Weldability of 780 MPa Super-High Strength Heavy-Duty Truck Crossbeam Steel
WANG Xiao-nan1,DI Hong-shuang2,ZHANG Chi2,DU Lin-xiu2,DONG Xue-xin2
1. Shagang School of Iron and Steel, Soochow University, Suzhou 215021, Jiangsu, China 2. State Key Laboratory of Rolling and Automation of Northeastern University, Shenyang 110004, Liaoning, China
Weldability of 780 MPa Super-High Strength Heavy-Duty Truck Crossbeam Steel
WANG Xiao-nan1,DI Hong-shuang2,ZHANG Chi2,DU Lin-xiu2,DONG Xue-xin2
1. Shagang School of Iron and Steel, Soochow University, Suzhou 215021, Jiangsu, China 2. State Key Laboratory of Rolling and Automation of Northeastern University, Shenyang 110004, Liaoning, China
ժҪ CO2-shielded welding experiments of newly developed, 780 MPa super-high strength heavy-duty truck crossbeam steel were conducted, and the microstructure, microhardness, mechanical properties, and impact toughness of the welded joint were studied. The evolution of the microstructure of the welded joint occurred as follows: welding seam (acicular ferrite+proeutectoid ferrite)��fusion zone (granular bainite-long strip M/A island)��coarse grain zone (granular bainite-long strip or short bar M/A island)��fine grain zone (ferrite+pearlite+blocky M/A island)��mixed grained zone (ferrite+granular bainite+blocky M/A island)��base metal (proeutectoid ferrite+granular bainite-blocky or granular M/A island). Increasing the density of the grain boundaries can effectively improve the impact toughness, and the blocky M/A island hindered crack propagation more effectively than the long strip M/A island. The new hot-rolled 780 MPa super-high strength steel had excellent weldability. The welding technology was applied under the following conditions: welding voltage was 20 to 21 V, welding current was 200 to 210 A, and the gas flow rate was 25 L/min.
Abstract��CO2-shielded welding experiments of newly developed, 780 MPa super-high strength heavy-duty truck crossbeam steel were conducted, and the microstructure, microhardness, mechanical properties, and impact toughness of the welded joint were studied. The evolution of the microstructure of the welded joint occurred as follows: welding seam (acicular ferrite+proeutectoid ferrite)��fusion zone (granular bainite-long strip M/A island)��coarse grain zone (granular bainite-long strip or short bar M/A island)��fine grain zone (ferrite+pearlite+blocky M/A island)��mixed grained zone (ferrite+granular bainite+blocky M/A island)��base metal (proeutectoid ferrite+granular bainite-blocky or granular M/A island). Increasing the density of the grain boundaries can effectively improve the impact toughness, and the blocky M/A island hindered crack propagation more effectively than the long strip M/A island. The new hot-rolled 780 MPa super-high strength steel had excellent weldability. The welding technology was applied under the following conditions: welding voltage was 20 to 21 V, welding current was 200 to 210 A, and the gas flow rate was 25 L/min.
�ո�����: 2011-02-25
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WANG Xiao-nan,DI Hong-shuang,ZHANG Chi,DU Lin-xiu,DONG Xue-xin. Weldability of 780 MPa Super-High Strength Heavy-Duty Truck Crossbeam Steel[J]. �й������ڿ���, 2012, 19(6): 64-69.
WANG Xiao-nan,DI Hong-shuang,ZHANG Chi,DU Lin-xiu,DONG Xue-xin. Weldability of 780 MPa Super-High Strength Heavy-Duty Truck Crossbeam Steel. Chinese Journal of Iron and Steel, 2012, 19(6): 64-69.
2012, Vol. 19 
