Carbide precipitation is a phenomena that happens to virtually all alloys that contain carbon. Carbon loves to gather together and attach itself to certain metallic elements of which Cr seems most reported. When it happens to austentic SS's it is generally referred to as sensitization . With CrMo's or carbon steels it is one of the metallurgical changes that take place with the heat of welding in HAZ's or PWHT assisting in stress relief as the carbon is removed from solution. With Nickel alloys these carbides can be corrosively detrimental. Basically it alters the grain structure of steel and thus weakens it.The kinetics of carbide precipitation is a function of time, temperature, and carbon content of the steel. Higher carbon contents will have less time in the CP temperature range than the lower carbon grades. So, a way to avoid CP, would be to use a low carbon grade or a stabilized grade of stainless steel (example is 321 or 347).
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