figure 3 is Figure 2 a top view of the bell in the present application;

[0031] Figure 4 For Figure 2 Local enlarged view of middle B part.

[0032] Wherein: 1, PLC control box; 2, welding device; 3, roller frame; 4, wear-resistant alloy layer; 5, bell. DETAILED DESCRIPTION

[0033] The exemplary embodiments will be described in detail herein below, and the embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Rather, they are merely examples consistent with some aspects of the present application as detailed in the appended claims.

[0034] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in conjunction with the accompanying drawings and examples.

[0035] Example 1

[0036] Referring to Figure 1 The present embodiment provides a surfacing process for a bell, specifically comprising the following steps:

[0037] Step 1, clean the surface of the bell to be surfaced, and preheat the welding starting point of the bell 5, controlling the preheating temperature to be no less than 120℃. The main function of preheating is to promote intermolecular bonding during welding and prevent cracks from occurring after welding.

[0038] Step 2, use gas shielded welding to perform surfacing, and the surfacing method is multi-layer and multi-pass welding, and the surfacing process parameters are as follows: the first surfacing current is 285A, the surfacing voltage is 33V, and the gas flow is 22ml / min; the second surfacing current is 295A, the surfacing voltage is 35V, and the gas flow is 26ml / min.

[0039] Step 3, after welding is completed and no major defects are found through visual inspection, perform heat treatment on the bell 5; the heat treatment is annealing treatment using an annealing furnace, specifically:

[0040] The temperature in the furnace is raised from room temperature to 100℃, controlling the temperature rising speed to be ≤40℃ / h, when the temperature is greater than 100℃, controlling the temperature rising speed to be ≤50℃ / h, uniformly heating to 550℃, and then maintaining the temperature for 5h;

[0041] Then, cooling to 300℃ at a cooling speed of no more than 50℃ / h, and then taking out and air cooling to room temperature.

[0042] Step 4, perform machining treatment on the bell 5 after heat treatment in a normal temperature state, to complete the surfacing of the wear-resistant alloy layer 4 on the surface of the bell 5.

[0043] Further, in step 1, the cleaning process specifically includes the following steps: first, using cotton yarn to dip kerosene to wipe the surfacing surface, and then using a baking gun (such as a propane baking gun) to dry, repeating the above steps twice to ensure the surfacing quality and avoid surfacing defects caused by rust, water and oil stains.

[0044] Further, in step 2, the gas shielded welding uses a high-hardness and high-anti-cracking martensitic tool steel gas shielded surfacing welding wire material, which has high hardness, high anti-cracking and high anti-cold and hot fatigue performance. In this embodiment, the "high-hardness and high-anti-cracking martensitic tool steel gas shielded surfacing welding wire (φ1.2)+(Ar+CO2)" gas shielded welding is used, the arc is in a suitable advanced position during the surfacing process, the welding wire is elongated by 10 mm, the welding is ensured to be formed in an attractive appearance, the surfacing bead lap width is 1 / 2 of the bead width (for example, the first pass bead width is 10 mm, and the second pass surfacing bead lap width should cover 1 / 2 of the first pass bead width, i.e. 5 mm, so as to ensure the compactness of the entire surfacing layer), the welding is continuously applied to ensure good fusion between the surfacing layers, and the weld surface is smooth.

[0045] Further, in step 2, the design of the surfacing process parameters controls the fusion zone, interlayer temperature and weld fusion ratio by formulating suitable welding current, surfacing voltage and gas flow, so as to ensure that the weld is formed well and the surface is smooth during the surfacing process. Multi-layer and multi-pass welding is used, the heat of the molten pool and the heat affected zone is concentrated, the cooling speed after welding is reduced, which can promote the crystalline fusion between the welds and the surface layer does not appear fusion defects. It should be further explained that the surfacing current, surfacing voltage and gas flow can be adaptively adjusted according to the actual working conditions, such as the surfacing current can be 300A, 320A, 340A, 360A, 380A or 400A, and the surfacing voltage can be 32V, 33V, 34V, 35V, 36V, 37V or 38V, and the gas flow can be 21ml / min, 22ml / min, 23ml / min, 24ml / min, 25ml / min, 26ml / min, 27ml / min or 28ml / min, and the like.

