Development of K55 Hi-frequency Electric Resistance Welded Casing

Briefed in the paper are the current production situations of the K55 casing both at home and abroad.Based on the shaping characteristics of the Baosteel HFW production line,it is pointed out that with the process of heat-treatment over the entire length of the welded pipe,relevant mechanical property targets can be met,while the chronic technical problem of material work hardening during the shaping process as employed is tackled.With considerations of the design conception of TRIP(transformation induced plasticity)steel and the requirements of OCTG end-users,massive production of the K55 HFW casing is realized at Baosteel by using the heat treatment process of whole-length inter-critical quenching and elevated-temperature tempering.