Welding process of high manganese and high aluminum steel anchor chains

Abstract

This invention discloses a welding process for high-manganese, high-alumina steel anchor chains, comprising the following steps: material preparation; ring bending; beveling; self-fusion root pass welding; filler layer welding on the front of the chain links; root cleaning; filler layer welding on the back of the chain links; and inspection. This invention uses high-manganese, high-alumina steel to manufacture the anchor chain. Due to the excellent impact resistance of high-manganese, high-alumina steel, it can effectively absorb the impact energy from the movement of engineering equipment in harsh marine environments, significantly improving the service life of the anchor chain and ensuring its safety during use. The welding process for high-manganese, high-alumina steel anchor chains provided by this invention solves many problems in the welding of high-manganese, high-alumina steel anchor chains in the prior art and is more suitable for the production of high-manganese, high-alumina steel anchor chains.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding and marine engineering technology, and more specifically, to a welding process for high-manganese, high-aluminum steel anchor chains. Background Technology

[0002] Anchor chains are the chains connecting anchors to ship hulls and marine engineering equipment, playing a crucial role in the safety of offshore operations. As marine engineering continues to expand into deeper waters, the marine environment becomes increasingly harsh. In addition to static tensile forces, chains are frequently subjected to impact tensile forces. Therefore, the impact resistance requirements for chains in various facilities are constantly rising. Traditional methods for improving the overall performance of chains mainly involve increasing chain specifications or strength grades. However, the diameter of chain links in marine facilities is constrained by many factors, and higher strength chains often come with a series of problems such as reduced plasticity, decreased impact resistance, and poor weldability.

[0003] High-manganese and high-aluminum steel, a newly developed steel material in recent years, has an austenitic microstructure. In addition to dislocation slip, its plastic deformation mode is also accompanied by twin-induced plastic deformation, which gives it excellent plasticity, tensile strength and impact resistance, and it is expected to be used in marine engineering.

[0004] Among anchor chain manufacturing methods, welded anchor chains are widely used due to their good quality and moderate manufacturing cost. Currently, highly automated flash welding is the mainstream production method for most anchor chains. However, this welding method is not suitable for welding high-manganese, high-alumina steel anchor chains. The main reason is that high-manganese, high-alumina steel contains aluminum and high levels of Mn and C. Flash butt welding, due to the lack of gas protection and the large heat input to the core, generates a large amount of smoke and dust during welding. Furthermore, the presence of upsetting force at the ends can cause misalignment, leading to increased anchor chain deformation and affecting joint strength. Therefore, flash butt welding is not suitable for the production of high-manganese, high-alumina steel anchor chains.

[0005] In conclusion, the welding methods used in the existing technology for welding high-manganese and high-alumina steel anchor chains are not suitable for the production of high-manganese and high-alumina steel anchor chains. Summary of the Invention

[0006] This invention provides a welding process for high-manganese, high-alumina steel anchor chains suitable for their production.

[0007] To achieve the above objectives, the present invention provides a welding process for high-manganese, high-aluminum steel anchor chains, comprising the following steps:

[0008] Material preparation steps: Select high manganese and high aluminum steel bars as raw materials. The specifications of the high manganese and high aluminum steel bars are Φ8~Φ30mm, yield strength ≥400MPa, tensile strength ≥800MPa, elongation ≥40%, and reduction of area ≥40%.

[0009] Bending steps: Bending high manganese and high aluminum steel bars on a bending machine. First, bend the high manganese and high aluminum steel bars around the bending mandrel into a U-shape with the bottom horizontal. Then, bend the two sides of the U-shape around the bending mandrel to the middle. Bring the two end faces of the chain ring closer to each other, ensuring that the gap between the two end faces does not exceed 2mm.

[0010] Beveling process steps: Beveling both ends of the chain link, grinding the bevel and at least 20mm on both sides to remove surface rust and water;

[0011] Self-fusion root pass welding steps: First, perform root pass welding using argon arc welding with self-fusion method. Both the front and back of the chain link are protected with argon-rich gas.

