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Gray Iron Casting (Grey Cast Iron) – Properties, Grades & Manufacturing

Name: Qingdao Casting Quality Industrial Co., Ltd
Address: No 51 Taiping Road, Qingdao City, Shandong Province, 266002, CN
Telephone: +86 53282972996
Price range: Gray Iron
Rating: 5

All you need to know about Gray Iron (Grey Iron) to explore our casting technologies below. Our company covers a wide range of casting technologies, from traditional sand casting to high-precision investment casting and advanced die casting solutions.

Table of Contents:

What is Gray Iron?
Gray Iron Advantage and Disadvantage?
how to produce Gray Iron?
Gray Iron Summary
Gray Iron Application
Gray Iron Grade Details

What is Gray Iron

Gray iron (grey cast iron) is a carbon-rich iron alloy containing 1.5–4.3% carbon and 0.3-5% silicon plus manganese, Sulphur and phosphorus. It has low tensile strength but it’s easy to cast. And grey iron is the cheapest metal material too.
Gray iron castings have been produced since the sixth century B.C. During solidification, when the composition and cooling rate are appropriate, carbon will precipitate in the form of graphite flakes that are interconnected within each eutectic cell. The cooling rate of the iron casting while it solidifies plays a major role in the size and shape of the graphite flakes.

How to produce Gray Iron

Different casting methods are selected based on part size, weight, and production volume.

Sand Casting

Suitable for all gray iron parts with low tooling cost.

Shell Casting

High precision, medium-to-high volume production.
Max weight to 100kgs

Lost Foam Casting

Simple shapes, medium weight parts

Investment Casting

Best for small and high-precision components

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As a professional supplier in the metal casting industry, we have over 15 years of experience in OEM manufacturing. CastingQuality connects global buyers with qualitifed metal products. We helped more than 100 customers to improve their design. Send us your drawings or requirements. Our engineers will recommend the most suitable process, material, and cost solution within 24–48 hours.

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Key Properties of Gray Iron

Good castability and low melting temperature

Grey iron can be melt in low temperature around 1500 ℃, and melted grey iron has very good liquid property, it means that grey iron casting can be designed as thin thickness 4.0mm only, but ductile iron will be difficult for 4mm thickness wall.

Low cost among ferrous materials

Grey iron is the cheapest material in all metal grade. It’s widely used in many usual application, such as Fence, solid pipe, lathe bed and others.

Good Mechanical property.

Grey/Gray Iron tensile strength normally ranges from 20,000 to 60,000 lb/in2 and is a function of chemistry, graphite morphology, and matrix microstructure. And yield strength or elongation is not normally required in Standard.

Good wear resistance

grey iron is very stable, it’s a good property for lathe bed and press machine body, and it also widely used as guide rail for lathe.

Good corrosion resistance property

Grey iron also have good corrosion resistance property, it’s suitable for sewer system which don’t have pressure, such as EN877 soil pipe, gully grating

Cast Iron Cylinder

Cast Iron Pump Impeller with Machining

Cast Iron Elevator Counterweight

International Grey Iron Grade Comparison

Below is a global comparison of gray cast iron grades.

Country	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5	Grade 6	Grade 7
China	—	HT350	HT300	HT250	HT200	HT150	HT100
Japanese	—	FC350	FC300	FC250	FC200	FC150	FC100
USA	NO.60	NO.50	NO.45	NO.35/ NO.40	NO.30	NO.25	NO.20
Russia	CЧ40	CЧ35	CЧ30	CЧ24/CЧ25	CЧ18/CЧ20/CЧ21	CЧ15	CЧ10
Germany	GG40	GG35	GG30	GG25	GG20	GG15	GG10
Italy	—	G35	G30	G25	G20	G15	G10
France	FGL400	FGL350	FGL300	FGL250	FGL200	FGL150	—
England	400	350	300	260	180/220	150	100
Poland	Z140	Z135	Z130	Z125	Z120	Z115	—
India	FG400	FG350	FG300	FG260	FG200	FG150	—
Romania	FC400	FC350	FC300	FC250	FC200	FC150	—
Spanish	—	FG35	FG30	FG25	FG20	FG15	—
Belgium	FGG40	FGG35	FGG30	FGG25	FGG20	FGG15	FGG10
Australia	T400	T350	T300	T260	T220	T150	—
Sweden	O140	O135	O130	O125	O120	O115	O110
Hungary	OV40	OV35	OV30	OV25	OV20	OV15	—
Bulgaria	—	Vch35	Vch30	Vch25	Vch20	Vch15	—
ISO	—	350	300	250	200	150	100
COPANT	FG400	FG350	FG300	FG250	FG200	FG150	FG100
Taiwan (China)	—	—	FC300	FC250	FC200	FC150	FC100
Holland	—	GG35	GG30	GG25	GG20	GG15	—
Luxembourg	FGG40	FGG35	FGG30	FGG25	FGG20	FGG15	—
Austria	—	GG35	GG30	GG25	GG20	GG15	—
Europe Norm	—	EN-GJL-350	EN-GJL-300	EN-GJL-250	EN-GJL-200	EN-GJL-150	—

Grey Iron Grade Details

Grey Iron in EN 1561

Grey Iron in EN 1561;EN 1561, EN-GJL-100, EN-GJL-150, EN-GJL-200, EN-GJL-250, EN-GJL-300, EN-GJL-350
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Grey Iron in ISO 185

Grey Cast Iron in ISO 185
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Grey Iron DIN 1691

Grey Iron in DIN 1691,GG10,GG15,GG20,GG25,GG30,GG35
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Austenitic Gray Iron in ASTM A436

Austenitic Gray Iron in ASTM A436
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Gray Iron in ASTM A48

Gray Iron in ASTM A48
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Gray Iron in ASTM A278

Gray Iron in ASTM A278 for Pressure-Containing Parts for Temperatures Up to 650°F (350°C)
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Gray Iron in ASTM A126

Gray Iron Class A, Class B and Class C in ASTM A126
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Grey Cast Iron Property and Chemistry in GB/T9439

Grey Cast Iron (Gray iron) HT200, HT250, HT300, HT350 in Chinese Standard GB/T 9439
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