不锈钢无缝管无中间退火连续环辊旋轧成形工艺  

Continuous ring-roller spinning process on stainless steel seamless tube without intermediate annealing

作　　者：许镱巍 李绍禄 赵军[2] 赵宁 赵春江[1,3] Xu Yiwei;Li Shaolu;Zhao Jun;Zhao Ning;Zhao Chunjiang(School of Mechanical Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;School of Information Science and Technology,Taiyuan University of Science and Technology,Taiyuan 030024,China;Transfer Preparatory Office of Modern College of Humanities and Sciences of Shanxi Normal University,Linfen 041000,China)

机构地区：[1]太原科技大学机械工程学院,山西太原030024 [2]太原科技大学信息科学与技术学院,山西太原030024 [3]山西师范大学现代文理学院转设筹备处,山西临汾041000

出　　处：《锻压技术》2023年第5期137-146,共10页Forging & Stamping Technology

基　　金：国家自然科学基金面上项目(52275358)。

摘　　要：提出了一种环辊旋轧成形新工艺,其存在变形区应力三轴度小于断裂截止值即η<-1/3的平面压缩剪切应力状态,探究了这种应力状态在管材环辊旋轧过程中对塑性变形的影响规律。采用有限元和材料表征相结合的方法,分别验证了变形区应力状态分布和基于此应力状态的微观组织演化特征。采用自主设计加工的回转式环辊旋轧机,对57 mm×3 mm的304奥氏体不锈钢无缝管进行减壁加工,经过5道次无中间退火连续环辊旋轧加工后,得到最小壁厚为0.35 mm的不锈钢无缝管。对加工后的各道次管材试样的形貌特征、材料性能和微观结构进行表征,结果表明,成形后管材壁厚均匀度好,马氏体相的体积分数增长至35%,达到峰值,在累积变形量达到1.8 mm时晶粒尺寸达到200 nm并保持稳定,后续的塑性变形过程通过晶粒拉伸断裂和晶界强化增塑效应实现。A new process of ring-roller spinning was proposed,which has a plane compressive shear stress state where the stress triaxiality in the deformation zone was less than the fracture cut-off value,namely,η<-1/3,and the influence laws of this stress state on the plastic deformation during the ring-roller spinning process for tube was investigated.Then,the stress state distribution in the deformation zone and the microstructure evolution characteristics based on this stress state were verified by a combination of finite element and material characterization method,and the wall-reducing processing of 304 austenitic stainless steel seamless tube with the size of 57 mm×3 mm was carried out by a rotary ring-roller spinning machine of independent design and processing.Furthermore,the stainless steel seamless tube with the minimum wall thickness of 0.35 mm were obtained after five passes of continuous ring-rolling spinning process without intermediate annealing,and the morphological characteristics,material properties and microstructure of the processed tube specimens were characterized.The results show that after forming the wall thickness uniformity of tube is good,the volume fraction of martensite phase increases to 35%,and reaches the peak value.When the cumulative deformation amount reaches 1.8 mm,the grain size reaches 200 nm and remains stable.The subsequent plastic deformation process is achieved through grain tensile fracture and grain boundary strengthening plasticizing effects.

关 键 词：环辊旋轧成形工艺 不锈钢无缝管 应力三轴度 微观组织 应力状态 

分 类 号：TG335.71[金属学及工艺—金属压力加工]