ASTM E1457-15
金属蠕变裂纹扩展时间测量的标准试验方法
Standard Test Method for Measurement of Creep Crack Growth Times in Metals
ASTM E1457-15 发布历史
ASTM E1457-15由美国材料与试验协会 US-ASTM 发布于 2015。
ASTM E1457-15在国际标准分类中归属于: 77.040.10 金属材料机械试验。
ASTM E1457-15的历代版本如下：
- 2019年 ASTM E1457-19e1 金属蠕变裂纹生长时间测量的标准测试方法
- 2019年 ASTM E1457-19 金属蠕变裂纹生长时间测量的标准测试方法
- 2015年 ASTM E1457-15 金属蠕变裂纹扩展时间测量的标准试验方法
- 2013年 ASTM E1457-13 测量金属蠕变开裂增长速度的标准试验方法
- 2007年 ASTM E1457-07e4 测量金属蠕变裂纹生长时间的标准试验方法
- 2007年 ASTM E1457-07e3 金属蠕变裂纹生长时间测量的标准测试方法
- 2007年 ASTM E1457-07e2 测量金属蠕变开裂增长次数的标准试验方法
- 2007年 ASTM E1457-07e1 金属蠕变裂纹生长时间测量的标准测试方法
- 2007年 ASTM E1457-07 金属中蠕变裂纹发展时期的测量用标准试验方法
- 2000年 ASTM E1457-00 金属蠕变裂纹生长时间测量的标准测试方法
6.1 Creep crack growth rate expressed as a function of the steady state C* or K characterizes the resistance of a material to crack growth under conditions of extensive creep deformation or under brittle creep conditions. Background information on the rationale for employing the fracture mechanics approach in the analyses of creep crack growth data is given in (11, 13, 30-35).
6.2 Aggressive environments at high temperatures can significantly affect the creep crack growth behavior. Attention must be given to the proper selection and control of temperature and environment in research studies and in generation of design data.
6.2.1 Expressing CCI time, t0.2 and CCG rate, da/dt as a function of an appropriate fracture mechanics related parameter generally provides results that are independent of specimen size and planar geometry for the same stress state at the crack tip for the range of geometries and sizes presented in this document (see Annex A1). Thus, the appropriate correlation will enable exchange and comparison of data obtained from a variety of specimen configurations and loading conditions. Moreover, this feature enables creep crack growth data to be utilized in the design and evaluation of engineering structures operated at elevated temperatures where creep deformation is a concern. The concept of similitude is assumed, implying that cracks of differing sizes subjected to the same nominal C*(t), Ct, or K will advance by equal increments of crack extension per unit time, provided the conditions for the validity for the specific crack growth rate relating parameter are met. See 11.7 for details.
6.2.2 The effects of crack tip constraint arising from variations in specimen size, geometry and material ductility can influence t0.2 and da/dt. For example, crack growth rates at the same value of C*(t), Ct in creep-ductile materials generally increases with increasing thickness. It is therefore ne......
