Effect of Microelements and Tempering Process on Hydrogen-attack Resistance of 1.25Cr-0.5Mo Steels

Effect of tempering temperature and microelements on hydrogen-attack (HA) resistance of 1.25Cr-0.5Mo steels was investigated.It is shown that HA resistance of the steels has a close relationship with tempering temperature.The higher the tempering temperature,the more stable the carbides precipitated,but not the better the HA resistance.Maximum HA resistance can only be achieved by optimum distribution of Cr element between the carbides and the matrix for these microalloyed steels.Microelements can affect mechanical properties of the alloys,but not remarkably to the HA resistance.