Laser Heat Treatment was Performed to Improve the Bending Property of Laser Welded Joints o Low-Alloy Ultrahigh-Strength Steel with Minimized Strength Loss

Abstract

The poor twisting property of laser-welded joints constrains the utilization of low-amalgam ultrahigh-quality steel (LAUHSS). Right now, phases of laser heat treatment (LHT) were performed to improve the face-and back-twisting property of joints with limited quality misfortune. The microstructures and mechanical properties were assessed, and the impact system of LHT on the bowing property was talked about. The first LHT meant to improve the back-bowing property, after which the joints were contained the austenized and treating zones. In the treating zone, the first inhomogeneous microstructures changed into comparative tempered martensite. This smoothed out the precarious hardness slope to generally uniform qualities. In the austenized zone, austenization happened and the hardness valley despite everything existed around the sides of the zone. The mechanical property test results demonstrated the back-bowing edge could be improved from 30 deg to more than 90 deg, while the face-twisting point indicated inadmissible outcomes with more than 1280 MPa elasticity. The second LHT was performed dependent on the first LHT to improve the face-twisting property of joints. With lower power in the second LHT, the double stage microstructures in the austenized zone tempered. Also, the hardness circulations of joints would in general be progressively uniform without valleys. A more than 90-deg face-twisting point and around 1205 MPa elasticity were acquired. After LHT, the scope of plastic misshapening during the bowing procedure extended as opposed to packing in the hardness valley zone, which prompted a bigger relative twisting range and less tractable weight on the bowing surface. This is gainful for the improvement of the bowing property.