Abstract
The lead adherence to the specimens which were previously annealed to eliminate the internal strain, relating to the effects of the grain size, structure and carbon contents, was studied. The following results were obtained.
(1) As lead diffuses into grain boundaries of the specimens lead coating on ferrite is possible. The specimen SPC-3 normalized at 950°C for 30 min yields heavy adherent coating. But the specimen annealed at 750°C for 30 min has in ferior coating to the raw material because of the coarse grain.
(2) Lead adheres to the pearlite and the spheroidized cementite in steel and to the graphite in plane cast iron: Accordingly, the adherence increases in the order of ferrite→hypo-eutectoid steel→eutectoid steel→hyper-eutectoid steel→cast iron, and the coating thickness increases with the carbon content.
(3) The coating on steel containing Mn and Si and on 13-Cr stainless steel is possible. In this case, it appears that the intermediate layer is formed.
(4) Lead cannot adhere to the oxide film and the decarburized layer in the specimen. The existence of inclusions, blow holes and lattice defects seems to make lead coating possible.
