Studies on Fusion Welding of High Nitrogen Stainless Steel: Microstructure, Mechanical and corrosion Behaviour

International Conference on Recent Advances in Materials, Mechanical and Civil Engineering

材料科学;机械制造;土木建筑工程

Mohammed, Raffi^1 ; Srinivasa Rao, K.^2 ; Madhusudhan Reddy, G.^3

Department of Metallurgical and Materials Engineering, NIT, Andhra Pradesh, India^1

Defence Metallurgical Research Laboratory, Hyderabad, India^2

Department of Metallurgical Engineering, Andhra University, Visakhapatnam, India^3

关键词: 3.5% nacl solutions;    Electron back scattered diffraction techniques;    Gas tungsten arc welding;    High nitrogen stainless steel;    High nitrogen steels;    Microstructural changes;    Shielded metal arc welding;    Uniform distribution;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/330/1/012035/pdf
DOI  :  10.1088/1757-899X/330/1/012035

来源: IOP

【 摘 要 】

An attempt has been made in the present investigation to weld high nitrogen steel of 5mm thick plates using various process i.e., shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW) and autogenous electron beam welding (EBW) process. Present work is aimed at studying the microstructural changes and its effects on mechanical properties and corrosion resistance. Microstructure is characterized by optical, scanning electron microscopy and electron back scattered diffraction technique. Vickers hardness, tensile properties, impact toughness and face bend ductility testing of the welds was carried out. Pitting corrosion resistance of welds was determined using potentio-dynamic polarization testing in 3.5%NaCl solution. Results of the present investigation established that SMA welds made using Cr-Mn-N electrode were observed to have a austenite dendritic grain structure in the weld metal and is having poor mechanical properties but good corrosion resistance. GTA welds made using 18Ni (MDN 250) filler wire were observed to have a reverted austenite in martensite matrix of the weld metal and formation of unmixed zone at the fusion boundary which resulted in better mechanical properties and poor corrosion resistance. Fine grains and uniform distribution of delta ferrite in the austenite matrix and narrow width of weld zone are observed in autogeneous electron beam welds. A good combination of mechanical properties and corrosion resistance was achieved for electron beam welds of high nitrogen steel when compared to SMA and GTA welds.