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Thick and large-section high-silicon-molybdenum ductile iron casting and its manufacturing method

A technology of ductile iron and a manufacturing method, which is applied in the field of thick and large-section high-silicon molybdenum ductile iron and its manufacturing field, can solve the problems of large brittleness, shrinkage cavities, easy generation of shrinkage porosity, etc., so as to reduce brittleness, reduce scrap rate, The effect of promoting graphite nodularization

Active Publication Date: 2017-08-25
RIYUE HEAVY IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the existing thick and large cross-section high-silicon-molybdenum ductile iron castings have the following problems: due to the constraints of high silicon and low carbon, not only the castings are prone to shrinkage porosity and shrinkage cavities during manufacture, but also have high brittleness. The scrap rate caused by brittleness is as high as 20% to 50%, especially when manufacturing castings with a wall thickness greater than 200mm, the above-mentioned defects are more likely to occur

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] In this embodiment, the medium-pressure outer cylinder of the steam turbine has a thick and large-section high-silicon-molybdenum ductile iron casting with a thickness of 470 mm at the thickest point and a thickness of 90 mm at the thinnest point. The single casting is 43,380 kg, produced with resin sand, and the matrix structure is ferrite.

[0062] The percentages by weight of the components in the medium-pressure outer cylinder of the steam turbine thick and large-section high-silicon-molybdenum ductile iron casting are: C: 3.4%, Si: 3.1%, Mn: 0.08%, P: 0.03%, S: 0.009%, Mg: 0.06%, Mo: 0.52%, Re: 0.11%, Sb: 0.005%, and the rest is iron.

[0063]The manufacturing method of the medium-pressure outer cylinder of the steam turbine with thick and large cross-section high-silicon-molybdenum ductile iron is as follows: 1. Raw materials are configured, and the raw materials include the following substances in weight percentages: pig iron: 45%, scrap steel: 26.4%, furnace char...

Embodiment 2

[0069] In this embodiment, the medium-pressure outer cylinder of the steam turbine has a thick and large-section high-silicon-molybdenum ductile iron casting with a thickness of 470 mm at the thickest point and a thickness of 90 mm at the thinnest point. The single casting is 43,380 kg, produced with resin sand, and the matrix structure is ferrite.

[0070] The percentages by weight of the components in the medium-pressure outer cylinder of the steam turbine thick and large-section high-silicon-molybdenum ductile iron casting are: C: 3.3%, Si: 3.2%, Mn: 0.08%, P: 0.02%, S: 0.008%, Mg: 0.05%, Mo: 0.6%, Re: 0.14%, Sb: 0.005%, and the balance is iron.

[0071] The manufacturing method of the medium-pressure outer cylinder of the steam turbine with thick and large cross-section high-silicon-molybdenum ductile iron castings is as follows: 1. Raw materials are configured, and the raw materials include the following substances in weight percentages: pig iron: 48%, scrap steel: 25%, fu...

Embodiment 3

[0077] In this embodiment, the medium-pressure outer cylinder of the steam turbine has a thick and large-section high-silicon-molybdenum ductile iron casting with a thickness of 470 mm at the thickest point and a thickness of 90 mm at the thinnest point. The single casting is 43,380 kg, produced with resin sand, and the matrix structure is ferrite.

[0078] The percentages by weight of the components in the medium-pressure outer cylinder of the steam turbine thick and large-section high-silicon-molybdenum ductile iron casting are: C: 3.5%, Si: 3.2%, Mn: 0.1%, P: 0.04%, S: 0.01%, Mg: 0.07%, Mo: 0.5%, Re: 0.09%, Sb: 0.004%, and the balance is iron.

[0079] The manufacturing method of the medium-pressure outer cylinder of the steam turbine with thick and large cross-section high-silicon-molybdenum ductile iron castings is as follows: 1. Raw materials are configured, and the raw materials include the following substances in weight percentages: pig iron: 42%, scrap steel: 27%, recy...

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Abstract

The invention relates to a thick large-section high-silicon-molybdenum spherical graphite iron casting. The casting comprises the ingredients, by weight percentage, of 3.3-3.5% of C, 3.0-3.2% of Si, smaller than or equal to 0.1% of Mn, smaller than or equal to 0.04% of P, smaller than or equal to 0.01% of S, 0.04-0.07% of Mg, 0.5-0.6% of Mo, 0.08-0.15% of Re, 0.004-0.005% of Sb and the balance of iron. A manufacturing method for the casting sequentially comprises the steps of configuring raw materials, smelting, sampling, analyzing, allocating, tapping iron, balling and inoculating. The manufacturing method has the beneficial effects of effectively overcoming the defects of shrinkage porosity and shrinkage cavity of the thick large-section casting, reducing the fragility of the casting and greatly reducing the rejection rate of the casting in manufacturing.

Description

technical field [0001] The invention relates to a high-silicon-molybdenum ductile iron cast iron and a manufacturing method thereof, in particular to a thick and large-section high-silicon-molybdenum ductile iron casting and a manufacturing method thereof. Background technique [0002] High-silicon-molybdenum ductile iron is widely used at home and abroad because of its good thermal fatigue resistance, high temperature strength, high temperature oxidation resistance and dimensional temperature resistance. At present, the existing thick and large cross-section high-silicon-molybdenum ductile iron castings have the following problems: due to the constraints of high silicon and low carbon, not only the castings are prone to shrinkage and shrinkage during manufacture, but also have high brittleness. The scrap rate caused by brittleness is as high as 20% to 50%, especially when manufacturing castings with a wall thickness greater than 200mm, the above-mentioned defects are more l...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C37/04C22C37/10C22C33/10
Inventor 张坤刘建东宋贤发傅明康
Owner RIYUE HEAVY IND