回火温度对低合金高强度贝氏体钢组织和性能的影响  

Effect of tempering temperature on microstructure and mechanical properties of high strength low alloy bainite steel

作　　者：彭云[1] 郑惠锦[2] PENG Yun ZHENG Hui-jin(Central Iron ＆ Steel Research Institute, Beijing 100081, China Shanghai Shipbuilding Technology Research Institute, Shanghai 200032, China)

机构地区：[1]钢铁研究总院,北京100081 [2]上海船舶工艺研究所,上海200032

出　　处：《材料热处理学报》2017年第7期114-119,共6页Transactions of Materials and Heat Treatment

摘　　要：研究了回火温度对一种低温压力容器用低合金高强度(HSLA)贝氏体钢组织和性能的影响。结果表明,经过910℃淬火后组织为粒状贝氏体,贝氏体板条界面及板条上分布有条状或块状M-A岛。回火温度在350~550℃区间升温时,M-A岛分解析出渗碳体;回火温度为635℃时,M-A岛完全分解为细小弥散的渗碳体颗粒;回火温度升至700℃时,贝氏体铁素体组织发生再结晶,板条结构消失,成为块状铁素体结构,渗碳体明显粗化。随着回火温度的升高,抗拉强度降低,伸长率和-50℃冲击功增加,屈服强度先升高后降低,冲击断口由脆性解理断口向韧性纤维断口变化。经过910℃淬火+635℃回火后达到最佳的强韧匹配度,抗拉强度为606 MPa,-50℃冲击功达到279 J。The effect of tempering temperature on microstructure and property of high strength low alloy bainite steel was investigated. The results show that the microstrueture of the steel is granular bainite after quenching at 910℃ , M-A islands distribute on the bainite lath and its boundary. M-A island is decomposed and cementite precipitated continually when tempering temperature increases from 350 to 550℃ ; when tempering temperature reaches 635℃ , M-A islands completely decompose into the fine and dispersion eementite panicles; when tempering temperature is up to 700 ℃ , the recrystallization of bainite ferritie structure occurs, and lath structure disappears and transforms into massive ferrite, and the eementite coarsens obviously. With the increasing of tempering temperature, the tensile strength of the steel decreases, and elongation and impact absorbed energy tested at -50 ℃ increase, and yield strength increases first and then decreases, and meanwhile the impact fracutre changes from brittle cleavage fracture to ductile fibrous fracture. The excellent matching of strength and toughness of the steel is obtained after quenching at 910 ℃ and tempering at 635℃ , and the tensile strength is 606 MPa and low temperature impact absorbed energy tested at -50℃ is 279 J.

关 键 词：回火温度 贝氏体 冲击功 M-A岛 

分 类 号：TG142.2[一般工业技术—材料科学与工程]