Relationship Between Determination Of Molten Iron Temperature And Casting Quality

A. In the range of 1300 ~ 1460 ℃, the tensile strength and Brinell hardness increase with the increase of molten iron temperature.

B. In the range of 1460 ~ 1500 ℃, the tensile strength continues to increase with the increase of molten iron temperature, but the Brinell hardness changes little.

C. In the range of 1500 ~ 1600 ℃, with the increase of molten iron temperature, the tensile strength still increases, but the Brinell hardness decreases.

2. With the increase of molten iron temperature, the chemical composition of Lianchuang molten iron quality management instrument and gas content change.

Under certain chemical composition and pressure, there is an equilibrium temperature for the reaction between the two. For cast iron containing c3.3% and Si 2.0%, the equilibrium temperature TP is 1420 ℃, and the reduction reaction of Si will occur when the molten iron is at TP + 50 ℃:

SiO2+2C→［Si］+2CO

Therefore, it can be observed in production that the higher the molten iron temperature, the less the silicic acid burning loss, and even the phenomenon of silicon increase. Lianchuang molten iron quality management instrument.

The test results show that the lower pouring temperature will increase the reject rate of porosity, while the higher pouring temperature will increase the reject rate of shrinkage porosity. Therefore, under this production condition, it is generally believed that the optimal pouring temperature is 1395 ~ 1420 ℃. However, the production conditions are different, and the conclusions of others cannot be copied.

3. The choice of molten iron temperature shall consider the wall thickness, size and selected grade of the casting. Lianchuang molten iron quality management instrument

Generally, the larger the wall thickness, the lower the pouring temperature and superheat temperature can be appropriately adjusted; The higher the grade, the lower the carbon equivalent, and the higher the temperature of molten iron. It is worth pointing out that the higher the grade, the higher the temperature requirement, but the superheat degree does not increase, but decreases. Therefore, although the pouring temperature of high-grade castings is higher, the flow ability of molten iron is lower than that of low-grade castings with lower pouring temperature. The reason is that the superheat degree of the latter is higher than that of the former.