How to Control Springback in the Deep Drawing Process of Titanium Strips

In the deep-drawing process for titanium strip, springback control requires coordinated optimization across multiple dimensions—material properties, die design, process parameters, and post-processing. Due to its high yield-to-tensile ratio and low elastic modulus, titanium strip is prone to significant elastic recovery after stamping, which directly affects part accuracy.

The Core Cause of Springback

During deep drawing, titanium strip undergoes a stage in which plastic and elastic deformations coexist. Upon unloading, the elastic component of the deformation recovers rapidly, causing geometric parameters such as bending angle and curvature to deviate from their design values. The root cause lies in:

High yield strength and low elastic modulus → large proportion of elastic strain and strong springback tendency.
Significant work hardening → increased deformation resistance, exacerbating stress non-uniformity and inconsistent springback.
Key Control Strategies

Mold Design Compensation Method

Bend Forming: Design the die angle 2° to 5° smaller than the target angle, and use overbending to counteract springback.
Springback Compensation Modeling: Predict the springback trend through finite element simulation and predefine compensation values on the die cavity surface (e.g., an outward tilt of 0.5° to 1.5° for the side walls of a U-shaped part).

Process Parameter Optimization

Enhance forming constraints: employ high blankholder force and an optimized draw-bead layout to improve material-flow control and reduce springback in free-deformation zones.
Control the degree of deformation: perform stepwise stamping to avoid excessive deformation in a single stroke, thereby reducing accumulated elastic strain energy.
Adjust the relative bending radius: reducing the r/t ratio (typically maintained within the range of 1.5 to 2.5t) can effectively suppress springback.

Temperature-assisted forming

Warm forming (200–350°C): enhances material ductility, reduces yield strength, and reduces springback angles to within 1°.
Hot forming (>400°C): Suitable for complex structural components; at elevated temperatures, the elastic modulus changes significantly, and springback is virtually negligible; however, inert gas shielding is required to prevent oxidation.

Material and State Selection

Annealed α-type titanium alloys (such as TA2 and TA1) are preferred due to their excellent ductility and relatively low springback (approximately 5%–10%).
Avoid using high-strength β-type or solution-treated materials, as they exhibit a more pronounced springback tendency.

Post-Plastic Surgery Correction

A forming operation is added at the end of the stamping process to apply holding pressure to critical areas via rigid blankholding, thereby enforcing precise part shaping.
For high-precision parts, multi-point localized embossing or roll forming is employed to precisely correct springback in targeted areas.

Friction and Blankholder Force Control

Increasing the blankholder force can improve material conformability and reduce springback; however, the risk of tearing must be carefully balanced.
Employ high-performance lubricants, such as MoS₂ coatings, to reduce friction non-uniformity and enhance forming consistency.