China Ductile Iron Casting Factory

1. Definition:

Cast iron is an iron-carbon alloy with a carbon content greater than 2.11%. It is obtained by high-temperature melting and casting of industrial pig iron, scrap steel and other steel and alloy materials. Except for Fe, cast iron with carbon in the form of graphite in the form of spheres is called ductile iron.

2. Performance characteristics

Ductile iron is a high-strength cast iron material developed from the late 1940s to the 1950s. It has excellent comprehensive performance. The specific performance characteristics can be explained from the following aspects:

1) Excellent mechanical properties

1.1. High strength. The tensile strength of ductile iron far exceeds that of gray cast iron and is equivalent to that of steel.

1.2. High yield strength. The yield strength of ductile iron is as low as 40K, while the yield strength of steel is only 36K, which shows the excellent performance of ductile iron under stress.

1.3. Good plasticity and toughness. Through spheroidization and inoculation treatment, the graphite inside ductile iron is spherical, which effectively improves the plasticity and toughness and avoids the tendency to crack.

2) Good physical properties

2.1) Good castability. Ductile iron has good casting properties and can cast parts with complex shapes and precise dimensions.

2.2) Excellent shock absorption. Due to the presence of graphite, when ductile iron is vibrated, the graphite balls can absorb part of the vibration energy, thereby reducing the vibration amplitude.

2.3) Wear resistance. Certain alloy elements can be added to ductile iron to obtain wear-resistant ductile iron, which can work under abrasive wear conditions.

2.4) Heat resistance. By adding specific elements such as (silicon, aluminum, nickel, etc.), a dense oxide film or antioxidant elements can be formed on the surface of the casting to hinder further oxidation, increase the critical temperature of ductile iron, and make it suitable for high-temperature working environments.

2.5) Corrosion resistance. Adding alloy elements such as silicon, chromium, aluminum, molybdenum, copper and nickel to ductile iron can form a protective film on the surface of the casting, which can improve the corrosion resistance of ductile iron and make it suitable for corrosive environments such as chemical parts.

3) Economic performance advantages

3.1. Low cost. Compared with steel, ductile iron is cheaper, which can significantly reduce casting costs.

3.2. Save materials. For parts that bear static loads, ductile iron saves more materials than cast steel, and is lighter, which helps reduce material, transportation and installation costs.

Chinese ductile iron grades and mechanical properties [GB/T 1348--1988]
Brand	tensile strength ob≥/MPa	Yield Strength 00.22/Mpa	Elongation 65≥(%)	hardness HBS	Matrix structure (volume fraction)
QT900-2	900	600	2	280-360	Bainite or tempered martensite (lower bainite or tempered martensite, tempered troostite)
QT800-2	800	480	2	245-335	Pearlite (pearlite or tempered troostite)
QT700-2	700	420	2	225-305	Pearlite (pearlite or tempered troostite)
QT700-2	700	420	2	225-305	Pearlite (pearlite or tempered troostite)
QT600-3	600	370	3	190-270	Pearlite + ferrite (P: 80%-30%)
QT500-7	500	320	7	170-230	Pearlite + ferrite (F: 80%-50%)
QT450-10	450	310	10	160-210	Ferrite (≥80% ferrite)
QT400-15	400	250	15	130-180	Ferrite (100% ferrite)
QT400-18	400	250	18	130-180	Ferrite (100% ferrite)

3、Chemical composition of commonly used ductile iron:

Chemical composition of ductile iron (for reference)
Brand and type		Chemical composition (mass fraction %)
Brand and type		C	Si	Mn	P	S	Mg	RE	Cu	Mo
QT900-2	Before pregnancy	3.5-3.7		≤0.50	≤0.08	≤0.025
QT900-2	After pregnancy		2.7-3.0				0.03-0.05	0.025-0.045	0.5-0.7	0.15-0.25
QT800-2	Before pregnancy	3.7-4.0		≤0.50	0.07	≤0.03
QT800-2	After pregnancy		2.5						0.82	0.39
QT700-2	Before pregnancy	3.7-4.0		0.5-0.8	≤0.08	≤0.02
QT700-2	After pregnancy		2.3-2.6				0.035-0.065	0.035-0.065	0.40-0.80	0.15-0.40
QT600-3	Before pregnancy	3.6-3.8		0.5-0.7	≤0.08	≤0.025
QT600-3	After pregnancy		2.0-2.4				0.035-0.05	0.025-0.045	0.50-0.75
QT500-7	Before pregnancy	3.6-3.8		≤0.60	≤0.08	≤0.025
QT500-7	After pregnancy		2.5-2.9				0.03-0.05	0.03-0.05
QT450-10	Before pregnancy	3.4-3.9		≤0.50	≤0.07	≤0.03
QT450-10	After pregnancy		2.2-2.8				0.03-0.06	0.02-0.04
QT400-15	Before pregnancy	3.5-3.9		≤0.50	≤0.07	≤0.02
QT400-15	After pregnancy		2.5-2.9				0.04-0.06	0.03-0.05
QT400-18	Before pregnancy	3.6-3.9		≤0.50	≤0.08	≤0.025
QT400-18	After pregnancy	3.6-3.9	2.2-2.8				0.04-0.06	0.03-0.05

