Effect of Laser Annealing on Hot-stretching Properties of 1Cr5Mo Steel Welded Joints

Abstract

The 1Cr5Mo heat-resistant steel welded joint was annealed with CO2 laser, the effect of temperature on hot-stretching properties of the samples before and after laser annealing was analyzed by using stretching tests. The grain changes, rupture modes and fracture morphologies before and after laser annealing were observed by SEM, and the status of residual stress on the surface of welded joints was measured by using X-ray stress analyzer. The results show that the yield strength, tensile strength and elongation rate of the samples after laser annealing at 200℃ increase by 32.5%, 22.5% and 4.6% than those of the original samples, respectively, while after laser annealing at 300℃,they only increase by 6.6%, 6.5% and 7.5%, respectively; the tensile fracture of the samples before and after laser annealing is tough fracture, but the dimple size of the samples after laser annealing is bigger than that of the original samples, with the increase of temperature,the dimple size increases further; the grain refinement and residual compressive stress generated on the surface of the samples after laser annealing are the main factors of hot-stretching properties improvement.

Keywords

• laser annealing
• 1Cr5Mo heat-resistant steel
• welded joint
• hot-stretching test