Development of TQ508-70Y hydraulic casing tongs with big caliber and high torque;

Based on the small borehole of bushing,un-breaking of main casing tong,less precision of torque meter,and inapplicable measure of whipstock in casing,several means are used to solve the said problems,that is 380 mm rotary Kelly and bushing,strain gauge torque meter and multi-stage self floating whipstock.

The author analyzes the impacts on tubing thread linking intensity of hydraulic tong with the finite element method,the Von Mises and contact pressure distributes of casing thread liking in condition of different holding position for backup tong have been obtained,and he puts forward the technological transformation measures of hydraulic holding system,designs a three-plate-style-tong-door.