600MPa and 800MPa steel plates employed to the White Crane Dam

600MPa and 800MPa steel plates with low crack-sensitivity and relevant welding materials have been employed to the White Crane Dam, the Mega kW class super hydropower station developed by the Three Gorges Group. The White Crane hydropower station is equipped with 16 1-million-kilowatt generator units with a total installed capacity of 16 million kilowatts. All completed and put into use, it will become the second largest hydropower station next to the Three Gorges. The 1 million kW class hydropower unit is second to none in the world, having higher requirements for the strength, toughness and weldability of steel plates. The maximum thickness of the plate is up to 125mm with the normal impact value at -40? and the aging impact value reaching above 100J at -20?. The low temperature toughness of the welding joint must be 47J or more. It’s very difficult technically. As per requirements for good weldability and high toughness from users, Shougang (Shouqin) redesigned production processes based on in-depth investigation and adjusted the alloy content of Ni, Cr, Mo, etc. Shougang performed a series of experiments on quenching, tempering and component specifications, ultimately achieving the best match between strength and toughness. Shougang spent two years developing weldable steel plates with 600MPa and 800MPa for large hydropower station, acquiring complete techniques from design, production to welding.