4、Comparison of ductile iron grades in various countries

Serial number	Country	Iron Plate
1	China	QT400-18	QT450-10	QT500-7	QT600-3	QT700-2	QT800-2	QT900-2
2	Japan	FCD400	FCD450	FCD500	FCD600	FCD700	FCD800
3	United States	60-40-18	65-45-12	70-50-05	80-60-03	100-70-03	120-90-02
4	Former Soviet Union	B440	BY45	BI50	B460	B470	BII80	B4100
5	Germany	GGG40		GGG50	GGG60	GGG70	GGG80
6	Italy	GS370-17	GS400-12	GS500-7	GS600-2	GS700-2	GS800-2
7	France	FGS370-17	FGS400-12	FGS500-7	FGS600-2	FGS700-2	FGS800-2
8	United Kingdom	400/17	420/12	500/7	600/7	700/2	800/2	900/2
9	Poland	ZS3817	ZS4012	ZS 4505 5002	ZS6002	ZS7002	ZS8002	ZS9002
10	India	SG370/17	SG400/12	SG500/7	SG600/3	SG700/2	SG800/2
11	Romania					FGN70-3
12	Spain	FGE38-17	FGE42-12	FGE50-7	FGE60-2	FGE70-2	FGE80-2
13	Belgium	FNG38-17	FNG42-12	FNG50-7	FNG60-2	FNG70-2	FNG80-2
14	Australia	300-17	400-12	500-7	600-3	700-2	800-2
15	Sweden	0717-02		0727-02	0732-03	0737-01	0864-03
16	Hungary	GǒV38	GǒV40	GǒV50	GǒV60	GǒV70
17	Bulgaria	380-17	400-12	450-5 500-2	600-2	700-2	800-2	900-2
18	International Standard (ISO)	400-18	450-10	500-7	600-3	700-2	800-2	900-2
19	Pan-American Standard (COPANT)		FMNP45007	FMNP55005	FMNP65003	FMNP70002
20	Finland	GRP400		GRP500	GRP600	GRP700	GRP800
21	Netherlands	GN38	GN42	GN50	GN60	GN70
22	Luxembourg	FNG38-17	FNG42-12	FNG50-7	FNG60-2	FNG70-2	FNG80-2

5、Ductile Iron Application Areas

1) Pressure Pipes and Fittings

When ductile iron was first used as pipes, iron pipes and fittings were mostly produced by major industrial countries. Ductile iron pipes have long been proven to be superior to gray cast iron pipes for transporting water and other liquids. The main reason for this change is that the strength and toughness of ferritic ductile iron make pipes made of this material able to withstand high operating pressures and can be easily loaded and unloaded during laying.

2) Automobile Applications

In terms of tonnage produced, the automotive industry is the second largest user of ductile iron castings. Ductile iron is used in three main places in automobiles: (1) Power source - engine components; (2) Power transmission - gear trains, gears and bushings; (3) Vehicle suspension, brakes and steering devices.

3) Agricultural, road and construction applications

Modern economical agricultural methods require agricultural machinery that can be provided with reliable and long service life when required.

Ductile iron castings widely used throughout the agricultural industry include various tractor parts, plows, brackets, clamps and pulleys. A typical component is the rear axle housing of a farm vehicle, which was originally made of cast steel. The road paving and construction industries require a considerable amount of various types of equipment including bulldozers, driving machines, cranes and compressors, and ductile iron castings are used in these areas.

4) General Applications

The ductile iron machine tool industry takes advantage of the engineering properties of ductile iron, which allows the design of complex machine tool components and heavy machine castings weighing more than 10 tons. Applications include injection molds, forging machine cylinders and pistons. The high tensile and yield strength of ductile iron and its good machinability allow the production of lighter castings while maintaining their rigidity. Similarly, the strength and toughness of ductile iron make it an ideal material for various hand tools such as wrenches, clamps and gauges.

5) Valve Manufacturing

Valve manufacturers are the main users of ductile iron (including austenitic ductile iron), and its applications include the successful conveying of various acids, salts and alkaline liquids.

View as

Buy Ductile Iron Casting from our factory - Zhiye Mechanical. As one of the China Ductile Iron Casting manufacturers and suppliers, we can provide customers with customized service. You can rest assured from our factory wholesale products, our product are latest selling, in stock and lower price than peers, we are happy to provide you with a discount quotation.