Welding method for corrosion-resistant steel with nano coating and low-alloy high-strength structural steel

Abstract

The invention relates to the technical field of steel and iron material welding, in particular to a welding method for corrosion-resisting steel with a nanometer coating and low-alloy high-strength structural steel. According to the method, high-quality welding is achieved through accurate welding material type selection, welding environment control and welding process scheme selection according to the difference between the mechanical property and the corrosion resistance of two kinds of special steel. A welding material combination matched with the toughness of a base material is selected, a corresponding groove structure and assembly precision requirements are designed according to the welding position and the joint form, control line energy is controlled through multi-layer and multi-pass welding, and measures such as preheating, back gouging and wind shielding are taken according to specific working conditions. According to the method, low-temperature impact toughness and welding efficiency can be considered, various joint forms such as butt joint and T-shaped angle joint are adapted, and all-position welding such as horizontal, vertical, transverse and pitching can be achieved, the process stability is good, the applicability is high, and the method can be widely applied to large-scale building engineering, especially steel structure construction in the coastal corrosive environment.

Description

Technical Field

[0001] This invention relates to the field of steel material welding technology, specifically to a welding method for corrosion-resistant steel with nano-coating and low-alloy high-strength structural steel. Background Technology

[0002] In large-scale engineering construction, low-alloy high-strength structural steel, such as Q355GJD high-strength structural steel, has become a key material for core load-bearing components due to its superior weldability, seismic resistance, and reliability. However, in humid or corrosive environments such as coastal areas, low-alloy high-strength structural steel is prone to corrosion, which seriously affects the service life and safety stability of the steel structure. Therefore, higher requirements are placed on the corrosion resistance of steel structures.

[0003] IMEC corrosion-resistant steel with nano-coating adopts a coating nano-modification treatment technology. Through a high-quality substrate treatment process and excellent surface sealing, the protective function of nano-materials can effectively block the contact between corrosive media and the steel plate substrate, significantly delaying the corrosion process. It can maintain good mechanical and corrosion resistance properties for a long time in harsh environments, providing an ideal material for steel structure applications in corrosive environments.

[0004] Currently, large-scale construction projects often require the welding of dissimilar materials, such as corrosion-resistant steel with nano-coatings and low-alloy high-strength structural steel. However, due to differences in the mechanical properties and chemical composition of the two types of steel, and the sensitivity of the nano-coating to welding heat input, traditional welding methods are prone to defects such as poor weld-base mismatch, damage to the nano-coating, and weld cracks, porosity, and lack of fusion, leading to decreased joint mechanical properties and corrosion resistance failure. Existing welding technologies have not yet developed a systematic welding solution for these two dissimilar steel materials, and cannot simultaneously ensure welding quality, efficiency, and structural service safety. Therefore, a highly adaptable and stable welding method is urgently needed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a welding method for corrosion-resistant steel with nano-coating and low-alloy high-strength structural steel. The method is stable, highly adaptable, and can achieve high-quality welding of two dissimilar steels, ensuring that the mechanical properties and corrosion resistance of the joint meet the engineering requirements.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A welding method for corrosion-resistant steel with a nano-coating to low-alloy high-strength structural steel mainly includes the following steps: S1, Substrate selection: Select corrosion-resistant steel with nano-coating and low-alloy high-strength structural steel with preset performance parameters as the substrate; S2, Welding material selection: Select a suitable welding material combination based on the performance parameters of the base material and the welding type. The welding type includes submerged arc welding and gas shielded welding. The welding materials include welding wire-flux combination for submerged arc welding and solid welding wire and flux-cored welding wire for gas shielded welding. S3, Welding Environment Control: Before formal welding, the current ambient temperature and humidity are controlled. If the welding ambient temperature is lower than the preset temperature value or the substrate thickness reaches the preset thickness value, a heating gun is used to uniformly preheat the substrate to be welded. S4, Beveling and Assembly: Based on the welding position and joint type of the substrate to be welded, a suitable beveling structure is adopted and the assembly accuracy is controlled. S5, Welding process implementation: A multi-layer, multi-pass welding process is adopted, and the corresponding welding method, welding materials and parameters are matched according to the welding position and joint type. At the same time, the welding heat input is controlled to complete the welding operation.

