Method of producing high strength sucker rod coupling

摘要

A sucker rod coupling 10 having a high ultimate tensile strength, resistance to corrosion, and resistance to surface cracking arising out of a method of making the sucker rod coupling 10, which employs a five- step process of forming a coupling 10. First, a hollow cylindrical core 12 from a heat treatable steel is formed. Second, a thin coating 18 of metallic alloy is applied to the outer surface of the core 12. Third, the core 12 is heat treated. Fourth, threads 20 are partially cut in the inner surface of the core 12. Fifth, the threads 20 are cold worked to transform the partially cut threads 20 into finished threads 20 and to place the thread roots 22 in compression.