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GB 1348 QT400-18 is ferrite type ductile iron, it has good welding and cutting performance.
Ductile iron QT400-18 mainly used for the parts which can withstand high impact vibration and torsion, such as power machinery crankshaft, camshaft, connecting shaft, connecting rod, gear, clutch plate, hydraulic cylinder and other parts.
According to the standard GB T 1348 1998, the cast iron foundries could adjust the chemical composition by themselves as long as the mechanical and physical properties of the castings could meet the requirements in Standards.
However, there is an approximate chemical composition range as the following. This range is just for reference, and can not be taken as the inspection yard.
Chemical composition in % for GB 1348 QT400-18 ductile cast iron |
C |
Si |
Mn |
S |
P |
Mg |
Re |
3.45~3.64 |
2.47~3.00 |
0.45~0.57 |
0.012~0.026 |
0.047~0.060 |
0.029~0.062 |
0.032~0.047 |
Physical and Mechanical Properties of GB 1348 QT400-18 ductile cast iron:
Physical and Mechanical Properties |
GB 1348 QT400-18 |
Tensile Strength, min, psi |
60,000 |
Tensile Strength, min, MPa |
414 |
Yield Strength, min, psi |
40,000 |
Yield Strength, min, MPa |
276 |
Elongation in 2 in. or 50 mm, min % |
18 |
Hardness HBS |
130~180 |
Density lb/in3 |
0.256 |
Density g/cm3 |
7.1 |
Melting Temperature (Degrees F) |
2,100 – 2,190 |
Melting Temperature (Degrees C) |
1,150 - 1,200 |
Compressive Strength Ksi |
429 |
Compressive Strength MPa |
2960 |
UNS |
F32800 |
Impact performance of V-notch test specimens of single block
Grades |
Room temperature impact toughness (23±5℃)αK≥/(J/cm2) |
Low temperature impact toughness (-20±2℃)αK≥/(J/cm2) |
The average of three samples |
Few values |
The average of three samples |
Few values |
QT400-18 |
14 |
11 |
– |
– |
QT400-18L |
– |
– |
12 |
9 |
Note: The letter "L" indicates the impact value of this grade at low temperature.
Impact strength of V-notch test blocks of ductile iron attached
Grade |
Casting wall thickness/mm |
Room temperature impact toughness (23±5℃)αK≥/(J/cm2) |
Low temperature impact toughness (-20±2℃)αK≥/(J/cm2) |
The average of three samples |
Few values |
The average of three samples |
Few values |
QT400-18A |
>30~60>60~200 |
1412 |
119 |
— |
— |
QT400-18AL |
>30~60>60~120 |
— |
— |
1210 |
97 |
Related grades for GB 1348 QT400-18 ductile cast iron:
Material Grade |
Standard |
Country Code |
Yield stress (Mpa) |
Tensile stress (Mpa) |
Elongation (%) |
Thick (mm) |
FCD 40 |
2869 |
CNS |
≧280 |
≧400 |
≧12 |
|
QT400-18 |
1348 |
GB |
≧250 |
≧400 |
≧18 |
|
FCD400-18 |
G5502 |
JIS |
≧205 |
≧400 |
≧12 |
|
60-40-18 |
A536 |
ASTM |
≧276 |
≧414 |
≧18 |
≦50 |
GGG-40 |
1693 |
DIN |
≧250 |
≧400 |
≧15 |
≦50 |
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