[0007] Preferably, in step S1, the nano-coated corrosion-resistant steel has a yield strength Rel ≥ 345 MPa, a tensile strength Rm1 ≥ 490 MPa, an elongation A1 ≥ 20%, and an impact energy of -20℃ KV. 21 ≥120J; The low-alloy high-strength structural steel has a yield strength ReH ≥ 355 MPa, tensile strength Rm2 = 490~610 MPa, elongation A2 ≥ 22%, and impact energy at -20℃ KV. 22 ≥47J.

[0008] Preferably, in step S1, the chemical composition of the low-alloy high-strength structural steel satisfies the following: C≤0.18, Si≤0.55, Mn≤1.60, P≤0.020, S≤0.010, Cr≤0.30, V≤0.150, Nb≤0.070, Ti≤0.035, Ni≤0.30, Cu≤0.30, Als≥0.015, CEV≤0.43.

[0009] Preferably, in step S2, the chemical composition of the solid welding wire includes: C: 0.06~0.15, Si: 0.80~1.15, Mn: 1.40~1.85, P≦0.025, S≦0.025, Ni≦0.15, Cr≦0.15, Cu≦0.50, Mo≦0.15, V≦0.03; The solid welding wire has a tensile strength Rm3 = 490~670MPa, a yield strength Rel3 ≥ 390MPa, an elongation A3 ≥ 22%, and an impact energy of -30℃ KV. 23 ≥47J.

[0010] Preferably, in step S2, the chemical composition of the flux-cored welding wire includes: C≦0.18, Si≦0.90, Mn≦2.0, P≦0.03, S≦0.03, Ni≦0.50, Cr≦0.2, Mo≦0.30, V≦0.08; The flux-cored welding wire has a tensile strength Rm4 = 490~670MPa, a yield strength Rel4 ≥ 390MPa, an elongation A4 ≥ 18%, and an impact energy of -20℃ KV. 24 ≥47J.

[0011] Preferably, in step S2, the flux for submerged arc welding is baked at 350°C for 2 hours and stored at a temperature of 100-230°C; the gas shielded welding uses a CO2 shielding gas with a concentration of ≥99.9%.

[0012] Preferably, in step S3, the preheating temperature of the uniform preheating treatment is controlled at 80-120°C, and the preheating range is a region greater than 100mm on both sides of the weld; the welding environment meets the following requirements: temperature not lower than 5°C, humidity not higher than 80%, and wind speed not exceeding 2m / s.

[0013] Preferably, in step S4, the bevel structure includes: a Y-shaped bevel, a V-shaped bevel, and a single-sided V-shaped bevel, with the bevel angle controlled at 45~50°, and the blunt edge thickness adapted to 2~6mm according to the welding method; the assembly accuracy meets the requirements of a gap of 0~1mm and a misalignment of no more than 1mm.

[0014] Preferably, in step S5, the welding method includes submerged arc welding, solid CO2 gas shielded welding, and flux-cored CO2 gas shielded welding; wherein submerged arc welding is used for filler and cover welds in parallel butt joints, solid wire gas shielded welding is used for parallel and root passes, and flux-cored wire gas shielded welding is used for vertical and overhead welds. The line energy parameters are controlled as follows: the line energy of the root pass weld is 13~18KJ / cm, the line energy of the fill and cover passes weld is 15~35KJ / cm, and the line energy of the gas shielded welding does not exceed 25KJ / cm. Meanwhile, for penetration welded joints, a reverse root cleaning treatment is performed after the root pass before completing the subsequent welding operations.

