PROCESS FOR PRODUCING LS-CRNIMO30C STEEL FORGING USING CONTINUOUS CASTING BILLET FOR SUBSEA OIL PRODUCTION WELLHEAD DEVICE

摘要

The invention provides a process for producing an LS-CrNiMo30C steel forging using a continuous casting billet, for use in a subsea oil production wellhead device. A forged round steel bar is produced employing a Φ600 mm continuous casting round billet. The process includes steps of smelting molten steel, continuous casting, forging, annealing, cooling, and the like. A temperature ramp rate when heating the casting billet during forging is ≤ 200ºC/h, a forging heating temperature is 1200-1250ºC, a primary forging temperature is higher than 1150ºC, and the final forging temperature is not less than 850ºC. After being removed from the production line, the forgings are slowly cooled in a sand pit under a high temperature of ≥ 500ºC. After the temperature decreases to below 200ºC, the forgings are removed from the sand pit and slowly cooled.