Preparation method of solid-solution-strengthened ferritic nodular cast iron for thick and large pieces

A solid solution strengthening, ductile iron technology, applied in the direction of improving process efficiency, can solve the problems of slow cooling rate, long eutectic solidification time, low tensile strength or elongation of ductile iron, etc. The effect of industrial production, reducing the overall quality

Inactive Publication Date: 2020-02-07
JIANGSU XIHUA FOUNDRY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Many ferritic ductile iron parts for wind power are thick and large (wall thickness greater than 60mm). However, due to the slow cooling rate and long eutectic solidification time of thick and large ductile iron, it is easy to produce fragmented graphite during the cooling process, which will Significantly reduce the tensile strength, elongation and other properties of ductile iron
[0004] Ordinary as-cast nodular cast iron such as QT400-18, QT450-10, QT500-7, QT600-3, QT700-2 and other grades cannot meet the requirements of thick and large par

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The 4MW wind power bearing end cover casting is selected for trial production. The base weighs 16 tons and the main wall thickness is 80-120mm. The preparation steps are as follows:

[0032] (1) Add pig iron and scrap steel to an intermediate frequency induction furnace, heat to 1470±10°C for melting, detect the content of carbon element in molten iron after all melting, and adjust the content of C element to 3.0% by adding carburant to form the original Molten iron, the temperature of molten iron out of the furnace is controlled at 1520±10°C;

[0033] (2) The molten iron is spheroidized by using the capping spheroidization method, the amount of the nodulizer rare earth magnesium added is 1.0% of the weight of the original molten iron, and Ce and Sb metal elements are added while spheroidizing;

[0034] (3) When the spheroidizing agent is tight during the preparation of the spheroidizing inoculation package, evenly cover the 75SiFe inoculant with a particle size of 3 to...

Embodiment 2

[0047] The 4MW wind power bearing end cover casting is selected for trial production. The base weighs 16 tons and the main wall thickness is 80-120mm. The preparation steps are as follows:

[0048] (1) Add pig iron and scrap steel to an intermediate frequency induction furnace, heat to 1490±10°C for melting, detect the content of carbon element in molten iron after all melting, and adjust the content of C element to 4.0% by adding carburant to form the original Molten iron, the temperature of molten iron out of the furnace is controlled at 1520±10°C;

[0049] (2) The molten iron is spheroidized by using the capping spheroidization method, the addition of the nodulizer rare earth magnesium is 2.0% of the weight of the original molten iron, and Ce and Sb metal elements are added while spheroidizing;

[0050] (3) When the spheroidizing agent is tight during the preparation of the spheroidizing inoculation package, evenly cover the 75SiFe inoculant with a particle size of 3 to 8 m...

Embodiment 3

[0063] The 4MW wind power bearing end cover casting is selected for trial production. The base weighs 16 tons and the main wall thickness is 80-120mm. The preparation steps are as follows:

[0064] (1) Add pig iron and scrap steel to an intermediate frequency induction furnace, heat to 1510±10°C for melting, detect the content of carbon element in molten iron after all melting, and adjust the content of C element to 3.5% by adding carburant to form the original Molten iron, the temperature of molten iron out of the furnace is controlled at 1520±10°C;

[0065] (2) Selecting the lid bag spheroidization method to carry out spheroidization to the molten iron, the addition of the nodulizer rare earth magnesium is 1.5% of the weight of the original molten iron, and Ce and Sb metal elements are added while spheroidizing;

[0066] (3) When the spheroidizing agent is tight during the preparation of the spheroidizing inoculation package, evenly cover the 75SiFe inoculant with a particle...

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PUM

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Abstract

The invention discloses a preparation method of solid-solution-strengthened ferritic nodular cast iron for thick and large pieces. The preparation method includes the following steps that (1) pig ironand scrap steel are heated to 1460 DEG C-1520 DEG C to be melted, and the content of the C element is adjusted to 3.0%-4.0% by adding a carburant; (2) molten iron is nodulized by using a covering nodulizing method, the amount of a nodulizing agent added is 1.0%-2.0% of the weight of the original molten iron, and metal elements of Ce and Sb are added while nodulizing is carried out; (3) when a nodulizing incubation bag is prepared and the nodulizing agent is tight, a 75SiFe inoculant with the particle size of 3-8 mm uniformly covers the upper part of the nodulizing agent; (4) 0.04%-0.1% of TiCand TiN mixed nano-powder is added, and a Bi alloy with the weight being 0.004%-0.008% of the weight of the original molten iron is added; (5) metal-stream inoculation is carried out during pouring;and (6) the strengthened ferritic nodular cast iron is obtained after the molten iron is cooled. According to the preparation method of the solid-solution-strengthened ferritic nodular cast iron for the thick and large pieces, after the incubation is completed, the TiC and TiN nano-powder and the Bi element are added, so that the tensile strength and elongation of the nodular cast iron are increased; and the preparation process of the preparation method is simple, the overall weight of the thick and large pieces can be reduced, the cost is low, and industrial production is easy to implement.

Description

technical field [0001] The invention relates to the field of preparation of ferritic nodular cast iron, in particular to a preparation method of solid solution strengthened ferritic nodular cast iron for thick and large pieces. Background technique [0002] With the development of wind power generator projects around the world, as the core components of wind power projects: hubs, bases, shafts and other parts, the ferritic nodular cast iron materials used in them have higher performance requirements as the geographical conditions become harsher. . [0003] Many ferritic ductile iron parts for wind power are thick and large (wall thickness greater than 60mm). However, due to the slow cooling rate and long eutectic solidification time of thick and large ductile iron, it is easy to produce fragmented graphite during the cooling process, which will Significantly reduce the tensile strength, elongation and other properties of ductile iron. [0004] Ordinary as-cast nodular cast...

Claims

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Application Information

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IPC IPC(8): C22C33/10C22C37/04C21C1/10
CPCC21C1/105C21D2211/005C22C33/10C22C37/04Y02P10/20
Inventor 王小磊程淦昌陈思杨正银贺献峰
Owner JIANGSU XIHUA FOUNDRY CO LTD
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