[0015] Compared with the prior art, the present invention has the following main advantages: 1) This invention ensures that the strength and low-temperature impact energy of the weld metal and the base material are matched through precise selection of welding materials. The weld structure is fine and has both strength and toughness, which effectively solves the problem of poor compatibility of welding dissimilar steels.

[0016] 2) This invention designs suitable bevel structures and welding parameters for different welding positions and joint types. Combined with precise control of heat input and processes such as root cleaning and preheating, it significantly reduces welding defects such as cracks, porosity, and lack of fusion. No obvious welding defects were found after testing, and the mechanical properties of the joint meet the requirements of the base material standard.

[0017] 3) The process of this invention is suitable for various joint forms such as mating joints and T-shaped corner joints, as well as welding in all positions such as flat, vertical, horizontal, and overhead. It can cope with different engineering conditions and can be widely used in large steel structure projects under harsh conditions such as coastal corrosive environments.

[0018] 4) The technical solution of this invention is simple and clear, with good process stability, suitable for large-scale industrial construction, which can significantly reduce construction costs, and takes into account both welding quality and construction efficiency, thus having significant engineering application value. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the welding method of corrosion-resistant steel with nano-coating and low-alloy high-strength structural steel in an embodiment of the present invention. Figure 2 This is a schematic diagram of the assembly of a backing-free flat butt submerged arc welding in an embodiment of the present invention; Figure 3 This is a schematic diagram of the cladding process for backing-free flat butt submerged arc welding in an embodiment of the present invention; Figure 4 This is a schematic diagram of the assembly of the ceramic gas-shielded welded vertical / horizontal butt joint in an embodiment of the present invention; Figure 5 This is a schematic diagram of the cladding process for vertical / horizontal butt welding of ceramic backing in an embodiment of the present invention; Figure 6 This is an assembly diagram of overhead penetration reverse root cleaning gas shielded welding in an embodiment of the present invention; Figure 7 This is a schematic diagram of the cladding process for overhead penetration and reverse root cleaning gas shielded welding in an embodiment of the present invention; Figure 8 This is an assembly diagram of the upright penetration reverse root cleaning gas shielded welding in an embodiment of the present invention; Figure 9 This is a schematic diagram of the cladding process for vertical penetration and reverse root cleaning gas shielded welding in an embodiment of the present invention; Figure 10 This is an assembly diagram of transverse penetration reverse root cleaning gas shielded welding in an embodiment of the present invention; Figure 11 This is a schematic diagram of the cladding process for transverse penetration and reverse root cleaning gas shielded welding in an embodiment of the present invention; Figure 12 This is an assembly diagram of the overhead T-type fillet weld gas shielded welding in an embodiment of the present invention; Figure 13This is a schematic diagram of the cladding process of gas shielded welding of overhead T-type fillet welds in an embodiment of the present invention; Figure 14 This is an assembly diagram of the gas shielded welding of the upright T-shaped fillet weld in an embodiment of the present invention; Figure 15 This is a schematic diagram of the cladding process of gas shielded welding of a vertical T-shaped fillet weld in an embodiment of the present invention; Figure 16 This is an assembly diagram of the gas shielded welding of the flat T-type fillet weld in an embodiment of the present invention; Figure 17 This is a schematic diagram of the gas shielded welding cladding of a flat T-shaped fillet weld in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0022] In this invention, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0023] Example 1: This example provides a welding method for corrosion-resistant steel with a nano-coating and low-alloy high-strength structural steel, such as... Figure 1 As shown, the main steps include the following: Step S1, Substrate selection: The nano-coated corrosion-resistant steel has a yield strength Rel ≥ 345 MPa, tensile strength Rm ≥ 490 MPa, elongation A ≥ 20%, and impact energy KV2 ≥ 120 J at -20℃; the low-alloy high-strength structural steel has a yield strength ReH ≥ 355 MPa (plate thickness > 6~16 mm) or 355~475 MPa (plate thickness > 16~100 mm), and tensile strength Rm = 490 MPa. The material has an impact strength of ~610MPa, an elongation A≥22%, an impact energy KV2≥47J at 20℃, and a chemical composition that satisfies the following conditions: C≤0.18, Si≤0.55, Mn≤1.60, P≤0.020, S≤0.010, Cr≤0.30, V≤0.150, Nb≤0.070, Ti≤0.035, Ni≤0.30, Cu≤0.30, Als≥0.015, and CEV≤0.43.

