VDI 3822 Blatt 2:2008-04

In this guideline, failures that result from mechanical conditions are described. By referring to the types of fracture described in this guideline, it is possible to classify fractures that occur in practice (Table 2 to Table 5). Types of fracture that occur almost exclusively in laboratory testing, e.g. the elongation of purely ductile metals to a point or blade, are not considered in this guideline. Production flaws that can lead to fractures are also not discussed. Therefore, failures that result from elongated slag inclusions or twinning will also not be addressed. Fatigue fractures in conjunction with tribology conditions (e.g. in roller bearings and gears) will be described in guideline VDI 3822 Part 5. Failures caused by deformation are addressed in guideline VDI 3822 Part 4, since they occur more frequently at higher temperatures. In cases where failures caused by deformation have occurred at room temperature VDI 3822 Part 4 applies analogously. Finally, it must also be kept in mind that strength factors are dependent upon temperature, and that the effects of coatings are also not considered.