Characteristics of steel casting technics

Steel casting, as one of important production line in our investment casting factory, is used to cast lots of components. Below, let's talk about some characteristics of steel casting.

1. Mechanical properties of steel castings is better than iron castings.

Mechanical properties of steel castings is better than iron castings. But the castability of steel is worse than iron casting. Melting point of steel is higher. The melt steel is easily oxidized. The liquidity of the melt steel water is bad and with big shinkages. Usually, the shrinkage for body is 10%-14%. The line shrinkage is about 1.8-2.5%. To avoid short pours, chills, shrinkages, porosity, craks, burnt-on sands, and other cast defects, we should use more complex casting process to make steel castings. Due to the high melting point, the casting temperature is also high.In high temperature situation, the chemical reaction often happened between steel water and the casting materials.Thus, we use high hot resistant artificial quartz sand to make the cast shells, and coat the surface with quartz powder.

2. Liquidity of the melt steel water is bad.

To avoid the short pours and chills defects, the wall thickness of the steel casting can't be less than 8mm. The casting pouring system should be as simple as possible.The sectional dimension should be biger than iron casting. Using dry casting shells or hot mold, and the casting temperature should be increased to around 1520°～1600℃. Hot temperature can increase the time of steel liquide state, thus to improve the bad liquidity of steel water. But if the temperture is too high, coarse grain, hot tears, pores and burnt-on sands defects will be caused. Thus, for small, thin wall thickness and complex structure steel castings, the casting temperature should be steel melt point + 150℃. For big and thick wall thickness steel castings, the casting temperature should be 100℃ higher than steel melt point. 

2. Shrinkage of steel casting is bigger than iron casting.

To avoid shrinkage and porosity casting defects,besides the bleeded feeder, we will add chill steel or addtional feeding channel to achieve progressive solidification. 

During design of the investment casting parts, we suggest to make the wall thickness consistent, and avoid sharp edge, right-angle structure. This will also help to avoid the casting defects during steel investment casting process.

If you have inquiries for steel investment castings, please contact us.