[0024] Step S2, Welding Material Selection: Use a combination of welding materials that matches the strength and toughness of the base material, specifically including: 1) Submerged arc welding uses SU34 welding wire (Φ4.0mm) + flux FB (SJ-101q), and its performance meets the standard of "Solid welding wire, flux-cored welding wire and welding wire-flux combination for non-alloy steel and fine grain steel for submerged arc welding" (GB / T 5293-2018); submerged arc automatic welding is specifically used for: material receiving, top plate butt filling and cover.

[0025] 2) Solid welding wire G49A3UC1S6 (Φ1.2mm) and flux-cored welding wire T492T1-1C1AUH5 (Φ1.2mm) are used for gas shielded welding. The tensile strength of the welding materials is 490-670MPa, and the yield strength is ≥390MPa, ensuring that the chemical composition of the weld metal is similar to that of the base material, the microstructure is mainly composed of fine ferrite, and it has both strength and toughness. The performance of the G49A3UC1S6 solid welding wire conforms to the requirements of "Solid Welding Wire of Non-Alloy Steel and Fine Grain Steel for Gas Metal Arc Welding" (GB / T 8110-2020), and is specifically used for flat and root pass welding. The T492T1-1C1AUH5 flux-cored welding wire conforms to the specifications of "Non-alloy steel and fine-grained steel flux-cored welding wire" (GB / T10045-2018) and is specifically used for vertical and overhead welds.

[0026] Among them, T492T1-1C1AUH5 has a tensile strength Rm490-670MPa, yield strength Rel≥390MPa, elongation A≥18%, and impact energy KV2≥47J at -20℃; G49A3UC1S6 has a tensile strength Rm490-670MPa, yield strength Rel≥390MPa, elongation A≥22%, and impact energy KV2≥47J at -30℃; SU34+FB(SJ101q) has a tensile strength Rm490-670MPa, yield strength Rel≥390MPa, elongation A≥18%, and impact energy KV2≥47J at -40℃.

[0027] Furthermore, the chemical composition of the T492T1-1C1AUH5 welding wire is: C≦0.18, Si≦0.90, Mn≦2.0, P≦0.03, S≦0.03, Ni≦0.50, Cr≦0.2, Mo≦0.30, V≦0.08; the chemical composition of the G49A3UC1S6 welding wire is: C: 0.06-0.15, Si: 0.80-1.15, Mn: 1.40-1.85, P≦0.025. The chemical composition of the SU34 welding wire is: C≦0.12, Si≦0.07, Mn: 1.50-1.90, P≦0.03, S≦0.03, Ni≦0.30, Cr≦0.20, Cu≦0.35; the chemical composition of the FB (SJ101q) flux is: P≦0.06, S≦0.05.

[0028] Step S3, Welding Environment Control: Before formal welding, control the ambient temperature to be no lower than 5℃ and the humidity to be no higher than 80%; when the wind speed exceeds 2m / s, take measures to shield the area and prohibit open-air welding; when the ambient temperature is lower than 5℃ or the plate thickness is ≥30mm, preheat the area more than 100mm on both sides of the weld to 80~120℃; complete welding within 24 hours after the main components are assembled; the submerged arc welding flux is baked at 350℃ for 2 hours and stored at 100~230℃; gas shielded welding uses CO2 shielding gas with a concentration of ≥99.9%.

