Hi! I am currently reviewing a fabrication drawing for a 6.0 mm thk. carbon steel KO drum with 2.0 mm thk. SS 304 cladding. The base plate is SA 516 Gr. 60 and the SS plate liner is SA 240 Gr. 304. The vessel design Pr. is 0.26 MPa @ 250 deg. C. Vessel dimensions are 1500 mm O.D x 6000 mm T/L. The vendor proposes to attach the SS liner by plug welding (10 mm plugs) at 300 mm rotated sqare pitch. Considering that SS has a higher co-efficient of thermal expansion than CS, would the proposed attachment method be adequate? Is their a method where by the pitch of plug welds can be ascertained for such cladding methods based on the design temperature / pressure? Ashish

Thank You Luis. This precisely is my problem. ASME Sec. VIII Div. 1 allows only 30 % of the total load to be carried by plug welds (UW-17). We are in no position to revise the equipment specs. NIDI paper on sheet lining underscores the importance of determinig the pitch of plug welds. Is their a reliable method to estimate the stresses on the plug weld ? Desperate designer! Ashish

Thank You Luis. For avoiding such problems in the future, is their a method where by the stress on the plug welds can be estimated, so that equipment specifications can be prepared accordingly. Ashish