Ductile iron

Ductile iron, Chinese standard:GB/T 1348-1998

 

Ductile iron cast a single test blocks of the mechanical properties and metallographic structure

Grades Intensity of tensionσb≥/MPa Yield strengthσ0.2≥/MPa Elongationδ5≥(%) HardnessHBS The main metallographic structure
QT400-18 400 250 18 130~180 Ferrite
QT400-15 400 250 15 130~180 Ferrite
QT450-10 450 310 10 160~210 Ferrite
QT500-7 500 320 7 170~230 Ferrite+pearlite
QT600-3 600 370 3 190~270 Pearlite+ferrite
QT700-2 700 420 2 225~305 Pearlite
QT800-2 800 480 2 245~335 Pearlite or tempering
QT900-2 900 600 2 280~360 Bainite or tempered martensite

 

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

 

Mechanical properties of ductile cast attached test block and metallographic structure

Grade Casting wall thickness/mm Intensity of tensionσb≥/MPa Yield strengthσ0.2≥/MPa Elongationδ5≥(%) HardnessHBS The main metallographic structure
QT400-18A >30~60>60~200 390370 250240 1812 130~180 Ferrite
QT400-15A >30~60>60~200 390370 250240 1512 130~180 Ferrite
QT500-7A >30~60>60~200 450420 300290 75 170~240 Ferrite+pearlite
QT600-3A >30~60>60~200 600550 360340 31 180~270 Pearlite+ferrite
QT700-2A >30~60>60~200 700650 400380 21 220~320 Pearlite

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

 

 

Hardness grades of ductile iron, hardness range and microstructure

Hardness grades HardnessHBS The main metallographic structure Mechanical properties (reference value)
Intensity of tensionσb≥/MPa Yield strengthσ0.2≥/MPa Elongationδ5≥(%)
QT-H330 280~360 Bainite or tempered martensite 900 600 2
QT-H300 245~335 Pearlite or tempering 800 480 2
QT-H265 225~305 Pearlite 700 420 2
QT-H230 190~270 Pearlite+ferrite 600 370 3
QT-H200 170~230 Ferrite+pearlite 500 320 7
QT-H185 160~210 Ferrite 450 310 10
QT-H155 130~180 Ferrite 400 250 15
QT-H150 130~180 Ferrite 400 250 15

 

ISO International standard:ISO 1083:1987

Ductile iron grades and mechanical properties of single test blocks,metallographic structure

Grade Intensity of tensionσb≥/Mpa Intensity of tensionσ0.2≥/Mpa Elongationδ≥(%) HardnessHBS The main metallographic structure
900-2 900 600 2 280~360 Bainite or tempered martensite
800-2 800 480 2 245-335 Pearlite or tempering
700-2 700 420 2 225~305 Pearlite
600-3 600 370 3 190~270 Pearlite+ferrite
500-7 500 320 7 170~230 Ferrite+pearlite
450-10 450 320 10 160~210 Ferrite+pearlite
400-15 400 250 15 130~180 Ferrite
400-18 400 250 18 130~180 Ferrite
350-22 350 220 22 ≤150 Ferrite