Zn-Ni AS A COATING LAYER ON SELF-DRILLING SCREWS OF AUSTENITIC STAINLESS STEEL

Abstract

A self-drilling screw (10) having a head (20), a shaft (30) at least partially wearing a thread (35) and a drill point (40). The base material of the screw (10) including the drill point (40) is integrally manufactured from an austenitic 300 series steel with a surface hardness (uncoated) of 400-600 HV 0.3. The surface of the screw has a top coating of Zn—Ni with a Ni-content between 12-15% deposited on the austenitic base material. This self-drilling screw (10) is manufactured from a blank of raw austenite 300 series steel which is initially squeezed by cold forming to reduce its diameter in a first operation and, in following cold forming operations the head, the drill point and a thread are formed.

Dependencies are inferred from the claim text.