[0012] Welding steps for the filler layer on the front of the chain link: The first filler weld is performed on the front of the chain link. Both the front and back of the chain link are welded using argon-rich gas. The welding material is solid welding wire with the same composition as the base material. After completing this pass, the next pass is performed until the weld reinforcement is higher than the surface of the chain link.

[0013] Cleaning steps: Clean the back of the chain link to remove carbon deposits and defects from the weld root. Grind the cleaned bevel and thoroughly remove the slag and burrs from the bevel and both sides after cleaning until the metal luster is exposed. Keep the width and depth of the bevel consistent along the direction of the weld.

[0014] Welding steps for the filler layer on the back of the chain link: The first filler weld is performed on the back of the chain link. Both the front and back of the chain link are welded using argon-rich gas shielding. The welding material is solid welding wire with the same composition as the base material. After completing this pass, the next pass is performed until the weld reinforcement is higher than the surface of the chain link.

[0015] Inspection steps: Inspect the gap between the two ends of the bent chain link and inspect the porosity and slag inclusions at the weld after chain link welding.

[0016] Furthermore, in the autogenous root pass welding step, the process parameters for argon arc welding include: gas flow rate of 15-20 L / min, welding current of 75-95 A, arc voltage of 18-22 V, and air cooling.

[0017] Furthermore, in the filler layer welding steps on the front and back of the chain links, the welding process parameters include: chain link preheating temperature of 100℃, welding current of 110~120A, arc voltage of 18~22V, and air cooling.

[0018] The technical effects achievable by this invention are as follows: 1. The anchor chain of this invention is formed by cold working, which is more efficient, convenient, and energy-saving than conventional hot working ring forming; 2. The welding process used in this invention employs argon arc welding, with argon gas used as a protective gas on both sides of the weld during welding, fully ensuring weld quality and effectively solving the problems of excessive carbon equivalent and the generation of a large amount of manganese dust during welding; 3. This invention uses solid core welding wire for welding, making the weld structure the same as the base structure, both being austenitic structures, ensuring excellent mechanical properties of the weld metal, reducing the solidification temperature range, and avoiding the generation of solidification cracks; 4. Furthermore, since this new high-manganese high-aluminum steel has excellent plastic deformation capacity, the strength grade of the anchor chain can be improved by pre-stretching; 5. The front and back welding of the chain links are performed on the two sides of the chain link respectively. This method can increase the strength and reliability of the weld, and also reduce welding deformation and stress. 6. This invention uses high-manganese, high-aluminum steel to manufacture anchor chains. Due to the excellent impact resistance of high-manganese, high-aluminum steel, it can effectively absorb the impact energy from the movement of engineering equipment in harsh marine environments, significantly improving the service life of the anchor chain and ensuring its safety during use. In summary, the welding process for high-manganese, high-aluminum steel anchor chains provided by this invention solves many problems in the welding of high-manganese, high-aluminum steel anchor chains in existing technologies and is more suitable for the production of high-manganese, high-aluminum steel anchor chains. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of the welding process for a high-manganese, high-aluminum steel anchor chain according to an embodiment of the present invention.

[0020] Figure 2 This is a bending diagram of a high-manganese, high-aluminum steel anchor chain according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the beveled joint structure of the high-manganese and high-aluminum steel anchor chain welded joint in an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the finished chain links after welding of the high-manganese and high-aluminum steel anchor chain according to an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the U-shaped chain stretching fixture in an embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0025] See Figure 1 As shown in the embodiment of the present invention, a welding process for a high-manganese, high-aluminum steel anchor chain is provided, characterized by comprising the following steps:

[0026] Material cutting step S10: Select high manganese and high aluminum steel bars as raw materials. The specifications of the high manganese and high aluminum steel bars are Φ8~Φ30mm, yield strength ≥400MPa, tensile strength ≥800MPa, elongation ≥40%, and reduction of area ≥40%.

[0027] Bending step S20: Bending the high manganese and high aluminum steel bar on the bending machine. First, bend the high manganese and high aluminum steel bar around the bending mandrel into a U-shape with the bottom horizontal. Then, bend the two sides of the U-shape around the bending mandrel to the middle. Bring the two end faces of the chain ring closer to each other to ensure that the gap between the two end faces does not exceed 2mm.

