Titanium and titanium alloys have a series of troubles, such as high-temperature pollution of the atmosphere (absorption of hydrogen, oxygen, and nitrogen), short tool life due to high strength, and sticking of the tool due to poor thermal conductivity. In addition, the inhomogeneous metal phase, coarse grains, residual stress, etc. caused by thermal processing are also difficult problems in the thermal processing of titanium alloys. Therefore, industrial pure titanium and titanium alloy substrates are basically free trade in the world, which is very different from the embargo on high-performance carbon fiber composite materials; however, it is not necessarily affordable because it is the processing technology. It is complicated and keeps most countries out of the application of titanium alloys. Below, we look at the processing technology of titanium and titanium alloys.
1. the Cutting process of blanking Before titanium and titanium alloy parts, a large piece of titanium and titanium alloy should be preliminarily cut to prepare for blanking. The cutting of titanium and titanium alloys, unlike ordinary metals, is difficult to use flame methods, otherwise, high-temperature pollution will cause material embrittlement. Therefore, plasma cutting, laser cutting, and milling are often used. However, in these methods, either the material is prone to thermal stress discrete deformation (such as laser cutting), or the cost is too high to meet mass production (such as ion beam cutting), or the residual material rate is high (such as milling). Therefore, people came up with another room temperature cutting method: high-pressure water cutting. Water cutting is a water jet. Before we heard that water droplet pierced through stones, it would take thousands of years. This time it is a water-cut titanium fracture, it is desirable to wait immediately. According to the China Aviation News, Pu Yongwei, the chief expert of the Technology Research Institute of Shenfei Company, has a deep accumulation of water cutting technology. He devoted himself to the study of the application of titanium cutting of this technology and was successful. He successfully implemented the cutting of titanium alloy plates with a thickness of 40-100 mm. . Because it is operated at room temperature, the cutting quality is good, and its efficiency is more than 50 times that of conventional cutting methods, and the material cost is greatly saved. So far, the water cutting method of titanium alloy has been applied in China for nearly 10 years.
2. Casting process Casting processing requires melting titanium and titanium alloy for pouring. Similarly, due to the chemical activity of titanium and titanium alloys, molten titanium and titanium alloys react with almost all refractory materials. Therefore, its melting and pouring must be carried out under the protection of inert gas (such as argon) or a vacuum environment. Domestic applications: China Shipbuilding News reported that on the basis of digesting and absorbing the foreign advanced technology, China has mastered and developed titanium alloy casting technologies such as metal molds, tamped molds, machined graphite molds, and oxide surface ceramic mold shells. It can produce integral titanium alloy castings with a maximum diameter of 1500 mm X 400 mm, a minimum wall thickness of 0.8 mm, and a unit weight of nearly 800 kg. The annual amount of casting titanium alloy reaches 5,000 tons. It has the basic production of titanium and titanium alloy precision castings. technology. According to the report of the Hot Working Forum: The application of cast titanium alloys for aerospace use in my country began in the mid-1980s. There are now ZTi3, ZTiAl4, ZTiAl5Sn2.5, ZTiAl6V4, ZTiAl6Zr2MoV, and other brands (the first letter of the brand, Z, stands for casting ). In 2001, the ZTC4 titanium alloy developed by Beihang University and the Huazhong University of Technology (ie, alloy parts after casting TC4), used hot isostatic pressing and investment precision casting technology to develop a certain type of titanium alloy precision casting for aircraft. The outer dimension of the casting is 630mm×300mm×130mm, the minimum wall thickness is 2.5mm, and it is a complex frame structure. In the future production and development, Wuxi Kexuan Special Steel Co., Ltd. will focus on titanium and titanium alloy products to further improve high-temperature strength, recrystallization temperature, improve low-temperature plasticity and increase oxidation resistance, improve production technology, expand varieties, and reduce The cost makes titanium and titanium alloy products more widely used.
