液氮温度下奥氏体不锈钢强度试验研究

Study on Strength of Austenitic Stainless Steel under Liquid- nitrogen Temperature

为研究低温和预应变对奥氏体不锈钢强度的影响规律,以奥氏体不锈钢S30408为例,对母材和9%预应变材料进行了液氮温度下恒定速率的拉伸试验。研究表明:材料屈服强度和抗拉强度规律均符合正态分布;在95%可靠度和90%置信度的条件下,母材和9%预应变材料屈服强度的标准值分别为383 MPa和449 MPa,抗拉强度的标准值分别为1521 MPa和1535 MPa;低温能够显著提高材料的屈服强度和抗拉强度,而预应变能够有效提高材料的屈服强度,但对于抗拉强度基本没有影响;低温会降低材料屈强比,而预应变则会提高屈强比。

To investigate the influence of low temperature and cold stretching on strength of austenitic stainless steel,the tensile tests were conducted under the liquid -nitrogen temperature with the parent metal and 9%-prestrained material of S30408.Results show that the distribution of yield strength and tensile strength can be described as normal distribution;Under the condition of 95%reliability and 90%confidence,the parent metal and 9%-prestrained metal′s standard values of yield strength are 383 MPa and 449 MPa respectively,and the standard values of ultimate tensile strength are 1521 MPa and 1535 MPa respectively;low temperature will increase yield strength and ultimate tensile strength dramatically, while the prestrain can only increase the yield strength;low temperature could decrease the yield ratio,yet cold stretching could increase it.