Hard alloy welding method and device

Abstract

The invention relates to the technical field of welding, in particular to a hard alloy welding method and device. According to the method, the two hard alloy parts are powered on to generate resistance heat, the contact faces of the two hard alloy parts start to be melted and combined in the high-temperature state, no extra weld-aid material needs to be added, and the production cost is effectively reduced; by adjusting the current flowing through the two hard alloy parts, the two hard alloy parts are preheated before being welded, so that the stability of the welding process is improved, it is guaranteed that the welded parts have the bending strength meeting the requirement, meanwhile, the welding time is shortened, and the production efficiency is improved; according to the welding part obtained through the welding method, welding scars can be completely removed, welding traces are not left, and therefore the welding method has the remarkable advantages in the aspects of production cost, production efficiency and production quality. The central axes of the two hard alloy parts are collinear with the straight line where the gravity direction is located, and are in contact connection, so that the two hard alloy parts still have the tendency of approaching each other.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and particularly to a method and device for welding cemented carbide. Background Art

[0002] In the field of tool production and manufacturing, integrally cemented carbide materials are generally used as the main materials for tools. However, only a small part of the tool is the actual cutting part, while most of the materials are non-cutting parts, which causes material waste to a certain extent. When the tool reaches the end of its service life, usually the entire tool will be scrapped, which not only wastes a large amount of cemented carbide materials in the non-cutting part but also increases the environmental burden. To solve this problem, in the related art, only the cutting part at the front end of the tool is removed, so that the obtained cemented carbide material can be reused. However, this method is limited by the reduction in the length of the cemented carbide material and cannot meet the requirements for reuse. Therefore, it is usually necessary to weld the shorter cemented carbide materials before reuse. Currently, most of the methods for welding cemented carbide materials on the market rely on adding soldering aids, which not only increases additional costs but also reduces production efficiency and is not conducive to large-scale production and manufacturing.

[0003] Therefore, there is an urgent need for a method for welding cemented carbide to solve the above technical problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for welding cemented carbide without additional soldering aids and improve the welding quality.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A method for welding cemented carbide for welding cemented carbide parts, comprising the following steps:

[0007] Pre-treat the cemented carbide parts to clean surface impurities;

[0008] Align the central axes of the two cemented carbide parts with the straight line in the direction of the gravity and contact and connect them;

[0009] Apply welding pressure to at least one of the two cemented carbide parts;

[0010] Preheat the two cemented carbide parts to form a contact point at the joint of the two cemented carbide parts and establish electrical connection; the parameters of the preheating include preheating current and preheating time;

[0011] Weld the two cemented carbide parts to form a fusion core at the contact point to obtain a welded part; the parameters of the welding include welding current and welding time;

[0012] The welded part of the welded component is processed to remove welding scars.

[0013] The cemented carbide welding method of the present invention has at least the following beneficial effects:

[0014] By applying electricity to two cemented carbide parts to generate resistance heat, the contact surfaces of the two start to melt and combine at high temperature, without the need to add additional soldering materials, effectively reducing production costs; by adjusting the current flowing through the two cemented carbide parts to preheat them before welding, the stability of the welding process is improved, ensuring that the welded component after welding has a bending strength that meets the requirements, while shortening the welding time and improving production efficiency; and for the welded component obtained by using the welding method of the present invention, the welding scars can be completely removed without leaving welding marks. Therefore, the present invention has significant advantages in terms of production cost, production efficiency, and production quality. In addition, the central axes of the two cemented carbide parts are collinear with the straight line in the direction of the gravity, and they are in contact connection, so that the two cemented carbide parts still have a tendency to approach each other.

[0015] As a preferred technical solution of the above cemented carbide welding method, the preheating current is I1, the preheating time is T1, 500A < I1 ≤ 1600A, 20ms < T1 ≤ 800ms;

[0016] The welding current is I2, the welding time is T2, 1800A < I2 ≤ 3000A, 100ms < T2 ≤ 800ms.

