摘要
分别采用水刀、激光和冲制3种方法在FB780钢板试样上加工圆孔。利用扩孔机、金相显微镜、扫面电镜和显微硬度计研究了用不同方法加工的圆孔的可延伸凸缘性能。结果显示,用水刀加工的圆孔扩孔率最高,冲制加工的圆孔扩孔率最低,前者的扩孔率是后者的2. 7~3. 3倍大。冲制加工的圆孔平整度差,扩孔过程中易发生应力集中,导致其扩孔率低。圆孔平整度越高,变形区域越大,则其延伸凸缘性能也越好。在扩展过程中圆孔外缘的应力最大。当原板面朝上对冲制加工的圆孔进行扩孔时,裂纹的扩展方向会发生很大的改变,从而阻碍裂纹扩展,使扩孔率增大。
The round holes were fabricated in FB780 steel plate specimens by using water-jet,laser and punching,respectively.Stretch-flange-formability of the round holes fabricated by the three processes was investigated by means of hole expanding machine,optical microscopy(OM),scanning electron microscopy(SEM),and micro-hardness tester.The results showed that expansion rate was the best for the round hole formed by water-jet,and the lowest for the round hole formed by punching process,and the expansion rate of the former was 2.7 to 3.3 times as great as that of the latter.Flatness of the round hole fabricated by punching was poor,and stress concentration was easy to occur during the hole expanding,which resulted in its low expansion rate.Both the better flatness of round hole and the larger deformation area was,the better stretch-flange-formability of round hole was.Stress developing during the hole expanding in outer edge of the round hole was the maximum.When the round hole fabricated by punching is expanded under condition that the original plate surface is upward,a considerable change in crack propagation direction will occur,which permits the crack propagation to be hindered,thus resulting in a better hole expansion rate.
作者
梁文
吴润
胡俊
王立新
甄瑞斌
王潇
Liang Wen;Wu Run;Hu Jun;Wang Lixin;Zhen Ruibing;Wang Xiao(College of Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan Hubei 430081,China;Research&Development Center of WISCO,Wuhan Hubei 430080,China;Quality Inspection Center of WISCO,Wuhan Hubei 430080,China)
出处
《上海金属》
CAS
北大核心
2018年第5期13-20,共8页
Shanghai Metals
基金
国家自然科学基金(No.51771139)
关键词
激光
水刀
冲制
FB780钢板
延伸凸缘性能
laser
water-jet
punching
FB780 steel plate
stretch flange formability
