Patent ID: 6878219

Claim:
A process of manufacturing a high strength steel pipe for an air bag having excellent bursting resistance, characterized by producing a pipe from a steel material having a composition, in mass %, of: C: 0.05-0.20%, Si: 0.1-1.0%, Mn: 0.20-2.0%, P: at most 0.025%, S: at most 0.010%, Cr: 0.05-1.0%, Al: at most 0.10%, and a remainder of Fe and impurities, subjecting the steel pipe to cold working to obtain predetermined dimensions, then heating it to a temperature of at least the Ac 1 transformation temperature followed by quenching, and then performing tempering at a temperature no higher than the Ac 1 transformation temperature, the steel pipe having a tensile strength of 900 Mpa or more.