Effects of High-Power Laser Heat Input on the Mechanical Properties of GPa-Grade Advanced High Strength TRIP Steel

Welding and local heat treatment with a high-power laser for GPa-grade transformation-induced plasticity (TRIP) steel were studied. When the focal length scan speed controlled under fixed power, defect-free full penetration conditions achieved at various inputs. The effects of input on mechanical properties evaluated. results showed that softened zone was lowered to 350 HV hardness by tempered martensite all conditions. As increased, became wider. an appropriate 20-60 mm/J irradiated, tensile strength elongation improved as compared base material. Under these conditions, significantly narrowed TRIP effect stress, metal fracture occurred. In addition, increased in weld further activated retained austenite. However, 90 J/mm, limited test due wide sub-critical affected during process. this study, effective formed full-penetration joint locally enhanced simultaneously.