[0046] Further, in step 4, the machining process is carried out at room temperature, and the size of the surface after machining is checked.

[0047] In addition, the present embodiment also provides a surfacing device applying the surfacing process as described above in part or in whole, which is shown in Figures 2 to 4, including the bottom of the bell 5, the supporting roller frame 3, a plurality of angle-adjustable welding devices 2 are uniformly distributed along the circumferential direction of the bell 5, each of the welding devices 2 is connected with the PLC control box 1, and the PLC control box 1 is also connected with the roller frame 3, so that the roller frame 3 rotates forwardly / reversely at a set rotating speed under the control of the PLC control box 1, and the spiral welding operation from top to bottom is realized under the cooperation of the welding device 2.

[0048] Further, the welding device 2 comprises a first support rod arranged vertically, a second support rod is hinged on the first support rod, and a MAG gas shielded welding device is mounted on the second support rod.

[0049] The installation process of the surfacing device is as follows: the bell 5 is smoothly placed on the roller frame 3, the welding device 2 is adjusted through the PLC control box 1, the welding device 2 can be 3-4 distributed along the circumferential direction of the bell 5 according to the size of the bell 5, and the welding gun is adjusted to reach the appropriate welding position through the PLC control box 1. Under the instruction of the PLC control box 1, the roller frame 3 rotates forwardly and reversely horizontally at a rotating speed set according to the process parameters, and the continuous spiral welding operation from bottom to top is realized. Specifically, the actual surfacing process is as follows: the bell with the material ZG270-500 is processed, the appropriate cold welding wire is selected, the direction angle adjustable welding device 2 is adjusted through the PLC control box 1, the appropriate welding position is selected, and the continuous welding operation is performed under the smooth horizontal rotation of the bell 5 on the roller frame 3, so that no welding defects can be ensured. The surfacing process discards the whole preheating process, reduces the number of welders, thereby reducing the corresponding cost while improving the welding quality.

[0050] Embodiment 2

[0051] Referring to Figure 1 The embodiment provides a surfacing process for a bell, and specifically comprises the following steps:

[0052] Step 1: The surface of the bell to be surfaced is cleaned, and the welding starting position of the bell 5 is preheated, and the preheating temperature is not less than 120 DEG C. The main function of preheating is to promote the intermolecular bonding during welding and prevent cracks after welding.

[0053] Step 2: The bell is surfaced by gas shielded welding, the surfacing mode adopts multi-layer and multi-pass welding, and the surfacing process parameters are as follows: the first surfacing current is 300 A, the surfacing voltage is 35 V, and the gas flow is 20 ml / min; the second surfacing current is 320 A, the surfacing voltage is 38 V, and the gas flow is 25 ml / min.

[0054] Step 3, after the welding is completed and no major defects are found by visual inspection, the bell 5 is subjected to heat treatment; the heat treatment is annealing treatment using an annealing furnace, specifically:

[0055] The temperature in the furnace is raised from room temperature to 100℃ at a rate of ≤40℃ / h, and when the temperature is greater than 100℃, the temperature is raised at a rate of ≤50℃ / h, and after uniform heating to 550℃, the temperature is maintained for 5h;

[0056] Then, the temperature is lowered to 300℃ at a rate of ≤50℃ / h, and the bell is removed and air-cooled to room temperature.

[0057] Step 4, the bell 5 after heat treatment is subjected to machining treatment, and the surfacing of the wear-resistant alloy layer 4 on the surface of the bell 5 is completed.

[0058] Further, in step 1, the cleaning treatment specifically includes: first using cotton yarn dipped in kerosene to wipe the surfacing surface, and then using a baking gun (such as a propane baking gun) to dry, and repeating the step twice to ensure the surfacing quality and avoid surfacing defects caused by rust, water, and oil stains.

