Process Control Matters For Alloy Steel Castings
In order to improve and ensure the quality of alloy steel castings, we need to pay attention to its processing process. This article summarizes the control matters in three different process periods. If you are interested, let’s learn about it.
1. Control of melting period
The main task of the melting period is to rapidly melt the solid charge into a uniform liquid with the least power consumption. At the same time as the charge is melted, various physical and chemical reactions also occur in the molten pool, mainly including volatilization and oxidation of elements and molten steel. Inhalation, heat transfer and dissipation, and the floating of inclusions, etc. Therefore, slag forming in advance to cover the molten steel surface during the melting period can not only reduce heat dissipation, reduce the suction volume of molten steel, but also promote the floating of inclusions, etc. Correct operation during the melting period can remove 60% of the phosphorus in the steel. Phosphorus is a harmful element in the steel for low alloy steel. During the smelting process, the phosphorus content in the steel should be reduced as much as possible. Generally, P<0.030% is required in high-quality steel, while phosphorus in high-quality steel requires P <0.015%, P<0.005% for very special requirements.
2. Control of the oxidation period
The CO or (CO+CO2) bubbles generated by the decarburization process of alloy steel castings during the oxidation period are formed by oxygen bubbles that are too late to participate in the reaction when blowing oxygen, and purposely blowing inert gas or pure CO gas directly into the molten pool. The bubbles rise and escape, causing the molten pool to boil, creating conditions for the removal of hydrogen and nitrogen.
3. Control of the recovery period
The main tasks of the reduction period of the alkaline electric arc furnace are deoxidation, desulfurization, alloying and adjustment of the composition of the molten steel and finally adjustment of the temperature of the molten steel. It is beneficial to desulfurization, and the chemical composition is stable, and the yield of gold-containing elements is also high. Therefore, deoxidation is a key link in the refining operation in the reduction period. After the completion of the oxidation period, all the oxidized slag should be quickly removed. If the oxidized slag is not removed. , in the reduction period will appear back to phosphorus. After removing the oxidized slag, add 2-2.5% slag-forming material by weight of molten steel, and then rapidly melt it with the maximum current. After the thin slag is formed, the reducing agent can be added to form the reduced slag for deoxidation and desulfurization.
The above content is some relevant knowledge about the process control of alloy steel castings. You can refer to it for reference. It has very strict requirements and requires our manufacturers to check every layer.