Heat transfer is depedent on 1. coeffiecent 2. temp difference 3 surface area change of moc can be offset by dereasing the wall thickness. Wall thickness is keeping in mind allowance corrosion due to sea water Use calorised Carbon steel it will be cheaper and better

Bob It is true what Krish has said on Aus S.S use in steam service especially when splashing or steam flash can result in accumulation of chlorides (of even low ppm) to cause SCC. Also, from heat transfer admiralty or Cu Ni is always better than Aus S.S Admiralty brass or Cu-Ni are widely used for steam turbine surface condenser usage for a long number of years (> 35 years) Admiralty can however fail if the steam is from boiler treated with hydrazine for scavenging oxygen. Excess ammonia from scavenged oxygen steam when flashed in surface condenser tubes can result in "season cracking" a well known phenomenon of SCC for brasses with traces of ammonia present. Many failures in admiralty tubes in surface condensers in steam turbine service were due to excess ammonia from steam (when hydrazine is used for scavenging oxygen from boiler drum / tubes). Cu-Ni may be a better alternative. Trust this helps you C.V.Srinivasan Nishi Engineers Pvt Ltd India August 6, 2007 E-mail: nishi@vsnl.com >In general for steam application ASS is not a prefered >material due to steam flashing and depositing of chloride in >the system.Even if less than 5ppm of chloride there have >been many failures reported due to ClSCC in ASS material if >the temperature exceeds more than 65 Deg.C. > >70-30 OR 90-10 Cu-Ni material is the bestion option to take >care both cooling water side as well as steam side to high >velocity resistant, > >regards,