激光增材制造技术在核电堆内构件304LN不锈钢大型复杂结构件上的应用

Application of Nuclear-grade 304LN Stainless Steel Components Prepared by Laser Additive Manufacturing

将激光增材制造技术用于核反应堆堆内构件304LN奥氏体不锈钢大型复杂结构件的制备,利用金相显微镜和扫描电镜分析,对焊态及热处理态熔覆层组织进行微观分析,并对熔覆态及热处理态熔覆层开展力学性能试验。结果表明:激光熔覆304LN不锈钢熔覆层组织由沿熔覆增高方向贯穿多层外延生长的柱状晶组成,柱状晶内包含多个细长整齐排列的树枝晶,奥氏体基体上分布着大量沿熔覆增高方向排列的残余铁素体;固溶处理后残余铁素体消除,奥氏体基体上析出大量碳化物。304LN奥氏体不锈钢熔覆态组织具有良好的力学性能。

The nuclear-grade 304LN stainless steel plate was prepared by laser melting deposition technology.The microstructure of the deposited and heat-treated samples was analyzed by metallographic microscope and scanning electron microscope,and the mechanical properties of the samples were tested.The results show that the microstructure of 304LN stainless steel deposited by laser melting is composed of columnar crystals that grow through multilayer epitaxial growth along the increase direction of deposition.The columnar crystals contain a number of elongated dendritic crystals arranged in neat order.A large number of ferrites arranged along the increase direction of deposition are distributed on the austenitic matrix.After solid solution treatment,ferritic elimination was involved,and a large number of carbides were precipitated on the austenite matrix.The deposited structure of 304LN austenitic stainless steel has good mechanical properties.