SUS304材料的小冲孔蠕变试验研究

Study on Small Punch Creep Test for SUS304

小冲孔蠕变试验技术是一种采用微小试样、近乎无损地评定材料高温力学性能的新方法,本文应用小冲孔蠕变试验技术评定SUS304材料的高温力学性能。在不同温度下,对SUS304奥氏体不锈钢进行载荷范围为443N～513N的小冲孔蠕变试验,得到材料在不同试验条件下的蠕变曲线,通过中断试样的扫描电镜观察分析了试样的变形过程,讨论了影响小冲孔蠕变试验的主要因素。试验结果表明,从小冲孔实验获得的蠕变曲线与传统单轴拉伸蠕变实验的蠕变曲线具有一致性,都具有三个明显的蠕变阶段,利用小冲孔蠕变试验技术测试材料的高温性能是可行的。试验载荷越大,试样瞬时变形挠度越大,蠕变第二阶段速率越快,断裂时间越短。载荷、温度、试样厚度、环境是小冲孔试验的主要影响因素,对试验结果影响很大。

Small punch creep test technique (SPC) using miniature specimen is a new technique which is applied to evaluate the creep properties of materials in high temperature nearly non-destructively. SPC has been applied to evaluate the creep property of SUS 304 stainless steel at different temperature and load range of 443N^513N. A series of deflection curves under different conditions were obtained. Then, the deformation of specimens during the test was analyzed through observing the interrupted specimens by scanning electron micrograph. Also, the major factors influencing the test are discussed. The test results showed that the creep curves, determined by means of the small punch creep test, are similar to those obtained from a conventional uniaxial creep test. That is, they exhibited clearly three creep stages. The specimen central initial deflection and the creep rate of secondary stage increased with an increase of test load level, while the rupture time decreased. Load, temperature, thickness of specimen and environment are the major factors influencing the test.