Deep-drawn parts made of spring sheet steel which are especially used as a lightweight structural member or vehicle body part, and a method for the production thereof

US6364973B1 · kind B1 · utility

Assignee

• Daimlerchrysler AG · US

Inventors

• Roland Golle · Erding, DE
• Hartmut Hoffmann · Bad Wimpfen, DE
• Volker Thoms · Calw, DE

Key dates

• Filing date: Mar 27, 2001
• Grant date: Apr 2, 2002
• Expiry date: Mar 27, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D9/46
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to drawn pieces made of steel plate, particularly for motor vehicles bodies, and to a process for manufacturing such drawn pieces. In order to be able to manufacture drawn pieces with a high piece strength but of a low weight and with a low susceptibility to denting in a simple manner, according to the invention, a spring steel plate which is already hardened in the initial state, particularly bainitized—for example, CK60 or C63 or 67SiCr5—is used during the drawing of the vehicle body parts. The yield point of the heat-treated plate bar material is approximately in the range of from 800 to 1,800 N/mm2; the tensile strength is above that. Because of these strength values, plate bars of a plate thickness of approximately 0.3 mm to 0.6 mm can be used, whereby approximately 20 to 60% of the previous piece weight can be saved. The drawn piece according to the invention is therefore a definite lightweight part. In addition to being bainitized, the spring steel plate can be mechanically hardened, for example, by cold rolling or by a heat treatment.