500MPa-grade low-slag gas shielded solid welding wire for automobile industry

Abstract

The invention provides a 500MPa-grade low-slag gas shielded solid welding wire for the automobile industry. The welding wire comprises the following chemical components in percentage by weight: 0.11-0.16% of C, 0.12-0.12% of S, 0.12-0.12% of Cr, 0.12-0.12% of Cr, 0.12-0.12% of 0.50% to 0.70% of Si; mn: 1.00 to 1.35%; plt; 0.015% of the total weight; the content of S is 0.005 to 0.015 percent, and the content of Cr + Ni + Mult; 0.15% by weight; 0.20% or less of Cu; the sum of the mass fractions of all the components is 100%, and the content of the Cu element comprises a welding wire copper plating layer. The welding wire is small in welding spatter, good in electric arc stability and all-position operability, basically free of slag and free of cleaning after welding, attractive in weld joint forming, excellent in welding process performance and excellent in weld joint metal mechanical performance.

Description

Technical Field

[0001] The invention belongs to the field of welding materials, and in particular relates to a 500MPa-grade low-slag gas-shielded solid welding wire for the automobile industry. Background Art

[0002] With the vigorous development of the automobile industry, the amount of steel used in automobiles has increased dramatically, and the matching gas shielded welding carbon steel solid welding wire is an important material in automobile manufacturing. In order to ensure the quality of welding, a large number of welds in automobile manufacturing need to undergo surface electrophoresis treatment. At present, there are many problems with solid welding wires in the automotive industry: the amount of welding slag is relatively large, and the welding slag is difficult to clean, which affects the electrophoresis effect at many weld positions that require later electrophoresis treatment, resulting in a decrease in the corrosion resistance of the weld. Some research has also been carried out at home and abroad on low-slag solid welding wires for automobiles. A low-slag solid welding wire has been developed abroad. The wire reduces the post-welding slag by reducing the Si content and increasing the Mn content while ensuring the strength, but its toughness will decrease after increasing excessive Mn. Therefore, it is now necessary to develop a solid welding wire with excellent mechanical properties and less slag or no slag for welding in the automotive industry. Summary of the invention

[0003] In view of this, the present invention aims to propose a 500MPa-grade low-slag gas-shielded solid welding wire for the automotive industry. The chemical composition ratio of the welding wire is scientific, the welding performance is stable, the obtained deposited metal has comprehensive mechanical properties, and there is basically no welding slag after welding. By increasing the C content in the solid welding wire, deoxidation is carried out during the welding process to reduce the burnout of Mn and Si alloy elements to reduce the amount of slag after welding of the solid welding wire. After changing the slag system, the welding slag is dispersed in a tiny shape on the surface of the weld metal, and no continuous welding slag is formed into pieces. The use of this solid welding wire for welding ensures that the weld bead is beautiful after welding, no slag cleaning is required, the mechanical properties meet the technical requirements, the man-hours of manual slag cleaning after welding are reduced, and the electrophoretic painting effect is better. It can be used for arc welding in the automotive industry to ensure welding quality and improve work efficiency.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A 500MPa-grade low-slag gas-shielded solid welding wire for the automotive industry, wherein the chemical composition of the welding wire comprises, by weight percentage: C: 0.11-0.16%; Si: 0.50-0.70%; Mn: 1.00-1.35%; P<0.015%; S: 0.005-0.015%, Cr+Ni+Mo<0.15%; Cu≤0.20%; the remainder is Fe and unavoidable impurities, the sum of the mass fractions of the various components is 100%, wherein the Cu element content includes the copper plating layer of the welding wire.

[0006] Furthermore, the chemical composition of the welding wire includes, by weight percentage: C: 0.11%, Mn: 1.19%, Si: 0.58%, Cr: 0.03%, S: 0.010%, P: 0.013%, Ni: 0.03%, Mo: 0.04%, Cu: 0.12%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

[0007] Furthermore, the chemical composition of the welding wire includes, by weight percentage: C: 0.12%, Mn: 1.30%, Si: 0.63%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.11%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

[0008] Furthermore, the chemical composition of the welding wire includes, by weight percentage: C: 0.13%, Mn: 1.35%, Si: 0.50%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.10%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

[0009] Furthermore, the chemical composition of the welding wire includes, by weight percentage: C: 0.15%, Mn: 1.35%, Si: 0.66%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.10%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

[0010] Furthermore, the welding wire is welded using 80% Ar+20% CO2 argon-rich mixed gas.

[0011] Furthermore, the yield strength Rel of the deposited metal of the welding wire is ≥400 MPa, the tensile strength Rm is ≥500 MPa, the elongation A is ≥22%, and the impact energy at -40°C is ≥47 J.

