新型0Cr17Mn17Mo3NiN奥氏体不锈钢模拟焊接热影响区的组织和性能

Microstructure and property of simulated heat affected zone of new austenitic stainless steel 0Cr17Mn17Mo3Ni N

利用Gleeble-3500热模拟试验机模拟0Cr17Mn17Mo3Ni N钢在3种不同的热输入量下的焊接热循环试验。通过光学显微镜(OM)、扫描电镜(SEM)、冲击试验机和显微硬度计对模拟焊接热影响区粗晶区的显微组织和力学性能进行研究。结果表明:随着热输入量的增加,试验区的晶粒不断粗化;在热输入量为5 k J/cm时,粗晶区有条状碳化物析出,热输入量增加后,碳化物的析出逐渐减少直至消失;热输入量的变化对粗晶区的冲击吸收能量影响较小,其断裂机理为韧性断裂,氧化夹杂物为其裂纹源;粗晶区的显微硬度随热输入量的增加,硬度值下降,但均高于母材,不存在明显的软化区。

The welding-thermal-cycling experiments for 0 Cr17 Mn17 Mo3 Ni N steel with different heat input were carried out on Gleeble-3500 thermal simulator. The microstructure and mechanical properties of the simulated zone of HAZ with the coarse grain were characterized by optical microscope（ OM）,scanning electron microscope（ SEM）,impact testing machine and micro-hardness tester. The results show that the grain size grows with the increase of heat input. When heat input is 5 k J/cm,there is strip carbide precipitation in coarse grain zone.When the heat input increases,the carbide precipitation gradually reduces until it disappears. The change of heat input has less effect on the impact absorbed energy of CGHAZ（ coarse grain heat affected zone）,its fracture mechanism is ductile fracture and oxide inclusions is its crack source. With the increase of heat input,the microhardness of coarse grain zone decreases,but it is higher than the base metal,and there is no softened zone observed.