Standard Practice for Extreme Value Analysis of Nonmetallic Inclusions in Steel and Other Microstructural Features

Importancia y uso:

5.1 This practice is used to assess the indigenous inclusions or second-phase constituents in metals using extreme value statistics.

5.2 It is well known that failures of mechanical components, such as gears and bearings, are often caused by the presence of large nonmetallic oxide inclusions. Failure of a component can often be traced to the presence of a large inclusion. Predictions related to component fatigue life are not possible with the evaluations provided by standards such as Test Methods E45, Practice E1122, or Practice E1245. The use of extreme value statistics has been related to component life and inclusion size distributions by several different investigators (3-8). The purpose of this practice is to create a standardized method of performing this analysis.

5.3 This practice is not suitable for assessing the exogenous inclusions in steels and other metals because of the unpredictable nature of the distribution of exogenous inclusions. Other methods involving complete inspection such as ultrasonics must be used to locate their presence.

Subcomité:

E04.09

Referida por:

A1089_A1089M-14R20

Volúmen:

03.01

Número ICS:

77.040.99 (Other methods of testing metals)

Palabras clave:

extreme value statistics; inclusion length; maximum inclusion length; maximum likelihood method;