A total of six different alloys—stainless steel (SS) Types 310, 310S, 347, and 446, and nickel alloys 800 and 671—were tested using the slow strain-rate test technique in oxidizing/sulfidizing and in oxidizing/sulfidizing/carburizing simulated coal gasification environments, and in helium (and other inert environments) at both 450 and 600°C at a strain rate of 10^-6/s. Of the six alloys, four (Types 310 stainless steel and 310S stainless steel, nickel alloy 800, and nickel alloy 671) were found to be susceptible to cracking at 600°C by possibly different mechanisms, however, all were detected by the slow strain-rate technique.

For cracking, the nickel alloy 671 required no reactive environment; it suffered internal cracking in helium and all other test environments used. However, the stainless steel Type 310, Type 310S, and nickel alloy 800, all of which failed through surface initiated cracking, required increasingly severe environments for cracking. The Type 310 stainless steel required very little reactive environment; it cracked not only in the simulated coal gasification gases but also in low vapor pressure O₂ or water (H₂O) environments, or both (for example, helium), as did the Type 310S stainless steel, although with greater ductility than the Type 310 stainless steel. The nickel alloy 800 required the rather reactive environment of the simulated coal gasification gases; it did not crack in the low vapor pressure O₂ and H₂O environments.

The detection of the environmentally independent failure of Alloy 671 shows that the use of the slow strain-rate technique need not be limited to use for testing for susceptibility to cracking by stress corrosion cracking. The slow strain-rate technique is shown to be a viable testing method for detecting an alloy's propensity to premature failure in simulated coal gasification environments.