Deep drawing formability of titanium alloy plates

Deep drawing formability of titanium alloy plates
Titanium alloy sheet has some unique properties and challenges when it comes to deep drawing. The following are some important aspects regarding the deep draw formability of titanium alloy sheets:
High strength and low plasticity: Titanium alloy has high strength and low plasticity, which requires greater forming force during the forming process. This may require more powerful equipment and more complex forming processes.
High Hardness: Titanium alloys are generally harder than some traditional metals such as steel or aluminum. This can lead to wear and tear during the forming process, requiring the use of more wear-resistant tools and equipment.
Temperature sensitivity: Titanium alloys are relatively sensitive to temperature changes. During the deep drawing process, temperature needs to be controlled to ensure suitable forming conditions. High temperatures may cause the material to be too soft, while low temperatures may make forming more difficult.

Oxidation problem: Titanium alloys easily react with oxygen at high temperatures to form oxides. This can lead to a decrease in surface quality and requires measures to prevent oxidation, such as the use of a protective atmosphere during the forming process.
Forming process optimization: Due to the unique properties of titanium alloys, the forming process needs to be optimized. This may include appropriate lubricants, forming speeds, temperature control and adjustments to process parameters.
Metal Flow: Titanium alloys have poor metal flow, which can lead to the formation of cracks or wrinkles during the forming process. Therefore, careful mold design and appropriate selection of forming parameters are required to ensure good metal flow.
Commonly used deep drawing of titanium plates and titanium rods
Common deformation methods of titanium plates can also be summarized as deep drawing, auxetic expansion, flanging, bending and composite forming. However, if a single deep drawing deformation method is used, it is difficult to produce a typical specimen. Therefore, the composite deformation method was actually used in the test. In addition, the test will inevitably bring about the influence of mold structure and operating process factors, so the evaluation of sheet drawing performance is a complex issue. The research work on national column-shaped titanium rods mainly uses the limit draw coefficient K (LDR) as an indicator. Various evaluation methods have been proposed from various perspectives such as analysis, inspection, and statistics, and many problems have been solved. However, most of them are mainly used in commonly used steel and aluminum materials, so they must be modified and supplemented before they can be used in titanium and titanium alloys. The pull-out test method for cylindrical parts was proposed by Swift in 1940, using a gradually increasing amount of wool to measure the ultimate pull-out coefficient K value. Recommended as an international standard by the International Drawing Research Society in 1967, a lot has been learned from this method. Deep drawing performance of steel, aluminum, copper and other plates.

When used in titanium, especially α and αβ titanium alloys, the following main problems exist:
A. Bending cracks will appear at the four corners of the punch; b. Wrinkles and cracks will appear at the rounded corners of the mold.
This is due to the poor bending and wrinkle resistance of titanium alloys, which cannot fully explain its deep drawing performance. For example, the drawing performance of GR5 and GR6 boards is poor or impossible to draw. Its pullability is measured using the Englhardt or maximum pullout force test method. The problem of bend damage is exacerbated because the material is required to be fully close to the punch and then the pullout force is measured. It is recommended to enlarge the rounded corners of the punch, take anti-wrinkle measures at the rounded corners of the concave die, and use graphite-containing lubricants to conduct titanium alloy deep drawing tests.
Overall, deep drawing of titanium alloy plates requires special handling and considerations to overcome its unique performance challenges. In practical applications, it is usually necessary to determine the optimal forming process parameters through experiments and optimization.