Non-preheating welding machining method for slewing bearing ring piece for transport vehicle

Abstract

The invention belongs to the technical field of welding, and particularly relates to a non-preheating welding processing method of a slewing bearing ring piece for a transport vehicle, the non-preheating welding processing method comprises the following steps of winding drum bending forming, preparation before welding, backing welding, filling welding and cosmetic welding, the whole welding process is not subjected to preheating before welding, and the welding process is finished. And after-welding heat treatment is not needed, continuous welding is kept in each welding process, an arc crater of an arc stopping part needs to be filled, and all-position welding of a welding path is completed by adopting a welding robot in the whole welding process. The multi-process combined welding method is simple and easy to operate, small in welding deformation, small in welding cracking tendency, smooth and attractive in welding seam surface forming, small in welding heat influence on base metal and capable of guaranteeing the joint strength.

Description

Technical Field

[0001] The invention relates to the technical field of welding, in particular to a non-preheating welding processing method for a slewing bearing ring for a transport vehicle. Background Art

[0002] As a special supporting structure, slewing bearing is widely used in engineering machinery, transportation and other fields. It is especially a direct load-bearing component in transport vehicles. It can transmit axial loads, thrust and tension. It is used in truck trailer turntable control, forced steering semi-trailer, semi-trailer connector, heavy truck and special vehicle fields. However, slewing bearing rings are mostly forged, which has high requirements for processing equipment, high production cost and long cycle. In order to further reduce costs and shorten manufacturing cycles, drum bending and welding combined processing methods are increasingly attracting the attention of domestic and foreign companies. Slewing bearing rings are mostly made of high-strength modulated steel, which is very easy to crack during welding. At present, the modulated steel used for slewing bearing rings needs to be preheated in advance during the welding process, which increases production costs and processing cycles. The development of non-preheating welding processing methods is conducive to reducing production costs while ensuring quality.

[0003] Therefore, we propose a non-preheating welding method for slewing bearing rings for transport vehicles to solve the above problems. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a non-preheating welding method for a slewing bearing ring for a transport vehicle, which solves the problems raised in the above-mentioned background technology.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] A non-preheating welding method for a slewing bearing ring for a transport vehicle, the non-preheating welding method comprising the following steps:

[0009] S1. Cut the slewing bearing ring by using a laser cutting machine, place the slewing bearing ring obtained after cutting on a drum bending machine, and adjust the bending speed and mold of the drum bending machine according to the inner diameter and thickness of the slewing bearing ring;

[0010] S2. Use appropriate bending speed to synchronously carry out integrated forming of the roll and bending to ensure uniform force. During the rolling and bending forming, heating treatment is carried out synchronously. After the roll is bent, stress relief annealing heat treatment is performed to reduce the residual stress of the workpiece;

[0011] S3. For the slewing bearing ring formed by drum bending, use a lathe to make a V-shaped groove at the connection, with a groove angle of 40°~65° and a blunt edge of 1~2mm. Grind the groove and both sides to remove oxide scale and oil stains. The grinding distance on each side is ≥40mm, and the polished surface is cleaned;

[0012] S4. Use a fixed fixture to fix the slewing bearing ring and keep the blunt edge clearance at 1 to 1.5 mm;

[0013] S5. Use wire-filled plasma arc welding for base welding, fill with 500MPa high-toughness welding wire, the angle between the welding gun and the welding direction is 90°, along the welding direction, the welding wire is in front and the welding gun is behind;

[0014] S6, filling welding uses double wire Ar and CO 2 Mixed gas shielded welding, using 800MPa high-strength and tough welding wire for welding, the double wire angle is 10°~15°, the double wire spacing is 8~15mm, the double wire diameter is 1.2mm, the welding current is 320A~450A, the wire feeding speed is 10~13m / min, the welding speed is 8~12mm / s, and the welding speed is controlled during the welding process to maintain the interlayer temperature at 150~180℃;

[0015] S7, cap welding uses 600MPa basic flux-cored wire with Ar and CO 2 Mixed gas shielded welding, welding wire diameter is 1.8-2.4mm, welding current is 200-300A, welding heat input is controlled at 15-22kJ / cm, welding speed is controlled during welding, and asbestos and other insulation materials are used to wrap the joint after welding to reduce the cooling speed of the joint area;

[0016] The entire welding process does not require preheating before welding or post-weld heat treatment. Each weld is performed continuously and the arc crater at the end of the arc needs to be filled. The entire welding process uses a welding robot to complete full-position welding of the welding path.