[0017] As a preferred technical solution of the above cemented carbide welding method, the preheating current is a constant current or the preheating current first gradually increases from a reference value, then remains constant, and then gradually decreases to the reference value;

[0018] The welding current is a constant current or the welding current first gradually increases from a reference value, then remains constant, and then gradually decreases to the reference value.

[0019] As a preferred technical solution of the above cemented carbide welding method, the reference value is 0.

[0020] As a preferred technical solution of the above cemented carbide welding method, the welding pressure is N, 10kg < N ≤ 100kg.

[0021] As a preferred technical solution of the above cemented carbide welding method, the acting direction of the welding pressure is the same as the direction of the gravity.

[0022] As a preferred technical solution of the above cemented carbide welding method, the pretreatment includes grinding, cleaning, and drying.

[0023] As a preferred technical solution of the above-mentioned cemented carbide welding method, in the step of processing the welding point of the welded part to remove welding scars, the processing method is centerless grinding.

[0024] In the second aspect, a cemented carbide welding device is provided, which adopts the cemented carbide welding method described in any of the above schemes, comprising a top pressure member, a push-down member, a first clamping member, a second clamping member and two electrode members, wherein the first clamping member and the second clamping member are spaced apart in the vertical direction, and the two electrode members are respectively arranged corresponding to the first clamping member and the second clamping member, the first clamping member and the relative electrode member can jointly clamp a cemented carbide member, and the second clamping member and the relative electrode member can jointly clamp another cemented carbide member, the top pressure member is arranged on the side of the first clamping member away from the second clamping member, the push-down member is arranged on the side of the second clamping member away from the first clamping member, the top pressure member is used to apply downward pressure to the corresponding cemented carbide member, and the push-down member is used to apply upward thrust to the corresponding cemented carbide member.

[0025] The cemented carbide device of the present invention can apply the above-mentioned cemented carbide welding method to realize automated welding, thereby further improving welding efficiency and process accuracy.

[0026] As a preferred technical solution of the above-mentioned cemented carbide welding device, both the first clamping member and the second clamping member are provided with limiting grooves.

[0027] As a preferred technical solution of the above-mentioned cemented carbide welding device, the cemented carbide welding device also includes a first moving component and a second moving component, both of which are used to clamp and move the cemented carbide part, the first moving component is located on the side of the first clamping part away from the second clamping part, and the second moving component is located on the side of the second clamping part away from the first clamping part. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0029] Figure 1 A flow chart of a cemented carbide welding method provided by an embodiment of the present invention;

[0030] Figure 2 A first relationship diagram of preheating current, welding current and welding time provided in an embodiment of the present invention;

[0031] Figure 3 The second relationship diagram of preheating current, welding current and welding time provided by the embodiment of the present invention;

[0032] Figure 4 Schematic diagram of the welding process of cemented carbide parts provided by the embodiment of the present invention;

[0033] Figure 5 Flexural strength test diagram provided by the embodiment of the present invention;

[0034] Figure 6 Column chart of flexural load of welded parts test provided by the embodiment of the present invention;

[0035] Figure 7 Column chart of flexural strength of welded parts test provided by the embodiment of the present invention;

[0036] Figure 8 Schematic diagram of the structure of the cemented carbide welding device provided by the embodiment of the present invention;

[0037] Figure 9 Connection diagram of the first moving cylinder, the second moving cylinder and the second chuck provided by the embodiment of the present invention;

[0038] Figure 10 Surface of the welded part obtained by the method provided by the embodiment of the present invention;

[0039] Figure 11 Fracture section of the welded part obtained by the method provided by the embodiment of the present invention;

[0040] Figure 12 Fracture section of the welded part obtained in Comparative Example 1;

[0041] Figure 13 Surface of the welded part obtained in Comparative Example 2;

[0042] Figure 14 Surface of the welded part obtained in Comparative Example 3;

[0043] Figure 15 Fracture section of the welded part obtained in Comparative Example 4.

