The advantage of friction welding is that, different steel qualities can be chosen for the mid-body section and the tool joints. High quality alloy steel is used for the tool joints, Zero maintenance, and long lasting life of the rods. When required, an additional surface hardening can be applied to the tool joints for increased wear resistance. The rods have spanner flats on the pin and box ends. Plastic/Metal thread protectors are available for all API connection types. The rods are suitable for both DTH hammer and rotary drilling on (Top Drive Machine) The drill pipes can also the supported with fully induction hardened to increase the life.