[0017] Furthermore, the slewing bearing ring in S1 is made of one of 42CrMo and 45CrMo steels, but is not limited to these two steels.

[0018] Furthermore, in said S2, the bending speed of the plate is in the range of 5 to 30 mm / min, the bending amount is in the range of 50 to 100 mm, and the temperature of the synchronous heating is in the range of 150° C. to 300° C.

[0019] Furthermore, the surface cleaning in S3 is to use anhydrous ethanol and acetone to clean the polished surface and dry it.

[0020] Furthermore, the S5 welding process parameters are as follows: a tungsten electrode diameter of 2.4 to 3.0 mm, a nozzle aperture of 3.2 to 3.6 mm, a DC positive polarity, a small hole with stable penetration, and the base welding is ensured to be fully melted; a welding current of 100 to 180 A; a plasma gas of 99.999% high-purity argon gas, a plasma gas flow rate of 8 to 10 L / min, a shielding gas of 99.999% high-purity argon gas, a gas flow rate of 10 to 18 L / min, a welding wire diameter of 2.0 to 2.4 mm, and in order to achieve good weld formation, the welding speed is adjusted to ensure that the welding heat input is controlled at 10 to 18 kJ / cm, and one base welding is performed.

[0021] Furthermore, the Ar and CO used in S6 and S7 are 2 Mixed protective gas of Ar and CO 2 The volume ratio is 85%~95%:15%~5%, and the sum of the volumes of the two is 100%, and the protective gas flow rate is 12~20L / min.

[0022] Furthermore, the S6 adopts a synchronous wire feeding device to achieve synchronous feeding of the double wires, ensuring that the double wires enter the same molten pool after being melted.

[0023] (III) Beneficial effects

[0024] Compared with the prior art, the present invention provides a non-preheating welding method for a slewing bearing ring for a transport vehicle, which has the following beneficial effects:

[0025] The present invention adopts filler wire plasma arc welding for base welding, the plasma arc energy is concentrated, the thermal influence on the parent material formed by the drum bending on both sides is small, the tendency of forming defects is reduced, and the low deformation welding of the slewing bearing ring can be achieved under the premise of ensuring the welding forming quality, and the welding heat input can be reasonably controlled to achieve single-sided welding and double-sided forming; in the filling welding, double-wire Ar and CO are used. 2 Mixed gas shielded welding, double wires melt synchronously into the molten pool, solidify to form a weld, can achieve high-speed welding, high welding processing efficiency, reasonable control of interlayer temperature, can reduce the coarsening of the previous weld grain caused by secondary heating, and can also effectively reduce the tendency of cracking. The cap welding uses Ar+CO2 mixed gas shielded welding with alkaline flux-cored wire to ensure the beautiful surface of the slewing bearing ring weld, reduce subsequent machining processes, reduce costs and shorten production cycles; multi-process combined welding methods are simple and easy to operate, with small welding deformation, small welding cracking tendency, smooth and beautiful weld surface, and the parent material is less affected by welding heat, which can ensure the strength of the joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the bottom welding in the present invention;

[0027] Figure 2 It is a schematic diagram of filling welding in the present invention;

[0028] Figure 3 It is a schematic diagram of the cover welding in the present invention;

[0029] Figure 4 It is a schematic diagram of the welding process flow of the present invention.

