The hydrogen embrittlement sensitivity of L80 steel under different hydrogen pressure at room temperature was evaluated this work. The variation rules of hydrogen embrittlement sensitivity of L80 steel at hydrogen pressure from 3 MPa to 12 MPa were studied by notch slow strain tensile test combined with fracture analysis. Results showed that L80 steel had no obvious brittleness at room temperature under hydrogen pressure of lower than 5 MPa, and yet had obvious brittleness under hydrogen pressure of more than 8 MPa. Under hydrogen pressure from 3 MPa to 12 MPa, the micro morpholgy at the center of the main section of L80 steel tensile sample changed from dimple morphology to coexistence of dimple morphology and cleavage morphology. The micro morphology at the edge gradually changed from dimple morphology to cleavage. In addition, the change rate of section shrinkage gradually increased from 16.19% to 46.79%. With the increase of hydrogen pressure, the plastic loss of L80 steel increased, the fracture showed obvious embrittlement characteristics, and the hydrogen embrittlement sensitivity gradually increased.
