Abstract: A rack bar and a method for production thereof. The rack bar is composed of a steel pipe (10) and an embedded metal core (14) placed therein. The steel pipe has rack teeth formed thereon by forging. The embedded metal core (14) is made of a metal softer than the steel pipe (10) and has its surface wave-shaped such that the bottom (20) is wide and the top (22) is narrow.

Abstract: Disclosed herein are a rack bar and a method for production thereof. The rack bar is composed of a steel pipe (10) and an embedded metal core (14) placed therein. The steel pipe has rack teeth formed thereon by forging. The embedded metal core (14) is made of a metal softer than the steel pipe (10) and has its surface wave-shaped such that the bottom (20) is wide and the top (22) is narrow.

Abstract: A method of manufacturing a part with a tooth profile by cold forging includes an initial step of forming a initial tooth profile and a finishing step of forming a completed tooth profile by sizing. Between the initial step and the finishing step, is an intermediate step tooth thickness of the initial tooth profile is either maintained or reduced by 10% or less from the tooth thickness of the initial tooth profile. In the intermediate step an addendum part is expanded beyond the initial tooth profile by cold forging.

Abstract: A method of manufacturing a tooth profile part by cold forging comprising: an initial step of forming a initial tooth profile: a completing step of forming a completed tooth profile by sizing: between the initial step and the completing step, maintaining a tooth thickness of the initial tooth profile identical to a tooth thickness of the initial tooth profile or reducing a tooth thickness within a range of 10% or less compared to a tooth thickness of the initial tooth profile, and at the same time including an intermediate step of ejecting an addendum part over the initial tooth profile by cold forging.