[0029] Step S4, beveling and assembly: Design the beveling structure according to the welding position and joint type (butt joint, T-joint), including Y-type beveling (50° angle, 6mm blunt edge), V-type beveling (45° angle) and single-sided V-type beveling (45° angle, 2mm blunt edge); control the assembly gap to 0-1mm, and the misalignment to not exceed 1mm. After assembly, mark the steel plate and clean the surface impurities.

[0030] Step S5, Welding Process Implementation: Multi-layer, multi-pass welding is adopted. The welding method, welding materials, and parameters are matched according to the joint type and welding position. The wire energy of gas shielded welding is controlled at 13-25 KJ / cm, and the wire energy of submerged arc welding is controlled at 23-35 KJ / cm. For penetration welds, reverse root cleaning measures are required, as follows: 1) Flat butt joint without backing: For the root pass, use G49A3UC1S6 solid welding wire (current 180±10A, voltage 26±2V, gas flow rate 16-18L / min); for the fill / cover pass, use SU34+FB (SJ-101q) submerged arc welding (current 620±10A, voltage 28±2V, welding speed 34-36cm / min). 2) Vertical butt joint with ceramic backing: T492T1-1C1AUH5 flux-cored welding wire is used throughout the process. The root pass is welded (current 140±10A, voltage 24±2V, gas flow rate 18-20L / min), and the fill / cover pass is welded (current 150±10A, voltage 26±2V, gas flow rate 18-20L / min). 3) Penetration welds (overhead / vertical / horizontal): After the root pass, perform back cleaning and then complete the subsequent welding. The welding materials and parameters should be adapted to the corresponding positions (T492T1-1C1AUH5 for overhead / vertical positions, and G49A3UC1S6 for horizontal positions). 4) T-type fillet weld: No full penetration is required. Use T492T1-1C1AUH5 for overhead / vertical positions and G49A3UC1S6 for horizontal positions. Weld according to the corresponding position parameters.

[0031] Example 2: This example provides a welding method for corrosion-resistant steel with a nano-coating and low-alloy high-strength structural steel. The welding process includes: 1) Unbacked flat butt submerged arc welding: Select one 16*200*600mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 2 The beveling process is performed as a Y-type bevel, with a bevel angle of 50° and a blunt edge of 6mm. The names of the plates, as well as the front and back sides, are clearly marked. The two test plates are assembled and positioned with an assembly precision gap of 0-1mm and a misalignment not exceeding 1mm. After surface cleaning, welding is performed according to… Figure 3 The welding sequence shown is as follows: First, perform the root pass welding using G49A3UC1S6 welding wire, with a welding current of 180±10A, a voltage of 26±2V, a gas flow rate of 16-18L / min, and a heat input of 13-18KJ / cm. Then, perform the fill and cover passes welding using submerged arc welding wire and flux SU34+FB (SJ101q), with a welding current of 620±10A, a voltage of 28±2V, a welding speed of 34-36cm / min, and a heat input of 23-35KJ / cm.

[0032] 2) Ceramic-lined gas-shielded vertical butt welding: Select one 16*200*600mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 4 The beveling process is performed as a V-shaped bevel with a bevel angle of 45°. The names of the plates, as well as the front and back sides, are clearly marked. The two test plates are assembled and positioned, with an assembly precision gap of 0-1mm and a misalignment not exceeding 1mm. After surface cleaning, welding is performed according to… Figure 5 The welding sequence shown is as follows: First, perform the root pass welding using T492T1-1C1AUH5 welding wire, with a welding current of 140±10A, a voltage of 24±2V, a gas flow rate of 18-20L / min, and a heat input of 13-18KJ / cm. Then, perform the fill and cover passes welding using a welding current of 150±10A, a voltage of 26±2V, a gas flow rate of 18-20L / min, and a heat input of 15-20KJ / cm.

