Gray iron investment castings

Fly foundry also supplys gray iron investment casting for our customers.As the production cost is low and the melted ingredients are simple,so gray iron is widely used in the manufacture of complex investment castings for its good casting properties,good cutting,wear resistance and abrasion resistance.

The characteristics of gray iron investment castings:

*Good abrasion resistance and elimination:Because of graphite in cast iron is favour of soothing and oil reservoir, so the wearability is good.As well,as the exsitance of graphite,the elimination of gray iron is better than steel.

*Good process performance:Due to high content carbon of gray iron,close to the eutectic composition,thus it could reach low melting point,good liquidity and small shrinkage rate.So gray iron is suitable for casting complex shapes and thin wall investment castings.

Normally,we manufacture gray iron investment casting with below two production technology:

*Resin sand casting:As good rigidity of resin sand and high strength of sand mould when early casting,then we could effectively eliminate the shrinkage cavity, shrinkage defects of gray iron investment castings.we mainly choose it for large parts.

*Lost foam casting:It has great advantages for manufacturing small gray iron invesmtent castings,which could save losts of wood mould cost,shorten production cycle,improve production efficiency.Also it could obtain high accuracy,small machining allowance and good surace quality.

Common material specifications for gray iron investment castings:

Gray Iron	Wall thickness/mm	C	Si	Mn	P≤	S≤
HT150	<30	3.3-3.5	2.0-2.4	0.5-0.8	0.2	0.12
	30-50	3.2-3.5	1.9-2.3	0.5-0.8	0.2	0.12
	>50	3.2-3.5	1.8-2.2	0.6-0.9	0.2	0.12
HT200	<30	3.2-3.5	1.6-2.0	0.7-0.9	0.15	0.12
	30-50	3.1-3.4	1.5-1.8	0.8-1.0	0.15	0.12
	>50	3.0-3.3	1.4-1.6	0.8-1.0	0.15	0.12
HT250	<30	3.0-3.3	1.4-1.7	0.8-1.0	0.15	0.12
	30-50	2.9-3.2	1.3-1.6	0.9-1.1	0.15	0.12
	>50	2.8-3.1	1.2-1.5	1.0-1.2	0.15	0.12

Application for Grey iron castings

Grey iron castings are with high strength and wear resistance. So, they are widely used as the main 

components for machine building.

For example, 

1)The cylinders, gears, sprockets, pumps of trucks and cars, and body, basis, bearing housing,cylinders, covers of punch press, pressing machine can be made by lost foam casting or sand casting process in material of grey iron.

2)Some containers, pumps, flanges that require for certain corrosivity and high strength 

requirements.

3)The grey iron castings can also be used as the mould for cold forgings.