Bimetal

Bimetal refers to an object that is composed of two separate metals joined together.

Trimetal and tetrametal refer to objects composed of three and four separate metals respectively.

Blades for bandsaws and reciprocating saws are often made with bimetal construction.

The teeth, made of high-speed steel, are bonded (by various methods, for example, electron beam welding or laser beam welding) to the softer high-carbon steel base.

Such construction makes for blades with a better combination of cutting speed and durability than shown by non-bimetal blades, because the advantages and disadvantages of each of the metals are applied in the best locations: the teeth are harder (and thus cut better), but therefore also brittler; meanwhile, the body area of the band is softer (which would make for poorer teeth), but also less brittle, and thus more resistant to cracking and breaking (which is desirable in the body area).