Testing technology for heat treatment effect and materials used

Testing technology for heat treatment effect and materials used

1. Main technical requirements of heat treatment equipment
1) Since the temperature difference between quenching (cuì huǒ) and aging temperature (fàn wéi) of aluminum (Al) alloy is not large (because the quenching temperature is close to the melting point of the low-melting eutectic component in the alloy), the temperature difference in the furnace should be controlled. at ±5°C;
2) The temperature measurement and temperature control instruments are required to be sensitive and accurate to ensure that the temperature is within the above error range;
3) The temperature of each zone in the furnace should be uniform, and the difference should be within the range of 1-2 °C;
4) The quenching tank has a heating device and a circulation device to ensure that the heating and temperature of the water are uniform;
5) Contaminated cooling water should be checked and replaced regularly. The lubrication of single-row tapered roller bearings is of great significance to the bearing. The lubricant in the bearing can not only reduce the frictional resistance, but also play the role of heat dissipation, reducing contact stress, absorbing vibration and preventing rust.
2. Quenching medium
Quenching medium is an important factor to ensure the realization of various heat treatment purposes or roles. The higher the cooling rate of the quenching medium, the more intense (fast) the cooling of the casting, the higher the degree of supersaturation of the α solid solution in the metal structure, and the better the mechanical properties of the casting, because a large number of strengthening phases such as intermetallic compounds (compounds) It was solid-dissolved into the α solid solution of Al. The quenching medium according to the speed of cooling the castings is: a mixture of dry ice and acetone (-68°C), ice water, water at room temperature, water at 80-90°C, water at 100°C, and atomized water , various oils (rapeseed oil, etc.), heating (heating) to 200-220 ℃ of various oils, air, etc.
In recent years, the cooling rate of aluminum alloy quenching (cuì huǒ) medium (the decisive substance) CL-1 developed in China is between water and oil. It can be dissolved in water in any proportion. The mixing ratio is different, and the cooling rate is different. Therefore, it is easy to adjust the cooling rate according to the quenching object. When the center line of the spherical roller bearing does not coincide with the center line of the bearing seat and there is an angular error, or when the shaft is bent or inclined due to the force of the shaft, the axis of the inner and outer rings of the bearing will be skewed. At this time, a self-aligning bearing with a certain self-aligning performance or a spherical ball bearing with a seat should be used. It does not need to be rinsed after quenching, and the surface is smooth, non-polluting and non-toxic to castings, and can prevent rust. Its main technical indicators are, appearance: light yellow to yellow viscous (jūn yún) liquid, density: 1.085-1.1234mg/㎡, viscosity Y38: ≥154MPa•s, inverse melting point: 80- 87℃, refractive index n: 1.4138-1.4450, critical cooling rate: ≥260℃/s (450-260℃).
The reason why CL-1 organic quenching agent aqueous solution (róng yè) has excellent quenching characteristics, the mechanism is that in the quenching process of the workpiece, when the temperature rises to a certain value, from the aqueous solution. The organic components are precipitated and decomposed, and a uniform conductive film (thin and soft transparent sheet) is formed on the surface of the workpiece. The quenching bubbles directly act on the film, rather than directly on the workpiece. The direct hammering effect that forms the quenching stress is reduced, thereby reducing the deformation and cracks of the workpiece, and after quenching, when the aqueous solution is cooled to a certain temperature, the organic film is dissolved in the aqueous solution and restored to the original uniform. The state of aqueous solution does not hinder the effect of repeated use.
3. Temperature measurement and temperature control instruments and materials (Material)
The accuracy of temperature measurement and temperature control instruments should not be lower than 0.5. The heat treatment furnace should be equipped with automatic recording, automatic alarm, automatic power-off, and power-recovery devices and instruments that can automatically measure and control temperature to ensure The temperature in the furnace is displayed and controlled accurately and the temperature is uniform.
For thermocouples, nickel-chromium-nickel-silicon (silicon), nickel-chromium-nickel-aluminum diameter 2.0-0.5 mm even wire. When the single-row tapered roller bearing selects the bearing according to the size of the load, compared with the point contact of the ball bearing, the main elements in the roller bearing are in line contact, which is easy to bear the load, and the deformation after loading is also small. In order to improve the sensitivity of the high temperature meter and reduce the temperature fluctuation range (fàn wéi), it is best to use Ф0.5-1.0mm of the above-mentioned even wire. And check and calibrate once before use and during use (once every 3 months).