焊接工艺对LNG储罐用高锰钢焊接接头组织和性能的影响OA北大核心CSTPCD

In order to promote the application of new domestic low-temperature high-manganese steel and corresponding welding consumables in the localization of LNG storage tanks,the effects of three different welding processes,i.e.,gas metal arc welding(GMAW),submerged arc welding(SAW)and shielded metal arc welding(SMAW)on the microstructure and mechanical properties of welded joints of high manganese steel for LNG storage tanks were investigated by scanning electron microscopy,optical microscopy and through tests such as tensile testing,bending test,impact toughness test and microhardness test.The results show that the microstructure of the heat affected zone of the three welding processes is composed of austenite and a small amount of inclusion particles.The grains near the fusion line are coarse and narrow,and the microstructure of the weld seam is columnar crystals.The lowest hardness values are all located at the center of the weld seam,and the fracture positions in the tensile test are all at the weld seam.The tensile strength of three welding processes welded joints is 839.2,863.8,675.2 MPa.The tensile and bending properties can meet the requirements.The-196℃impact energy of submerged arc welding seam is 123,100,83.7 J.The impact fracture surface is ductile fracture.The welding heat input of low-temperature high manganese steel should be strictly controlled so as to ensure welding quality of low-temperature high manganese steel.