HFW pipe straightness

Straightness is a measure of HFW (high frequency welding)

An important indicator of the quality of steel. The higher the straightness, the easier it is to ensure the quality of the oil well pipe thread, but also for the subsequent processing and testing facilitated. In the production, the causes of excess HFW pipe straightness are the following:

1, frame straightening improper adjustment

1) bending phenomenon

HFW pipe bowing out from the sizing units, and fixed bend in one direction.

2) Remedy

HFW straightening, using Turkey head adjustment straightness. Turkish first reverse bend properly adjusted deflection is the key to control HFW pipe bending. For the leveler frame improper adjustment, the operator should be kept near the Turkish flying saw head frame is fixed, according to the bending direction, another Turkish first reverse appropriately adjusted.

2. Coil strength uneven

1) bending phenomenon

Pipe bending phenomenon is more serious, and pipe bending direction is not the one direction.

2) Remedy

Due to the bending strength caused by uneven coil, must be resolved by the coil production plant by improving its rolling level. Intensity difference around the coil should be controlled within 30MPa.

3, the upper and lower surfaces of the steel pipe temperature unevenness

1) bending phenomenon

Production of steel pipe after cutting it straight, but curved occurred while finishing bench cooling, and the same overall pipe bending direction.

2) Remedy

Transform cooling device, the upper surface of the cooling water the size of a controlled amount of water, the surface temperature of the upper and lower steel remains the same; for large diameter steel pipe, when a water-cooled cooling water to maximum, the surface temperature is still higher than the lower surface, may be appropriate to reduce the production line Susu or install coolant towers, accelerate cooling liquid cooling; with anti-transfer method, which depending on the direction and extent of bending steel finishing bench in reverse when sizing straightening adjustments.

4, will be less than the diameter amount

1) bending phenomenon

Fixed before the hydrostatic test pipe is straight, but after the hydrostatic test bending phenomenon, and bending direction.

2) Remedy

By an appropriate increase in the amount of sizing, reducing excessive residual stress HFW pipe, bending phenomenon can be avoided, after sizing 若果 increase the amount of bending phenomenon persists, it is necessary to further adjust the forming pass, giving a sheet additional deformation to compensate for springback deformation, reducing residual stress, and ultimately solve the problem of such bent tubes.