Rod A 335 P 11 is supplied in annealed, normalized, normalized and tempered condition. Depending on the conditions specified in P.O grain size will alter according to the condition of heat treatment desired and needed for supply while ordering. Generally, grain size of P 11 will be ASTM No: 5 or smaller if it is meant for furnace tubes - depending on the design temp specified in process heater tubes - and if specified in normalized and tempered condition. Generally, the tempering temp should be at least 50 deg F higher if ordered. If you have not specified at the time of P.O, then manufacturer can supply in ASTM No: 5 or smaller and this should be acceptable for use. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Feb 6, 2008 E-mail: nishi@vsnl.com >Dear collegues, > >If it is not specified to the manufacturer: Is there any >range of grain size in which the A335 P11 is produced ? Do >you know any source to clarify this ? > >The reason is that we are evaluating this type of tubes in >an oil refinery furnace, and there is no data about original >microstructure condition (because this supplementary >requirement was not required by the purchaser), in order to >compare. > >Thanks for your help. > >rod