[0044] In the figure:

[0045] 1. Top pressing part; 2. Lower pushing part; 3. Electrode part; 4. First clamping part; 5. Second clamping part; 6. First moving cylinder; 7. Second moving cylinder; 8. Third moving cylinder; 9. Fourth moving cylinder; 10. First chuck; 101. Clamping arm; 11. Second chuck; 12. Top pressing cylinder; 13. First electrode cylinder; 14. Second electrode cylinder; 15. Welding controller; 151. Pressure control circuit; 152. Current output circuit; 16. Pressure head; 100. Cemented carbide part; 200. Welded part; 201. Welding position. Detailed implementation mode

[0046] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0047] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected", "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0048] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0049] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0050] When the tool reaches the end of its service life, usually the entire tool will be scrapped, which not only wastes a large amount of cemented carbide material in the non-cutting part but also increases the environmental burden. Therefore, it is necessary to weld the non-cutting part. However, the existing cemented carbide parts are welded with used rod materials using brazing solder for reuse, which can greatly reduce the production cost of the tool, improve the utilization rate of raw materials, and has simple operation and low cost. But this method requires flux materials, which is not conducive to high-efficiency and low-cost manufacturing. In addition, the welding uses high-frequency welding method, which has complex operation and low efficiency and is not conducive to mass production.

[0051] Therefore, this embodiment provides a cemented carbide welding method that does not require additional flux materials, can realize the reuse of cemented carbide materials, and improve the production efficiency.

[0052] Combined with Figure 1 and Figure 4 As shown, this embodiment provides a cemented carbide welding method for welding a cemented carbide part 100, and the method includes the following steps:

[0053] S101. Pretreat the cemented carbide part 100 to clean the surface impurities;

[0054] S102. Align the central axes of the two cemented carbide parts 100 with the straight line in the direction of the gravity and contact and connect them;

[0055] S103. Apply welding pressure to at least one of the two cemented carbide parts 100;

[0056] S104. Preheat the two cemented carbide parts 100 to form contact points at the connection of the two cemented carbide parts 100 and establish electrical connection; the preheating parameters include preheating current and preheating time;

[0057] S105. Weld the two cemented carbide parts 100 to form a fusion core at the contact point to obtain a welded part 200; the welding parameters include welding current and welding time;

[0058] S106. Treat the welded part of the welded part 200 to remove the welding scars.

[0059] In step S101, removing the surface impurities of the cemented carbide part 100 can ensure its good electrical conductivity. Specifically, the pretreatment includes grinding, cleaning, and drying. Among them, grinding includes peripheral grinding and end face grinding. The peripheral grinding method can be centerless grinding, cylindrical grinding or other grinding methods, and the end face can be ground by a grinding wheel for end face grinding; the cleaning method can be ultrasonic cleaning, plasma cleaning or other cleaning methods; the drying method can be natural drying, hot air drying, infrared drying or other drying methods.

[0060] In step S103, the welding pressure is N, where 10 kg < N ≤ 100 kg, and the acting direction of the welding pressure is the same as the direction of gravity. Applying the welding pressure can ensure that the two cemented carbide parts 100 always tend to approach each other. Since the acting direction of the welding pressure is the same as the direction of gravity, the error tolerance rate can be increased. Even under the action of gravity alone, the two cemented carbide parts 100 still tend to approach each other.

[0061] In step S104, the two cemented carbide parts 100 enter the preheating stage. The preheating current is I1 and the preheating time is T1, where 500 A < I1 ≤ 1600 A and 20 ms < T1 ≤ 800 ms. Through step S104, impurities such as oxide films and oil films on the surfaces of the cemented carbide parts 100 that cannot be eliminated by pretreatment can be removed, thereby reducing the contact resistance, avoiding burn-through or electrode damage due to excessive contact resistance during the welding process, and also being able to slow down the cooling rate of the contact surfaces of the two cemented carbide parts 100, avoiding the formation of hardened structures, reducing the stress during welding, and reducing the degree of deformation during welding, thereby preventing the generation of welding cracks.

