Stainless steel composite steel T-shaped joint welding structure and mechanical property testing device

Abstract

The invention discloses a stainless steel composite steel T-shaped joint welding structure which is characterized in that stainless steel composite steel comprises base layer low alloy steel and composite layer stainless steel, a groove of a stainless steel composite steel T-shaped joint is a 60-degree V-shaped groove, and local composite layer stainless steel is milled off or not milled off before welding; the welding seam sequentially comprises a base layer area, a transition layer area and a multi-layer area from inside to outside. The thickness of the multi-layer area is not less than that of the multi-layer stainless steel; and the thickness of the transition layer area is not less than 2mm. Meanwhile, the invention discloses a mechanical property testing device for the stainless steel composite steel T-shaped joint welding structure. The invention provides a stainless steel composite steel T-shaped joint welding structure suitable for structural engineering, provides a testing device convenient for testing the mechanical property of a stainless steel composite steel T-shaped joint, and fills the technical gap.

Description

Technical Field

[0001] The invention relates to the field of structural engineering, and in particular to a stainless steel composite steel T-joint welding structure and a mechanical property testing device. Background Art

[0002] In the face of the corrosion problem of steel structures, the traditional method mainly improves its corrosion resistance through anti-corrosion coatings, but there are mainly the following problems: the cost of anti-corrosion coatings is high, the durability of the coatings themselves is not easy to be guaranteed, and the spraying of anti-corrosion coatings in offshore or marine engineering is prone to water pollution and high environmental risks. In order to solve the problems of anti-corrosion coatings, new materials represented by high-performance steels have begun to receive more and more attention, such as weathering steel and new stainless steels. Among them, the surface oxide layer of weathering steel will gradually turn black and brown as the corrosion time increases, seriously affecting the appearance. Stainless steel contains a large amount of alloy elements such as Ni and Cr, and its overall material cost is high, which is not conducive to large-scale engineering applications in the construction field. Against the above background, new composite steels have emerged. Through the composite process, stainless steel and low-alloy steel with different characteristics are combined together. While retaining the performance advantages of the two metals, the overall production cost of the material can be reduced, and high performance (such as corrosion resistance) and low cost can be well balanced.

[0003] Due to the special nature of double-layer metal, stainless steel composite steel has large differences in physical properties and chemical composition between the base and composite materials. Especially for special joints (such as T-joints), carbon element migration and diffusion, alloy element dilution, and uneven deformation of the base and composite due to differences in physical properties are prone to occur, causing deterioration of the performance of the welded joint, thereby affecting the welding quality of the entire component. In addition, in addition to butt joints, common structural components and nodes in structural engineering often involve T-joint connections, while there are many structures related to stainless steel composite steel butt joints in current standards and literature, and there are no welding structure recommendations for stainless steel composite steel T-shaped special joints.

[0004] Therefore, it is necessary to develop a new type of stainless steel composite steel T-joint welding structure and mechanical properties testing equipment to fill this technical gap. Summary of the invention

[0005] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides a stainless steel composite steel T-joint welding structure and a mechanical property testing device, proposes a stainless steel composite steel T-joint welding structure suitable for structural engineering, and proposes a testing device that is convenient for testing the mechanical properties of stainless steel composite steel T-joints, filling this technical gap.

[0006] Technical solution: The stainless steel composite steel T-joint welding structure of the present invention is characterized in that the stainless steel composite steel includes a base low alloy steel and a composite stainless steel, the groove form of the stainless steel composite steel T-joint is a 60° V-shaped groove, the partial composite stainless steel is milled off or not before welding, and the weld includes a base area, a transition layer area and a composite area from the inside to the outside in sequence; the thickness of the composite area is not less than the thickness of the composite stainless steel; the thickness of the transition layer area is not less than 2 mm.

[0007] Among them, when the local composite stainless steel is milled off before welding, the base low alloy steel in the corresponding area is exposed, and the milling range includes the transition layer area and the base area, and does not exceed the composite area.

