MICROSTRUCTURE OF FE-CR-C HARDFACING ALLOYS WITH ADDITIONS OF NB, TI AND, B (REPRINTED FROM METALLOGRAPHY, VOL 20, PG 401-429, 1987)

The abrasive wear of machine parts and tools used in the mining, earth moving, and transporting of mineral materials can be lowered by fille r wire welding of hardfacing alloys. In this paper, the microstructure s of Fe-Cr-C and Fe-Cr-C-Nb/Ti hardfacing alloys and deposits and thos e of newly developed Fe-Cr-C-B and Fe-Ti-Cr-C-B ones are described. Th ey show up to 85 vol.% of primarily solidified coarse hard phases: i.e ., Carbides of MC-, M7C3-, M3C-type and Borides of MB2-, M3B2-, M2B-, M3B-, M23B6-type, which are embedded in a hard eutectic. This itself c onsists of eutectic hard phases and a martensitic or austenitic metal matrix. The newly developed Fe-Cr-C-B alloys reach hardness values of up to 1200 HV and are harder than all purchased ones. The primary soli dification of the MB2-type phase of titanium requires such high amount s of titanium and boron that these alloys are not practical for manufa cture as commercial filler wires.