method of producing a high verformungsarbeit and an outer corrosion protection for labour stahlprofiles and its use for the manufacture of a tubular stahlprofils for reinforcing the door of a motor vehicle

摘要

Prodn. of a deformation resistant, externally corrosion protected steel profile with at least 1100 N/sq.mm. tensile strength and at least 8% galvanising. The novelty is that (a) the profile is made of a known C-Mn-Ti-B steel of compsn. (by wt.) 0.18-0.21% C, 0.3-0.5% Si; 1.1-1.3% Mn, 0.02-0.07% Ti, 0.002-0.007% B, balance Fe and impurities; and (b) the hardened steel profile is descaled, hot dip galvanised at max. 460 deg.C in a zinc bath contg. an added low melting element (pref. Pb) for max. 1 min. and then cooled to room temp. USE/ADVANTAGE - The process is used to produce tubular steel profiles for reinforcing automobile doors (claimed). The profile is produced from an inexpensive alloy steel which is free of expensive elements such as Ni, and has both the requisite corrosion protection and mechanical properties, i.e. tensile strength (Rm) of at least 1100 N/sq.mm., yield strength (Rt) of at least 800 N/sq.mm., elongation at fracture (H5) of at least 8% and deformation resistance (W-150) of at least 1900J.