Heat treatment process optimization and quality control of wind power bolt

The general specification of wind power bolts is greater than M30,the tensile strength of bolts after heat treatment is required to be≥1040MPa,and the impact absorption energy at-40℃is required to be≥27J.Due to the ductile-brittle transition temperature of the material,there is a risk of fracture when the tower and blade special-shaped bolts are used below this temperature,so it is very important to improve the low-temperature impact property of the steel for bolts.The continuous improvement and development of heat treatment process for wind power bolt were introduced,and the effects of raw material defects,banded structure in steel and tempering temperature on mechanical properties of bolt steel were discussed.Finally,the new design of steel composition for bolt and quality control measures for wind power bolt were put forward.