Luis A 333 G r 6 can be ordered and heat treated to get varying fine grain size - i.e, from grain size - six to nine. Generally, when and if used for low temp service, fine grain steel will give better impact strength. Also fatigue properties are improved in fine grained A 333 Gr 6. Depending on the grain size needed as per order and achieved, low temp impact and also fatigue strength can be improved in A 333 Gr . Trust this helps you C.V.Srinivasan Nishi Engineers Pvt Ltd India Mar 23,2007 E-mail: nishi@vsnl.com >Dear Sir.s > >I would like know if we have any correlation bettewen grain >size and steels to low temperature (ex: A333 Gr 6). > >Many thanks > >Luis