API IIB AISI4140/4130 Sucker rod coupling

API IIB AISI4140/4130 Sucker rod coupling   Product Description Spraying alloy powder on sucker rod coupling doubles the rate of surface hardness; and extends a longer service life. Specifications of Sucker Rod Coupling Type Model OD mm Width of Wrench Square  mm Length of Wrench   mm   Rounding chamfer      θ…