[0008] Furthermore, the base area is welded with corresponding base low alloy steel welding materials that match the strength of the base low alloy steel, the composite area is welded with corresponding composite stainless steel welding materials that match the strength of the composite stainless steel, and the transition layer area is also welded with corresponding composite stainless steel welding materials.

[0009] Among them, when the local composite stainless steel is not milled off before welding, the composite metal in the welding area is not processed in any way, and the entire weld area is directly welded with the corresponding composite stainless steel welding material that matches the strength of the composite stainless steel.

[0010] The T-joint specimen of the stainless steel composite steel T-joint welding structure of the present invention is characterized in that it includes a T-joint specimen, the T-joint specimen includes a base layer of low alloy steel, a composite layer of stainless steel and a weld, the upper end cross-section of the vertical plate of the T-joint specimen is enlarged, the vertical plate is provided with screw holes for loading connection, and the width of the enlarged cross-section of the vertical plate is greater than the width of the plate at the connecting weld.

[0011] The mechanical property testing device of the present invention is characterized by being a device for testing the mechanical properties of a T-joint specimen.

[0012] The mechanical property testing device of the present invention is characterized in that it includes a test bench, a thick cover plate is provided on the test bench, a pad is provided at the bottom of the thick cover plate, and the thick cover plate is connected to the test bench through high-strength bolts at both ends; the T-joint specimen is located between the thick cover plate and the ear plate welding fixture, and the ear plate welding fixture is connected to the jack.

[0013] Among them, the thick cover plate has a central opening with a hole size of l1×l2, l1 is parallel to the length direction of the thick plate and is 3 times the thickness of the stainless steel composite plate, l2 is perpendicular to the length direction of the thick plate and the value should be greater than the width of the expanded section of the upper end of the vertical plate of the T-joint specimen, and bolt holes are opened at both ends of the thick cover plate.

[0014] The ear plate welding tooling comprises a flat plate and two sets of double ear plates, the two sets of double ear plates are respectively welded on both sides of the flat plate and are perpendicular to each other, and are respectively used to connect the T-joint specimen and the jack.

[0015] Among them, a bolt hole is opened in the center of the pad, the hole diameter is the same as the bolt hole diameter at both ends of the thick cover plate, and the thickness of the pad is the same as the thickness of the T-joint specimen; the test bench is located on the floor of the laboratory.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention proposes a stainless steel composite steel T-joint welding structure, which provides welding technology support for composite steel components and fills this technical gap. The present invention can expand the application of composite steel to steel pipe nodes, etc., and promote the application of stainless steel composite steel in structural engineering. Compared with the traditional stainless steel composite steel butt joint welding structure, the T-joint welding structure proposed by the present invention reduces the types of welding materials, reduces welding costs and the risk of misuse or mixing of welding materials. Through the technical solution of the present invention, it is easy to obtain the mechanical performance of stainless steel composite steel T-joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a T-joint groove structure 1 of the present invention;

[0018] Figure 2 It is a structural schematic diagram of the T-joint groove structure 2 of the present invention;

[0019] Figure 3 It is a structural schematic diagram of a T-joint welding structure 1 of the present invention;

[0020] Figure 4 It is a structural schematic diagram of the T-joint welding structure 2 of the present invention;

[0021] Figure 5 It is a schematic structural diagram of a T-joint specimen of the present invention;

[0022] Figure 6 It is a structural schematic diagram of the mechanical property testing device of the present invention in a vertical loading state;

[0023] Figure 7 It is a structural schematic diagram of the mechanical property testing device of the present invention in a horizontal loading state;

[0024] Figure 8 It is a structural schematic diagram of the test bench of the present invention;

[0025] Fig. 9 It is a structural schematic diagram of a thick cover plate of the present invention;

[0026] Fig.10 It is a structural schematic diagram of the ear plate welding tool of the present invention;

[0027] Fig.11 It is a structural schematic diagram of the pad of the present invention;

