Atlas 310/310S/310H are chromium-nickel austenitic stainless steels. They combine excellent high temperature properties with good ductility and weldability. Atlas 310S (UNS S31008) is used when the application environment involves moist corrodents in a temperature range lower than that which is normally considered “high temperature” service. The lower carbon content of 310S does reduce its high temperature strength as compared to that of 310H. Atlas 310H (UNS S31009) has a carbon content restricted to exclude the lower end of the Atlas 310 range. It is the grade of choice for high temperature applications. Grade 310L encompasses a series of proprietary grades, generally with a 0.03% maximum carbon and sometimes used for very specific corrosive environments such as urea production. Like other austenitic grades, the 310 family has excellent toughness, even down to cryogenic temperatures, although other grades are normally used in sub-zero environments.