[0033] 3) Ceramic-lined gas-shielded flat butt weld: Select one 16*200*600mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 4 The beveling process is performed as a V-shaped bevel with a bevel angle of 45°. The names of the plates, as well as the front and back sides, are clearly marked. The two test plates are assembled and positioned, with an assembly precision gap of 0-1mm and a misalignment not exceeding 1mm. After surface cleaning, welding is performed according to… Figure 5 The welding sequence shown is as follows: First, perform the root pass welding using G49A3UC1S6 welding wire, with a welding current of 180±10A, a voltage of 26±2V, a gas flow rate of 16-18L / min, and a heat input of 13-18KJ / cm. Then, perform the fill and cover passes welding using a welding current of 200±10A, a voltage of 28±2V, a gas flow rate of 16-18L / min, and a heat input of 15-20KJ / cm.

[0034] 4) Overhead penetration and root cleaning gas shielded welding: Select one 16*150*400mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 6 The nano-corrosion-resistant steel is beveled into a single-sided V-shaped bevel with a bevel angle of 45° and a blunt edge of 2mm. The names of the plates, as well as the front and back sides, are clearly marked. The two test plates are assembled and positioned with an assembly precision gap of 0-1mm. After surface cleaning, welding is performed according to… Figure 7 The welding sequence shown is as follows: First, perform the root pass welding using T492T1-1C1AUH5 welding wire, with a welding current of 150±10A, a voltage of 24±2V, a gas flow rate of 20-22L / min, and a heat input of 13-18KJ / cm. Then, perform the reverse root pass welding, with a welding current of 160±10A, a voltage of 26±2V, a gas flow rate of 20-22L / min, and a heat input of 15-20KJ / cm.

[0035] 5) Vertical penetration and root cleaning gas shielded welding: Select one 16*150*400mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 8 The nano-corrosion-resistant steel is beveled into a single-sided V-shaped bevel with a bevel angle of 45° and a blunt edge of 2mm. The names of the plates, as well as the front and back sides, are clearly marked. The two test plates are assembled and positioned with an assembly precision gap of 0-1mm. After surface cleaning, welding is performed according to… Figure 9 The welding sequence shown is as follows: First, perform root pass welding using T492T1-1C1AUH5 welding wire, welding current 140±10A, voltage 24±2V, gas flow rate 18-20L / min, and heat input 13-18KJ / cm. Then, perform root pass cleaning welding on the reverse side using welding current 150±10A, voltage 26±2V, gas flow rate 18-20L / min, and heat input 15-20KJ / cm.

[0036] 6) Horizontal penetration reverse root cleaning gas shielded welding: Select one 16*150*400 steel plate with nano-coated corrosion-resistant steel and one low-alloy high-strength structural steel plate, and weld them according to... Figure 10 The nano-corrosion-resistant steel is beveled into a single-sided V-shaped bevel with a bevel angle of 45° and a blunt edge of 2mm. The names of the plates, as well as the front and back sides, are clearly marked. The two test plates are assembled and positioned with an assembly precision gap of 0-1mm. After surface cleaning, welding is performed according to… Figure 11 The welding sequence shown is as follows: First, perform the root pass welding using G49A3UC1S6 welding wire, with a welding current of 180±10A, a voltage of 26±2V, a gas flow rate of 16-18L / min, and a heat input of 13-18KJ / cm. Then, perform the reverse root pass welding with a welding current of 200±10A, a voltage of 28±2V, a gas flow rate of 16-18L / min, and a heat input of 15-20KJ / cm.

[0037] 7) Gas shielded welding of overhead T-shaped fillet welds: Select one 16*150*400mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 12 The two test plates are assembled and positioned as shown, with an assembly precision gap of 0-1mm. After cleaning the surfaces, they are welded according to... Figure 13 The welding sequence shown is as follows: First, perform the root pass welding using T492T1-1C1AUH5 welding wire, with a welding current of 150±10A, a voltage of 24±2V, a gas flow rate of 20-22L / min, and a heat input of 13-18KJ / cm. Then, perform the reverse pass welding using a welding current of 160±10A, a voltage of 26±2V, a gas flow rate of 20-22L / min, and a heat input of 15-20KJ / cm.

