Cause Analyses on Fracture of Absorber Spline Outer Canister for Oil Drilling Stem

Visual and microcosmic analyses on the fracture of absorber spline outer canister for oil drilling stem (spline outer canister for short) were performed.The material quality stress state and main configuration of the absorber were analyzed.It is indicated that the breakdown of the spline outer canister was fatigue fracture,and the cause of fracture was related to insufficient material toughness and inconsequential configuration with stress concentration.It is suggested that material toughness of spline outer canister should be enhanced,and the configuration at broken position should be improved.