[0028] In the figure, 1 is a T-joint specimen; 2 is an ear plate welding tool; 3 is a thick cover plate; 4 is a pad; 5 is a high-strength bolt; 6 is a test bench; 7 is a test room floor; 8 is a jack; 11 is a vertical plate; 12 is a weld; 13 is a base low alloy steel; 14 is a composite stainless steel; 15 is the corresponding base low alloy steel welding material; 16 is the corresponding composite stainless steel welding material; 17 is a base area; 18 is a transition layer area; 19 is a composite area. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0030] The stainless steel composite steel T-joint welding structure of the present invention comprises a base low alloy steel 13 and a composite stainless steel 14. The groove form of the stainless steel composite steel T-joint is a 60° V-shaped groove. The composite stainless steel 14 is partially milled off or not before welding. The weld 12 comprises a base region 17, a transition layer region 18 and a composite region 19 from the inside to the outside in sequence. The thickness of the composite region 19 is not less than the thickness of the composite stainless steel 14. The thickness of the transition layer region 18 is not less than 2 mm.

[0031] T-joint welding structure 1: When the local composite stainless steel 14 is milled off before welding, the base low alloy steel 13 in the corresponding area is exposed, and the milling range includes the transition layer area 18 and the base area 17, and does not exceed the composite area 19. The base area 17 is welded with the corresponding base low alloy steel welding material 15 that matches the strength of the base low alloy steel 13, the composite area 19 is welded with the corresponding composite stainless steel welding material 16 that matches the strength of the composite stainless steel 14, and the transition layer area 18 is also welded with the corresponding composite stainless steel welding material 16.

[0032] T-joint welding structure 2: When the local composite stainless steel 14 is not milled off before welding, the composite metal in the welding area is not processed in any way, and the entire weld area is directly welded with the corresponding composite stainless steel welding material 16 that matches the strength of the composite stainless steel 14.

[0033] The T-joint specimen of the stainless steel composite steel T-joint welding structure of the present invention includes a T-joint specimen 1, which includes a base low alloy steel 13, a composite stainless steel 14 and a weld 12. The upper end cross-section of the vertical plate 11 of the T-joint specimen 1 is enlarged, and the vertical plate 11 is provided with a screw hole for loading connection. The width of the enlarged cross-section of the vertical plate 11 is greater than the width of the plate at the connecting weld.

[0034] The mechanical property testing device of the present invention is a device for testing the mechanical properties of a T-joint specimen. It includes a test bench 6, a thick cover plate 3 is provided on the test bench 6, a pad 4 is provided at the bottom of the thick cover plate 3, and the thick cover plate 3 is connected to the test bench 6 through high-strength bolts 5 at both ends; the T-joint specimen 1 is located between the thick cover plate 3 and the ear plate welding fixture 2, and the ear plate welding fixture 2 is connected to the jack 8. Among them, the thick cover plate 3 has a central opening, and the hole size is l1×l2, l1 is parallel to the length direction of the thick plate, and is 3 times the thickness of the stainless steel composite plate, l2 is perpendicular to the length direction of the thick plate, and the value should be greater than the width of the expanded cross-section of the upper end of the vertical plate of the T-joint specimen, and bolt holes are provided at both ends of the thick cover plate 3. The ear plate welding fixture 2 includes a flat plate and two groups of double ear plates, and the two groups of double ear plates are respectively welded on both sides of the flat plate and are perpendicular to each other, and are respectively used to connect the T-joint specimen 1 and the jack 8. A bolt hole is provided at the center of the pad 4 , the diameter of which is the same as that of the bolt holes at both ends of the thick cover plate 3 , and the thickness of the pad 4 is the same as that of the T-joint specimen 1 ; the test bench seat 6 is located on the test room floor 7 .

[0035] The present invention proposes a stainless steel composite steel T-joint welding structure, which provides welding technology support for composite steel components and fills this technical gap. The present invention can expand the application of composite steel to steel pipe nodes, etc., and promote the application of stainless steel composite steel in structural engineering. Compared with the traditional stainless steel composite steel butt joint welding structure, the T-joint welding structure proposed in the present invention reduces the types of welding materials, reduces welding costs and the risk of misuse or mixing of welding materials. Through the technical solution of the present invention, it is easy to obtain the mechanical performance of stainless steel composite steel T-joints.

