Requirements for heat treatment process of heat-resistant steel precision castings

Heating is one of the important processes in the heat treatment of heat-resistant steel precision castings. There are many heating methods. In the past, charcoal and coal were used as heat sources, but now more liquid and gas fuels are used for heating. Nevertheless, it is recommended to use electric heating for heat-resistant steel precision castings, which is not only easy to control but also has no environmental pollution.

Application industry of heat-resistant steel castings

Heat-resistant steel castings refer to steels that work at high temperatures, and are called heat-resistant steel castings due to their heat resistance, corrosion resistance and oxidation resistance.

What are the main heat-resistant components of heat-resistant steel precision castings?

Heat-resistant steel precision castings refer to steels that work at high temperatures. The development of heat-resistant steel precision castings is closely related to the technological progress of various industrial sectors such as power stations, boilers, gas turbines, internal combustion engines, and aero engines. Due to the different temperatures and stresses experienced by various machines and devices, as well as different environments, the types of steel used are also different.

Heat treatment process of heat resistant steel castings

Heating is one of the important processes in the heat treatment of heat-resistant steel castings. There are many heating methods. In the past, charcoal and coal were used as heat sources, but now more liquid and gas fuels are used for heating. Nevertheless, it is recommended to use electric heating for heat-resistant steel castings, which is not only easy to control but also has no environmental pollution.

What are the factors that cause the dimensional accuracy defects of heat-resistant steel precision castings?

1. The influence of casting structure The wall thickness of the casting is large, the shrinkage rate is large, the wall thickness of the casting is thin, and the shrinkage rate is small; 2. The influence of casting material The higher the carbon content in the material, the smaller the linear shrinkage, the lower the carbon content, the greater the linear shrinkage; 3. The influence of mold making on the linear shrinkage rate of castings The influence of wax injection temperature, wax injection pressure and holding pressure time on the size of the investment mold is more obvious with the wax injection temperature, followed by the wax injection pressure. The holding pressure time has little effect on the final size of the investment mold after ensuring the investment molding; The linear shrinkage rate of the material is about 0.9-1.1%; when the investment mold is stored, further shrinkage will occur, and its shrinkage value is about 10% of the total shrinkage, but after 12 hours of storage, the size of the investment mold is basically stable; The shrinkage rate in the longitudinal direction is only 30-40% of the shrinkage rate in the length direction, and the influence of the wax injection temperature on the free shrinkage rate is much greater than that on the hindered shrinkage rate. 4. Influence of shell material The use of zircon sand, zircon powder, Shangdian sand and Shangdian powder is negligible because of its small expansion coefficient, which is only 4.6×10-6/℃. 5. The influence of shell roasting Due to the small expansion coefficient of the shell, when the shell temperature is 1150 ℃, it is only 0.053%, so it can be ignored. 6. The influence of casting temperature The higher the pouring temperature, the greater the shrinkage rate, the lower the pouring temperature, the smaller the shrinkage rate, so the pouring temperature should be appropriate.

Why do heat-resistant steel castings produce pores?

Air holes in heat-resistant steel. In the casting process of the lost mold, it is a common phenomenon.

What are the main heat-resistant components of heat-resistant steel precision castings?

The welding device used for the production of heat-resistant steel precision castings includes: mounting plate, shock-absorbing base mechanism.

Adaptation environment of heat-resistant steel castings

Heat-resistant steel castings refer to steels that work at high temperatures. The development of heat-resistant steel castings is closely related to the technological progress of various industrial sectors such as power plants, boilers, gas turbines, internal combustion engines, and aero engines. Due to the different temperatures and stresses experienced by various machines and devices, as well as different environments, the types of steel used are also different.

What is the material of the hearth roll used in the heat treatment furnace for the production of stainless steel?

At present, with the increasing demand for stainless steel in major industries, the production enterprises are of course increasing year by year. Then we all know that some heat treatment furnaces are used in the production of stainless steel, and the demand for furnace rolls (heart rolls) used in these heat treatment furnaces has gradually increased. Since the temperature in the heat treatment furnace is often very high, generally as high as about 1100 °C, the furnace bottom rollers usually used need high temperature resistance, wear resistance, impact resistance, etc., so they are generally made of high-quality heat-resistant stainless steel. . This is the material selection of furnace rollers. Of course, due to different technologies, manufacturers will have different materials selection. Users can also choose according to their own needs.

What is the role of the hearth roll in the metallurgical industry?

The hearth roll is an indispensable processing equipment in the steel plate smelting and production process. In order to ensure the requirements of the steel plate production, the hearth roll also has high requirements for use. Hearth roll is a typical centrifugal casting pipe fitting, which is one of the important parts for supporting and transporting slabs in metallurgical equipment. It is widely used in steel plate continuous casting and rolling production lines. During the rolling process, the slab needs to be continuously and stably heated in the heating furnace to a rolling temperature of 1050-1150 °C, and the slab is supported stably by the hearth roller to ensure smooth and uniform transportation. Since the middle section of the hearth roll is directly installed in the billet calcining furnace, the furnace gas temperature is as high as about 1150 ℃ during the production process, and it is usually made of high-temperature alloy materials such as ZG45Cr28Ni48W5Si2. At the same time, since the support part in the middle of the furnace bottom roll is directly installed in the furnace, and the cone section and the bearing support part are respectively installed in the furnace wall and outside the calcining furnace, the temperature gradient of different parts of the furnace bottom roll is very large, so The furnace bottom roller is generally welded by the cylinder, the cone and the shaft. In order to reduce the burning loss on the inner surface of the cone, a heat insulation plate is designed inside the cone. In order to ensure the smooth transportation of high temperature slabs, it is required that the roller shaft is not deformed and the outer roller ring is heat-resistant and wear-resistant. Now everyone understands the application of hearth roll re-metallurgy. Only by understanding its function can it be used better. Moreover, in order to ensure the good performance of the hearth roll and prolong the service life, regular inspection and maintenance should be carried out.