Cast iron

Grey or laminar cast iron DIN 1691

The grey or laminar cast irons are cast materials that contain at least 3% carbon. They are created in an oven with electric arc flash or by induction. These materials are used in this implementation without additional treatment. Annealing is performed at temperatures between 540° C and 600 ° C, by keeping the temperature constant for 1 hour per 25 mm thickness. The DIN-standards refer to a number of types of grey or laminar cast iron. The grey or laminar cast types of iron usually allow a good resistance to wear and generally offer good resistance in places where the lubrication leaves to be desired. These also allow a good internal damping. Gear pairs in grey or laminar cast iron allow average generally ¾ of the load surface in accordance with gears in steel with the same reference circle and facewidth; their break resistance is hardly ⅓ compared to gears in steel with the same modulus. The use of grey or laminar cast iron is rarely applied nowadays: one finds them in the construction of large gears with large modules.

Nodular cast iron DIN 1693

The nodular cast iron types are composed of Fe-Si, containing at least 3% carbon. The graphite is present in ball shape into the material. General one can assume that nodular cast iron is obtained if the alloy contains the following elements: Fe, C, Si, Mn, S and P. For the alloyed cast iron types one adds of his choice 0.5% à 3,5% of the following elements: Ni, Cr, Cu and Mo.
Cast iron in a liquid state gets a metallurgical treatment by adding magnesium that transforms the graphite into ball shape. Without this treatment one obtains laminar cast iron. The construction of nodular cast iron is not only bound by the chemical composition but also to factors of preparation such as the solidification and cooling and firmness of the casting mould.
This cast irons are less sensitive to thickness variations and grant equally desired properties at solidification. To further improve the mechanical properties during the solidification, the value of S-compounds in function of solidification speed and the thickness of the casting is optimized.

The following are some of the features of nodular cast iron:

Static formability
When a certain distortion is required one chooses better a ferritic or perlito ferritic nodular cast iron.

Dynamic fatigue
The nodular cast irons are applied in heavy load cases.

Dynamic loading with shocks
Generally plastic deformations are excluded. However, for certain applications nodular cast iron could be applied.

Resistance at high temperatures
For temperatures between 0° C and 60° C it is the best to use nodular cast iron.

Corrosion resistance:
For temperatures up to 400° C mechanical properties are not affected. For temperatures between 400° C and 500° C it is the best way to use the nodular cast irons in light alloyed condition. For temperatures between 550° C and 700° C it is the best way to apply nodular cast irons alloyed with Mo and Si so that the stability is even better than the perlitic types.

Resistance at low temperatures
For temperatures between 0° C and 60° C it is the best to use nodular cast iron.

Corrosion resistance
Lightly alloyed nodular cast irons give good corrosion resistance.
NI <  3%: increases resistance to alkaline solutions
Cu by 0.5% to 1.5%: increases resistance to light acid or sulfur solutions
Cr < 1%: provides a corrosion resistance to salt water and not oxidizing acids

