Product details of API Spec 7-1 standards Drilling Rig Square Kelly and Hexagonal Kelly for Sale Kelly is the drive part of whole drill string, it transmit the torsional energy from the rotary table to the in the bottom of the hole. The precision-machined kelly is a heavy square or hexagonal steel bar supported by the swivel through the rotary table and connected to the first joint of drill pipe in the drill string. Our kelly has been approved by the NS-1 certification. Straightness is the key manufacturing process. Straightness is checked before, during and after each machning operation. Flats are precision-milled to API and NS-1 specifications. All milling is performed on specially designed rigid kelly mills.Each kelly is furnished with a pressed steel thread protectors. Features of Kelly They are made of AISI 4142H-4145H forged or rolled alloy structural steel. Quenching plus tempering thermal treatment will be conducted over the whole length. Its Brinell hardness can reach 285-341 on the basis of such thermal treatment. Charpy impact energy: 54J. The formulated process can ensure that the misalignment of the hole reaches the standard wall thickness. When ordering the Kelly please specify: 1. kelly type(square or hexagonal) 2. nominal size and overall length 3. upper and lower connection
