Chromium acts as a carbide stabilizer in cast iron. Thus it intensifies chilling of cast Iron , Increases strength , hardness and wear - resistance and is conductive to fine grain structure. Most additions of chromium range from 0.15 to 0.90 percent with or without other alloying elements. Chromium of 1.0 percent or more make castings hard to machine. With 3.0 percent chromium, white cast iron is formed. Special Irons to resist corrosion and high temperatures contain as much as 35 percent chromium.
Advantages Of Air Refrigeration : 1. The refrigerant used namely air is cheap and easily available. 2. There is no danger of fire or toxic effects due to leakages. 3. The weight to ton of refrigeration ratio is less as compared to other systems. Disadvantages Of Air Refrigeration : 1. The quantity of Refrigerant used per ton of refrigeration is high as compared to other systems. 2. The COP of the system is very low. Therefore running cost is high. 3. The danger of frosting at the expander valves is more as the air contains moisture content.
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