Introduction: Heat resistant castings are corrosion free and can work in high temperatures like 120oc. The heat resistant casting that are used in metallurgical, steel, cooking and other industries.
The sensivity of the metal must be considered because in workshops andindustries which involves heating, low heat resistant metal will melt even without giving a hint, like turning red before melting. Forming operations where a blow torch is used therefore require some expertise, because no visual signs reveal how close the material is to melting.
» Process for heat treatment: Metals are also subject to internal stresses and strains when it is overheated; the tendency of the metal to creep under these stresses tends to result in delayed distortions. For example, the warping or cracking of overheated aluminium automobile cylinder heads is commonly observed, sometimes years later, as is the tendency of welded aluminium bicycle frames to gradually twist out of alignment from the stresses of the welding process. Thus, the aerospace industry avoids heat altogether by joining parts with adhesives or mechanical fasteners. Adhesive bonding was used in some bicycle frames in the 1970s, with unfortunate results when the aluminium tubing corroded slightly, loosening the adhesive and collapsing the frame.
Stresses in overheated aluminium can be relieved by heat-treating the parts in an oven and gradually cooling it in effect annealing the stresses. Yet these parts may still become distorted, so that heat-treating of welded bicycle frames, for instance, can result in a significant fraction becoming misaligned. If the misalignment is not too severe, the cooled parts may be bent into alignment. Of course, if the frame is properly designed for rigidity that bending will require enormous force.
» Application: Heat resistant casting is used for hydro, gas and steam turbines, metal and miscellaneous process equipment, combustion and thermal resistant equipment, etc.
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