[0038] 8) Gas shielded welding of vertical T-shaped fillet welds: Select one 16*150*400mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 14 The two test plates are assembled and positioned as shown, with an assembly precision gap of 0-1mm. After cleaning the surfaces, they are welded according to... Figure 15 The welding sequence shown is as follows: First, perform the root pass welding using T492T1-1C1AUH5 welding wire, with a welding current of 140±10A, a voltage of 24±2V, a gas flow rate of 18-20L / min, and a heat input of 13-18KJ / cm. Then, perform the reverse pass welding using a welding current of 150±10A, a voltage of 26±2V, a gas flow rate of 18-20L / min, and a heat input of 15-20KJ / cm.

[0039] 9) Gas shielded welding of T-shaped fillet welds at horizontal positions: Select one 16*150*400mm corrosion-resistant steel plate with nano-coating and one low-alloy high-strength structural steel plate, and weld them according to... Figure 16 The two test plates are assembled and positioned as shown, with an assembly precision gap of 0-1mm. After cleaning the surfaces, they are welded according to... Figure 17 The welding sequence shown is as follows: First, perform the root pass welding using G49A3UC1S6 welding wire, with a welding current of 180±10A, a voltage of 26±2V, a gas flow rate of 16-18L / min, and a heat input of 13-18KJ / cm. Then, perform welding on the reverse side using a welding current of 200±10A, a voltage of 28±2V, a gas flow rate of 16-18L / min, and a heat input of 15-20KJ / cm.

[0040] Example 3: Based on the same inventive concept, this example also provides a bridge steel component, which is made by welding corrosion-resistant steel with nano-coating and low-alloy high-strength structural steel as described above.

[0041] Furthermore, all parts of this application that are not described in detail are the same as or implemented using existing technology.

[0042] In summary: 1) This invention ensures that the strength and low-temperature impact energy of the weld metal and the base material are matched through precise selection of welding materials. The weld structure is fine and has both strength and toughness, which effectively solves the problem of poor compatibility of welding dissimilar steels.

[0043] 2) This invention designs suitable bevel structures and welding parameters for different welding positions and joint types. Combined with precise control of heat input and processes such as root cleaning and preheating, it significantly reduces welding defects such as cracks, porosity, and lack of fusion. No obvious welding defects were found after testing, and the mechanical properties of the joint meet the requirements of the base material standard.

[0044] 3) The process of this invention is suitable for various joint forms such as mating joints and T-shaped corner joints, as well as welding in all positions such as flat, vertical, horizontal, and overhead. It can cope with different engineering conditions and can be widely used in large steel structure projects under harsh conditions such as coastal corrosive environments.

[0045] 4) The technical solution of this invention is simple and clear, with good process stability, suitable for large-scale industrial construction, which can significantly reduce construction costs, and takes into account both welding quality and construction efficiency, thus having significant engineering application value.

[0046] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0047] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0048] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel, characterized in that, It comprises the following steps: S1, substrate selection: select the preset performance parameters of the nano-coated corrosion-resistant steel and low-alloy high-strength structural steel as the substrate; S2, welding material selection: according to the performance parameters of the substrate and the welding type, select a suitable welding material combination, the welding type includes submerged arc welding and gas shielded welding, the welding material includes a submerged arc welding wire-solder combination and a solid welding wire, a flux-cored wire for gas shielded welding; S3, welding environment control: before formal welding, control the current environmental temperature and humidity, if the welding environment temperature is lower than the preset temperature value or the substrate plate thickness reaches the preset thickness value, use the oven to uniformly preheat the to-be-welded substrate; S4, groove processing and assembly: according to the welding position and joint form of the to-be-welded substrate, adopt a suitable groove structure and control the assembly accuracy; S5, welding process implementation: adopt a multi-layer multi-pass welding process, and according to the welding position and joint form, match the corresponding welding method, welding material and parameters, and control the welding line energy to complete the welding work.

