Welding structure for dissimilar metal shaft type thin-wall parts

Abstract

The invention provides a dissimilar metal shaft type thin-wall part welding structure which comprises a first shaft type thin-wall part and a second shaft type thin-wall part which are made of dissimilar metal, the first shaft type thin-wall part and the second shaft type thin-wall part are attached, and a welding seam position is formed at the end face; a boss structure is arranged at the end, close to the weld joint position, of the first shaft thin-wall part in the circumferential direction, and a stress release groove is formed in the end, close to the weld joint position, of the second shaft thin-wall part in the circumferential direction. According to the invention, the boss is arranged at the end of one base material, and is melted and filled to the end face of the joint in the welding process, so that more metal exists in the weld joint for improving the shape of the weld joint and filling the internal crack of the weld joint, and the stress release groove is arranged at the end of the other base material; axial tensile stress applied to a welding pool by cooling shrinkage of base metal in the cooling and solidification process of the welding pool is reduced, the welding internal stress can be reduced through combined action of the two, the forming probability of cracks in a welding seam is reduced, and the dissimilar metal welding qualification rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of dissimilar metal welding, in particular to a dissimilar metal shaft thin-walled parts welding structure, in particular to a soft magnetic alloy-stainless steel shaft thin-walled parts welding structure. Background Art

[0002] Soft magnetic materials have the advantages of low coercive force, easy magnetization and demagnetization, and low hysteresis loss. When combined with stainless steel materials, they can manufacture precision electromagnets and other structures, and are widely used in the aerospace field. Among them, the typical soft magnetic alloy 1J22 has low strength, poor toughness, strong sensitivity to defects, and poor welding performance after heat treatment. When the soft magnetic alloy is welded with austenitic stainless steel dissimilar metals, due to the difference in physical and chemical properties of the dissimilar metals, the internal stress generated during the welding process is higher than the yield limit of the material, and welding cracks are easily generated inside the weld, affecting the welding quality. That is, the welding internal stress is the direct cause of the formation of cracks in the soft magnetic alloy-stainless steel dissimilar metal welding pool.

[0003] In order to improve the qualified rate of dissimilar metal welding products, the existing technology mainly adopts two methods: optimizing process parameters and adding heat treatment measures to improve the welding state of parts. Studies have shown that optimizing process parameters can reduce welding internal stress and thus reduce the occurrence of welding cracks. However, the process window obtained by this method is narrow, resulting in unreliable welding process, unstable welding quality, and difficulty in engineering application. Preheating before welding and slow cooling after welding will increase the production cycle of components, reduce production efficiency, and increase the production cost of components. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a welding structure of thin-walled parts of dissimilar metal shafts.

[0005] The welding structure of dissimilar metal thin-walled shaft parts provided by the present invention comprises a first thin-walled shaft part and a second thin-walled shaft part, wherein a first welding end face of the first thin-walled shaft part is used to fit with a second welding end face of the second thin-walled shaft part to form a weld position; The first shaft-like thin-walled part and the second shaft-like thin-walled part are made of dissimilar metals, and a boss structure is circumferentially arranged at one end of the first shaft-like thin-walled part and / or the second shaft-like thin-walled part close to the weld position, and a stress relief groove is circumferentially arranged at one end of the first shaft-like thin-walled part and / or the second shaft-like thin-walled part close to the weld position.

[0006] Preferably, one of the first shaft-like thin-walled part and the second shaft-like thin-walled part is a stainless steel shaft-like thin-walled part, and the other of the first shaft-like thin-walled part and the second shaft-like thin-walled part is a soft magnetic alloy shaft-like thin-walled part.

[0007] Preferably, the cross-section of the boss structure is a rectangle, and a side of the rectangle close to the weld position is located on the same plane as the first welding end face.

[0008] Preferably, the cross section of the boss structure is J-shaped, and the J-shaped structure includes a first rectangular structure arranged on the outer surface of the first shaft-type thin-walled part and a second rectangular structure stacked on top of the first rectangular structure; The width of the second rectangular structure is smaller than that of the first rectangular structure, and a side of the first rectangular structure close to the weld position and a side of the second rectangular structure close to the weld position are both located on the same plane as the first welding end surface.

[0009] Preferably, during welding, the width of the bottom of the boss structure matches the width of the molten pool at the weld position, and the bottom of the boss structure is located in the molten pool.

[0010] Preferably, the cross-section of the stress release groove is rectangular.

[0011] Preferably, the cross-section of the stress release groove is V-shaped.

[0012] Preferably, the depth of the stress relief groove is smaller than the machining allowance of the second shaft-type thin-walled part.

[0013] Preferably, the surface width of the stress release groove is 0.3-2 mm.

