GB/T 15248-2008 in English

《GB/T 15248-2008金属材料轴向等幅低循环疲劳试验方法》由519（中国航空工业集团公司）归口，主管部门为中国航空工业集团公司。
本标准代替GB/T 15248-1994《金属材料轴向等幅低循环疲劳试验方法》。本标准规定了金属材料轴向等幅低循环疲劳试验的设备、试样、试验程序、试验结果的处理及试验报告。本标准适用于金属材料等截面和漏斗形试样承受轴向等幅应力或应变的低循环疲劳试验，不包括全尺寸部件、结构件的试验。适用于时间相关的非弹性应变和时间无关的非弹性应变相比较小或与之相当的温度和应变速率。本标准与GB/T 15248-1994《金属材料轴向等幅低循环疲劳试验方法》相比，主要变化如下：
―――将标准的适用范围从适用于“与时间有关的非弹性应变和与时间无关的非弹性应变相比小得可以忽略不计的温度和应变速率下试验”改为适用于“时间相关的非弹性应变和时间无关的非弹性应变相比较小或与之相当的温度和应变速率”下的试验；
―――删除原附录Ｃ“带过渡圆弧试样应变范围修正”及正文中标距内带圆弧的试样及其相关内容；
―――删除使用差动变压器和上、下引伸杆组成的引伸计系统示意图；
―――在数据处理中推荐采用循环弹性模量进行计算，增加了与循环弹性模量相关的符号和说明；
―――对图、表、设备、试样、试验环境、记录和失效判定等中的部分技术内容进行了修改；
―――将原标准中表述可能引起分歧的部分及文字错误进行了修改。

1 Scope

This standard specifies the equipment, sample, test procedure, treatment of test result and test report, etc. for the axial loading constant-amplitude low-cycle fatigue test of metallic materials.
This standard is applicable to the low-cycle fatigue tests of funnel-like samples that are made of metallic materials and with equal section in case of bearing axial constant-amplitude stress or strain, excluding the test of full-size component and structural member, and also applicable to the tests carried out at lower or equal temperature and strain rate than those of time-dependent inelastic strain and time-independent inelastic strain. It is permitted to conduct test under such environmental factors as temperature, pressure, humidity and media, which, however, shall remain constant during the entire test.
Note: this standard may serve as a guideline for low-cycle fatigue test in material development, mechanical design, technology and quality control, product performance determination and failure analysis.

2 Normative References

The following documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments to (excluding corrections), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest editions of these documents are applicable. For undated references, the latest editions apply.
GB/T 10623 Metallic Materials—Terms of Mechanical Test
GB/T 12160 Calibration of Extensometers Used in Uniaxial Testing
JJG 556 Verification Regulation of Axial Force Fatigue Testing Machines

3 Symbols

See Table 1 for symbols, names and units used in this standard and explanations.

Foreword I
1 Scope
2 Normative References
3 Symbols
4 Terms and Definitions
5 Apparatus
6 Sample
7 Test Procedure
8 Treatment of Test Results
9 Test Report
Appendix A (Informative) Functional Relation
Appendix B (Informative) Conversion of Radial Strain to Axial Strain for Isotropic Materials
Appendix C (Informative) Example for Sample Machining Method
Appendix D (Informative) High Temperature Test with Hold Period