Abstract: There is provided a wear-resistant chain having a high durability even in severe use environments such as those of a timing chain of an engine even though it is highly efficient and productive. A miniaturizing agent containing silicon is doped in a vanadium cementation process of a base material of steel. Vanadium carbide forming a surface-hardened layer contains a secondary phase composed of an amorphous structure containing silicon within crystal grains and a crystal grain size of the vanadium carbide is miniaturized to 1 ?m or less.

Abstract: A silent chain using double-sided driving link plates having symmetrical upper and lower teeth has a problem that it is unable to assure a required risky sectional area of the plates because a width between upper and lower crotches is narrow. The invention provides a silent chain using double-sided driving link plates whose required risky sectional area is maintained by using link plate whose back side is undercut and whose upper and lower parts are unsymmetrical even though its front side has a shape of a normal link plate. A distance from a line connecting centers of pin holes to a bottom of an upper-side crotch is equal to or more than ½ of a diameter of the pin hole to assure the risky sectional area. Teeth of the back side are cut away to form a flat surface to assure a contact area with a shoe and others.

Abstract: There is provided a wear-resistant chain having a high durability even in severe use environments such as those of a timing chain of an engine even though it is highly efficient and productive. A miniaturizing agent containing silicon is doped in a vanadium cementation process of a base material of steel. Vanadium carbide forming a surface-hardened layer contains a secondary phase composed of an amorphous structure containing silicon within crystal grains and a crystal grain size of the vanadium carbide is miniaturized to 1 ?m or less.