The basic principle of forming adjustment of welded pipe

Achieving high-quality welded pipes requires careful adjustment during the forming process. Understanding the following principles is crucial to ensure proper alignment, precision, and stability in the production of welded pipes.

Horizontal and Vertical Alignment

Horizontal Alignment: The upper and lower flat roller axes must be perfectly level with the horizontal plane, ensuring that neither end is higher or lower than the other. The axes must remain parallel both under load and without load.

Vertical Alignment: The vertical roller must be perpendicular to the working table of the welded pipe unit. Horizontal alignment impacts the force applied to the tube blank, while vertical alignment ensures the stable operation of the tube blank.

Roll Adjustment According to the Rolling Line

Height Correction: The forming lower roll and vertical roll should be adjusted to align with the rolling bottom line, ensuring that the passes of these rolls match the elevation of the rolling line.

Pass Symmetry Inspection: The symmetry of the forming lower roll and vertical roll passes should be checked against the rolling center line. Misalignment can lead to production defects and issues with welded pipes.

Clear Division of Labor for Vertical Rolls

The forming flat roll is primarily responsible for power transmission and lateral deformation, while the vertical roll controls the tube blank's rebound after exiting the flat roll pass. It also guides the tube blank into the next pass smoothly. Over-reliance on vertical roll forming can increase rolling resistance and lead to instability, so its function should be gradually minimized while enhancing its control and guidance roles.

Ensuring Equipment Precision

High precision in equipment is essential for consistent forming adjustments. Producing high-precision welded pipes is impossible without stable and accurately aligned equipment.

Timely Solidification of Adjustments

Once the forming adjustments are completed and test runs are successful, all adjusted parts should be tightened to prevent any loosening or positional changes that could undo the work.

Principle of Invalid Reset

Forming adjustment involves various factors, including pass design, tube billet performance, and equipment accuracy. As this process is more experience-based than theory-driven, trial and error is common. If an adjustment doesn't yield the expected results or worsens the condition, it's crucial to revert to the original state to prevent compounding issues.

Choosing the Lesser of Two Evils

While striving for perfection in welded pipe adjustment, sometimes compromises are necessary. When faced with a dilemma, one should weigh the pros and cons and choose the option that minimizes potential harm.

Systematic Consideration

Adjustments should be made with consideration of their potential impact on the welding and sizing processes, and vice versa. For instance, excessive forming allowance consumption may lead to insufficient sizing allowance, complicating sizing adjustments.

Understanding and applying these principles during the forming adjustment process is vital for producing high-quality welded pipes with precision and consistency.