Austenitic Stainless Steel are probably the most important under this group is that containing 15 to 20 percent chromium and 7 to 10 per cent nickel. A steel containing 18 per cent chromium and 8 per cent nickel is very widely used and is commonly referred to as 18/8 stainless steels. Such a steel may be readily cold - worked so that the hardness and tensile strength are markedly increased and wire may be produced by cold working. Owing to the high ductility , The steel lends itself readily to manipulate and fabrication, and is used extensively for the production of pressings. The steel is readily weldable after welding, it is susceptible to corrosive attack in an arc adjacent to the weld. Additions of molybdenum are made to certain grades to increase their corrosion resistance, whilst others have titanium or niobium added to stabilize the carbon. They cannot be hardened by heat treatment. Austenite in these steels is stable at all service temperatures. Austenite stainless steels are non - magnetic
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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