[0028] Beveling step S30: Beveling the two ends of the chain link, grinding the bevel and at least 20mm on both sides to remove surface rust and water;

[0029] Self-fusion root pass welding step S40: First, perform root pass welding. The welding method is argon arc welding self-fusion root pass. Both the front and back of the chain link are protected with argon-rich gas.

[0030] Step S50: Welding the filler layer on the front of the chain link: Weld the first filler weld on the front of the chain link. Both the front and back of the chain link are welded with argon-rich gas. The welding material is solid welding wire with the same composition as the base material. After completing this pass, proceed to the next pass until the weld reinforcement is higher than the surface of the chain link.

[0031] Root cleaning step S60: Root cleaning is performed on the back of the chain link to remove carbon deposits and defects in the weld root. The cleaned bevel is then ground and the slag and burrs on both sides of the bevel after root cleaning are thoroughly removed until the metal luster is exposed. The width and depth of the bevel after root cleaning are kept consistent along the direction of the weld.

[0032] Step S70: Welding the filler layer on the back of the chain link: Weld the first filler weld on the back of the chain link. Welding is performed on both the front and back of the chain link using argon-rich gas. Welding material is solid welding wire with the same composition as the base material. After completing this pass, we proceed to the next pass until the weld reinforcement is higher than the surface of the chain link.

[0033] Inspection step S80: Inspect the gap between the two ends of the bent chain link and inspect the porosity and slag inclusions at the weld after chain link welding.

[0034] The technical solution of this invention utilizes a novel high-manganese, high-aluminum steel bar in the ring bending step, which possesses excellent cold-bending performance. It can be bent into qualified chain links without hot working, significantly saving energy. The beveling step prevents defects during welding from affecting the mechanical properties of the weldment. The combined use of the self-fusion root pass welding step, the filler layer welding step on the front of the chain link, and the filler layer welding step on the back of the chain link effectively solves the problems of excessive carbon equivalent and the generation of large amounts of manganese fumes during welding, while simultaneously showcasing the excellent plasticity and impact resistance of this novel high-manganese, high-aluminum steel.

[0035] The technical effects achievable by this invention are as follows: 1. The anchor chain of this invention is formed by cold working, which is more efficient, convenient, and energy-saving than conventional hot working ring forming; 2. The welding process used in this invention employs argon arc welding, with argon gas used as a protective gas on both sides of the weld during welding, fully ensuring weld quality and effectively solving the problems of excessive carbon equivalent and the generation of a large amount of manganese dust during welding; 3. This invention uses solid core welding wire for welding, making the weld structure the same as the base structure, both being austenitic structures, ensuring excellent mechanical properties of the weld metal, reducing the solidification temperature range, and avoiding the generation of solidification cracks; 4. Furthermore, since this new high-manganese high-aluminum steel has excellent plastic deformation capacity, the strength grade of the anchor chain can be improved by pre-stretching; 5. The front and back welding of the chain links are performed on the two sides of the chain link respectively. This method can increase the strength and reliability of the weld, and also reduce welding deformation and stress. 6. This invention uses high-manganese, high-aluminum steel to manufacture anchor chains. Due to the excellent impact resistance of high-manganese, high-aluminum steel, it can effectively absorb the impact energy from the movement of engineering equipment in harsh marine environments, significantly improving the service life of the anchor chain and ensuring its safety during use. In summary, the welding process for high-manganese, high-aluminum steel anchor chains provided by this invention solves many problems in the welding of high-manganese, high-aluminum steel anchor chains in existing technologies and is more suitable for the production of high-manganese, high-aluminum steel anchor chains.

[0036] Preferably, in the autogenous root pass welding step, the process parameters for argon arc welding include: gas flow rate of 15-20 L / min, welding current of 75-95 A, arc voltage of 18-22 V, and air cooling.

[0037] Preferably, in the filler layer welding steps on the front and back of the chain links, the welding process parameters include: chain link preheating temperature of 100°C, welding current of 110-120A, arc voltage of 18-22V, and air cooling.

