Titanium Plate Surface Deformability via Controlled Roughness
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Solution Overview
Problem
Existing titanium plate technologies fail to effectively improve formability while controlling surface profile and preventing brittle hardened layer formation, leading to potential cracking and reduced yield rates during processing.
Innovation Solution
A titanium plate with a Vickers hardness of 150 or less at a load of 0.245 N, an average length of profile elements RSm of 80 μm or less, and a maximum height Rz of less than 1.5 μm, achieved through specific surface treatment and rolling processes, including pickling and annealing in non-oxidizing atmospheres, to enhance surface deformability and prevent stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide film or a nitride film is formed prior to pickling to improve lubricity, then the lubricity improves, but the films serve as the starting point of cracks during bulge forming and decrease the formability
Solution Approach 1:
The patent converts the harmful effect of surface irregularities (which cause stress concentration and cracking) into a beneficial effect by controlling them within a specific range (Ra: 0.25-2.5 μm, Rz: 1.0-3.0 μm). This controlled roughness provides adequate lubricant retention while preventing excessive stress concentration, thus converting what would normally be a harmful defect into a beneficial surface characteristic that improves both lubricity and formability simultaneously
Solution Approach 2:
The patent applies parameter changes by precisely controlling the surface roughness parameters (Ra and Rz) within specific ranges, and by controlling the Vickers hardness ratio (Hv0.098/Hv4.9 ≥ 20) to achieve optimal formability. This quantitative control of surface parameters transforms the qualitative issue of surface quality into a measurable and controllable process that resolves the contradiction between lubricity and formability
2Productivity
If the surface roughness is increased to improve oil retainability, then the amount of lubricant drawn-in increases and formability improves, but large irregularities may serve as starting points for stress concentration and induce cracking
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges for surface roughness (Ra: 0.25-2.5 μm, Rz: 1.0-3.0 μm) that optimize the balance between lubricant retention and stress concentration prevention. By controlling the arithmetic average roughness and maximum height of irregularities within these ranges, the patent ensures adequate oil retainability for improved formability while preventing the formation of excessively large irregularities that would cause stress concentration and cracking
3Ease of manufacture
If pickling and skin pass rolling are performed to adjust surface profile and improve formability, then oil retainability is exerted, but protrusions of irregularities are smoothed and large recesses may serve as starting points for stress concentration
Solution Approach 1:
The patent controls the surface profile parameters (Ra and Rz) within specific ranges to achieve optimal formability while preventing stress concentration. By maintaining Rz within 1.0-3.0 μm, the patent ensures that recesses are not excessively deep, thereby preventing them from serving as stress concentration points while still providing adequate surface irregularity for lubricant retention
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a titanium plate with improved surface deformability, reducing the risk of cracking and enhancing formability, making it suitable for use in heat exchangers in chemical and food processing plants.
Implementation Method 1
annealing in non-oxidizing atmospheres
Implementation Method 2
pickling and skin pass rolling after atmospheric annealing
Data Source
AI summary
A titanium plate is provided in which a Vickers hardness Hv0.025 at a load of 0.245 N at a surface is 150 or less, and an average length of the profile elements RSm is 80 μm or less and a maximum height Rz is less than 1.5 μm, RSm and Rz being as defined in JIS B 0601: 2013. The titanium plate has good surface deformability.