This standard outlines the conditions that enhance the risk of hydrogen embrittlement of steel and define the relief procedures required to minimize the risk of hydrogen embrittlement. It is intended to control the process. 1.1 Hydrogen embrittlement of steel, which can cause brittle fractures under stress, occurs as a result of the absorption of hydrogen during cleaning, phosphate coating and plating processes. The susceptibility to hydrogen embrittlement increases with increasing stress (internal or externally applied stress) and increasing material strength. 1.2 Hardness readings in this specification are in Vickers scale. SAE J417 should be referred to for conversion to other scales. NOTE 1: All references to temperatures relate to part core temperature and not the indicated oven air temperature. Statistical data of verifications in temperature at the center of the oven load and oven temperature shall be established to develop the oven profile. The temperature of parts in a batch type of baking furnace shall be monitored with a thermocouple placed in the middle of the load. For continuous bake ovens a temperature trace through the oven must be run with a calibrated thermocouple in the lowest temperature position, at least once a year.