[0062] In step S105, the two cemented carbide parts 100 enter the welding stage. The welding time is T2 and the welding current is I2, where 1800 A < I2 ≤ 3000 A and 100 ms < T2 ≤ 800 ms. As the current flowing through the two cemented carbide parts 100 increases, the temperature of the metal at the contact point rises and melts to form liquid metal, and then a fusion core is formed. As the welding time increases, under the thermo-mechanical coupling effect, a plastic ring is formed around the fusion core. The plastic ring surrounds the melting zone where the fusion core is located, preventing the melted metal from being extruded under the action of pressure, thereby avoiding spatter.

[0063] It should be noted that the differences between preheating and welding are as follows: 1. Different functions. Preheating is mainly to prepare for the welding process, ensuring the stability of the current channel and reducing the contact resistance, while welding is to locally melt the cemented carbide parts 100 through the heat generated by the current to form a fusion core and complete the welding. 2. Different current states. Preheating usually uses a relatively small preheating current, mainly aiming to improve the contact of the workpiece, while welding uses a relatively large welding current to generate enough heat to melt the cemented carbide parts 100. 3. Different temperature changes. The preheating temperature is relatively low, mainly to increase the initial temperature of the cemented carbide parts 100 and reduce the thermal stress during the welding process. The welding temperature is relatively high, high enough to locally melt the cemented carbide parts 100 to form liquid metal. 4. Different process controls. Preheating requires controlling the magnitude of the preheating current and the preheating time to ensure good contact on the surfaces of the cemented carbide parts 100, and welding requires precisely controlling the welding current, welding time, and welding pressure to ensure the formation of the fusion core and the welding quality.

[0064] It should be noted that in some embodiments, such as Figure 2As shown, the preheating current first gradually increases from the reference value, then remains constant, and then gradually decreases back to the reference value. The welding current first gradually increases from the reference value, then remains constant, and then gradually decreases back to the reference value. Such a setting can extend the discharge time to meet the welding requirements between the cemented carbide parts 100.

[0065] Among them, the reference value can be 0. Of course, in some other embodiments, it can also be greater than 0.

[0066] In some other embodiments, as Figure 3 shown, the welding current is a constant current, and the preheating current is a constant current. This can ensure a long current discharge time to meet the welding requirements of the cemented carbide part 100 welding the cemented carbide part 100.

[0067] In step S106, the way to process the welding part 200 of the welded part is centerless grinding. Removing the welding scar can make the appearance of the welded part 200 more beautiful and facilitate the cutting process of the welded part 200.

[0068] To better illustrate the effects of the above cemented carbide welding method, the following examples and comparative examples are used for further illustration.

[0069] The following Examples 1-3 and Comparative Examples 1-4 all include the above steps S101-S106, and the processing methods used in steps S101 and S106 are the same. The cemented carbide parts 100 in Examples 1-2 and Comparative Examples 1-4 are all tungsten steel bars of D6, and the cemented carbide bar in Example 3 is a tungsten steel bar of D4. The welding process parameters of Examples 1-3 and Comparative Examples 1-4 are set as follows:

[0070] Example 1

[0071] The preheating current I1 = 1300A, the preheating time T1 = 600ms, the welding current I2 = 2850A, the welding time T2 = 600ms, the welding pressure N = 25kg, and both the preheating current and the welding current are constant currents.

[0072] Example 2

[0073] The preheating current I1 = 1300A, the preheating time T1 = 600ms, the welding current I2 = 2850A, the welding time T2 = 600ms, the welding pressure N = 25kg, and both the preheating current and the welding current gradually increase from 0, then remain constant, and then gradually decrease to 0.

[0074] Example 3

[0075] The preheating current I1 = 1000 A, the preheating time T1 = 120 ms, the welding current I2 = 2400 A, the welding time T2 = 315 ms, the welding pressure N = 60 kg. Both the preheating current and the welding current gradually increase from 0, then remain constant, and then gradually decrease to 0.