[0012] Compared with the prior art, the 500MPa low-slag gas-shielded solid welding wire for the automotive industry described in the present invention has the following advantages:

[0013] 1. The welding wire of the present invention is smelted in an industrial converter, rolled in a high-speed twist-free rolling mill, and drawn into a finished welding wire, which is easy to produce.

[0014] 2. The welding wire of the present invention can be welded with 80% Ar + 20% CO2 argon-rich mixed gas, with small welding spatter, good arc stability and all-position operability, basically no slag after welding and no need for cleaning, beautiful weld formation, excellent welding process performance of the welding wire, and excellent mechanical properties of the weld metal.

[0015] 3. The yield strength Rel of the deposited metal of the welding wire described in the present invention is ≥400MPa, the tensile strength Rm is ≥500MPa, the elongation A is ≥22%, and the impact energy at -40°C is ≥47J.

[0016] 4. The present invention can significantly improve the welding quality in the automotive industry and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 This is a picture after welding using the 500MPa grade low slag gas shielded solid welding wire for the automotive industry described in Example 1 of the present invention;

[0019] Figure 2 This is the welding wire after welding of comparative example 1;

[0020] Figure 3 This is the welding wire after welding of comparative example 2;

[0021] Figure 4 This is the welding wire after welding of comparative example 3;

[0022] Figure 5 This is the picture after welding of the welding wire of comparative example 4. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] A 500MPa-grade low-slag gas-shielded solid welding wire for the automotive industry. The chemical composition of the welding wire includes, by weight percentage, C: 0.11%, Mn: 1.19%, Si: 0.58%, Cr: 0.03%, S: 0.010%, P: 0.013%, Ni: 0.03%, Mo: 0.04%, Cu: 0.12%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of the various components is 100%.

[0027] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 425MPa; the tensile strength Rm is 512MPa; the elongation A is 26%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 120J.

[0028] Example 2

[0029] A 500MPa-grade low-slag gas-shielded solid welding wire for the automotive industry. The chemical composition of the welding wire includes, by weight percentage, C: 0.12%, Mn: 1.30%, Si: 0.63%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.11%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of the components is 100%.

[0030] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 435MPa; the tensile strength Rm is 525MPa; the elongation A is 24.5%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 91J.

[0031] Example 3

[0032] A 500MPa-grade low-slag gas-shielded solid welding wire for the automotive industry. The chemical composition of the welding wire includes, by weight percentage, C: 0.13%, Mn: 1.35%, Si: 0.50%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.10%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of the various components is 100%.

[0033] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 442MPa; the tensile strength Rm is 545MPa; the elongation A is 23.5%; the low-temperature impact toughness is: the weld impact energy at -40℃ is 82J.

[0034] Example 4

[0035] A 500MPa-grade low-slag gas-shielded solid welding wire for the automotive industry. The chemical composition of the welding wire includes, by weight percentage, C: 0.15%, Mn: 1.35%, Si: 0.66%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.10%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of the various components is 100%.

[0036] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 452MPa; the tensile strength Rm is 558MPa; the elongation A is 22%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 70J.

[0037] Preparation method of welding wire:

[0038] Desulfurized hot metal is used to control the sulfur content of hot metal entering the furnace. Converter steelmaking is used. Raw materials with low S and P content are selected. Top and bottom composite blowing process is adopted to control C, S and P at a low level at the end of smelting. After deoxidation and alloying, LF furnace and other off-furnace refining processes are adopted to smelt molten steel with components that meet the requirements. The molten steel is cast into continuous casting billets with full protection by the variety casting machine. The continuous casting billets are rolled into Φ5.5mm wire rods by high-speed non-twisting rolling mills. The wire rods are made into Φ1.2mm finished welding wires through shelling, pickling, borax coating, rough drawing, fine drawing and copper plating.

[0039] Comparative Example 1

[0040] A gas shielded welding wire, the chemical composition of which includes C: 0.074%, Mn: 1.28%, Si: 0.63%, Cr: 0.02%, S: 0.011%, P: 0.011%, Ni: 0.02%, Mo: 0.03%, Cu: 0.12%, and the balance is Fe; the sum of the mass percentages of the components is 100%.

[0041] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 430MPa; the tensile strength Rm is 525MPa; the elongation A is 28%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 102J.

[0042] Comparative Example 2

[0043] A gas shielded welding wire, the chemical composition of which includes C: 0.12%, Mn: 1.33%, Si: 0.85%, Cr: 0.02%, S: 0.011%, P: 0.011%, Ni: 0.02%, Mo: 0.03%, Cu: 0.12%, and the balance is Fe; the sum of the mass percentages of the components is 100%.

