| 摘要 |
PROBLEM TO BE SOLVED: To produce a seamless steel tube for an accumulator for air bag system, excellent in workability and weldability and having high strength and high toughness. SOLUTION: A steel, having a composition consisting of 0.01-<0.20% C, <=0.50% Si, 0.30-2.00% Mn, <=0.020% P, <=0.020% S, <=0.10% Al, and the balance Fe with inevitable impurities, is subjected to hot tube making at >=750 deg.C final finishing temp. The resultant steel tube is used in this state or used in a state after subjected, after hot tube making, to stress relief annealing, normalizing, annealing, and hardening or is used after subjected to quench-and-temper treatment. By this method, the seamless steel tube, excellent in workability and weldability and having high strength and high toughness, can be produced. |
