NP550钢板淬火开裂的关键组织结构因素  

Key microstructural structure factors for quench cracking of NP550 steel sheet

作　　者：白洁 靳慎豹 梁川 闫强军 尤泽生 赵永好[1] 刘丽华 沙刚 BAI Jie;JIN Shen-bao;LIANG Chuan;YAN Qiang-jun;YOU Ze-sheng;ZHAO Yong-hao;LIU Li-hua;SHA Gang(School of Materials Science and Engineering/Herbert Gleiter Institute,Nanjing University of Science and Technology,Nanjing 210094,China;Nanjing Iron and Steel Co.,Ltd.,Nanjing 210035,China)

机构地区：[1]南京理工大学材料科学与工程学院/格莱特研究院,江苏南京210094 [2]南京钢铁股份有限公司,江苏南京210035

出　　处：《塑性工程学报》2023年第1期155-161,共7页Journal of Plasticity Engineering

摘　　要：为探究影响NP550含硼钢薄板淬火开裂的关键因素,采用扫描电镜、透射电镜以及三维原子探针等多尺度表征手段对NP550淬火未开裂钢板表面和淬火开裂钢板表面和心部的微观组织、合金元素分布以及力学性能进行了对比分析。结果表明,开裂钢板的裂纹起始于板厚中心区域的原奥氏体晶界处并沿原奥氏体晶界扩展。钢板心部原奥晶粒粗化、沿晶界的铁素体和脆性渗碳体的析出以及硼元素被晶界含硼相的消耗是导致开裂钢板,特别是板厚中心处强度和塑性降低的主要原因。钢板在淬火应力下发生剧烈开裂。结合淬火工艺,生产过程中应注意控制高压水的出水量,保证冷却速率,有效防止淬裂现象发生。To study the key factors responsible for the quench cracking of NP550 boron-containing steel thin-sheet,the microstructure,alloy element distribution and mechanical properties of uncracked steel sheet surface,cracked steel sheet surface and cracked steel sheet center of NP550 were analyzed using multiscale characterizations including scanning electron microscopy(SEM),transmission electron microscopy(TEM)and atom probe tomography(APT).The results show that the crack of the cracked steel sheet starts from the primary austenite grain boundary in the center of the sheet thickness and extends along the primary austenite grain boundary.The coarsening of the primary austenite grains in the center of the steel sheet,the precipitation of ferrite and brittle cementite along the grain boundaries,and the consumption of boron at the grain boundary by boron-containing phase are the main reasons for the reduction of strength and plasticity of the cracked steel sheet,especially in the center of the sheet thickness.The steel sheet cracks seriously under the quenching stress.Combining with the quenching process,the water yield of high-pressure water should be controlled well in the production process to ensure the cooling rate and effectively prevent quench cracking phenomenon.

关 键 词：含硼钢 淬火开裂 元素分布 析出相 三维原子探针 

分 类 号：TB3[一般工业技术—材料科学与工程]