[0076] Comparative Example 1

[0077] I1 = 1300 A, the preheating time T1 = 600 ms, the welding current I2 = 2850 A, the welding time T2 = 600 ms, the welding pressure N = 25 kg. Both the preheating current and the welding current are pulsed currents with a pulse width = 50 ms and a pulse interval = 50 ms.

[0078] Comparative Example 2

[0079] The preheating current I1 = 2000 A, the preheating time T1 = 850 ms, the welding current I2 = 3000 A, the welding time T2 = 850 ms, the welding pressure N = 75 kg. Both the preheating current and the welding current are constant currents.

[0080] Comparative Example 3

[0081] The preheating current I1 = 1300 A, the preheating time T1 = 850 ms, the welding current I2 = 2850 A, the welding time T2 = 850 ms, the welding pressure N = 120 kg. Both the preheating current and the welding current are constant currents.

[0082] Comparative Example 4

[0083] The preheating current I1 = 400 A, the preheating time T1 = 150 ms, the welding current I2 = 2000 A, the welding time T2 = 300 ms, the welding pressure N = 10 kg. Both the preheating current and the welding current are constant currents.

[0084] Observe the melting degree during the welding process of the above Examples 1 - 3 and Comparative Examples 1 - 4, as well as the appearance of the finished welded part 200, and place it on a three-point flexure testing device for flexure testing, and observe the fracture cross-section of the finished welded part 200.

[0085] The flexure test is as Figure 4As shown in the figure, in the three-point flexural testing equipment, the span L between the two supports is 35 mm, the radius R1 of one support is 5 mm, the radius R2 of the other support is 5 mm, and the diameter D of the indenter 16 is 10 mm. Substituting the specific value of the diameter d of the welded part 200 into the span calculation formula, it can be obtained that the span L of the tungsten carbide bar stock of D6 is selected from 35 mm to 41 mm, and the lower limit is selected in this calculation, that is, 35 mm; the span L of the tungsten carbide bar stock of D4 is selected from 30 mm to 34 mm, and the lower limit is selected in this calculation, that is, 30 mm. The pressing speed of the indenter 16 of the three-point flexural testing equipment is 1 mm / min. Among them, the span calculation formula is: L = (R1 + R2 + D + 3d) ± (d / 2); the flexural strength calculation formula is: σb = (8FL) / (πd3); σb is the flexural strength, and the unit is Mpa.

[0086] The welding effects of the above Examples 1-3 and Comparative Examples 1-4 are shown in Table 1 below. Among them, the melting degree is the melting degree of the contact surface between the two tungsten carbide bar stocks during the welding stage, the welding mark is the welding mark of the welded part 200 after removing the welding scar treatment, the fracture cross-section is the cross-section of the welded part 200 after fracture, the flexural load F is the maximum flexural load when the welded part 200 fractures, the flexural strength is the flexural strength σb obtained by the flexural test calculation. Examples 1-3 and Comparative Examples 1-4 were each tested 10 times, and the average values of the flexural load and flexural strength obtained from the 10 tests were taken.

[0087]

[0088] Figure 6 The flexural load in is the test result of 10 flexural load tests obtained in Example 1, while Figure 7 The flexural strength in is the test result of 10 flexural strength tests obtained in Example 1.

[0089] There are no welding marks on the surface of the welded parts 200 in Examples 1-3 (as Figure 10 shown), and the cross-sections after fracture are all ductile fractures (as Figure 11 shown), indicating a high welding firmness; its flexural strength is close to 3000 Mpa, reaching more than 60% of the flexural strength of the original tungsten carbide bar stock, which can meet the use requirements, and the welding rate is high. For example, for the tungsten carbide bar stock of D6 in Examples 1 and 2, about 30 pieces can be welded per minute.

