MENG Liang, WANG Honghong, CHEN Yakui, et al. Research on cryogenic impact toughness of deposited metals of high manganese steel for LNG[J]. Eletric Welding Machine2020, 50(11): 120-123.DOI: 10.7512/j.issn.1001-2303.2020.11.22.
Research on cryogenic impact toughness of deposited metals of high manganese steel for LNG
Three different compositions of cryogenic austenitic high manganese steel(12~20 wt.% Mn) deposited metal are designed for LNG. The OM
SEM and XRD were used for the microstructure analysis
fracture observation and phase analysis of deposited metal respectively. The results show that the microstructure of Fe-(12 ~13) Mn deposited metal is austenite and α’-martensite
and the microstructure of Fe-20 Mn deposited metal is all austenite. At room temperature
the austenite contents of deposited metals are 78%
85%
96%and 100% respectively. The Fe-(12 ~13) Mn deposited metal undergoes γ →α’-M phase transformation during impact process
and the impact absorption energy at-196 ℃ are 6.7 J and 11.7 J respectively
showing brittle fracture. After the Fe-20 Mn impact test
the deposited metal still retains the full austenite microstructure
the average impact absorption energy at-196 ℃ is 67 J
and the fracture form is ductile fracture.Controlling and avoiding TRIP effect is the key to the design of cryogenic austenitic high manganese steel deposited metal.