*New Challenges in Residual Stress Measurements and Evaluation*

stress, survival probability and surface roughness were considered [8]. As a result, quantitative fatigue safety factor as shown in **Figure 26** was obtained.

the shrinkage and relaxation of the existing material. Therefore, it is possible to perform a definite durability assessment only by the basic relationship between the

basic load and the material (**Figures 27** and **28**) [10].

*Durability Assessment Considering Residual Stress DOI: http://dx.doi.org/10.5772/intechopen.90298*

**Figure 27.**

**Figure 28.**

**141**

*Continuous cooling transformation diagram.*

*Phase diagram of Fe-Fe3C.*

The residual stresses and assessment methods mentioned in the above studies can often be different from the residual stresses in welding and their more complicated assessment methods. This is because, in the case of welding, the change of the metal structure due to the introduction of heat energy occurs, and thus a complicated residual stress is formed. However, the residual stress generated in this study is not related to the residual stress due to the temperature change and is related to

**Figure 25.** *Method for durability assessment.*
