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CN-122007579-A - Method for welding different steel materials of quenching distribution steel and dual-phase steel

CN122007579ACN 122007579 ACN122007579 ACN 122007579ACN-122007579-A

Abstract

The invention discloses a method for welding quenching distribution steel and dual-phase steel dissimilar steel, and belongs to the technical field of high-strength steel welding. The welding method comprises the steps of cleaning the surfaces to be welded of the quenching distribution steel and the dual-phase steel, keeping the surfaces dry, overlapping one end of the quenching distribution steel with the other end of the dual-phase steel, fixing the quenching distribution steel and the dual-phase steel on a resistance welding machine, enabling the surfaces to be welded to be closely attached by a welding wheel, carrying out narrow overlap welding according to set parameters, and carrying out thinning treatment on a welding line by using a rolling wheel to reduce the thickness of the welding line to the thickness of a base metal. The method enables the welding seam to bear the external stress within 140.17-263.98 KN at the high temperature of 800-880 ℃ and meets the continuous production requirement of the external tension of 14.0-26.3 KN in the high-temperature annealing process.

Inventors

  • LIU HONGYAN
  • XIE YU
  • CHEN XIAOHU
  • CHEN ZIGANG
  • WANG XIAONAN
  • LI SHOUHUA
  • CAO XIAOEN
  • GUAN LIANSHENG
  • DUAN JIAWEI
  • LIU ZIQUAN
  • JIA YAFEI

Assignees

  • 邯郸钢铁集团有限责任公司
  • 河钢股份有限公司邯郸分公司

Dates

Publication Date
20260512
Application Date
20260313

Claims (8)

  1. 1. The welding method of the dissimilar steel products of the quenching distribution steel and the dual-phase steel is characterized by comprising the following steps of: (1) Obtaining a cold-hardening quenching split steel strip coil after hot rolling, laminar cooling, pickling and cold rolling; The cold and hard state quenching split steel comprises a hot rolling process, a laminar cooling process and a cold rolling process, wherein the finish rolling temperature is 860-890 ℃, the finish cooling temperature is 520-550 ℃, and the comprehensive reduction rate is 38-68%; the dual-phase steel is subjected to a hot rolling process, wherein the final rolling temperature is 820-910 ℃; a laminar cooling process, namely a final cooling temperature of 550-620 ℃ and a cold rolling process, namely a comprehensive reduction rate of 45-70%; (2) Carrying out on-line high-speed wind and cleaning agent cleaning treatment on the surfaces to be welded of the quenched and distributed steel and the dual-phase steel, and keeping the surfaces dry; (3) Overlapping one end of the quenching distribution steel with the other end of the dual-phase steel, fixing the quenching distribution steel on a resistance welding machine, tightly attaching a surface to be welded by a welding wheel, and carrying out narrow overlap welding according to set parameters; (4) And (3) carrying out thinning treatment on the welding line by using a rolling wheel so as to reduce the thickness of the welding line to the thickness of a base material.
  2. 2. The method for welding the dissimilar steel products of the quenching and distribution steel and the dual-phase steel according to claim 1, wherein in the step (3), parameters are set to be 1.0-2.5 mm in thickness of strip steel, 1000-1650 mm in width, 5-32 KA in welding current, 2.0-15 m/min in welding speed, 3-30 KN in electrode pressure, 1.2-3 mm in welding overlap joint amount, 0.2-2.0 mm in welding compensation amount and 20-28 KN in rolling wheel pressure.
  3. 3. The method for welding the dissimilar steel products of the quenching and distribution steel and the dual-phase steel according to claim 1, wherein in the step (3), the set parameters are preferably 1.0-2.5 mm in thickness of the strip steel, 1000-1650 mm in width, 10-25 KA in welding current, 7.0-14 m/min in welding speed, 10-26 KN in electrode pressure, 1.5-2.4 mm in welding overlap, 0.2-1.5 mm in welding compensation amount and 21-27 KN in rolling wheel pressure.
  4. 4. The welding method for the dissimilar steel products of the quenching and partitioning steel and the dual-phase steel, which is disclosed in claim 1, is characterized in that the width of a welding line and a heat affected zone is 2-7 mm, and the weld joint interface is enlarged by 50 times, no obvious boundary line exists on the observation of the welding line, the fusion property is good, and no crack exists.
  5. 5. The welding method for the dissimilar steel products of the quenching and partitioning steel and the dual-phase steel according to any one of claims 1 to 4, wherein the welding method is characterized in that a weld cupping result is perpendicular to a weld, the cracking mode is acceptable qualified cracking, the cupping value is 6.24-7.85 mm, and the maximum force range is 48.99-58.46 KN.
  6. 6. The welding method for the dissimilar steels of the quenched and split steel and the dual-phase steel according to any one of claims 1 to 4, wherein the welding method is characterized in that the average hardness of the center of a welding line is 437.1 to 466.4hv, the average hardness of the HAZ at the qp980 side is 315.2 to 337.2hv, and the average hardness of the HAZ at the dp980 side is 328.7 to 355.6hv.
  7. 7. The welding method for the quenching split steel and the dual-phase steel according to any one of claims 1 to 4, wherein the welding method is characterized in that the high-temperature tensile property of a welding line at 800-880 ℃ is detected, the yield strength of the welding line is 105-134 MPa, the thickness of the welding line is 1.0-2.5 mm, the length of the welding line is 750-1335 mm, the area range of the cross section of the welding line is 1335-1970 mm 2 , the external stress bearing range of the welding line is 140.17-263.98 KN, the practical settable tension range of continuous production is 14.0-26.3 KN, and the continuous annealing furnace is heated and kept at the heating temperature, so that the continuous belt tension requirement of 10-25 KN is met.
  8. 8. The method for welding dissimilar steels of quenching split steel and dual-phase steel according to any one of claims 1 to 4, wherein the quenching split steel is QP980 and QP1180, and the dual-phase steel is DP980 and DP1180.