[0059] Further, in step 2, the gas shielded welding uses a high-hardness and high-anti-cracking martensitic tool steel gas shielded surfacing welding wire material, which has high hardness, high anti-cracking, and high anti-cold and hot fatigue performance. In this embodiment, "high-hardness and high-anti-cracking martensitic tool steel gas shielded surfacing welding wire (φ1.2)+(Ar+CO2)" gas shielded welding is used, the arc is placed in a suitable advanced position during surfacing, the welding wire is stretched by 15mm, the welding is ensured to be aesthetically formed, the surfacing bead overlap width is 1 / 2 of the bead width, the welding is continuously applied, the interlayer fusion of the surfacing layer is ensured to be good, and the weld surface is smooth.

[0060] Further, in step 2, the design of the surfacing process parameters controls the fusion zone, interlayer temperature, and weld fusion ratio by formulating suitable welding current, surfacing voltage, and gas flow, so as to ensure that the weld is well formed and the surface is smooth during surfacing. Multi-layer and multi-pass welding is used, the heat of the molten pool and the heat affected zone is concentrated, the cooling speed after welding is reduced, which can promote the crystalline fusion between the welds, and no fusion defects occur in the surface layer.

[0061] Embodiment 3

[0062] Referring to Figure 1 The embodiment provides a surfacing process for a bell, specifically including the following steps:

[0063] Step 1, the surface of the bell to be surfaced is subjected to cleaning treatment, and the welding starting position of the bell 5 is preheated, and the preheating temperature is controlled to be not less than 120℃. The main function of preheating is to promote the intermolecular bonding during welding and prevent cracks after welding.

[0064] Step 2, using gas shielded welding, the welding method adopts multi-layer multi-pass welding, and the welding process parameters are as follows: the first pass welding current is 380A, the welding voltage is 36V, and the gas flow is 26ml / min; the second pass welding current is 400A, the welding voltage is 38V, and the gas flow is 28ml / min;

[0065] Step 3, after the welding is completed and no major defects are found by visual inspection, the bell 5 is subjected to heat treatment; the heat treatment adopts annealing furnace for annealing treatment, specifically:

[0066] The temperature in the furnace is increased from room temperature to 100℃, the temperature increasing speed is controlled to be ≤40℃ / h, when the temperature is greater than 100℃, the temperature increasing speed is controlled to be ≤50℃ / h, and after uniform heating to 550℃, the temperature is kept for 5h;

[0067] Then, the temperature is decreased to 300℃ at a decreasing speed of not more than 50℃ / h, and then the bell is taken out and air-cooled to room temperature.

[0068] Step 4, the bell 5 after heat treatment is subjected to machining treatment, and the surfacing of the wear-resistant alloy layer 4 on the surface of the bell 5 is completed.

[0069] Further, in step 1, the cleaning treatment specifically includes the following steps: first, using cotton yarn dipped in kerosene to wipe the surfacing surface, and then using a baking gun (such as a propane baking gun) to dry, repeating the steps twice to ensure the surfacing quality and avoid surfacing defects caused by rust, water and oil stains.

[0070] Further, in step 2, the gas shielded welding uses a high-hardness and high-anti-cracking martensitic tool steel gas shielded welding wire material, which has high hardness, high anti-cracking and high anti-cold and hot fatigue performance. In this embodiment, "high-hardness and high-anti-cracking martensitic tool steel gas shielded welding wire (φ1.2)+(Ar+CO2)" gas shielded welding is used, the arc is in a suitable advanced position during the surfacing process, the welding wire is stretched by 12mm, the welding is formed in an attractive appearance, the surfacing welding bead lap width is 1 / 2 of the welding bead width, the welding is continuously applied, the fusion between the surfacing layers is ensured to be good, and the welding seam surface is smooth.

[0071] Further, in step 2, the design of the surfacing process parameters controls the fusion zone, interlayer temperature and welding fusion ratio by formulating suitable welding current, surfacing voltage and gas flow, so as to ensure that the welding seam is formed well and the surface is smooth during the surfacing process. Multi-layer multi-pass welding is adopted, the heat of the molten pool and the heat affected zone is concentrated, the cooling speed after welding is reduced, which can promote the crystalline fusion between the welding seams, and no fusion defects appear on the surface layer.

