The component has a black finish that I believe is from an iron phosphate process.
Analysis shows high concentrations of calcium in addition to iron, phosphorus and oxygen.
Can anyone tell me what the surface coating process may be and its potential for hydrogen embrittlement. The steel is a low alloy steel heat treated to about 50 HRC, so it will not take much hydrogen to cause embrittlement. Since yours if Rc 50, the possitility of failure due to embrittlement does exist. So does the possibility of thermal shock from the heat treating operation causing a microscopic crack. Were the parts flourecent magnetic particle inspected prior to phoscoat.