Patent ID: 9080223
Filing Date: 2015-07-14
Classification: B60R,C21D,C22C,Y02P

Abstract:
1. A seamless steel tube for an airbag characterized by having a quenched-and-tempered microstructure and a steel composition which consists of, in mass percent, C: 0.05-0.20%, Si: 0.10-0.50%, Mn: 0.10-1.00%, P: at most 0.025%, S: at most 0.005%, Al: 0.005-0.10%, Ca: 0.0005-0.0050%, Nb: 0.005-0.050%, Ti: 0.005-0.050%, Cu: 0.01-0.50%, Ni: 0.01-0.50%, Cr: 0.01-0.50%, B: 0.0005-0.0050%, N: 0.002-0.010%, and a remainder of Fe and unavoidable impurities, and which satisfies the following Equation (1), the tube having a tensile strength of at least 1000 MPa, a yield strength of at least 960 MPa, and a high toughness such that vTrs100 is −100° C. or below: wherein M indicates Cr, and the symbols for elements indicate the contents in mass percent of those elements.