微波淬火对低合金船板钢梯度组织结构及性能的影响

Effect of microwave quenching on gradient structure and properties of low-alloyed ship plate steel

为制备具有梯度结构的船板钢,采用了微波淬火及冷轧工艺在船板钢厚度方向上形成温度梯度,并利用光学显微镜(OM)、扫描电镜(SEM)、硬度测试及拉伸试验等研究了微波淬火保温时间对船板钢显微梯度组织结构及性能的影响。结果表明:随微波淬火保温时间的增加试验钢组织和硬度梯度化加深,抗拉强度显著提升。在微波淬火保温10 min与冷轧后,试验钢表层与心部硬度差值最大,为126.6 HV0.1,抗拉强度较传统淬火工艺提高了57%,为1218 MPa。此时,试验钢的拉伸断口形貌为密集细小的韧窝状,且分布均匀,有利于提高材料抵抗拉伸变形的能力。

Ship plate steel with gradient structure was prepared by forming temperature gradient in its thickness direction using microwave quenching and cold rolling processes,and the effect of microwave quenching holding time on microstructure and properties of the steel was studied by means of optical microscope(OM),scanning electron microscope(SEM),hardness test and tensile test.The results show that with the increase of microwave quenching holding time,the microstructure and hardness gradients of the tested steel are deepened,and the tensile strength is also significantly increased.After microwave quenching for 10 min and cold rolling,the hardness difference between the surface and the core of the tested steel is 126.6 HV0.1 as the largest,and compared with that of the traditional quenching process,the tensile strength is increased by 57%,which is 1218 MPa.The tensile fracture morphology of the tested steel is composed of dense and fine dimples with uniform distribution,which is beneficial to improve the resistance to tensile deformation of the material.