The superalloy can work at 760 ~ 1500 ℃ for a long time and bear certain stress. Because the superalloy is a single austenite structure with good structural stability, high specific strength, oxidation resistance, corrosion resistance, fatigue performance and other comprehensive advantages, it is widely used in the automotive field, such as engine, turbocharger turbine. The main superalloys are Ni based and Co based. With the rapid development of science and technology and the continuous improvement of production and processing technology, people put forward higher and higher requirements for the comprehensive properties of automotive superalloys. The development and research of new superalloys is imminent. The casting process of Superalloy can give full play to its advantages of stability, thermal strength and thermal fatigue.
The addition of titanium, aluminum, rhenium and ruthenium can improve the strength, creep and fatigue properties of the alloy, and improve the ability to withstand high temperature, but it will also reduce the structural stability of the alloy, increase the casting defects, increase the production cost, and restrict the further development of superalloys. Therefore, the research and development of the new superalloy should focus on improving the structural stability and high temperature mechanical properties of the alloy and extending the service life of the alloy. The casting experiment of new superalloy for automobile was carried out, and the casting process was optimized.
The high temperature wear resistance, high temperature oxidation resistance, microstructure and grain size of the new superalloy for turbocharger turbine were tested, compared and analyzed by different casting process parameters
(1) With the increase of pouring temperature from 1320 ℃ to 1400 ℃ and mold preheating temperature from 700 ℃ to 1200 ℃, the wear volume, mass gain per unit area and average grain size of Superalloy samples decrease at first and then increase, and high-temperature properties first increase and then decrease.
(2) When the pouring temperature is 1360 ℃, the wear volume, mass gain per unit area and average grain size of the samples are 11 × 10-30-33 mmm3, 2.1 g / CMM2 and 53 μ m, respectively, which are 59.3%, 64.4% and 43% lower than those prepared at 1320 ℃.
(3) The wear volume, mass gain per unit area and average grain size of the samples were 11 × 10-30-33 mmm3, 2.1 g / CMM2 and 53 μ m, respectively, which were reduced by 52.2%, 59.6% and 40.4% compared with those prepared at 700 ℃.
(4) In order to improve the high temperature properties of the new superalloy for turbocharger turbine, the casting process parameters are 1360 ℃ pouring temperature and 1100 ℃ mold preheating temperature.