This question does not belong in a materials/corrosion related forum Suugest that you re-post on www.eng-tips.com.... There are forums there that discuss heat exchangers and pressure vessels. MJC

Suneel First of all please remember that cast materials of HK / HP centri cast materials do not come under API code. Cast HP material - as centrigugally cast have tolerances for out of straightness as per normal piping code tolerances. as per ACI (Alloy Casting Institute designations and tolerances specified in this) Normally these cast tubes (in reformer service) coem in segments of 3 M to 4 M as cast with out of roundness, straightness tolerance specified in ACI cast tube designations. ACI more or less follows the Piping standard for out of roundness and out of straightness code . Refer any Piping Hand book for details or ASA B 31.3 code also. Besdies these, the centri cast reformer tubes are welded in two or three or four segments to make up as a reformer tube - 12 M to 13 M long - with out of straightness or dimensional tolerance for straightness made to each manufacturing purchase order specifications. P.O. specificattions and stringency can vary from purchaser to purchaser of these materials as reformer tube materials. Each process and manufcturing design specifies this straightness requirements to each P.O. Generally these also follow the piping standard requirements for out of roundenss and out of straightness. Deviation should be strictly less than 1 % that of O.D of each pipe or cast segment so that the slender reformer tube - 12 M to 13 M long - does not have too much out of straightness in a 12 M long piece as welded. This is tested at the shops before final assembly is accepted according to P.O. specification for straightness at each stage. Trust this is of help for your problem. C.V.Srinivasan Nishi Engineers Pvt Ltd Chennai 20 India Feb 26,2005 E-mail: nishi@vsnl.com . nishi@hathway.com >Mr. Cronin >Either you could not understand the qusetion , becauase this >is a qusetion related to cast material 25Cr35Ni that is why >i have put on this forum. >Thanks for your suggestion >Suneel