[0090] The difference between Comparative Example 1 and Example 1 is the type of current. The cross-section of the welded part 200 in Comparative Example 1 after fracture is as Figure 12 shown. The cross-section is smooth, there is a part of false welding, the welding firmness is low, and its flexural strength is also low, not meeting the use standard.

[0091] The surface of the welded part 200 in Comparative Example 2 is as Figure 13As shown, although its bending strength meets the use requirements, due to the high temperature of the contact surface during the welding process, cracks still exist on the surface of the weld even after the welding scar is removed.

[0092] The surface of the weldment 200 of Comparative Example 3 is as follows Figure 14 As shown, although its bending strength meets the use requirements, due to the excessive welding pressure during the welding process, it will leave scars on the surface of the weld that cannot be removed.

[0093] The temperature of comparative example 4 is relatively low and the welding pressure is insufficient, so a strong weld cannot be formed at the welding position. The cross section of the welded part 200 after fracture is as follows: Figure 15 As shown, the cross-section after fracture is smooth and flat, and the bending strength is low, which does not meet the use requirements.

[0094] In summary, the cemented carbide welding method of the present invention has high welding efficiency and good welding quality, can realize the reuse of cemented carbide materials, improve material utilization, save costs, and reduce waste; and the welded part 200 made using the cemented carbide welding method of the present invention has no defects in appearance, high bending strength, and extremely high practical value.

[0095] The present invention also provides a cemented carbide welding device, such as Figure 8 and Figure 9 As shown, the cemented carbide part 100 can be welded by a cemented carbide welding device, which includes a top pressure member 1, a push-down member 2, two electrode members 3, a first clamping member 4 and a second clamping member 5. The two electrode members 3 are respectively arranged corresponding to the first clamping member 4 and the second clamping member 5. The first clamping member 4 and the relative electrode member 3 can jointly clamp a cemented carbide part 100, and the second clamping member 5 and the relative electrode member 3 can jointly clamp another cemented carbide part 100. The top pressure member 1 is arranged on the side of the first clamping member 4 away from the second clamping member 5, and the push-down member 2 is arranged on the side of the second clamping member 5 away from the first clamping member 4. The top pressure member 1 is used to apply downward pressure to the corresponding cemented carbide part 100, and the push-down member 2 is used to apply upward thrust to the corresponding cemented carbide part 100.

[0096] The first clamping member 4 and the second clamping member 5 are located on the same side of the cemented carbide member 100 and are used to limit the cemented carbide member 100 in the axial vertical direction. In addition, one of the electrode members 3 is arranged opposite to the first clamping member 4, and the other electrode member 3 is arranged opposite to the second clamping member 5, so that the electrode member 3 and the corresponding clamping member cooperate with each other to clamp the cemented carbide member 100, and the top pressure member 1 and the push-down member 2 are used to limit the axial position of the cemented carbide member 100.

[0097] The first clamping member 4 and the second clamping member 5 are both provided with a limiting groove, and the limiting groove is a V-shaped groove. For example, the first clamping member 4 and the second clamping member 5 are both V-shaped blocks, and the V-shaped blocks have a V-shaped groove.

[0098] The cemented carbide welding device further includes a first moving component and a second moving component. Specifically, the first moving component is located on the side of the first clamping member 4 away from the second clamping member 5, and the second moving component is located on the side of the second clamping member 5 away from the first clamping member 4. The first moving component includes a first moving cylinder 6, a second moving cylinder 7, and a first chuck 10. The first moving cylinder 6 is connected to the first chuck 10 and can drive the first chuck 10 to horizontally move the cemented carbide rod to the position of the pressing member 1. The second moving cylinder 7 is connected to the first chuck 10 and can adjust the two clamping arms 101 of the first chuck 10 to move closer to or away from each other. The second moving component includes a third moving cylinder 8, a fourth moving cylinder 9, and a second chuck 11. The third moving cylinder 8 is connected to the second chuck 11 and can drive the second chuck 11 to horizontally move the cemented carbide rod to the pushing member 2. The fourth moving cylinder 9 is connected to the second chuck 11 and can adjust the two clamping arms 101 of the second chuck 11 to move closer to or away from each other.

