Methods For Straightening Seamless Titanium Tubes in Grade 2

Commonly used straightening methods for titanium tubes include: tension straightening, sinusoidal straightening, and pressure straightening.

Tension straightening is a processing method, also known as tensile straightening, that applies a vertical tension to the workpiece that exceeds the yield limit of the material, resulting in plasticity prolongation and correcting shape defects. When straightening, tension is applied to titanium rods, wires and tubes with wave shape defects on a tension straightening machine. The tension stress accumulates with the original residual stress of the titanium rods. In the larger extension, part of the tensile stress resist each other, reducing the actual deformation stress, straightening plasticity extension is smaller; in the original smaller extension, due to the accumulation of tensile stress, the deformation stress is actually enlarged, straightening plasticity expansion. Therefore, under tension, all parts of the straightened workpiece extend uniformly, eliminating the shortcomings of wavy shape.

Sinusoidal straightening method is widely used in the production of simple cross-section rods and wires and tubes. Titanium tubes and rods are carried out on the inclined roller straightening machine. The number of rolls of the straightening machine is greater than 4 (usually 5~29 rolls), and its working principle is to bend the workpiece at three consecutive points through each roll, gradually reducing the range of changes in the residual curvature of the workpiece.

Sinusoidal straightening is usually used in conjunction with pressure straightening, whereby the workpieces with larger curvatures are first straightened by the pressure straightening machine, and then straightened by inclined rolls. The straightening effect depends mainly on the straightener pressure and the roll inclination. The size of the pressure depends on the yield strength and bending degree of the alloy material. If the titanium alloy with high strength and large bending degree, the straightening pressure should be larger, and vice versa, smaller. The size of the roll inclination depends on the diameter of the workpiece,, the diameter of the workpiece should be larger than the small straightening inclination. Straightening should also be unqualified workpiece to return to re-straighten. Can not straighten the titanium tube should be sent to the tension straightening machine straightening.

Titanium tube roller straightening of the basic principles:

(1) the smaller the roll diameter, the more the number of rolls, the higher the straightening accuracy; roll distance is small, conducive to the workpiece bite and the establishment of the straightening process.

(2) titanium tube roller straightening the main function of the first few rolls is to reduce the length of the workpiece along the residual curvature of the difference between the main function of the last few rolls is to reduce the residual curvature so that it tends to be uniform.

(3) The quality of straightening the key to determine the quality of the workpiece under the rolls of the anti-curvature rate. The first few rolls (the second and third rolls) using a larger anti-curvature rate, the subsequent rolls on the anti-curvature rate is based on the residual curvature can be completely straightened near the front rolls to determine.

(4) The larger the hardening factor 7, the more difficult it is to straighten the material. At this point, a larger bending rate, more straightening rolls and smaller roll diameter should be used.