[0072] In summary, the present application firstly cleans the surface of the to-be-bead-bonded material bell, preheats the welding starting position, controls the fusion zone, interlayer temperature and weld fusion ratio through specific welding current, bead-bonding voltage and gas flow, ensures that the weld is well formed and the surface is smooth during the bead-bonding process; multi-layer and multi-pass welding is adopted to concentrate the heat of the molten pool and the heat affected zone, reduce the cooling speed after welding, and be beneficial to promote the crystalline fusion between the welds, so that the surface layer does not appear fusion defects. The overall preheating process is omitted, the number of electric welding workers is reduced, and the welding quality is improved while the corresponding cost is reduced.

[0073] The above description is merely a specific implementation of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application.

[0074] It should be understood that the present application is not limited to the above-described and described, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A surfacing process for a bell, characterized in that: The specific steps include: Step 1: Clean the surface of the material bell to be welded and preheat the welding starting point of the material bell (5); Step 2: surfacing welding is performed using gas shielded welding, with multi-layer and multi-pass welding being used, and the surfacing welding process parameters are as follows: surfacing welding current is 280-400A, surfacing welding voltage is 32-38V, and gas flow rate is 20-28ml / min; Step 3: After welding is completed and no defects are found after inspection, the material bell (5) is subjected to heat treatment; Step 4: machining the heat-treated bell (5) to complete the surfacing of the wear-resistant alloy layer (4) on the surface of the bell (5).

2. The surfacing welding process for a bell according to claim 1, characterized in that: In step 1, the cleaning process specifically includes the following steps: first, use cotton yarn dipped in kerosene to wipe the surfacing surface, then use a baking gun to dry it, and repeat the steps twice.

3. The surfacing welding process for a bell according to claim 1, characterized in that: In step 1, the preheating temperature is controlled to be no less than 120°C.

4. The surfacing process for a bell according to claim 1, characterized in that: In step 2, the welding wire material used in the gas shielded welding is a high-hardness and high-crack-resistant martensitic tool steel gas shielded surfacing welding wire material, and the surfacing weld overlap width is 1 / 2 of the current weld width.

5. The surfacing welding process for a bell according to claim 4, characterized in that: The diameter of the welding wire material used in the gas shielded welding is 1.2 mm.

6. The surfacing welding process for a bell according to claim 4, characterized in that: The shielding gas used in the gas shielded welding is Ar+CO2 mixed gas.

7. The surfacing welding process for a bell according to claim 1, characterized in that: In step 3, the heat treatment is performed in an annealing furnace, specifically: The temperature in the furnace rises from room temperature to 100°C, and the heating rate is controlled to be ≤40°C / h. When the temperature is greater than 100°C, the heating rate is controlled to be ≤50°C / h. After uniformly heating to 550°C, keep warm for 5 hours. Then cool down to 300℃ at a cooling rate of no more than 50℃ / h, take out and air cool to room temperature.

8. A surfacing device using the surfacing process according to any one of claims 1 to 7, characterized in that: The invention comprises a roller frame (3) located at the bottom of a material bell (5) and playing a supporting role, and a plurality of welding devices (2) capable of adjusting angles are evenly distributed along the circumferential direction of the material bell (5). Each welding device (2) is connected to a PLC control box (1). The PLC control box (1) is also connected to the roller frame (3) so that the roller frame (3) can rotate forward / reverse at a set rotation speed under the control of the PLC control box (1), and realizes a spiral welding operation from top to bottom in cooperation with the welding devices (2).

9. The surfacing welding device according to claim 8, characterized in that: The welding device (2) comprises a first support rod arranged vertically, a second support rod is hingedly connected to the first support rod, and a MAG gas shielded welding device is installed on the second support rod.

10. The surfacing device according to claim 8, characterized in that: The material of the material bell (5) is ZG270-500 carbon cast steel.

Images