Why is carbon steel precision casting carbon content lower and harder to cast?

- Mar 12, 2018-

The lower the carbon content, the higher the melting point, the lower the casting performance, the lower the fluidity, and the tendency of crack tendency. Carbon steel containing less than 0.2% is precision casting medium carbon steel with a carbon content of 0.5%-0.5%, which is precision casting high carbon steel with a carbon content of more than 0.5%. And so on as carbon content increases the casting cost increases.

What are the reasons for the surface of carbon steel precision casting?

(1) metal oxide inclusions brought in by the deoxidation of molten steel;

(2) complete deoxidation condition is: choose dry, clean furnace charge, first add after rongqing ferromanganese and ferrosilicon after deoxidization, plus calcium silicon deoxidation, electricity and let stand for 2 min and studied.the after adding aluminum insulation pouring. After pouring, add wood chips or waste wax to seal and cool down.

The lower carbon content of carbon steel precision casting is difficult to cast.

Avoid measures:

1. The main factor that affects the production of precision castings of carbon steel is the quality of molten steel.

Type 2, because the casting shell temperature about 800 ℃ above, pouring the molten steel temperature is about 1600 ℃ above, contact at this time the temperature of the high carbon steel precision casting appearance, bright metal not solidified, especially thick wall parts, the atmospheric oxygen appearance, easy through the shell and metal oxides, and the inclusions in molten steel, pitting, therefore, big when pouring, to participate in the sawdust (or charcoal), insulation module after the photo, immediately to waste wax block cover tank insulation, this is one of the important measures to avoid pitting produce.

3, shell roasting temperature is not lower than 1150 ℃, holding time not less than 35 min. If the shell is not fully burned, there will be a small amount of gas in the pouring, and it will participate in the interface reaction of the steel liquid and the shell, and bring the oxygen into the molten steel to form a secondary oxidation. Carbon steel is high in C and does not contain Cr, so when it is cooled in the air, the interface reaction can only form the decarburization layer without producing the hemp. If there is a pitting, the shell is not cooked.

4. Refractory materials, especially the surface layer refractory materials, except the main component should reach the request, with Fe2O3 as the main impurity content must be low. The high Fe2O3 content will aggravate the oxidizing atmosphere of the interface and lead to the production of hemp.

The above is the reason for the low carbon content of carbon steel precision casting and the measures to prevent the surface of carbon steel precision castings. I hope it will be helpful to you.

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