Debasis SCC of Austenitic SS - Relationship of grain size for resistance to SCC depends on several factors viz., corrosive medium, concentration, temperature, agitation, aeration or no aeration, stress - whether applied or residual or a combination of both including thermal stresses ( predominantly tensile in nature). Difficult to give a general answer to a general question like this. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Nov 4, 2007 E-mail: nishi@vsnl.com This depends on corrosive service, concentration, temp, agitation or aeration >Fine Grain Steels are much more resistant to Stress >Corrosion Cracking than Coarse Grain Steel. > >Can this forum put on some light on what should be the ASTM >No. to demark fine/ coarse grain steel to reduce the >susceptibility towards SCC of austenitic SS w.r.t. this >aspect. > >regards

[updated:LAST EDITED ON Nov-05-07 AT 11:14 AM (CDT)]In addition to Srinivasan and Krish123 I can add the following: "SCC is believed to be nucleated at pitting damage sites and develops under the action of local tensile stresses as a highly branched network of fine cracks. At each crack tip the combined action of the tensile stress and specific ions in the corrosive media cause continual crack propagation with little evidence of local deformation. In austenitic stainless steels, for example, warm chloride solutions in the presence of residual tensile stress can lead to cracking. SCC tendency is slight in low Ni ferritic and martensitic grades but is severe in the 8-10% Ni austenitic steels. Duplex stainless steels have greater SCC resistance than austenitic since the duplex microstructure helps to inhibit the growth of SCC cracks, which tend to be deflected or arrested at austenite-ferrite interfaces." REGARDS luis marques