High-toughness high-wear-resistance carbide-containing isothermal quenching nodular cast iron and preparation method thereof

A high wear resistance, isothermal quenching technology, applied in the field of wear-resistant materials, can solve the problems of low impact toughness, low CADI impact toughness, high crushing rate, improve impact toughness, good promotion prospects, good graphite roundness Effect

Active Publication Date: 2018-11-06
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] At present, the main reason why the carbide-containing austempering ductile iron has not been widely used in the grinding ball industry is the low CADI impact toughness and high breakage rate.
Especially for CADI with high chromium content, there are more grain boundary carbides and stress concentration, resulting in low impact toughness, and it is difficult to achieve the ideal match of high hardness, high wear resistance and high toughness

Method used

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  • High-toughness high-wear-resistance carbide-containing isothermal quenching nodular cast iron and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] A 500 kg intermediate frequency electric furnace was used to smelt molten iron (wt%) with the following chemical composition: C: 3.45, Si: 1.53, Mn: 0.51, Cr: 1.12, P: 0.035; S: 0.006, with the balance Fe. Heat to 1490°C, add 0.15% pure aluminum for deoxidation, and then transfer to ladle. The inoculants and nodulizers are placed at the bottom of the ladle, and the nodularization and inoculation treatments are carried out by the flushing method. The inoculant uses FeSi75 (75wt% Si), and the addition amount is 1.2wt%. The nodulizer uses FeSiMg6Re2 (6%Mg+2%Re+40wt%Si), the addition amount is 1.5wt%, stir the molten metal in the ladle to ensure complete reaction and remove the slag in the ladle. The pouring temperature is 1380°C. After cooling, the casting is boxed, cleaned and polished.

[0028] After coating the surface of the obtained casting with antioxidant, put it into a heat treatment furnace, heat it to 1100°C, and keep it warm for 10 minutes, take it out of the ...

Embodiment 2

[0030] A 500 kg intermediate frequency electric furnace was used to smelt molten iron with the following chemical composition (wt%): C: 3.56, Si: 1.48, Mn: 0.49, Cr: 1.34, P: 0.031; S: 0.007, with the balance Fe. Heat to 1500°C, add 0.15% pure aluminum for deoxidation, and then transfer to ladle. The inoculants and nodulizers are placed at the bottom of the ladle, and the nodularization and inoculation treatments are carried out by the flushing method. The inoculant uses FeSi75 (75wt% Si), and the addition amount is 1.2wt%. The nodulizer uses FeSiMg6Re2 (6%Mg+2%Re+40wt%Si), the addition amount is 1.5wt%, stir the molten metal in the ladle to ensure complete reaction and remove the slag in the ladle. The pouring temperature is 1351°C. After cooling, the castings are obtained after boxing, cleaning and grinding.

[0031] After coating the surface of the obtained casting with antioxidant, put it into a heat treatment furnace, heat it to 1090°C, and keep it warm for 13 minutes, ...

Embodiment 3

[0033] The cupola is used to smelt molten iron (wt%) with the following chemical composition: C: 3.52, Si: 1.60, Mn: 0.54, Cr: 1.45, P: 0.031; S: 0.007, and the balance is Fe. Heat to 1480°C, add 0.15% pure aluminum for deoxidation, and then transfer to ladle. The inoculants and nodulizers are placed at the bottom of the ladle, and the nodularization and inoculation treatments are carried out by the flushing method. The inoculant uses FeSi75 (75wt% Si), and the addition amount is 1.2wt%. The nodulizer uses FeSiMg6Re2 (6%Mg+2%Re+40wt%Si), the addition amount is 1.5wt%, stir the molten metal in the ladle to ensure complete reaction and remove the slag in the ladle. The pouring temperature is 1370°C. After cooling, the castings are obtained after boxing, cleaning and grinding.

[0034] After coating the surface of the obtained casting with antioxidant, put it into a heat treatment furnace, heat it to 1110°C, and keep it warm for 12 minutes, take it out of the furnace and air co...

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Abstract

The invention discloses high-toughness high-wear-resistance carbide-containing isothermal quenching nodular cast iron and a preparation method thereof, and belongs to the technical field of wear-resistant materials. The produced nodular cast iron comprises the following chemical components of, by weight (wt%), of 3.3-3.8% of C, 1.3-1.7% of Si, 0.4-0.7% of Mn, 1.0-1.5% of Cr, less than or equal to0.040% of P, less than or equal to 0.007% of S, and the balance Fe. The preparation method comprises the following steps that the surface of a casting is coated with an antioxidant, then the casting is placed into a heat treatment furnace to be heated to 1080-1110 DEG C, undergoes heat preservation for 10-15 minutes, and is discharged out of the furnace to undergo air cooling to reach 300-350 DEGC, then the casting is re-fed into the furnace to be heated to 880-900 DEG C, undergoes heat preservation for 90-150 minutes, then is rapidly taken out to be put into a nitrate solution with the temperature of 250-320 DEG C, undergoes heat preservation for 1-3 hours, and then is taken out to be cooled in the air to reach the room temperature. The impact toughness is improved by 120% or more, and meanwhile, the hardness and the wear resistance are not reduced.

Description

technical field [0001] The invention discloses a method for preparing carbide-containing austempering ductile iron, in particular discloses a heat treatment method for improving toughness and wear resistance, and belongs to the technical field of wear-resistant materials. Background technique [0002] Mine wet mills consume a lot of grinding balls and are widely used. The domestic annual consumption is about 2.4 million tons or more. Carbidic Austempered Ductile Iron (CADI) has good casting performance, low density, good wear and corrosion resistance, and low cost. It is an ideal ball material for wet mills. However, due to the existence of a large number of eutectic carbides at the grain boundaries of CADI, the impact toughness of the material is seriously reduced, and the problem of high breakage rate is displayed during installation, which limits the application of CADI. [0003] In order to improve the impact toughness of CADI, Chinese invention patent CN105132790A disc...

Claims

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Application Information

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IPC IPC(8): C22C37/10C22C37/06C22C37/04C22C33/08C21C1/10C21D1/70C21D1/20C21D5/00C21D1/607
Inventor 杨鹏辉符寒光符定梅林健郭星晔雷永平
Owner BEIJING UNIV OF TECH
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