Several tensile test bars with the sizes of Φ 7mm × 90mm, Φ 12mm × 100mm and Φ 17mm × 110mm (made by wire cutting) were cut from the Φ 50mm ductile iron test bar for isothermal quenching at 920 ℃ / 2H + 280 ℃ / 1.5h. The...
Nov282020
Archives
Nov272020
Effect of austempering process on tensile properties of Austempered Ductile Iron
Several samples with diameter of 7 mm are taken from the Φ 50 mm ductile iron test bar for isothermal quenching treatment under different process parameters. T γ is 920 ℃, t γ is 1 h and 2 h, Ta is 280 ℃, 330 ℃ and 380, Ta is...
Nov262020
Phase composition of Austempered Ductile Iron
The as cast microstructure of ductile iron with modulus Ms = 1.25cm is 6.0% pearlite + 94.0% ferrite. Several samples with the size of Φ 10cm × 10cm were cut from the ductile iron test bar, and then they were isothermal transformed at 920 ℃ / 2H + X...
Nov232020
Variation of microstructure of as cast ductile iron with casting modulus (wall thickness)
For austempered ductile iron, the carbon content in high temperature austenite and retained austenite has a significant effect on the subsequent isothermal transformation and mechanical properties of the alloy. However, the solubility of carbon atoms in austenite varies with the as cast microstructure and austenitizing process. This experiment plans...
Nov152020
Hardness of austempered ductile iron alloy
Effect of as cast microstructure on hardness of Austempered Ductile Iron The hardness test results of Austempered Ductile Iron with different as cast microstructure after treatment at 920 ℃ / 2H + 280 ℃ / 1.5hr shows that when the modulus Ms = 0.25mm, ADI has the largest hardness,...
Nov152020
Research contents of Austempered Ductile Iron
(1) EPMA analysis of carbon content in austenite of ductile iron ① The effects of austenitizing temperature and austenitizing holding time on carbon content in austenite of nodular iron during austenitizing process; ② The correlation between matrix type and casting modulus of as cast ductile iron and carbon content...
Nov142020
Effect of austempering process on tensile fracture morphology of Austempered Ductile Iron
The drawing shows SEM photos of tensile fracture morphology of Austempered Ductile Iron with different austempering process parameters. It can be seen from the figure that the fracture mode of austempered ductile iron obtained by isothermal transformation at 280 ℃ is quasi cleavage fracture At 320 ℃, in addition...
Nov142020
Research target of Austempered Ductile Iron
By strictly controlling the chemical composition, melting process, spheroidizing inoculation process and casting modulus of nodular iron, high-quality nodular iron with different as cast structure was prepared. The nodularization rate of graphite was more than 80%, the number of graphite balls was not less than 170 / mm2, and...
Nov132020
Effect of casting wall thickness on tensile fracture morphology of Austempered Ductile Iron
The figure shows the secondary electron image of tensile fracture of Austempered Ductile Iron with different wall thickness treated at 920 ℃ / 2H + 280 ℃ / 1.5h. It can be found from the figure that the tensile fracture morphology of Austempered Ductile Iron with casting wall thickness...
Nov132020
Problems in research of Austempered Ductile Iron
Heat treatment is usually used in strengthening and toughening treatment of ductile iron. The heating temperature of most heat treatment processes is higher than the upper limit of critical eutectoid temperature (AC upper limit) of nodular iron heating, which involves the austenization process of nodular iron matrix structure, which...