A method is disclosed of producing a billet which can be heated and rolled or otherwise worked with conventional equipment to form a product with a steel core and a cladding of an alloy including stainless steel, nickel-chrome, nickel-copper or copper-nickel. For a product such as corrosion resistant reinforcing bar, the billet includes a solid steel core inserted in a tube of the alloy on which swaging operations are carried out, decreasing the transverse size of discrete portions of the tube. The part of the tube interfacing with the steel body may be swaged, increasing the length of the tube and decreasing the transverse size of the steel body at the interface. To prevent oxidation of chrome and other metals in the tube, one or more briquettes of scavenging metal are inserted in the parts of the tube that project clear of an end of the core.