Qualitative Comparison
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Qualitative Comparison








Pipe thread type & 1:16 taper

 "Open-space" thread processing, teeth, especially taper forming is instability

The conical rollers is excellent, durable and wear-resistant tools makes "closed-space" forming, to ensure the thread shape and taper and other dimensions being consistency over and over

When the lathe tool is cutting V-thread, the friction and wear between the blade, the front and the back of the tool and the steel pipe are uneven. The axial movement of the tool when the unstable lathe machine  is working will exacerbate this instability


Dimensional stability of thread in mass production

Tool wear and machine instability can be compensated by numerical control system through empirical data, the effect is not ideal, the production cost is high, and it is difficult to achieve in large-scale production or on-site construction

The long life of the rolling system ensures that the product quality consistency



Poor, easy to destroy internal and
external threads when installation

Good, self-centering technology, to ensure that the two ends of the pipe thread concentricity is good, easy to install

The concentricity of the inner threaded parts will be required higher and higher


Surface roughness

The point contact between the knife and the steel pipe causes the surface of the thread to be rough, and the spot welding phenomenon that damages both male and female threads during large torque-tightening

The roller is in contact with the steel pipe, and the height between the convex and concave peaks and valleys of the thread after forming is 1~4um, which is almost equivalent to grinding

Look-like-grinding roughness makes it fit well with the internal thread. The poor tightness is one of the reasons causing easy leakage of the connection


Strength of extension

50% lower than the original steel pipe

Compared with cutting pipe threads, the tensile strength is increased by 150-180%

Compared with the metal fiber in the thread section, the metal fiber in the thread section is extruded and extended by rolling, and the metal grain density is increased. After extrusion, the thread is thick and dense and hardened by cold forming thread, resulting in greatly improved mechanical connection strength of the thread

Bending strength

50% lower than the original steel pipe

Compared with cutting pipe threads, the bending strength is increased by 150-170%

Shear strength

50% lower than the original steel pipe

Compared with cutting pipe threads, its shear resistance is increased by 140~170%

Fatigue resistance

200% lower than the original steel pipe

Compared with cutting pipe thread, its fatigue strength is increased by 250~400%


Thread surface strength

The friction heating of steel pipe causes the hardness of thread surface to decrease

Compared with the cutting thread, the surface hardness is increased by 130%


Pressure bearing capacity of
steel pipe

50% lower than the original steel pipe

The weight per unit length of the rolled steel pipe thread is equal to that of the original pipe


Corrosion resistance of pipe thread section

The hot dip galvanizing layer is 100% removed, and the thread section has no corrosion resistance

The galvanized layer is 100% retained, and the corrosion resistance is equal to that of the original pipe even better

Improved oxidation resistance of thread surface 40 times or more, increasing corrosion resistance of joints

The metal fibers are cut, and the surface is "scarred" with high roughness

The grain structure density of the steel pipe in the thread section is increased from grade 6 to 8.5