[0044] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 440MPa; the tensile strength Rm is 545MPa; the elongation A is 26%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 95J.

[0045] Comparative Example 3

[0046] A gas shielded welding wire, the chemical composition of which includes C: 0.18%, Mn: 1.19%, Si: 0.66%, Cr: 0.02%, S: 0.011%, P: 0.011%, Ni: 0.02%, Mo: 0.03%, Cu: 0.12%, and the balance is Fe; the sum of the mass percentages of the components is 100%.

[0047] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 435MPa; the tensile strength Rm is 555MPa; the elongation A is 25%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 66J.

[0048] Comparative Example 4

[0049] The conventional ER50-6 welding wire is used for welding.

[0050] The deposited metal performance test of the welding wire in this example is as follows: the yield strength Rel is 465MPa; the tensile strength Rm is 565MPa; the elongation A is 24%, and the low-temperature impact toughness is: the weld impact energy at -40℃ is 90J.

[0051] In the above embodiments and comparative examples, the welding wire is welded with an Ar-rich mixed gas having a volume percentage of 80% Ar and 20% CO2 to obtain the cladding metal, wherein the welding parameters are: welding speed: 5-6mm / s; gas flow: 20L / min; current: 280A, voltage: about 30V, and track temperature 150°C.

[0052] Table 1 Summary of chemical composition of welding wires of various embodiments and comparative examples

[0053]

[0054] Table 2 Summary of properties of welding wire cladding metals in various embodiments and comparative examples

[0055]

[0056] From the above examples, comparative examples and summary tables and Figure 1-5It can be seen that the effect of changing the carbon content and silicon content in the welding wire on the yield strength, tensile strength, elongation after fracture, and low-temperature impact toughness is not much different, but it will affect the welding slag. In comparative example 1: due to the reduction of carbon content in the welding wire, the amount of slag is large. In comparative example 2: due to the increase in silicon content added to the welding wire, the size of the slag after welding is larger, and the welding slag is not significantly reduced compared with the conventional ER50-6 welding wire in comparative example 4. In comparative example 3: due to excessive carbon content, the welding process is deteriorated, which has an impact on the mechanical properties after welding.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A 500MPa low slag gas shielded solid welding wire for the automotive industry, characterized by: The chemical composition of the welding wire includes, by weight percentage: C: 0.11-0.16%; Si: 0.50-0.70%; Mn: 1.00-1.35%; P<0.015%; S: 0.005-0.015%, Cr+Ni+Mo<0.15%; Cu≤0.20%; the remainder is Fe and inevitable impurities, the sum of the mass fractions of each component is 100%, wherein the Cu element content includes the copper plating layer of the welding wire.

2. The 500MPa low slag gas shielded solid welding wire for the automotive industry according to claim 1, characterized in that: The chemical composition of the welding wire includes, by weight percentage: C: 0.11%, Mn: 1.19%, Si: 0.58%, Cr: 0.03%, S: 0.010%, P: 0.013%, Ni: 0.03%, Mo: 0.04%, Cu: 0.12%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

3. The 500MPa low slag gas shielded solid welding wire for the automotive industry according to claim 1, characterized in that: The chemical composition of the welding wire includes, by weight percentage: C: 0.12%, Mn: 1.30%, Si: 0.63%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.11%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

4. The 500MPa low slag gas shielded solid welding wire for the automotive industry according to claim 1, characterized in that: The chemical composition of the welding wire includes, by weight percentage: C: 0.13%, Mn: 1.35%, Si: 0.50%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.10%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

5. The 500MPa low slag gas shielded solid welding wire for the automotive industry according to claim 1, characterized in that: The chemical composition of the welding wire includes, by weight percentage: C: 0.15%, Mn: 1.35%, Si: 0.66%, Cr: 0.03%, S: 0.011%, P: 0.012%, Ni: 0.03%, Mo: 0.04%, Cu: 0.10%, and it is impossible to avoid the residual amount of Fe; the sum of the mass percentages of each component is 100%.

6. The 500MPa low slag gas shielded solid welding wire for the automotive industry according to claim 1, characterized in that: The welding wire is welded by using 80% Ar+20% CO2 argon-rich mixed gas.

7. The 500MPa low slag gas shielded solid welding wire for the automotive industry according to claim 1, characterized in that: The yield strength Rel of the deposited metal of the welding wire is ≥400MPa, the tensile strength Rm is ≥500MPa, the elongation A is ≥22%, and the impact energy at -40°C is ≥47J.

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