Common Rolling Defects of Titanium Foil: Causes and Solutions Edge Crack, Wave, Thickness Deviation, Roll Sticking, Peeling

Titanium foil is a core basic material widely used in high-end electronics, hydrogen energy, aerospace and medical industries, requiring extremely high standards in surface quality, thickness accuracy, flatness and shape. Titanium features a hexagonal close-packed crystal structure, high work hardening rate, large deformation resistance, poor thermal conductivity, easy oxidation and strong adhesion tendency. These properties make Ultra-Thin Titanium Foil prone to edge cracks, wave deformation, thickness deviation, roll sticking and peeling during rolling, which directly affects product yield and production stability.

We have previously explained why titanium foil rolling is far more difficult than aluminum foil and copper foil. For detailed information, you can refer to :”Why Is Titanium Foil Much Harder to Roll Than Aluminum or Copper Foil？”

The occurrence of titanium foil rolling defects is rarely caused by a single factor, but results from the combined effect of billet condition, roll system performance, lubrication and cooling, tension control, speed regulation and temperature field distribution. This paper analyzes the defect characteristics and formation mechanisms separately without repeating subsequent solutions.

1. Characteristics and Formation Mechanisms of Five Major Defects

1.1 Edge Crack

Edge crack appears as serrated notches, splits and edge chipping on titanium foil, and may even lead to strip breakage in severe cases.Formation mechanism: Titanium has low plasticity with severe stress concentration at the edge; raw material edges have burrs and shearing marks; edge elongation exceeds the central part during rolling and causes tensile cracking; improper roll crown leads to excessive reduction at the edge; excessive single-pass reduction without intermediate annealing treatment.

1.2 Wave Deformation (Edge Wave / Center Wave / Rib Wave)

Wave deformation refers to undulation caused by uneven elongation along the foil width direction.Formation mechanism: Mismatch between roll crown and incoming strip shape; roll thermal crown variation caused by temperature rise during rolling; uneven tension distribution; local friction coefficient mutation due to poor lubrication; parallelism deviation of roll system.

1.3 Thickness Deviation (Transverse / Longitudinal Thickness Difference)

Thickness deviation is a key index determining the precision grade of titanium foil.Formation mechanism: Insufficient rolling mill rigidity; unstable roll gap; fluctuating lubricant film thickness; uneven hardness of incoming material; slow response of rolling force closed-loop control; tension fluctuation changing real-time deformation resistance.

1.4 Roll Sticking

Roll sticking manifests as pitting, tearing marks, bright spots and local adhesion transfer on the titanium foil surface.Formation mechanism: Titanium has extremely high chemical activity and forms diffusion bonding with roll materials under high temperature and high pressure; rupture of lubricating oil film leads to boundary friction; improper surface roughness of work rolls; excessive rolling speed causes accumulation of deformation heat.

1.5 Peeling

Peeling refers to sheet-like surface warping, delamination and chipping of titanium foil.Formation mechanism: Inclusions and residual oxide scale on raw material surface; surface hydrogen embrittlement and gas infiltration; pickling residue; inconsistent deformation between surface layer and substrate; excessive work hardening inducing surface cracking.

2. Summary of Defect Control Measures

For on-site quick reference, the following table lists targeted solutions only:

3. FAQ

Q1: Which two defects most frequently occur simultaneously in titanium foil rolling?

A: Wave deformation and thickness deviation are the most common combination, as roll profile deviation affects both elongation uniformity and thickness distribution. Roll sticking and peeling also often appear together, both closely related to surface condition and lubrication performance.

Q2: Can edge cracks be solved simply by increasing rolling tension?

A: No. Higher tension will aggravate tensile stress at the edge and worsen cracking. The correct approach is to reduce pass reduction, trim strip edges and optimize roll crown.

Q3: Is it allowable to continue rolling after roll sticking occurs?

A: It is not recommended. Adhered substances on the roll surface will be continuously pressed into the foil, causing batch defects. It is necessary to stop production to clean rolls and inspect lubrication condition and roll surface roughness.

Q4: What is the most effective quick adjustment method for excessive thickness deviation?

A: Prioritize stabilizing lubricant film thickness and rolling tension, then check roll gap inclination and roll profile. These three factors account for over 80% of on-site thickness fluctuation.

Q5: How to quickly distinguish peeling from roll sticking?

A: Peeling is the spontaneous delamination of the titanium foil surface itself, belonging to material inherent quality problems. Roll sticking is surface tearing caused by adhesion between titanium foil and work rolls, belonging to friction and lubrication failure problems.

Conclusion

Defect control in titanium foil rolling is a typical multi-variable coupling system engineering. Its technical difficulty is far higher than that of aluminum foil and copper foil rolling, which is fundamentally determined by titanium’s low plasticity, high deformation resistance, strong chemical activity and poor thermal conductivity. Only by precise matching of raw material quality, roll system configuration, lubrication cooling, tension regulation, temperature control and rolling process parameters can we effectively suppress edge cracks, wave deformation, thickness deviation, roll sticking and peeling, and realize high-quality mass production of high-end titanium foil.

ProX Metal has been deeply involved in the precision manufacturing of titanium foil for many years. Through extensive technical expertise and continuous process improvements, we have established a mature and stable titanium foil rolling production system. We possess significant advantages in defect control, thickness accuracy, surface quality, and performance consistency, enabling us to consistently deliver high-quality, high-standard titanium foil products that meet the stringent application requirements of high-end electronics, hydrogen energy equipment, aerospace, and medical devices.

If you have any procurement, customization, or technical consultation needs, please feel free to contact us at any time. We will provide you with one-stop solutions and comprehensive support through our professional expertise, reliable quality, and efficient service.