1. Before heat treatment, oil stains, paints, fingerprints and other foreign objects (rag wire, fine iron scraps, etc.) on the surface of the parts should be cleaned, otherwise, it will easily cause pollution during heating and affect the performance of the parts. In particular, the danger of fingerprints should be pointed out. The high-temperature test shows that when the sample is stressed and comes into contact with pure NaCl, the sample will crack, which is the result of hot salt stress corrosion. In 1955, it was found that the Ti-6Al-4V alloy sample after creeping test at 371 ℃ had surface cracks. Through research and analysis, it is determined that the appearance of these cracks is usually related to fingerprints. Since handprints are harmful to the workpiece, you should avoid direct contact between your fingers and the workpiece during operation. You must wear clean white gloves when taking parts at room temperature. In addition, titanium alloys cannot be processed in the same furnace as aluminium, copper, etc., nor can they be processed in the same tray.
2. The parts are heated to a higher temperature during heat treatment and maintained at a high temperature for a certain period of time. Because the material in the heated state is soft and easily deformed, the position of the parts on the tray or bracket is very important. If the tray itself is not flat, it will cause the parts to deform. If a heat treatment jig is used to improve the deformation of the part, the expansion of the part and the jig after heating should be considered.
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