[0030] In the figure: 1. nozzle; 2. welding wire; 3. tungsten electrode; 4. slewing bearing ring; 5. gas protective layer. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1-4 As shown, an embodiment of the present invention provides a non-preheating welding method for a slewing bearing ring for a transport vehicle, and the non-preheating welding method comprises the following steps:

[0034] S1. Cut the slewing bearing ring by using a laser cutting machine, place the slewing bearing ring obtained after cutting on a drum bending machine, and adjust the bending speed and mold of the drum bending machine according to the inner diameter and thickness of the slewing bearing ring;

[0035] S2. Use appropriate bending speed to carry out integrated forming of rolling and bending forming simultaneously to ensure uniform force. During rolling and bending forming, heat treatment is carried out simultaneously to increase the plasticity of the material and avoid cracking caused by rolling and bending forming. After the rolling bending is completed, stress relief annealing heat treatment is carried out to reduce the residual stress of the workpiece;

[0036] S3. For the slewing bearing ring formed by drum bending, use a lathe to make a V-shaped groove at the connection, with a groove angle of 40°~65° and a blunt edge of 1~2mm. Grind the groove and both sides to remove oxide scale and oil stains. The grinding distance on each side is ≥40mm, and the polished surface is cleaned;

[0037] S4. Use a fixed fixture to fix the slewing bearing ring and keep the blunt edge clearance at 1 to 1.5 mm;

[0038] S5. Use wire-filled plasma arc welding for base welding, fill with 500MPa high-toughness welding wire, the angle between the welding gun and the welding direction is 90°, along the welding direction, the welding wire is in front and the welding gun is behind;

[0039] S6, filling welding uses double wire Ar and CO 2 Mixed gas shielded welding, using 800MPa high-strength and tough welding wire for welding, the double wire angle is 10°~15°, the double wire spacing is 8~15mm, the double wire diameter is 1.2mm, the welding current is 320A~450A, the wire feeding speed is 10~13m / min, the welding speed is 8~12mm / s, and the welding speed is controlled during the welding process to maintain the interlayer temperature at 150~180℃;

[0040] S7, cap welding uses 600MPa basic flux-cored wire with Ar and CO 2 Mixed gas shielded welding, welding wire diameter is 1.8-2.4mm, welding current is 200-300A, welding heat input is controlled at 15-22kJ / cm, welding speed is controlled during welding, and asbestos and other insulation materials are used to wrap the joint after welding to reduce the cooling speed of the joint area;

[0041] The entire welding process does not require preheating before welding or post-weld heat treatment. Each weld is performed continuously and the arc crater at the end of the arc needs to be filled. The entire welding process uses a welding robot to complete full-position welding of the welding path.

[0042] In some embodiments, the slewing bearing ring in S1 is made of one of 42CrMo and 45CrMo steels, but is not limited to these two steels.

[0043] In some embodiments, the bending speed of the plate in S2 is in the range of 5 to 30 mm / min, the bending amount is in the range of 50 to 100 mm, and the temperature range of the synchronous heating is in the range of 150° C. to 300° C.

[0044] In some embodiments, the surface cleaning in S3 is to use anhydrous ethanol and acetone to clean the polished surface and then dry it.

[0045] In some embodiments, the S5 welding process parameters are: tungsten electrode diameter 2.4-3.0mm, nozzle aperture 3.2-3.6mm, direct current positive polarity is used to form a small hole with stable penetration to ensure the base welding is fully melted, welding current 100-180A, plasma gas using high-purity argon with a purity of 99.999%, plasma gas flow rate 8-10L / min, shielding gas using high-purity argon with a purity of 99.999%, gas flow rate 10-18L / min, welding wire diameter 2.0-2.4mm, in order to achieve good weld formation, the welding speed is adjusted to ensure that the welding heat input is controlled at 10-18kJ / cm, and one base welding is performed.

[0046] In some embodiments, the Ar and CO used in S6 and S7 2 Mixed protective gas of Ar and CO 2 The volume ratio is 85%~95%:15%~5%, and the sum of the volumes of the two is 100%, and the protective gas flow rate is 12~20L / min.

