This is the case in the manufacture of saws. The saw is first hardened and tempered and then straightened on an anvil by means of a hammer. After it is hammered true, it is ground and polished a little, then blued to stiffen it and then is subjected to the grinding process. Before bluing, the metal is full of strains; these are entirely removed by the heat required to produce the blue color. Often a piano-wire spring will not stand long wear if used without heating, while if heated it will last for years.
To Render Fine Cracks In Tools Visible.
To Utilize Drill Chips.
To Remove Fragments Of Steel From Other Metals.
Testing Steel.
Welding Compound.
The precaution should be observed, the same as with any of the cyanides, to avoid breathing the poisonous fumes.