Grey Cast Iron (also known as gray iron castings), as already discussed in our previous blogs, is an iron type found in castings popular for its grey color and appearance created in the material’s graphite fracture. To be more specific, what actually makes grey iron is that which is produced during the process of cooling from the carbon present in the component. Grey Iron is a product of both the materials utilized and the process employed for casting a part. Put differently, the grey iron’s properties will vary according to the materials that are melted together for pouring into the mould in addition to the process utilized for casting (it is necessarily the cooling part of the process which defines the cast part’s characteristics compared to all other parts of the process). 

Using a powerful microscope, you can view the graphitic microstructure making grey iron easily recognizable. In grey iron castings, you can view tiny black flakes of graphite. These flakes lead to fractures and give the material a grey appearance. The shape and size of the graphite flakes found in the microstructure determine their mechanical properties which are characterized as per the guidelines provided by the STM.

Being one of the leading casting companies in Coimbatore, we produce tons of grey iron castings every year compared to any other type of casting. A case in point is the manhole cover or car’s disc brakes that are mostly made of grey iron. Cast Iron is popular worldwide due to its array of industrial applications including gears, plow shares, weights and counter-weights, machinery bases, wind turbine housings, truck suspension components, truck parts, valves, stove parts, steering knuckles, pumps, automotive suspension components, linkages, hydraulic components and many more.
So why is grey iron castings still popular? We already know it is one of the cheapest iron castings types to produce. Grey iron castings have excellent tensile strength, ductility, impact resistance, and yield strength for many applications. Grey iron castings exhibit high thermal conductivity and can withstand thermal cycling exceedingly well. 

Whilst the shock resistance and tensile strength levels of grey cast irons are lower compared to other casting types or maybe, it displays a compressive strength which is on a par with low-and medium-carbon steel. The shape and size of the graphite flakes found in the casting microstructure control the mechanical properties. We are proud to assert that we are one of the major grey iron casting manufacturers in Coimbatore. Talk to us today for all enquiries.