Pillow plate Material
Most plates are stainless steel 304L to 254SMO. Keppels has laser-welded copper, aluminium and titanium pillow plates on IPG fiber-laser machines, described in Heat Exchanger World. New alloys still need a weld and inflation trial.
Figure: stainless pillow plate beside a aluminum, copper and titanium pillow plate.
Which metals?
Daily work is austenitic stainless (304L through 254SMO). Duplex and carbon steel are possible. Copper, aluminum and titanium need qualified parameters, inflation trials and, for titanium, oxygen-free shielding. Unequal thickness is normal for single-embossed plates. Do not copy a 304 procedure onto copper or titanium. Copper starting gauges sit in the thin-sheet range (published copper tops from about 0.1 to 1.5 mm (0.004–0.059 in).
