Delayed fracture resistance of 1500 MPa grade bolts influenced by galvaniccorrosion

Delayed fracture resistance of 1500 MPa grade bolts was investigated taking account of hydrogen absorption due to galvanic corrosion. 1500 MPa grade b olts with various chemical compositions were served for accelerated delayed fracture test under the given clamp conditions. Delayed fracture resistanc e of the bolts appeared to be improved with increase in their K(1)scc value s. However, 1500 MPa grade maraging type steel bolts were delayed fractured although it had extremely high K(1)scc value. In order to estimate hydroge n amount absorbed into the testing bolts due to galvanic corrosion, Thermal Desorption Spectrometry (TDS) analysis was conducted. It was revealed that maraging type steel touched with a mild steel absorbed large amount of dif fusive hydrogen owing to galvanic corrosion. The relationship between delay ed fracture resistance of 1500 MPa grade bolts and their K(1)scc values was discussed from the viewpoint of galvanic corrosion.