- 期刊
The Influence of Welding Speed on the Properties of Dual-Phase Steel Welded Joints
摘要
In this study, Nd:YAG laser was used to laser weld DP steel, and the effects of different welding speeds on the microstructure and mechanical properties of the welded joints were explored in detail by means of metallurgical microscope, Rockwell hardness tester and universal tensile tester. The experimental results show that the microstructure after welding can be divided into six zones: Fusion Zone (FZ), Coarse Grain Heat Affected Zone (CGHAZ), Fine Grain Heat Affected Zone (FGHAZ), Intercritical Heat Affected Zone (ICHAZ), Subcritical Heat Affected Zone (SCHAZ), and Base Metal (BM). With the increase of welding speed, the weld width shows a trend of increasing and then decreasing, while the organization of the weld zone is gradually refined. The yield strength and tensile strength of the welded joints also increased firstly and then decreased with the increase of welding speed. In the range of welding speeds from 4 m/min to 5.5 m/min, the tensile strength and elongation at break of the welded joints reached the optimum values of 1277.88 MPa and 1.97%, respectively, when the welding speed was 5 m/min.