摘要
易切削不锈钢1Cr17MoS中硫化物随冶炼控制方式的差异会呈现不同的形态。采用正常冶炼方式对1Cr17MoS钢进行锻制,硫化物呈细长条形状,长度一般为50~80μm,长宽比为5~12;夹杂物尺寸为1~5μm,大部分夹杂物小于3μm。在冶炼中通过添加微量元素使1Cr17MoS钢经过锻制后的硫化物呈纺锤状、点球状,长度为10~30μm,长宽比为2~5;夹杂物尺寸为3~20μm,大部分夹杂物为10~20μm。通过对不同硫化物形态的1Cr17MoS钢进行纵向和横向拉伸试验,结果表明,2种形态下1Cr17MoS钢的纵向拉伸断口均为韧窝断口,韧窝数量和大小受硫化物数量和宽度的影响,其形态与力学性能没有明显关系;1Cr17MoS的横向拉伸断口以准解理断口为主,还存在部分韧窝断口。传统冶炼方式中,冶炼过程未经过硫化物形态处理,细长条状硫化物破坏了试验钢基体的连续性,加速了横向拉伸的脆性断裂。而经过硫化物形态处理的冶炼方式中,纺锤状和点球状硫化物以韧窝形态出现,保留了试验钢的塑性特征,使其具备较好的横向拉伸性能。
Sulfide morphology in free-cutting stainless steels 1Cr17MoS is shown different with different control techniques in steelmaking practice.For 1Cr17MoS steels with traditional steelmaking practice and forging process,sulfides presented thin and long stringers with the length of 50-80μm and aspect ratio of 5-12,the sizes of sulfides were generally between 1μm and 5μm and most sulfides were less than 3μm.However,for 1Cr17MoS steels with the addition of microalloying elements in steelmaking practice and forging process,spindle and globular sulfides were formed with the length of 10-30μm and aspect ratio of 2-5,sizes of sulfide were generally between 3μm and 20μm and most sulfides were between 10μm and 20μm.The longitudinal and transverse tensile tests of 1Cr17MoS steel with different sulfide morphology were carried out.It is testified that fractures in 1Cr17MoS steels are dimple fractures in longitudinal tensile test at both conditions,the quantity and size of dimples are influenced by the quantity and thickness of sulfides,while the morphology of dimples have no obvious effect on mechanical properties of steels.The transverse tensile fractures of 1Cr17MoS steels are mainly quasi-cleavage fractures,and also have partial dimple fractures at both conditions.In traditional steelmaking practice with no sulfide morphology treatment,sulfide stringers break the continuities of matrix for test steel,which accelerate the brittle rupture of transverse tensile fractures.However,with sulfide morphology treatment in steelmaking practice,sulfides in spindle and globular shapes occur as dimples in fracture,which lead to better transverse tensile properties due to the remained plastic properties.
作者
张军
张秀丽
李造宇
杨娥
ZHANG Jun;ZHANG Xiu-li;LI Zao-yu;YANG E(Special Metallurgical Products Research Institute,Daye Special Steel Co.,Ltd.,Huangshi 435001,Hubei,China;Hubei Provincial Key Laboratory of High-quality Special Steel,Huangshi 435001,Hubei,China)
出处
《中国冶金》
CAS
北大核心
2022年第6期134-138,共5页
China Metallurgy