[0047] In some embodiments, the S6 uses a synchronous wire feeding device to achieve synchronous feeding of the two wires, ensuring that the two wires enter the same molten pool after melting.

[0048] Example 2

[0049] like Figure 1-4 As shown, an embodiment of the present invention provides a non-preheating welding method for a slewing bearing ring for a transport vehicle, and the non-preheating welding method comprises the following steps:

[0050] Step 1: Roll bending

[0051] The 42CrMo steel plate obtained by flat plate cutting is placed on a roll bending machine and heated to 300°C. Subsequently, the roll and bending are gradually formed into one piece at a bending speed of 30mm / min to ensure uniform force. And synchronous heating is performed during the forming process to avoid cracking. After the roll bending is completed, a slewing bearing ring with an inner diameter of 800mm, a thickness of 40mm, and a bending amount of 50mm is obtained. Finally, it is subjected to stress relief annealing heat treatment;

[0052] Step 2: Preparation before welding

[0053] The 42CrMo steel slewing bearing ring formed by drum bending is machined into a V-shaped groove with a groove angle of 40° and a blunt edge of 1mm on a lathe. The 40mm range on both sides of the groove is polished to remove oxide scale and oil, and the surface is cleaned with acetone and anhydrous ethanol. The slewing bearing ring is fixed with a fixed fixture to keep the blunt edge gap at 1mm;

[0054] Step 3: Base welding

[0055] First, a base welding is performed. No preheating treatment is required before welding. The base welding is performed by filler wire plasma arc welding. The filler wire is 500MPa high-toughness welding wire. The angle between the welding gun and the welding direction is 90°. Along the welding direction, the welding wire is in front and the welding gun is behind. The welding process parameters are a tungsten electrode diameter of 2.4mm and a nozzle aperture of 3.2mm. DC positive polarity is used to form a small hole with stable penetration to ensure that the base welding is fully penetrated. The welding current is 100A, and the plasma gas uses high-purity argon with a purity of 99.999%. The plasma gas flow rate is 8L / min. The shielding gas uses high-purity argon with a purity of 99.999%, and the gas flow rate is 10L / min. The wire diameter is 2.0mm. In order to achieve good weld formation, the welding speed is adjusted to ensure that the welding heat input is controlled at 10kJ / cm;

[0056] Step 4: Filling welding

[0057] Filling welding uses double wire Ar and CO 2 Mixed gas shielded welding, mixed shielding gas Ar and CO 2 The volume ratio is 85%:15%, and the protective gas flow rate is 12L / min. 800MPa high-strength and tough welding wire is used for welding, the double wire angle is 10°, the double wire spacing is 8mm, the double wire diameter is 1.2mm, the welding current is 320A, and the welding speed is 8mm / s. The welding speed is strictly controlled during the welding process to maintain the interlayer temperature at 150℃. The wire feeding speed is 10m / min, and a synchronous wire feeding device is used to achieve synchronous feeding of the double wires to ensure that the double wires enter the same molten pool after melting;

[0058] Step 5: Cover welding

[0059] The cap welding uses 600MPa basic flux-cored wire with Ar and CO 2 Mixed gas shielded welding, Ar and CO 2 The volume ratio is 95%:5%, and the protective gas flow rate is 20L / min. The diameter of the welding wire is 1.8mm, the welding current is 200A, and the welding heat input is controlled at 15kJ / cm; the welding speed is strictly controlled during the welding process, and asbestos and other insulation materials are used to wrap the joints after welding to reduce the cooling speed of the joint area;

[0060] The joints were inspected after welding and found that the welds were well formed, the weld surface was smooth and beautiful, without defects such as cracks, pores, undercuts, and lack of fusion. The heat affected zone was narrow and the welding deformation rate was less than 5%.

