徐娟娟， 王克鸿， 彭　勇， 江俊龙， 杨嘉佳

(1.南京理工大学 材料科学与工程学院， 江苏 南京210094; 2.泰州南京理工大学研究院， 江苏 泰州 225300)



热输入对高氮钢光纤激光焊接接头气孔及组织性能的影响

徐娟娟1，2， 王克鸿1,2， 彭勇1， 江俊龙1,2， 杨嘉佳1

(1.南京理工大学 材料科学与工程学院， 江苏 南京210094; 2.泰州南京理工大学研究院， 江苏 泰州 225300)

摘要采用光纤激光对7 mm高氮钢进行焊接，研究了不同热输入对高氮钢焊接接头气孔及微观组织性能的影响。结果表明：随着焊接热输入的提高，焊缝中气孔数量呈现先减少后增加的趋势，当热输入为400 kJ/m 时几乎无气孔。高氮钢母材组织为奥氏体，部分以孪晶形式存在；焊缝组织为铸态细晶粒奥氏体组织，弥散分布部分CrN析出物；随着热输入的增加，热影响区宽度及晶粒尺寸明显增加。对比接头显微硬度值和力学性能可知，随着热输入的增加，焊缝及热影响区硬度值逐渐减小。拉伸试验断裂部位均为焊缝区，最高抗拉强度为971.4 MPa，达到母材强度的94.3%。

关键词激光焊接高氮钢热输入气孔微观组织力学性能

Effect of Heat Input on Stomatal Resistance and Mechanical Properties of High Nitrogen Steel Plate Laser Welding Joint

XU Juan-juan1,2, WANG Ke-hong1,2, PENG Yong1,JIANG Jun-long1,2, YANG Jia-jia1

(1.College of Materials Science and Engineering, Nanjing University of Science and Technology,Nanjing Jiangsu 210094, China; 2.Taizhou Research Institute of Nanjing University of Science and Technology, Taizhou Jiangsu 225300, China)

AbstractThis paper is carried out basing on the 7 mm high nitrogen steels fiber laser welding. The effect of heat input on stomatal resistance, microstructure and mechanical properties are researched. Results are as following: with the improvement of heat input, the number of stoma reduced but then increased later. when the heat input is 400 kJ/m, the stoma is almost disappeared. The high nitrogen austenitic stainless steel base metal is of austenite and part is in the form of twins. The weld is of cast fine austenite grains， partly dispersing Cr2N nitrides. Heat-affected zone width and the grain size increased significantly with the increasing of heat input. Comparing the micro-hardness and mechanical properties of different welding parameters, we can know that the hardness of the weld and heat-affected zone decreased with the increasing of heat input. Cleavage sites are all the weld zone during tensile test. The maximum tensile strength is 971.4 MPa, reaching 94.3% of the base material strength.

Keywords WeldingHigh nitrogen steelHeat inputStomaMicrostructure

Mechanical property

0引言

近年来不锈钢发展迅猛，导致了对镍的需求升高，寻求代替镍元素并同时获得较好力学性能和耐蚀性的元素成为行业人士研究的重点。

通常来说，高氮奥氏体不锈钢 (以下简称高氮钢)的氮含量超过0.4%，其主要利用N元素部分甚至完全代替合金元素Ni在室温甚至低温下获得单相奥氏体组织[1]。利用氮进行合金化具有很多优点[2～5]：(1) 与碳相比,氮为更加有效的固溶强化元素,同时可以促进晶粒细化；……