Roll forming of electric resistance welded pipes with high ductility

近年来，为了减轻汽车重量，开发深井油气藏，对高强度钢制电阻焊管的需求越来越大。另一方面，高强度钢强调回弹和加工硬化，这使得钢管的制造比常规钢困难得多。本文详细研究了轧辊类型、轧辊直径和板材强度对管材辊弯成形的影响。使用了以下两种轧辊：一种(A型)是通过上下辊在圆周方向上完全夹紧薄板的辊架，另一种(B型)是只在边缘夹住薄板的辊架。通过实验和数值研究，阐明了管材辊弯成形的基本变形机理，并发现B型轧辊在辊弯成形过程中产生的加工硬化具有较好的成形性。

Recently electric resistance welded pipes made of high strength steel are increasingly needed to decrease weight of cars and to develop deep wells of gas and oil. On the other hand, springback and work-hardening are emphasized in high strength steels, which yield the manufacturing of the pipes much more difficult than conventional steels. In this study, the influence of roll type, roll diameter and sheet strength on the roll forming of the pipes was examined in detail. The following two kinds of rolls were used: The one (Type A) was the roll stand that pinched the sheet entirely in circumferential direction by top and bottom rolls, and the other one (Type B) was the roll stand that pinched the sheet only in the edge. From the experimental and numerical investigations, a basic deformation mechanism of roll forming of the pipe could be clarified, and moreover, it was found that Type B roll gave better formability in terms of work-hardening that arose during the roll forming process.