Malleable Iron

Malleable Cast Iron Hardness Requirements

Pearlitic malleable iron castings (ASTM A220 M-88)

Pearlitic malleable iron castings (ASTM A220 M-88) are commonly used in general engineering with the work temperature from ordinary to 400 centigrade.

If the purchase contract requires hardness test, the acceptable hardness range should be stated, and the test spot should be clearly shown in the drawings.

Whenever possible, we should use Brinell hardness test method specified by ASTM E10, and we’d better use the 3000kg force / 10mm ball test condition, if the size or shape is not suitable, we can use the 1500kg force / 10mm ball. In particular cases, Brinell hardness tester is not available, so we can choose the Rockwell hardness test method instead in accordance with the provisions of ASTM E18.

The mechanical properties of pearlitic malleable cast iron of different grades are as follows:

Tensile test requirements				Typical hardness range
Grade	Tensile strength (MPa)	Yield strength (MPa)	Elongation (%)	Typical hardness (HB)	Typical indentation diameter (mm)
280M10 310M8 310M6 340M5 410M4 480M3 550M2 620M1	400 450 450 480 550 590 650 720	280 310 310 340 410 480 550 620	10 8 6 5 4 3 2 1	149-197 156-197 156-207 179-229 197-241 217-269 241-285 269-321	4.3-4.9 4.3-4.8 4.2-4.8 4.0-4.5 3.9-4.3 3.7-4.1 3.6-3.9 3.4-3.7

Ferritic malleable iron castings (ASTM A47M-90)

This kind of Ferritic malleable iron castings (ASTM A47M-90) are commonly used under work conditions from room temperature to 400 centigrade in general engineering.The tensile test and hardness requirements of typical parts are as follows:

Tensile test requirements				Typical hardness
Grade	Minimum tensile strength MPa	Minimum yield strength MPa	Elongation 50 mm gauge  minimum,%	Maximum hardness HB	Indentation diameter mm
22010	340	220	10	156

Malleable iron castings for automobiles (ASTM A602-87)

They are used for automotive and the same industrial products with the same grade of ferrite, pearlite, tempered pearlite and tempered martensite. The castings should be heat-treated.

Hardness requirements

Castings should implement the necessary control and inspection procedures to ensure the compliance with the provisions of the hardness range. Hardness readings should be in accordance with ASTM E10, read after removing enough thickness of materials from casting surface, which can ensure the representation of the hardness value. This should be conducted after negotiations between both parties to determine the casting surface or area for hardness inspection.

The mechanical properties of malleable iron castings are as follows:

Grade	Hardness range	Heat treatment	Tensile strength Lb / in 2 (MPa)	Yield strength residual deformation0.2% lb / in 2 (MPa)	Elongation 2 inches or 50 mm%	Elastic modulus One million pounds / inch 2 (MPa)
	≤156HB ≥4.8BID	Annealing	50000 (345)	32000 (221)	10	25 (172)
M4504	163-217HB 4.7-4.1BID	Air quenching or liquid quenching& tempering	65000 (448)	45000 (310)	4	26 (179)
M5003	187-241 HB 4.4-3.9BID	Air quenching or liquid quenching& tempering	75000 (517)	50000 (345)	3	26 (179)
M5503	187-241HB 4.4-3.9BID	Liquid quenching& tempering	75000 (517)	55000 (379)	3	26 (179)
M7002	229-269HB 4.0-3.7BID	Liquid quenching& tempering	90000 (621)	70000 (483)	2	26 (179)
M8501	269-302HB 3.7-3.5BID	Liquid quenching& tempering	105000 (724)	85000 (586)	1	26 (179)