Q460高强度钢冷挤压内螺纹的表层显微组织及力学性能  

Microstructure and Mechanical Properties of Internal Thread during Cold Extrusion for Q460High Strength Steel

作　　者：缪宏[1] 左敦稳[2] 张瑞宏[1] 

机构地区：[1]扬州大学机械工程学院,江苏扬州225009 [2]南京航空航天大学机电学院,江苏南京210016

出　　处：《高压物理学报》2013年第3期337-342,共6页Chinese Journal of High Pressure Physics

基　　金：国家863计划(SQ2008AA10XK1468859)

摘　　要：根据冷挤压内螺纹的成型过程,对螺纹表层的微观结构、显微硬度和力学性能进行了测试,得到了牙顶、牙侧和牙底3个位置硬化程度、硬化层深度及沿层深的组织变化规律。结果表明,冷挤压加工可使内螺纹表层组织显著细化,在挤压过程中,表层纤维组织被压紧到难以分辨出晶粒的程度,形成一层流线,平稳绕过牙底并沿牙侧向牙顶方向流动。其中牙根处晶粒最细,牙顶处晶粒最粗,牙侧部分介于二者之间。同时,挤压过程中螺纹表层的显微硬度与抗拉强度显著增加,而塑性和韧性出现下降,产生了加工硬化现象,大大提高了冷挤压内螺纹的表面质量和机械强度。According to the forming process of internal thread, the microstructure, microhardness and mechanical properties of internal thread surface layer were investigated. The microstructure change and deformation mechanism, harden ability and depth of hardening layers on the crest, the flank and the root of the thread along the layer depth direction were obtained. The results showed that the grains on the surface layers of the thread were refined after the cold extrusion. Fibrous structure of the metal surfaces on the root of thread was pressed to distinguish the grains difficultly, and formed a layer of flown line and smoothly rounded the root to flow from the flank to the crest. The grains on the root were the smallest, followed by the flank and the crest. In the extrusion processes, the mierohardness and the tensile strength of the material were increased significantly,and the plasticity and the toughness were decreased. The work-hardening phenomenon greatly increased the surface texture and the mechanical strength of internal thread with cold extrusion.

关 键 词：内螺纹 挤压成型 显微组织 力学性能 

分 类 号：TG376.2[金属学及工艺—金属压力加工]