Special nodulizer for low-temperature impact resistant and high-ductility nodular cast iron and method for preparing special nodulizer

A technology of nodular cast iron and nodularizers, which is applied in the production of nodularizers for foundry, can solve the problems of unsatisfactory, waste of rare earth resources, high rare earth content, etc., and achieve strong anti-recession ability, saving rare earth resources, and high absorption rate Effect

Inactive Publication Date: 2012-08-01
JIANGSU YAFENG ALLOY MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The traditional common nodularizer cannot meet the requirements of producing such ductile iron castings, and its rare earth content is too high (2-6% by mass), which wastes precious rare earth resources

Method used

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  • Special nodulizer for low-temperature impact resistant and high-ductility nodular cast iron and method for preparing special nodulizer
  • Special nodulizer for low-temperature impact resistant and high-ductility nodular cast iron and method for preparing special nodulizer
  • Special nodulizer for low-temperature impact resistant and high-ductility nodular cast iron and method for preparing special nodulizer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Put 99.4 kg of ferrosilicon and 53 kg of rust-removing scrap steel into the induction furnace for melting, and add slag remover to remove slag during the process. When the temperature is 1430°C, add 5.7 kg of silicon-calcium alloy, rare earth metal (rare earth metal is lanthanum cerium rare earth metal, wherein in terms of mass percentage: lanthanum (La) 30-40%, cerium (Ce) 60-70%) 1.6 kg, and all melted. The entire melting process takes 50 minutes. After melting, inert gas protection is blown into the alloy liquid surface, the alloy temperature is kept at 1450°C, 11 kg of metal magnesium is pressed into the alloy liquid, and kept for 3 minutes, and the melting of metal magnesium is completed. Finally, the ingot is cast at 1350°C under the protection of inert gas. Alloy ingots are crushed in special equipment, and then sieved to obtain alloys that meet the particle size required for use. The weight percent of the chemical composition of the nodulizer thus prepared is...

Embodiment 2

[0021] 198 kg of ferrosilicon and 106 kg of scrap steel are added to the induction furnace for melting, and a slag remover is added in the process to remove slag. When the temperature is 1440°C, add 11.5 kilograms of rare earth metals of silicon-calcium alloy (rare earth metals are lanthanum and cerium rare earth metals, wherein in terms of mass percentage: lanthanum (La) 30-40%, cerium (Ce) 60-70%) 3.3 kg , and all melted. The entire melting process takes 53 minutes. After melting, inert gas protection is blown into the alloy liquid surface, the alloy temperature is kept at 1450° C., 22.2 kg of magnesium metal is pressed into the alloy liquid, and kept for 4 minutes, and the melting of metal magnesium is completed. Finally, it is cast into an ingot at 1340°C under the protection of an inert gas. Alloy ingots are crushed in special equipment, and then sieved to obtain alloys that meet the particle size required for use. The weight percent of the chemical components of the n...

Embodiment 3

[0025] Add 213 kg of ferrosilicon and 115 kg of rust-removing steel scrap into the induction furnace for melting, and add a slag remover to remove the slag during the process. Add 12.3 kg of silicon-calcium alloy, rare earth metal (rare earth metal is lanthanum cerium rare earth metal, wherein in mass percentage: containing lanthanum (La) 30-40%, cerium (Ce) 60-70%) 3.5 kg, and all melted. The entire melting process takes 60 minutes. After melting, inert gas protection is blown into the alloy liquid surface, the alloy temperature is kept at 1450°C, 24 kg of metal magnesium is pressed into the alloy liquid, and kept for 4 minutes, and the melting of metal magnesium is completed. Finally, the ingot is cast at 1350°C under the protection of inert gas. Alloy ingots are crushed in special equipment, and then sieved to obtain alloys that meet the particle size required for use. The weight percent of the chemical composition of the nodulizer thus prepared is: RE: 0.92%, Mg: 5.98%,...

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Abstract

The invention discloses a special nodulizer for low-temperature impact resistant and high-ductility nodular cast iron and a method for preparing the special nodulizer. Components of the special nodulizer include, in mass percent, 0.5-1.5% of RE, 4-7% of Mg, 42-49% of Si, 0.5-3% of Ca, less than or equal to 0.5% of Al, less than 0.4% of MgO and the balance Fe. The special nodulizer requires high purity, has the stable components, and is small in segregation, strict in granular control and reasonable in distribution. When in use, the special nodulizer has the advantages that nodularity is higher than 85% and recession resistance is high when Mg residues in castings are controlled within the low limit of 0.036-0.040%, Mg absorption rate is high, addition of the special nodulizer is decreased by 20-30% as compared with that of a general nodulizer, less slag is generated in nodulizing reaction, slag inclusion defects of the castings are obviously decreased, magnetic particle inspection passing rate is obviously increased, the number of graphite nodules ranges from 120 to 150, the tendency of shrinkage porosity of the castings is obviously decreased, and ultrasonic inspection passing rate is obviously increased. The content of rare earth in a traditional common nodulizer generally ranges from 2% to 6%, the content of rare earth in the special nodulizer ranges from 0.5% to 1.5%, and previous rare earth resources are saved.

Description

technical field [0001] The invention belongs to the technical field of nodulizer production for casting, and in particular relates to a special nodulizer for producing low-temperature impact-resistant and high-toughness ductile iron castings and a preparation method thereof. Background technique [0002] The key components of the wind turbine, such as hubs, bases, and gearbox housings, are low-temperature impact-resistant, high-toughness ductile iron castings. Due to the very harsh working conditions and high installation and maintenance costs, the quality requirements of the castings are very high; for example, the mechanical properties of the castings require that the low-temperature impact value at -40°C is greater than 12J, and the strength is greater than 370Mpa; the metallographic structure ensures the spheroidization rate of the casting body > 85%, ferrite > 95%; castings must be subjected to surface magnetic particle flaw detection and ultrasonic flaw detection...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D1/00C21C1/10C22C33/10
Inventor 陈明
Owner JIANGSU YAFENG ALLOY MATERIAL
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