Raw material N° DIN NBN ASTM SAE BS AFNOR Condition NRM in N/mm2 Re in N/mm2 σb in N/mm2 Rek in % E in N/mm2 x 103 Hardness in HB
Laminar cast irons DIN1691
0.6020 GG20 FGG20 ±30B G300 ± Grade 14 FGL200 200 130 400 0.8 105 170-210
0.6025 GG25 FGG25 ±35B ± Grade 17 FGL250 250 170 450 0.8 118 195-235
0.6030 GG30 FGG30 ±45B ± Grade 20 FGL300 300 200 500 0.8 130 210-260
0.6035 GG35 FGG35 50B ± Grade 23 FGL350 350 230 600 0.8 140 220-270
0.6040 GG40 FGG40 ±60B ± Grade 26 FGL400 400 260 700 0.8 150 230-280
Nodular cast irons DIN1693
0.7033 GGG35.3 GGG35.3 FGS350-22 350 220 670 22 160 140-180
GGG38 GGG38 SNG24/17 FGS380-15 380
0.7043 GGG40.3 GGG40.3 FGS400-18 400 250 760 18 160 150-190
0.7040 GGG40 GGG40 FGS400-15 400 250 760 15 165 150-190
GGG42 GGG42 60-40-18 D.4018 SNG27/12 FGS420-12 420 280 160-210
GGG45 GGG45 65-45-12 D.4512 FGS450-10 450 310 810 12 165 170-230
0.7050 GGG50 GGG50 SNG32/7 FGS500-7 500 320 850 7 170 190-250
80-55-06 D.5506 560 385 200-260
0.7060 GGG60 GGG60 SNG37/2 FGS600-3 600 370 900 3 175 215-280
0.7070 GGG70 GGG70 100-70-03 D.7003 SNG42/2 FGS700-2 700 420 990 2 175 240-300
0.7080 GGG80 GGG80 120-90-02 SNG47/2 FGS800-2 800 480 1070 2
FGS900-2 900 600 1130

 

PRODUCTION GUIDELINES – CAST IRON
Dimensions Casting steel DIN 1683 Nodular cast iron DIN 1685
Tolerances on linear sizes Tolerances on thickness Tolerances on linear sizes Tolerances on thickness Tolerances on linear sizes Tolerances on thickness
GTB19* GTB19* GTB19* GTB19*
>18 ±4,5
18-30 >6 ±4,7 ±4,7
30-50 6-10 ±5 ±5
50-80 10-18 ±5,5 ±4,5 ±5,5 ±4,5
80-120 18-30 ±6 ±7,5 ±6 ±7,5
120-180 30-50 ±6,5 ±8 ±6,5 ±8
180-250 50-80 ±7 ±8,5 ±7 ±8,5
250-315 80-120 ±7,5 ±9 ±7,5 ±9
315-400 120-180 ±8 ±10 ±8 ±10
400-500 180-250 ±8,5 ±11 ±8,5
500-630 250-315 ±9,5 ±11 ±9,5
630-800 315-400 ±10 ±10
800-1000 400-500 ±11 ±11
1000-1250 ±12 ±12
1250-1600 ±13 ±13
1600-2000 ±14 ±14
2000-2500 ±15 ±15
2500-3150 ±17 ±17
PRODUCTION GUIDELINES – CAST IRON
Laminar cast iron DIN 1686 Casting steel DIN 1683 Large sizes Laminar and nodular cast iron DIN 1685 & 1686 Overmaten
Tolerances on linear sizes Tolerances on thickness Per surface Per surface of pieces with welding to be used For surfaces in the height or vert position in the casting mould Per surface For surfaces in the height or vert position in the casting mould
GTB19* GTB19*
±4,5
±4,7 ±4 ±11,5 ±2 ±4 ±2
±5 ±5 ±12 ±2 ±4 ±2
±5,5 ±4,5 ±6 ±13 ±2 ±4 ±2
±6 ±7,5 ±6 ±13 ±2 ±4 ±2
±6,5 ±8 ±6 ±13 ±2 ±4 ±2
±7 ±8,5 ±7 ±14 ±2 ±5 ±2
±7,5 ±9 ±7 ±14 ±2 ±5 ±2
±8 ±10 ±8 ±14 ±2 ±5 ±2
±8,5 ±8 ±14 ±2 ±5 ±2
±9,5 ±10 ±16 ±3 ±6 ±2
±10 ±10 ±16 ±3 ±6 ±2
±11 ±12 ±16 ±3 ±8 ±2
±12 ±12 ±16 ±3 ±8 ±2
±13 ±14 ±17,5 ±4 ±10 ±2
±14 ±16 ±17,5 ±4 ±12 ±3
±15 ±16 ±17,5 ±4 ±12 ±3
±17 ±18 ±23 ±5 ±15 ±4

*Other tolerance fields or quality grades are according to GTB15 up to GTB20.