[0061] Example 3

[0062] like Figure 1-4As shown, an embodiment of the present invention provides a non-preheating welding method for a slewing bearing ring for a transport vehicle, and the non-preheating welding method comprises the following steps:

[0063] Step 1: Roll bending

[0064] The 45 steel plate obtained by cutting the flat plate is placed on the roll bending machine and heated to 150°C. Subsequently, the roll and bending are gradually formed into one piece at a bending speed of 5mm / min to ensure uniform force. And synchronous heating is performed during the forming process to avoid cracking. After the roll bending is completed, a slewing bearing ring with an inner diameter of 1000mm, a thickness of 55mm, and a bending amount of 100mm is obtained. Finally, it is subjected to stress relief annealing heat treatment;

[0065] Step 2: Preparation before welding

[0066] The 45 steel slewing bearing ring formed by drum bending, with an inner diameter of 1000mm and a thickness of 55mm, is machined into a V-shaped groove with a groove angle of 65° and a blunt edge of 2mm. The 40mm range on both sides of the groove is polished to remove oxide scale and oil stains, and the surface is cleaned with acetone and anhydrous ethanol. The slewing bearing ring is fixed with a fixed fixture to keep the blunt edge gap at 1.5mm;

[0067] Step 3: Base welding

[0068] First, a base welding is performed. No preheating treatment is required before welding. The base welding is performed by wire-filled plasma arc welding. The filling wire is a 500MPa high-toughness welding wire. The angle between the welding gun and the welding direction is 90°. Along the welding direction, the welding wire is in front and the welding gun is behind. The welding process parameters are a tungsten electrode diameter of 3.0mm and a nozzle aperture of 3.6mm. DC positive polarity is used to form a small hole with stable penetration to ensure that the base welding is fully penetrated. The welding current is 180A, and the plasma gas uses high-purity argon with a purity of 99.999%. The plasma gas flow rate is 10L / min. The shielding gas uses high-purity argon with a purity of 99.999%, and the gas flow rate is 18L / min. The wire diameter is 2.4mm. In order to achieve good weld formation, the welding speed is adjusted to ensure that the welding heat input is controlled at 18kJ / cm;

[0069] Step 4: Filling welding

[0070] Filling welding uses double wire Ar and CO 2 Mixed gas shielded welding, mixed shielding gas Ar and CO 2The volume ratio is 95%:5%, and the protective gas flow rate is 20L / min. 800MPa high-strength and tough welding wire is used for welding, the double wire angle is 15°, the double wire spacing is 15mm, the double wire diameter is 1.2mm, the welding current is 450A, and the welding speed is 12mm / s. The welding speed is strictly controlled during the welding process to maintain the interlayer temperature at 180℃. The wire feeding speed is 13m / min, and a synchronous wire feeding device is used to achieve synchronous feeding of the double wires to ensure that the double wires enter the same molten pool after melting;

[0071] Step 5: Cover welding

[0072] The cap welding uses 600MPa basic flux-cored wire with Ar and CO 2 Mixed gas shielded welding, Ar and CO 2 The volume ratio is 85%:15%, and the protective gas flow rate is 12L / min. The wire diameter is 1.8mm, the welding current is 300A, and the welding heat input is controlled at 22kJ / cm. The welding speed is strictly controlled during the welding process, and asbestos and other insulation materials are used to wrap the joints after welding to reduce the cooling speed of the joint area;

[0073] The weld is well formed, the weld surface is smooth and beautiful, without defects such as cracks, pores, undercuts, and lack of fusion. The heat affected zone is narrow and the welding deformation rate is less than 3%.