2. A method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel according to claim 1, characterized in that In step S1, the nano-coated corrosion-resistant steel has a yield strength Rel≥345 MPa, a tensile strength Rm1≥490 MPa, an elongation A1≥20%, and a -20℃ impact energy KV 21 ≥120 J. The low-alloy high-strength structural steel has a yield strength ReH≥355 MPa, a tensile strength Rm2=490-610 MPa, an elongation A2≥22%, and an impact energy KV 22 ≥47 J at -20 °C.

3. A method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel according to claim 2, characterized in that In step S1, the chemical composition of the low-alloy high-strength structural steel satisfies: C≤0.18, Si≤0.55, Mn≤1.60, P≤0.020, S≤0.010, Cr≤0.30, V≤0.150, Nb≤0.070, Ti≤0.035, Ni≤0.30, Cu≤0.30, Als≥0.015, CEV≤0.

43.

4. The method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel of claim 1, wherein In step S2, the chemical composition of the solid welding wire includes: C: 0.06~0.15, Si: 0.80~1.15, Mn: 1.40~1.85, P≦0.025, S≦0.025, Ni≦0.15, Cr≦0.15, Cu≦0.50, Mo≦0.15, V≦0.03; The solid welding wire has a tensile strength Rm3 = 490 ~ 670 MPa, a yield strength Rel3 ≥ 390 MPa, an elongation A3 ≥ 22%, and a -30 ℃ impact energy KV 23 ≥ 47 J.

5. A method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel according to claim 4, characterized in that In step S2, the chemical composition of the flux-cored wire includes: C≦0.18, Si≦0.90, Mn≦2.0, P≦0.03, S≦0.03, Ni≦0.50, Cr≦0.2, Mo≦0.30, V≦0.08; The flux-cored welding wire has a tensile strength Rm4 = 490~670MPa, a yield strength Rel4 ≥ 390MPa, an elongation A4 ≥ 18%, and an impact energy of -20℃ KV. 24 ≥47J.

6. A method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel according to claim 5, characterized in that In step S2, the flux for submerged arc welding is baked at 350℃ for 2 hours, and the storage temperature is 100~230℃; the gas shielded welding uses CO2 protective gas with a concentration of ≥99.9%.

7. The method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel of claim 1, wherein In step S3, the preheating temperature of the uniform preheating treatment is controlled at 80~120℃, and the preheating range is an area greater than 100mm on both sides of the weld; the welding environment satisfies: temperature not lower than 5℃, humidity not higher than 80%, and wind force not more than 2m / s.

8. A method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel according to claim 1, characterized in that In step S4, the groove structure includes: Y-type groove, V-type groove and single-side V-type groove, the groove angle is controlled at 45~50°, and the root face thickness is adapted to 2~6mm according to the welding form; the assembly accuracy satisfies: gap 0~1mm, and misalignment amount not more than 1mm.

9. The method of welding a nano-coated corrosion resistant steel to a low alloy high strength structural steel of claim 1, wherein In step S5, the welding method comprises submerged arc welding, solid CO2 gas shielded welding and flux cored CO2 gas shielded welding; wherein the submerged arc welding is used for filling and cover welding of flat butt joint, the solid wire gas shielded welding is used for flat and backing welding, and the flux cored wire gas shielded welding is used for vertical and overhead welding; The line energy parameter is controlled as follows: the line energy of backing welding is 13-18 KJ / cm, the line energy of filling and cover welding is 15-35 KJ / cm, and the line energy of gas shielded welding is not more than 25 KJ / cm; Meanwhile, for the fusion type welded joint, the reverse side is cleaned after backing welding, and then subsequent welding operation is completed.

10. A bridge steel member characterized by, The method is used for welding the corrosion-resistant steel with nano coating and low-alloy high-strength structural steel according to any one of claims 1 to 9.

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