[0099] The cemented carbide welding device further includes a pressing cylinder 12, a first electrode cylinder 13, and a second electrode cylinder 14. Specifically, the pressing member 1 is connected to the pressing cylinder 12 and is driven by the pressing cylinder 12 to move closer to or away from the cemented carbide part 100. The pushing member 2 is connected to a motor and is driven by the motor to move closer to or away from the cemented carbide part 100. Among the two electrode parts 3, one is connected to the first electrode cylinder 13 and is driven by the first electrode cylinder 13 to move closer to or away from the cemented carbide part 100, and the other is connected to the second electrode cylinder 14 and is driven by the second electrode cylinder 14 to move closer to or away from the cemented carbide part 100.

[0100] The pressing member 1 and the pushing member 2 are used to axially limit the two cemented carbide parts 100 from above and below.

[0101] The cemented carbide welding device further includes a welding controller 15. Both electrode parts 3 are electrically connected to the welding controller 15 to achieve the purpose of enabling the two electrode parts 3 to be controlled to work simultaneously. The pressure control circuit 151 of the welding controller 15 is used to control the moving distance of the pressing cylinder 12 to control the pressure exerted by the pressing member 1 on the cemented carbide part 100. The current output circuit 152 of the welding controller 15 is used to control the magnitude and type of the current. As Figure 2 and Figure 3 shown, there are two control methods for both the welding current and the preheating current. Both currents are direct current. One is a constant current, and the other consists of a rising current, a constant value current, and a falling current. It should be noted that the maximum value of the preheating current is less than the maximum value of the welding current. In addition, the welding controller 15 is also used to control the pressure of the pressing member 1 and the operation of each cylinder.

[0102] Combined with Figure 8 and Figure 9, in this embodiment, the specific welding process of the cemented carbide welding device is as follows:

[0103] S1. The fourth moving cylinder 9 drives the second chuck 11 to clamp the cemented carbide part 100. And driven by the third moving cylinder 8, the cemented carbide part 100 is pushed to the axis of the downward pushing part 2, so that the axis of the cemented carbide part 100 coincides with the axis of the downward pushing part 2; then the fourth moving cylinder 9 drives the second chuck 11 to release the cemented carbide part 100, and the third moving cylinder 8 drives the chuck to retract to its original position;

[0104] S2. Driven by the motor, the downward pushing part 2 moves upward. After pushing the cemented carbide part 100 to the middle position between the gaps of the first clamping part 4 and the second clamping part 5, the motor stops, and the downward pushing part 2 fixes this position, holds the cemented carbide part 100, and gives a supporting effect;

[0105] S3. Driven by the second electrode cylinder 14, the first electrode part 3 presses the cemented carbide part 100 to make it fit with the second clamping part 5. Through the groove structure of the second clamping part 5, the axis of the cemented carbide part 100 coincides with the welding axis;

[0106] S4. The second moving cylinder 7 drives the first chuck 10 to clamp the cemented carbide part 100. And driven by the first moving cylinder 6, the cemented carbide part 100 is pushed to the axis of the pressing part 1, so that the axis of the cemented carbide part 100 coincides with the axis of the pressing part 1. Then the second moving cylinder 7 drives the first chuck 10 to release the cemented carbide part 100, and the first moving cylinder 6 drives the chuck to retract to its original position. The cemented carbide part 100 falls naturally and contacts the welding surface of the cemented carbide part 100;

[0107] S5. Driven by the first electrode cylinder 13, the second electrode part 3 presses the cemented carbide part 100 to make it fit with the first clamping part 4. Through the groove structure of the clamping part, the axis of the cemented carbide part 100 coincides with the axis of the cemented carbide part 100 and the welding axis;

[0108] S6. The pressing cylinder 12 drives the pressing part 1 to move downward, pressing the cemented carbide part 100 tightly so that the cemented carbide part 100 fits closely with the cemented carbide part 100;

