SG Iron Grades

SG iron is also called as spheroidal graphite cast iron, in USA, they are also called as ductile iron. There are many different sg iron grades in different countries and standards, however, most of grades have similar requirements to the mechanical properties, especially to tensile strength, yield strength and elongation. The followings are the main sg iron grades worldwide.

Country	Standard	SG Iron Grades (Spheroidal Graphite Cast Iron)
ISO	ISO 1083	400-15 400-18	450-10	500-7	600-3	700-2	800-2	900-2
China	GB 1348	QT400-18	QT450-10	QT500-7	QT600-3	QT700-2	QT800-2	QT900-2
USA	ASTM A536	60-40-18	60-42-10 65-45-12	70-50-05	80-55-06 80-60-03	100-70-03	120-90-02	-
Germany Austria	DIN 1693	GGG40	-	GGG50	GGG60	GGG70	GGG80	-
European	EN 1563	EN-GJS-400-15 EN-GJS-400-18	EN-GJS-450-10	EN-GJS-500-7	EN-GJS-600-3	EN-GJS-700-2	EN-GJS-800-2	EN-GJS-900-2
Japan	JIS G5502	FCD400	FCD450	FCD500	FCD600	FCD700	FCD800	-
Italy	UNI 4544	GS370-17	GS400-12	GS500-7	GS600-2	GS700-2	GS800-2	-
France	NF A32-201	FGS370-17	FGS400-12	FGS500-7	FGS600-2	FGS700-2	FGS800-2	-
UK	BS 2789	400/17	420/12	500/7	600/7	700/2	800/2	900/2
India	IS 1865	SG370/17	SG400/12	SG500/7	SG600/3	SG700/2	SG800/2	-
Spain	UNF	FGE38-17	FGE42-12	FGE50-7	FGE60-2	FGE70-2	FGE80-2	-
Belgium	NBN 830-02	FNG38-17	FNG42-12	FNG50-7	FNG60-2	FNG70-2	FNG80-2	-
Australia	AS 1831	300-17 400-12	-	500-7	600-3	700-2	800-2	-
Sweden	SS 14 07	0717-02	-	0727-02	0732-03	0737-01	0864-03	-
Norway	NS11 301	SJK-400.3 SJK-400	-	SJK-500	SJK-600	SJK-700	SJK-800

The following is the microstructure of sg iron. The graphite is existed by spherical shapes. Therefore, the concentration of inside stress is very small, so its mechanical properties are very well. Very high tensile strength, yield strength and elongation. The iron foundries can also control their hardness by controlling their chemical composition.

Because of their excellent mechanical properties, sg cast iron has been widely used worldwide, which is replacing malleable cast iron and cast steel for many types of metal parts.