[0074] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A non-preheating welding method for a slewing bearing ring for a transport vehicle, characterized in that: The non-preheating welding processing method comprises the following steps: S1. Cut the slewing bearing ring by using a laser cutting machine, place the slewing bearing ring obtained after cutting on a drum bending machine, and adjust the bending speed and mold of the drum bending machine according to the inner diameter and thickness of the slewing bearing ring; S2. Use appropriate bending speed to synchronously carry out integrated forming of the roll and bending to ensure uniform force. During the rolling and bending forming, heating treatment is carried out synchronously. After the roll is bent, stress relief annealing heat treatment is performed to reduce the residual stress of the workpiece; S3. For the slewing bearing ring formed by drum bending, use a lathe to make a V-shaped groove at the connection, with a groove angle of 40°~65° and a blunt edge of 1~2mm. Grind the groove and both sides to remove oxide scale and oil stains. The grinding distance on each side is ≥40mm, and the polished surface is cleaned; S4. Use a fixed fixture to fix the slewing bearing ring and keep the blunt edge clearance at 1 to 1.5 mm; S5. Use wire-filled plasma arc welding for base welding, fill with 500MPa high-toughness welding wire, the angle between the welding gun and the welding direction is 90°, along the welding direction, the welding wire is in front and the welding gun is behind; S6. The filling welding adopts double-wire Ar and CO2 mixed gas shielded welding, and 800MPa high-strength and tough welding wire is used for welding. The double-wire angle is 10°~15°, the double-wire spacing is 8~15mm, the double-wire diameter is 1.2mm, the welding current is 320A~450A, the wire feeding speed is 10~13m / min, and the welding speed is 8~12mm / s. The welding speed is controlled during the welding process to maintain the interlayer temperature at 150~180℃; S7, cap welding adopts Ar and CO2 mixed gas shielded welding with 600MPa alkaline flux-cored wire, the wire diameter is 1.8-2.4mm, the welding current is 200-300A, the welding heat input is controlled at 15-22kJ / cm, the welding speed is controlled during the welding process, and the joint is wrapped with asbestos and other insulation materials after welding to reduce the cooling rate of the joint area; The entire welding process does not require preheating before welding or post-weld heat treatment. Each weld is performed continuously and the arc crater at the end of the arc needs to be filled. The entire welding process uses a welding robot to complete full-position welding of the welding path.

2. The method for welding a slewing bearing ring for a transport vehicle without preheating according to claim 1, characterized in that: The slewing bearing ring in S1 is made of one of 42CrMo and 45CrMo steels, but is not limited to these two steels.

3. The method for welding a slewing bearing ring for a transport vehicle without preheating according to claim 1, characterized in that: In the S2, the bending speed of the plate is in the range of 5 to 30 mm / min, the bending amount is in the range of 50 to 100 mm, and the temperature range of the synchronous heating is in the range of 150° C. to 300° C.

4. The method for welding a slewing bearing ring for a transport vehicle without preheating according to claim 1, characterized in that: The surface cleaning in S3 is to use anhydrous ethanol and acetone to clean the polished surface and dry it.

5. The method for welding a slewing bearing ring for a transport vehicle without preheating according to claim 1, characterized in that: The S5 welding process parameters are as follows: a tungsten electrode diameter of 2.4 to 3.0 mm, a nozzle aperture of 3.2 to 3.6 mm, a direct current positive polarity, a small hole with stable penetration is formed to ensure the base welding is fully melted, a welding current of 100 to 180 A, a plasma gas of 99.999% high-purity argon gas, a plasma gas flow rate of 8 to 10 L / min, a shielding gas of 99.999% high-purity argon gas, a gas flow rate of 10 to 18 L / min, a welding wire diameter of 2.0 to 2.4 mm, and in order to achieve good weld formation, the welding speed is adjusted to ensure that the welding heat input is controlled at 10 to 18 kJ / cm, and one base welding is performed.

6. The method for welding a slewing bearing ring for a transport vehicle without preheating according to claim 1, characterized in that: The volume ratio of Ar to CO2 in the Ar and CO2 mixed protective gas used in S6 and S7 is 85% to 95%: 15% to 5%, and the sum of the volumes of the two is 100%, and the protective gas flow rate is 12 to 20 L / min.

7. The method for welding a slewing bearing ring for a transport vehicle without preheating according to claim 1, characterized in that: The S6 adopts a synchronous wire feeding device to realize synchronous feeding of the double wires, ensuring that the double wires enter the same molten pool after being melted.

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