Manufacture - Casting

CASTING

Fig. 22-3 Method of producing an engine component by sand casting.

Fig. 22-4 Automatic investment casting.

20. An increasing percentage of the gas turbine engine is produced from cast components using sand casting, ref. fig. 22-3, die casting and investment casting techniques; the latter becoming the foremost in use because of its capability to produce components with surfaces that require no further machining. It is essential that all castings are defect free by the disciplines of cleanliness during the casting process otherwise they could cause component failure.

21. All casting techniques depend upon care with methods of inspection such as correct chemica composition, test of mechanical properties, radiolog- ical and microscopic examination, tensile strength and creep tests. 22. The complexity of configurations together with accurate tolerances in size and surface finish is totally dependent upon close liaison with design, manufacturing, metallurgist, chemist, die maker, furnace operator and final casting.