Claims

1. Stainless steel composite steel T-joint welding structure, characterized by: The stainless steel composite steel comprises a base low alloy steel (13) and a composite stainless steel (14); the groove of the stainless steel composite steel T-joint is a 60° V-shaped groove; a part of the composite stainless steel (14) is milled off or not before welding; the weld (12) comprises a base region (17), a transition layer region (18) and a composite region (19) from the inside to the outside; the thickness of the composite region (19) is not less than the thickness of the composite stainless steel (14); and the thickness of the transition layer region (18) is not less than 2 mm.

2. The stainless steel composite steel T-joint welding structure according to claim 1, characterized in that: When the local composite stainless steel (14) is milled off before welding, the base low alloy steel (13) in the corresponding area is exposed, and the milling range includes the transition layer area (18) and the base area (17), and does not exceed the composite area (19).

3. The stainless steel composite steel T-joint welding structure according to claim 2, characterized in that: The base region (17) is welded using a corresponding base low alloy steel welding material (15) whose strength matches that of the base low alloy steel (13); the composite region (19) is welded using a corresponding composite stainless steel welding material (16) whose strength matches that of the composite stainless steel (14); and the transition layer region (18) is also welded using a corresponding composite stainless steel welding material (16).

4. The stainless steel composite steel T-joint welding structure according to claim 1, characterized in that: When the local composite stainless steel (14) is not milled off before welding, the composite metal in the welding area is not processed in any way, and the entire weld area is directly welded using a corresponding composite stainless steel welding material (16) that matches the strength of the composite stainless steel (14).

5. The T-joint test piece of the stainless steel composite steel T-joint welding structure according to any one of claims 1 to 4, characterized in that: The invention comprises a T-shaped joint specimen (1), wherein the T-shaped joint specimen (1) comprises a base layer of low alloy steel (13), a composite layer of stainless steel (14) and a weld (12), wherein the upper end cross section of a vertical plate (11) of the T-shaped joint specimen (1) is enlarged, and a screw hole for loading connection is provided on the vertical plate (11), and the width of the enlarged cross section of the vertical plate (11) is greater than the width of the plate at the connection weld.

6. Mechanical properties testing device, characterized in that: A device for testing the mechanical properties of the T-joint specimen described in claim 5.

7. The mechanical properties testing device according to claim 6, characterized in that: The invention comprises a test bench seat (6), a thick cover plate (3) is provided on the test bench seat (6), a pad (4) is provided at the bottom of the thick cover plate (3), and the thick cover plate (3) is connected to the test bench seat (6) via high-strength bolts (5) at both ends; the T-shaped joint test piece (1) is located between the thick cover plate (3) and the ear plate welding fixture (2), and the ear plate welding fixture (2) is connected to a jack (8).

8. The mechanical properties testing device according to claim 7, characterized in that: The thick cover plate (3) has a central opening with a hole size of l1×l2, l1 is parallel to the length direction of the thick plate and is 3 times the thickness of the stainless steel composite plate, l2 is perpendicular to the length direction of the thick plate and should be greater than the width of the expanded cross-section of the upper end of the vertical plate of the T-joint specimen, and bolt holes are provided at both ends of the thick cover plate (3).

9. The mechanical properties testing device according to claim 8, characterized in that: The ear plate welding tool (2) comprises a flat plate and two sets of double ear plates. The two sets of double ear plates are respectively welded to both sides of the flat plate and are perpendicular to each other, and are respectively used to connect the T-joint specimen (1) and the jack (8).

10. The mechanical properties testing device according to claim 9, characterized in that: The center of the pad (4) is provided with a bolt hole, the diameter of which is the same as that of the bolt holes at both ends of the thick cover plate (3); the thickness of the pad (4) is the same as that of the T-joint test piece (1); and the test bench (6) is located on the test room floor (7).

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