[0014] Preferably, during welding, there is a gap between a side of the opening of the stress relief groove close to the weld position and an edge of the molten pool.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention has a simple structure and is easy to operate. A boss is arranged at the end of one parent material, which is melted and filled into the end face of the joint during the welding process, so that there is more metal in the weld to fill the internal cracks of the weld and improve the weld formation. A stress relief groove is arranged at the end of the other parent material to reduce the axial tensile stress applied to the molten pool by the cooling and contraction of the parent material during the cooling and solidification of the welding molten pool. The combined effect of the two can reduce the internal stress of the weld, reduce the probability of internal crack formation in the weld, and improve the qualified rate of dissimilar metal welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a schematic diagram of the overall structure of Example 1; Figure 2 This is a schematic diagram of the structure of the soft magnetic alloy shaft thin-walled parts in Example 1; Figure 3This is a schematic diagram of the structure of a stainless steel shaft thin-walled part in Example 1; Figure 4 It is a schematic diagram of the overall structure of Example 2; Figure 5 This is a schematic diagram of the structure of the soft magnetic alloy shaft thin-walled parts in Example 2; Figure 6 This is a schematic diagram of the structure of the stainless steel shaft thin-walled parts in Example 2.

[0017] The figure shows: DETAILED DESCRIPTION

[0018] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0019] The present invention discloses a welding structure for thin-walled parts of dissimilar metal shafts. A boss is arranged at the weld, which is melted and filled into the end face of the joint during the welding process, so that more metal is available in the weld to fill cracks inside the weld and improve the weld forming effect. A stress relief groove is arranged on one side of the weld to reduce the axial tensile stress exerted on the molten pool by the cooling and shrinkage of the parent material during the cooling and solidification of the welding molten pool. The internal stress of the weld is reduced through the combined action of the two.

[0020] According to the welding structure of dissimilar metal shaft thin-walled parts provided by the present invention, Figure 1 As shown, it includes a first shaft-like thin-walled part 1 and a second shaft-like thin-walled part 2, wherein the first welding end face 7 of the first shaft-like thin-walled part 1 is used to fit with the second welding end face 6 of the second shaft-like thin-walled part 2 to form a weld position 3; the first shaft-like thin-walled part 1 and the second shaft-like thin-walled part 2 are made of dissimilar metals, preferably, one of the first shaft-like thin-walled part 1 and the second shaft-like thin-walled part 2 is a stainless steel shaft-like thin-walled part, and the other of the first shaft-like thin-walled part 1 and the second shaft-like thin-walled part 2 is a soft magnetic alloy shaft-like thin-walled part.

[0021] In view of the problem that when welding dissimilar metals, due to the difference in physical and chemical properties, the internal stress generated in the welding process is higher than the yield limit of the material, which easily leads to welding cracks inside the weld and affects the welding quality, the present invention adopts a technical solution of providing a boss structure at the weld position of the parent material to fill the internal cracks of the weld and improve the weld formation, and providing a stress release groove at the edge of the weld position to release the axial tensile stress applied to the molten pool, which is specifically described as follows: The first shaft-like thin-walled part 1 and / or the second shaft-like thin-walled part 2 is provided with a boss structure 4 along the circumferential direction at one end near the weld position 3. For the case where the weld depth is deep, the cross section of the boss structure 4 is rectangular, and the side of the rectangle near the weld position 3 is located on the same plane as the first welding end face 7. For the case where the weld depth is shallow, the cross section of the boss structure 4 is J-shaped, and the J-shaped structure includes a first rectangular structure arranged on the outer surface of the first shaft-like thin-walled part 1 and a second rectangular structure stacked on top of the first rectangular structure; the width of the second rectangular structure is smaller than the width of the first rectangular structure, and the side of the first rectangular structure near the weld position 3 and the side of the second rectangular structure near the weld position 3 are both located on the same plane as the first welding end face 7.

[0022] Specifically, the shape of the boss structure 4 is mainly affected by the amount of filling material. The rectangular boss has more material, while the "J"-shaped boss has less material. When the weld depth is small, the weld is less concave after welding, and the "J"-shaped boss is selected. When the weld depth is large, the weld is severely concave after welding, and a rectangular boss is selected. During welding, the width of the bottom of the boss structure 4 matches the width of the molten pool at the weld position 3. The bottom of the boss structure 4 is located in the molten pool. The boss structure 4 will be melted at high temperature and filled into the molten pool, playing a role in filling the cracks in the weld.

[0023] A stress relief groove 5 is circumferentially arranged at one end of the first shaft-like thin-walled part 1 and / or the second shaft-like thin-walled part 2 near the weld position 3. The cross-section of the stress relief groove 5 is rectangular or V-shaped. The depth of the stress relief groove 5 is set according to the machining allowance of the part. Generally, the depth of the stress relief groove 5 is less than the machining allowance of the component, and the surface width is 0.3-2mm. During welding, there is a gap between the side of the opening of the stress relief groove 5 near the weld position 3 and the edge of the molten pool. The stress relief groove 5 on the side of the weld can reduce the axial tensile stress exerted on the molten pool by the cooling and contraction of the parent material during the cooling and solidification of the welding molten pool.

