1.2 Heat treatment control

Heat treatment will greatly improve the material strength and increase the thread wear life 

of the rods and casings. We conduct either tru-wall or both ends heat treatment to the 

tube body. After heat treatment, strength, hardness, straightness and concentricity of the 

treated tubes will be tested in our lab. 

1.3 Thread opening process:   

Accuracy of threads will determine the use effects and life time of drill rod and casings.  

CNC latches and form cutter are used in thread opening processing to minimize error

made by anthropic factors. 

1.4 Additional thread treatment:

Surface of the threads will be cleaned to remove burr adhered after threads are opened.

Afterwards, the tread surface will be phosphated to improve surface conditions.