Hi, what would be the material with higher resistance to H2S environment? I refer to fontana, it says that higher Ni will be susceptible to sulfur attack due to Ni-S stability. Now I am using 304L, what is it a better material weldable and no galvanic corr that can replace the 304L? 2205? What other material beside it? Thanks! Cita

Hi Rahimi, yes, very similar to H2 embrittlement, but basically, the hydrogen molecules are produced from the reaction of H2S and the Fe. This very small molecule hidrogen then enter the material and cause the material becomes brittle than normal condition. The crack can be initiated by H2 due to its molecular pressure, combined to existing residual stresses or applied stress. And Mr Hendrix, and others.... I am still a bit confuse to determine better material that is better than 304L. Refer to several articles, it is consistantly stated that 316L will be better than 304L, why is that so? is it because 316L contains higher Nickel? Why is it also stated in other reference book that Ni will increase susceptibility of the material? what is it exaclty the correlation between Ni and Fe+H2S reaction? Because refer to the tensile strength, reducing the possibility of SSC from occuring is to avoid using high hardness, or high strength materials which is obviously susceptible bec of their brittleness, i have compared the strength of 304L and 316L and they both are similar, including the hardness number. so, what is the basic reason of choosing 304L instead of 316L? (under condition : Temperature less than 100 Celcius,differential, moderate pressure). Thanks! CITA