Titanium is a very active metal element and can interact with all elements. In heating, titanium can interact with oxygen to form an oxide film on the surface. At different heating temperatures, the structure and properties of the oxide film are different. The thermoforming of titanium plates is more complicated, and the mechanical properties of each batch are not the same. In order to ensure the quality of the materials, the manufacturers have prepared certificates and test reports.
- 1. The raw material supply status requirements for the preparation of titanium plates
Primary deformation of titanium plate-rolled into a plate in a metallurgical plant, the performance of the repeatability is poor. The mechanical properties of titanium plates of the same composition produced domestically and abroad are not small; the performance of plates produced by different domestic factories will not be the same, even if the products of a factory have different mechanical properties, the mechanical properties are also different. Therefore, in order to ensure the quality of parts, the quality of raw materials should be ensured first. The titanium and titanium alloy sheet materials received from the warehouse shall be provided with a certificate of ex-factory certificate and a certificate of re-inspection of the factory. In order to facilitate verification in the future, the certificate should be kept. When necessary, the workshop can make a record of the basic situation of parts manufactured by each sheet for future reference.
All plates must be supplied in an annealed condition. In order to ensure the quality of the parts, the oxide layer and other pollution on the surface of the plate should be removed. The surface of the titanium plate shall be free from defects such as cracks, peeling, buckling, inclusions, and traces of pickling. The sheet material should be straight and wrapped in paper before leaving the warehouse. In the subsequent cutting, forming, assembling, transportation and storage, care should be taken to prevent surface scratches.
- 2. Blanking of titanium plate blank
The preparation method of wool used in various sheet metal parts has many similarities. Because the thickness of the titanium plate used is generally less than 2 mm, and there are few parts with a thickness of more than 1.5 mm, the blanking of the titanium plate can be performed at room temperature using existing equipment.
When blanking, care should be taken to smooth the edges of the wool as much as possible, especially to prevent defects such as cracks, bites and cut marks on the edges, and more attention should be paid when cutting thick plates.
The wool should be deburred and sharp edges removed before forming. Because titanium plates are highly sensitive to crack propagation, this work is extremely important in order to eliminate stress concentration and prevent wool from cracking and scratching the mold during forming. It can be deburred or polished by filing, abrasive belt grinding or sandpaper.
It should be noted that no matter which method is used for cutting, only ink and pen that do not produce pollution can be used for marking, and steel stamping is not allowed on the wool, only offset printing or specially equipped labels.
- 3. Degreasing and cleaning before forming.
Before any thermoforming, the surface grease or other contaminants should be removed to avoid contamination of titanium when heated. In addition, oxides on the surface of the wool will reduce the plasticity of the material and should be removed before forming. Therefore, in order to reduce various effects under the atmosphere, vacuum quenching furnace and vacuum annealing furnace are generally used for heating. The inert gas in the vacuum furnace can protect the titanium and titanium alloy materials from contamination during the heating process.