What are the methods for straightening titanium tubes?

Straighten titanium tubes using methods such as tension straightening, sine straightening, and pressure straightening.

Tension straightening is a processing method that applies a vertical tension to a workpiece that exceeds the yield limit of the material, prolonging its plasticity and achieving shape defect correction. It is also known as tension straightening. During straightening, a tensile stress exceeding the material yield limit is applied to titanium rods, wires, and tubes with waveform defects on the tension straightening machine.

The accumulation of tensile stress and residual stress in the titanium rod partially offsets the tensile stress at larger extensions, thereby reducing the actual deformation stress and resulting in smaller plastic extension during straightening; In previously smaller areas, due to the accumulation of tensile stress, the deformation stress actually expands, and plastic widening occurs during straightening.

Therefore, after the tension is applied, all parts of the straightened workpiece are uniformly extended, thereby eliminating waveform defects.

In production, the sine straightening method is widely used for simple cross-section bars and pipes. The titanium tube and titanium rod are carried out on an inclined roller straightening machine. The number of rolls in a straightening machine is greater than 4 (usually 5-29 rolls), and its working principle is to gradually reduce the range of residual curvature of the workpiece by continuously bending three points of the workpiece with each roll.

Sinusoidal straightening is usually used in conjunction with pressure straightening. Firstly, use a pressure straightening machine to straighten workpieces with high curvature, and then straighten the inclined rollers. The straightening effect mainly depends on the pressure and roll inclination angle of the straightening machine. The pressure depends on the yield strength and degree of bending of the alloy material. If it is a high-strength titanium alloy, when the bending degree is large, the straightening pressure should be greater, and vice versa. The size of the roll inclination angle depends on the diameter of the workpiece, and larger diameter workpieces should have a greater inclination angle than smaller straightening angles. After straightening, unqualified workpieces should also be returned for re straightening. Titanium tubes that cannot be straightened should be sent to a tension straightening machine for straightening.