FAQ

Why sometimes the surface color of the product different?

We prepare thermal refined material, and relieve stress after molding as necessary.
The color may be changed by heat treatment.
The amount of oil attaching on the surface of material or the state of heat-treatment furnace are different. It causes the difference in color of the oxidation film of the products at heat treatment.                     
However, the difference in color of the oxidation film may not have any influence on the mechanical feature of the products.