Research on cryogenic impact toughness of deposited metals of high manganese steel for LNG

MENG Liang; WANG Honghong; CHEN Yakui; MENG Qingrun; WANG Changhong

doi:10.7512/j.issn.1001-2303.2020.11.22

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Research on cryogenic impact toughness of deposited metals of high manganese steel for LNG
Vol. 50, Issue 11, Pages: 120-123(2020)
DOI： 10.7512/j.issn.1001-2303.2020.11.22

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MENG Liang, WANG Honghong, CHEN Yakui, et al. Research on cryogenic impact toughness of deposited metals of high manganese steel for LNG. [J]. 50(11):120-123(2020)
DOI：

MENG Liang, WANG Honghong, CHEN Yakui, et al. Research on cryogenic impact toughness of deposited metals of high manganese steel for LNG. [J]. 50(11):120-123(2020) DOI： 10.7512/j.issn.1001-2303.2020.11.22.

摘要

设计三种不同Mn含量(12%～20%)的LNG用超低温奥氏体高锰钢熔敷金属,采用OM、SEM、XRD分别对熔敷金属进行组织分析、断口观察和物相分析,测定低温冲击韧性。结果表明:Fe-(12～13)Mn熔敷金属显微组织为奥氏体(A)和α’马氏体(α’-M),Fe-20Mn熔敷金属的显微组织为全奥氏体(A)。室温下,A含量分别为78%、85%、96%、100%。Fe-(12～13)Mn熔敷金属在冲击过程中发生γ→α’-M相变,-196℃冲击吸收功分别为6.7 J、11.7 J,表现为脆性断裂。Fe-20Mn冲击试验后熔敷金属仍保持全奥氏体组织,-196℃平均冲击吸收功为67 J,断裂形式属于韧性断裂。控制和避免发生TRIP效应是超低温奥氏体高锰钢熔敷金属设计的关键。

Abstract

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.