304不锈钢薄壁管环向材料力学行为的实验表征

Experimental characterization on material mechanical behavior in the hoop direction of 304 stainless steel thin-walled tubes

为了改进管件内高压成形工艺,用实验研究了某种304不锈钢薄壁金属管材料力学特性。研究了薄壁金属管的环向材料力学行为,搭建了环向拉伸试验装置,建立了环状试件测试段受力和夹具受力之间的关系,分析了摩擦和试件装夹位置的影响;用数字图像相关分析技术(DIC),测量了环向拉伸应变;利用各向同性材料验证了环向拉伸试验方法的可靠性。结果表明:试验管材环向应力应变曲线呈S形,试验管材轴向和环向材料力学行为有显著差异。

Thin-walled 304 steel tube material behavior was investigated experimentally to improve the technique of tube hydro-forming. A ring hoop tension test （RHTT） system was built, and the simplified analytical model for the RHTT specimen was analyzed to evaluate the impact of friction and specimen position. The RHTT specimen strain was measured by using a digital image correlation （DIC） non-contact measurement system. The RHTT system and data processing method were verified using an isotropic material. The results show that an ＂S-shape＂ style is detected in the measured 304 tube hoop stress strain curve in large plastic deformation phase and there is significant difference between the material behavior in tube axial direction and that in hoop direction.