Titanium Alloy Application In Silencer
Titanium alloys are excellent in light weight, corrosion resistance and formability, and are highly versatile and creative. They are used in silencers. In the automotive industry, because the silencer is hidden in an invisible place, coupled with the inability to emphasize its sense of high quality and creativity, the exhaust temperature is higher than that of the locomotive, under the problem of high temperature oxidation resistance and high temperature strength. Titanium alloys are limited in special silencers. In response to similar situations, some companies have developed Ti-1.5Al to improve the high temperature oxidation resistance and high temperature strength in order to avoid substantial damage to the formability of titanium alloy. Titanium was developed based on engine and catalyst conversion, and the exhaust gas temperature was developed from the previous height to 700 to 750 ° C, so it was adopted by the muffler of the automobile. In 2009, when I entered the ASTM specification, I also obtained licenses from the United States, the United Kingdom, Germany, Italy, and France.
As far as the car is concerned, there is a lower temperature in the part after the center tube, but even for this type of vehicle, even the exhaust temperature of this part reaches 700 to 800 °C. Titanium metal is exposed to such high temperatures for a long time, and according to the diffusion of oxygen, the edge portion of the surface becomes weak due to the formation of a hardened layer. At the same time, a peeling oxidation ratio is generated, and the titanium metal portion reacts, which lowers the strength. Further, fatigue strength is reduced and embrittlement is caused by coarsening of crystal grains. In a high-temperature environment like this, Ti-1.5Al also has a place where it cannot cope with oxidation resistance. Therefore, if it is possible to develop a titanium material which retains the high temperature oxidation resistance of Ti-1.5Al or more and maintains the strength characteristics of Ti-1.5Al in the forming process of the composite parts of the muffler system, it will be the best muffling. Material.
Ti-0.5A1-0.45Si-0.2Nb titanium alloy is considered to be more promising. Compared with the two kinds of pure titanium and Ti-1.5Al of JIS, the titanium alloy and the existing muffler material have better high temperature oxidation resistance. These existing materials cannot be used due to problems such as embrittlement and are considered to be used for high temperature. The possibility of the environment. At the same time, the high-temperature strength is close to that of Ti-1.5Al. Compared with JIS two kinds of pure titanium, the 400-degree-reduced strength is 3 to 4 times that of pure titanium, and the tensile strength is 2 to 3 times that of pure titanium. Therefore, such a titanium alloy has characteristics suitable for high temperature strength similarly to Ti-1.5Al. Further, it is expected that such an alloy has the same level of formability as the two kinds of pure titanium of JIS.