摘要
针对HR-2抗氢脆不锈钢开展了不同体能量密度下的激光选区熔化工艺试验,重点研究了成形件的组织与性能。结果表明,在一定范围内,随体能量密度增加,成形件的致密度、显微硬度、拉伸强度与延伸率均升高。在最高体能量密度113.3 J/mm^(3)下,成形件致密度高达99.9%,其对应的抗拉强度为765.5 MPa,屈服强度为634 MPa,断后伸长率为44.0%,断面收缩率为61%,达到了GJB 5724标准中HR-2锻件的性能要求。HR-2的打印态组织为明显的柱状晶,在XY面内晶粒呈等轴状,在YZ面内晶粒呈柱状。在XY面内,随体能量密度增加,晶粒尺寸先增加后减小,这是热输入不足导致的熔合不良孔隙、扫描速度降低导致的过冷度增加与扫描间距减小导致的重熔区占比增加对晶粒度的共同作用。
An HR-2 hydrogen embrittlement resistant stainless steel was subjected to selective laser melting process testing performed at different levels of volume energy density.The microstructure and properties of the formed parts were characterized.The results revealed that,for a certain range of volume energy density values,the density,microhardness,tensile strength,and elongation of the parts increased with increasing volume energy density.At the maximum energy density of 113.3 J/mm^(3),the maximum density of the formed part,corresponding tensile strength,yield strength,elongation after fracture,and reduction in area were 99.9%,765.5 MPa,634 MPa,44.0%,and 61%,respectively.These values satisfy the performance requirements of HR-2 forging specified in the GJB 5724 standard.The printed structure of HR-2 is composed of columnar crystals,with equiaxed grains in the XY plane and columnar grains in the YZ plane.In the XY plane,the grain size increases first and then decreases with the increase of bulk energy density.This is the combined effect of poor fusion pores caused by insufficient heat input,the increase of undercooling caused by the decrease of scanning speed,and the increase of the proportion of remelting zone caused by the decrease of scanning spacing on grain size.
作者
刘宁昭
王国伟
秦煜
王开甲
沈显峰
Liu Ningzhao;Wang Guowei;Qin Yu;Wang Kaijia;Shen Xianfeng(Institute of Machinery Manufacturing Technology,China Academy of Engineering Physics,Mianyang 621900,Sichuan,China)
出处
《激光与光电子学进展》
CSCD
北大核心
2023年第7期221-230,共10页
Laser & Optoelectronics Progress
关键词
激光技术
激光选区熔化
抗氢钢HR-2
能量密度
致密度
晶粒尺寸
laser technique
selective laser melting
hydrogen resistant steel HR-2
energy density
density
grain size