[0024] Through the above-mentioned solution of matching the stress release groove 5 with the boss structure 4, the internal stress of welding can be reduced without increasing the process flow and only slightly changing the welding parameters, thereby reducing the probability of crack formation inside the weld.

[0025] Example 1 The existing soft magnetic alloy-stainless steel dissimilar metal welds are mainly designed as butt joints or bottom lock structures with different wall thicknesses according to the use requirements. During the welding process, the parent material is heated and melted, and then quickly cooled and solidified after the heat source leaves. The molten pool is subjected to tensile stress along the axial direction, and there is not enough material in the molten pool to fill the gaps. The combined effect of the two causes cracks in the weld.

[0026] In view of the above problems, this embodiment discloses a welding structure for improving the stress state of soft magnetic alloy-stainless steel dissimilar metal welding, such as Figure 1-3 As shown, a circle of rectangular boss structure is added to the stainless steel ring, and rectangular stress release grooves are set on the side of the soft magnetic alloy near the weld and the outer side of the boss to improve the stress state of the soft magnetic alloy-stainless steel dissimilar metal welding.

[0027] Among them, the depth of the stress relief groove is set according to the machining allowance of the part. Generally, the depth of the stress relief groove is less than the machining allowance of the component, and the surface width is 0.3~2mm. The stainless steel boss is set to a rectangle with a cross section of 2×1, and the boss width is changed according to the width of the molten pool.

[0028] Example 2 This embodiment discloses a welding structure for improving the stress state of soft magnetic alloy-stainless steel dissimilar metal welding, as a variation of embodiment 1, such as Figure 4-6 As shown in the figure, a circle of "J"-shaped boss structure is added to the stainless steel ring, and a "V"-shaped stress relief groove is set on the side of the soft magnetic alloy near the weld and the outer side of the boss to improve the stress state of the soft magnetic alloy-stainless steel dissimilar metal welding. Based on Example 1, the boss shape is changed to a "J" type according to the residual height of the molten pool and the transition state of the parent material.

[0029] The present invention reduces the axial tensile stress imposed on the molten pool by the cooling and contraction of the parent material during the cooling and solidification of the welding molten pool by means of stress release grooves on both sides of the weld. The stainless steel end boss is melted and filled into the end face of the joint during the welding process, so that there is more metal in the weld to fill the internal cracks of the weld. The qualified rate of dissimilar metal welding is improved. The welding structure of the present invention for improving the stress state of dissimilar metal welding of soft magnetic alloy and stainless steel reduces the internal stress of the weld and reduces the probability of internal crack formation in the weld without increasing the process flow and only slightly changing the welding parameters.

[0030] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A welding structure of thin-walled parts of dissimilar metal shafts, characterized in that: It comprises a first shaft-like thin-walled component (1) and a second shaft-like thin-walled component (2), wherein a first welding end surface (7) of the first shaft-like thin-walled component (1) is used to fit with a second welding end surface (6) of the second shaft-like thin-walled component (2) to form a welding seam position (3); The first shaft-like thin-walled part (1) and the second shaft-like thin-walled part (2) are made of dissimilar metals; one end of the first shaft-like thin-walled part (1) and / or the second shaft-like thin-walled part (2) close to the weld position (3) is provided with a boss structure (4) along the circumferential direction; and one end of the first shaft-like thin-walled part (1) and / or the second shaft-like thin-walled part (2) close to the weld position (3) is provided with a stress relief groove (5) along the circumferential direction.

2. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: One of the first shaft-like thin-walled part (1) and the second shaft-like thin-walled part (2) is a stainless steel shaft-like thin-walled part, and the other of the first shaft-like thin-walled part (1) and the second shaft-like thin-walled part (2) is a soft magnetic alloy shaft-like thin-walled part.

3. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: The cross-section of the boss structure (4) is a rectangle, and a side of the rectangle close to the weld position (3) is located on the same plane as the first welding end surface (7).

4. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: The cross section of the boss structure (4) is J-shaped, and the J-shaped structure comprises a first rectangular structure arranged on the outer surface of the first shaft-type thin-walled part (1) and a second rectangular structure stacked on top of the first rectangular structure; The width of the second rectangular structure is smaller than the width of the first rectangular structure, and the side of the first rectangular structure close to the weld position (3) and the side of the second rectangular structure close to the weld position (3) are both located on the same plane as the first welding end surface (7).

5. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: During welding, the width of the bottom of the boss structure (4) matches the width of the molten pool at the weld position (3), and the bottom of the boss structure (4) is located in the molten pool.

6. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: The cross section of the stress release groove (5) is rectangular.

7. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: The cross section of the stress release groove (5) is V-shaped.

8. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: The depth of the stress release groove (5) is less than the machining allowance of the second shaft-type thin-walled part (2).

9. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1 is characterized in that: The surface width of the stress release groove (5) is 0.3-2 mm.

10. The welding structure of thin-walled parts of dissimilar metal shafts according to claim 1, characterized in that: During welding, a gap exists between the side of the opening of the stress release groove (5) close to the weld position (3) and the edge of the molten pool.

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