Abstract: Effect of continuous annealing temperature on tensile properties, hydrogen permeability, microstructure and precipitates of Ti-containing ultra-low carbon steel was studied. The results show that with the increase of annealing temperature, the strength of the tested steel decreases gradually, the formability and hydrogen permeability increase gradually, the average grain size increases gradually, and the proportion of small size precipitates within 50 nm increases obviously. When the annealing temperature is 830 ℃, the tensile strength is 290 MPa, the yield strength is 130 MPa, the elongation is 46.5%, the n value is 0.25, the r value is 3.0, the hydrogen permeation time is 12.0 min, and the average grain diameter is 14.3 μm, showing the best of formability and hydrogen permeation performance.

Key words: ultra-low carbon steel containing titanium, annealing temperature, microstructure, hydrogen permeation time, precipitates