[0109] S7. The welding controller 15 is started to output a current signal. The current passes through the first electrode part 3 - the first cemented carbide part 100 - the welding position 201 - the second cemented carbide part 100 - the second electrode part 3 to form a loop. First, it is preheated and then welded. Resistance heat is generated during the welding process, so that the first cemented carbide part 100 and the second cemented carbide part 100 are firmly bonded;

[0110] S8. After welding is completed, the pressing member 1 retracts to its original position driven by the pressing cylinder 12;

[0111] S9. The pushing member 2 moves downward driven by the motor, driving the welding rod material to retract to its original position;

[0112] S10. The third moving cylinder 8 drives the second chuck 11 to move to the position of the welding rod material, then the fourth moving cylinder 9 drives the second chuck 11 to clamp the welding rod material, and then the third moving cylinder 8 drives the second chuck 11 to retract to its original position to take out the welding rod material.

[0113] In addition, the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments only. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A cemented carbide welding method, characterized in that, For welding cemented carbide parts, the following steps are included: Pre-treat the cemented carbide parts to clean the surface impurities; Align the central axes of the two cemented carbide parts with the line where the gravity direction is located and contact and connect them; Apply welding pressure to at least one of the two cemented carbide parts; Preheat the two cemented carbide parts to form a contact point and establish electrical connection at the joint of the two cemented carbide parts; the parameters of the preheating include preheating current and preheating time; Weld the two cemented carbide parts to make the contact point form a nugget to obtain a welded part; the parameters of the welding include welding current and welding time; Treat the welded joint of the welded part to remove welding scars.

2. The cemented carbide welding method according to claim 1, characterized in that, The preheating current is I1, the preheating time is T1, 500A < I1 ≤ 1600A, 20ms < T1 ≤ 800ms; The welding current is I2, the welding time is T2, 1800A < I2 ≤ 3000A, 100ms < T2 ≤ 800ms.

3. The cemented carbide welding method according to claim 1 or 2, characterized in that, The preheating current is a constant current or the preheating current gradually increases from a reference value first, then remains constant, and then gradually decreases to the reference value; The welding current is a constant current or the welding current gradually increases from a reference value first, then remains constant, and then gradually decreases to the reference value.

4. The cemented carbide welding method according to claim 3, characterized in that, The reference value is 0.

5. The cemented carbide welding method according to claim 1, characterized in that, The welding pressure is N, 10kg < N ≤ 100kg.

6. The cemented carbide welding method according to claim 1, 2 or 5, characterized in that, The acting direction of the welding pressure is the same as the gravity direction.

7. The cemented carbide welding method according to claim 1, 2 or 5, characterized in that, The pre-treatment includes grinding, cleaning and drying.

8. The cemented carbide welding method according to claim 1, 2 or 5, characterized in that, In the step of treating the welded joint of the welded part to remove welding scars, the treatment method is centerless grinding.

9. A cemented carbide welding device, characterized in that, Applied to the cemented carbide welding method according to any one of claims 1-8, the cemented carbide welding device includes: A top pressing part, a downward pushing part, a first clamping part, a second clamping part and two electrode parts. The first clamping part and the second clamping part are spaced apart in the vertical direction. The two electrode parts are respectively arranged corresponding to the first clamping part and the second clamping part. The first clamping part and the opposite electrode part can jointly clamp a cemented carbide part, and the second clamping part and the opposite electrode part can jointly clamp another cemented carbide part. The top pressing part is arranged on the side of the first clamping part facing away from the second clamping part, and the downward pushing part is arranged on the side of the second clamping part facing away from the first clamping part. The top pressing part is used to apply a downward pressure to the corresponding cemented carbide part, and the downward pushing part is used to apply an upward thrust to the corresponding cemented carbide part.

10. The cemented carbide welding device according to claim 9, characterized in that, Both the first clamping part and the second clamping part are provided with limiting grooves.

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