[0038] This embodiment uses the processing and welding of a new type of high-manganese, high-aluminum steel anchor chain with a diameter of 12.5mm as an example, following the procedure as follows: Figure 2 As shown, it is cold-bent into anchor chain 10a, and according to... Figure 3As shown, the two ends of the anchor chain are machined into 30° double V-shaped welding bevels 10b.

[0039] The root pass was performed using argon arc welding, and the fill pass was performed using argon arc welding with a 2.4mm diameter solid welding wire. Argon gas was used as a shielding gas on the back of the anchor chain, with a gas flow rate of 15-20L / min. Specific welding parameters are shown in Table 1.

[0040] Table 1:

[0041]

[0042] Finished chain links after welding Figure 4 As shown, the weld surface is well fused, and no welding defects such as cracks, porosity, or slag inclusions are observed.

[0043] According to such Figure 5 The U-shaped fixture shown fixes a certain number of chains and loads them at a tensile speed of 10.0 mm / min. The tensile displacement and tensile load are continuously measured until the chain breaks. The breaking force and elongation after fracture (tensile properties of welded joint) of the Φ12.5mm chain are shown in Table 2.

[0044] Table 2:

[0045] Chain link size / mm Breaking force / KN Elongation after fracture / % fracture location 12.5×45×75 750 30 Chain link shoulder

[0046] The welding process of the high-manganese and high-alumina steel anchor chain in this embodiment adopts cold bending forming, argon arc self-melting for the root pass, and then adding solid welding wire for welding. Combined with low heat input and front and back protection, it effectively solves the problems of excessive carbon equivalent and the generation of a large amount of manganese dust during welding. At the same time, it brings out the excellent plasticity and impact resistance of the new high-manganese and high-alumina steel itself, and is expected to replace anchor chain steel of the same strength level in future marine engineering.

[0047] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] Of course, the above are preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the basic principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A welding process for a high-manganese, high-aluminum steel anchor chain, characterized in that, Includes the following steps: Material preparation steps: Select high-manganese and high-aluminum steel bars as raw materials. The specifications of the high-manganese and high-aluminum steel bars are Φ8~Φ30mm, yield strength ≥400MPa, tensile strength ≥800MPa, elongation ≥40%, and reduction of area ≥40%. Bending steps: Bending high manganese and high aluminum steel bars on a bending machine. First, bend the high manganese and high aluminum steel bars around the bending mandrel into a U-shape with the bottom horizontal. Then, bend the two sides of the U-shape around the bending mandrel to the middle. Bring the two end faces of the chain ring closer to each other, ensuring that the gap between the two end faces does not exceed 2mm. Beveling process steps: Beveling both ends of the chain link, grinding the bevel and at least 20mm on both sides to remove surface rust and water; Self-fusion root pass welding steps: First, perform root pass welding using argon arc welding. Both the front and back sides of the chain link are protected with argon-rich gas. The argon arc welding process parameters include: gas flow rate of 15~20L / min, welding current of 75~95A, arc voltage of 18~22V, and air cooling. Welding steps for the filler layer on the front of the chain link: The first filler weld is performed on the front of the chain link. Both the front and back of the chain link are welded using argon-rich gas shielding. The welding material is solid welding wire with the same composition as the base material. After completing this pass, the next pass is performed until the weld reinforcement is higher than the surface of the chain link. The welding process parameters include: chain link preheating temperature of 100℃, welding current of 110~120A, arc voltage of 18~22V, and air cooling. Cleaning steps: Clean the back of the chain link to remove carbon deposits and defects from the weld root. Grind the cleaned bevel and thoroughly remove the slag and burrs from the bevel and both sides after cleaning until the metal luster is exposed. The width and depth of the bevel after cleaning should be consistent along the direction of the weld. Welding steps for the filler layer on the back of the chain link: The first filler weld is performed on the back of the chain link. Both the front and back of the chain link are welded using argon-rich gas shielding. The welding material is solid welding wire with the same composition as the base material. After completing this pass, the next pass is performed until the weld reinforcement is higher than the surface of the chain link. Inspection steps: Inspect the gap between the two ends of the bent chain link and inspect the porosity and slag inclusions at the weld after chain link welding.

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