Materials and methods for casting process test of new superalloy for automobile

1. Test materials

The test material is superalloy K4002 Sr. When 0.4-0.6% SR is added to the alloy, the chemical composition of the alloy sample is shown in Table 1. The casting equipment is a 60kg vacuum induction fine grain furnace. The test material is placed in the induction furnace for remelting and pouring. The preheating temperature and pouring temperature of the mold are controlled by the induction heating holding furnace in the furnace. The temperature measuring instrument is W-Re immersion thermocouple, and the mold is self-made. The size of cast superalloy sample is 400mm × 30mm. Casting process parameters. During the casting process, the pouring temperature and preheating temperature of the mould were changed by keeping the pouring time of 3S unchanged. The new cast superalloy was not heat treated.

2 Test method

High temperature wear resistance: cut two parallel wear test blocks and take the arithmetic mean value as the test value. The size of the wear test block is 30 mm × 5 mm, and the test temperature is 900 ℃. The wear time is 10 min, the load is 100 N, the speed is 200 R / min, and the total revolution is 2000 R. the wear volume is calculated and recorded. The morphology of the worn sample is observed by evo18 scanning electron microscope.

High temperature oxidation resistance: cut two high temperature oxidation test blocks in the middle of the sample, and take the arithmetic mean value of the two parallel test blocks as the test value of the sample. The samples were tested in rjx-8-13 resistance furnace and at 900 ℃. The size of the high temperature oxidation resistance test block is 20 mm × 8 mm. Several samples are polished and polished, and cleaned with ethanol and acetone. Before oxidation, the sample mass is weighed with a balance. After 5 h of oxidation, the sample is taken out and air cooled for 40 min, and then the sample mass is weighed again to calculate the increase value of the mass per unit area (g / cmm22).

Microstructure: the metallographic test block with a diameter of 5 mm was cut from the middle of each sample, and the surface of the test block was polished and corroded with sandpaper. The microstructure of the test block was observed by polarm et, and the average grain size was calculated by image pro plus.

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