Description

Method for welding different steel materials of quenching distribution steel and dual-phase steel Technical Field The invention belongs to the technical field of high-strength steel welding, and particularly relates to a method for welding quenching distribution steel and dual-phase steel dissimilar steel. Background Advanced high-strength steel has become a core material for lightweight manufacturing of automobiles due to its high rigidity, excellent collision energy absorbing ability and good formability. By adopting the advanced high-strength steel to manufacture the automobile stamping part, the weight reduction of single part can be realized by up to 50 percent, and meanwhile, the structural performance is obviously improved. The use of ultra-high strength steel (such as QP steel) is effective in suppressing intrusion deformation of the cockpit during a collision. The quenching and distributing steel (QP) takes martensite as a matrix, utilizes the TRIP effect of residual austenite, has high work hardening capacity, high plasticity and good forming performance, is commonly applied to the production of automobile safety parts and structural parts with complex shapes, such as B column reinforcing plates and the like, and the dual-phase steel (DP) takes ferrite and martensite as main materials, has the characteristics of low yield ratio, high work hardening index and the like, and is commonly applied to the production of structural parts, reinforcing parts, anti-collision parts, such as anti-collision rods and the like. When the QP980 steel in the cold and hard state is welded in the prior art, due to the high hardness and high strength characteristics of the material and the influence of heat input in the welding process, the performance and reliability of the welded joint are extremely easy to be adversely affected, on one hand, the brittleness of the welded joint is increased, the toughness is reduced, brittle fracture is easy to occur when the welded joint is stressed, and the fatigue resistance and the impact resistance of the structure are reduced, on the other hand, a certain amount of residual austenite and cold and hard martensite are contained in a QP980 matrix, partial austenitization can occur in a region with the temperature between 'critical regions' (Ac 1-Ac 3) in a heat affected zone during welding, a coarse martensite and ferrite mixed structure is formed after cooling, and the performance difference of each phase structure is large, so that the strength and the hardness are reduced. It follows that the core problems of conventional welded cold-hard QP980 steels are concentrated on "crack sensitivity due to hard and brittle structure" and "heat affected zone performance deterioration". To ameliorate these disadvantages, reduced heat input from the welding process, optimized welding parameters, or the use of matched high strength low alloy steel weldments can be used in combination with post-weld treatments. In actual production, the cold-rolled quenching split steel (QP) and dual-phase steel (DP) strip steel needs to be subjected to uncoiling, welding and continuous annealing heat treatment. The narrow lap resistance welding is an important device of the continuous production line of the ultra-high strength steel continuous annealing line, and has the main effects of connecting front and rear strip steel together in a welding mode, thereby ensuring the continuity and stability of unit production. However, when the cold and hard state QP980 and DP980 different steel types are welded by adopting the traditional narrow lap welding process, the welding joint is softened and the microstructure is deteriorated due to the characteristics of different components, different tissues, high hardness and high strength, so that the belt breakage is caused by high-temperature tension production in the subsequent continuous annealing heating furnace, and the production efficiency and stability are greatly reduced. Therefore, it is necessary to provide a narrow lap welding method for cold and hard QP980 steel and DP980 steel dissimilar steels, so that the welding quality and the production efficiency are improved, and the continuous production requirement of an enterprise continuous annealing production line is met. Disclosure of Invention The invention aims to provide a narrow lap welding method for a quenching and distribution steel dual-phase steel dissimilar steel material, which is characterized in that cold hard steel materials subjected to hot rolling, laminar cooling, pickling and cold rolling are subjected to narrow lap welding, a welding wheel tightly bonds the surfaces to be welded in the welding process, the forming performance of a welded joint is improved by adjusting welding parameters, a rolling wheel is used for flattening a welding seam after welding, the welding seam bears an external stress range of 140.17-263.98 KN at a high temperature of 800-880 ℃, and the continuous production requi