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Fragmented graphite prevention large-section nodular cast iron sectional material and process

A technology of nodular cast iron and block graphite, applied in the field of cast iron materials and foundry metallurgy, can solve the problems of fragmented block graphite, long eutectic solidification time, affecting the roundness of profiles and section compactness, etc. Small, good graphite nodularization grade, good graphite morphology

Inactive Publication Date: 2019-09-27
HANDAN HENGGONG METALLURGICAL MACHINERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Spheroidal graphite cast iron is obtained through spheroidization and inoculation treatment. When the horizontal continuous casting process is used to produce large-section (diameter greater than 250mm) nodular cast iron profiles, because the eutectic solidification time is long, the decline of spheroidization and inoculation is prone to occur. It is often accompanied by fragmented graphite, which seriously affects the roundness of the profile and the compactness of the section and other comprehensive properties

Method used

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  • Fragmented graphite prevention large-section nodular cast iron sectional material and process
  • Fragmented graphite prevention large-section nodular cast iron sectional material and process
  • Fragmented graphite prevention large-section nodular cast iron sectional material and process

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Effect test

Embodiment 1

[0054] A large-section ductile iron profile that prevents the formation of fragmented graphite. The mass percentage ranges of carbon, silicon, manganese, bismuth and antimony in the large-section ductile iron profile are: carbon: 3.40%-3.50%, silicon: 2.45%- 2.55%, manganese: 0.35%-0.40%, bismuth: 0.010%-0.014%, antimony: 0.015%-0.025%, and the rest is iron. The mass percentages of carbon, silicon, manganese, bismuth and antimony in large-section ductile iron profiles are: carbon: 3.48%, silicon: 2.50%, manganese: 0.37%, bismuth: 0.012%, antimony: 0.020%, and the rest is iron . The graphite shape of the large-section ductile iron profile is good, the graphite spheroidization grade is good, the graphite spheres are complete and small, and the metallographic structure has no fragmented graphite. And the cross-section is uniform and dense, and the mechanical comprehensive performance is high.

Embodiment 2

[0056] A technology for large-section ductile iron profiles to prevent the formation of fragmented graphite, selected to produce QT500-10 materials The profile has a larger cross-section, and the liquid center will still exist far away from the drawing outlet. During production, the drawing speed is too fast and the liquid level is too low, which will affect the quality of the cross-section structure. Therefore, the production line of Hebei Henggong Machinery Equipment Technology Co., Ltd. Adding alloy bismuth and antimony in the post-inoculation stage, the process specifically includes the following steps:

[0057] (1) For the smelting of molten iron, two 10-ton medium-frequency induction furnaces are used to smelt molten iron. Each package of molten iron is 1.2-1.3 tons. The ratio of pig iron: scrap steel: scrap rod or iron filings is 50:35:15 The post-furnace batching is weighed, and the post-furnace batching described in the post-furnace batching is high-quality pig iron...

Embodiment 3

[0066] Get common graphite cast iron profile and the QT500-10 material that adopts embodiment 2 to produce respectively The section of the profile, observe the metallographic image under the metallographic microscope, and get the metallographic structure diagram, such as figure 1 , figure 2 , image 3 as well as Figure 4 shown.

[0067] Will figure 1 and figure 2 To observe and compare, figure 2 The ratio of the number of graphite balls figure 1 The increase in , indicating that the spheroidization rate of the core of the profile has been improved, and the overall quality of the profile has been improved. figure 2 The roundness ratio of the edge of the graphite ball figure 1 The roundness of the edge of the medium graphite ball is high. image 3 More fragmented graphite with irregular edges was formed in the Figure 4 Spherical graphite with relatively rounded edges is distributed in the middle. It can be concluded from the above that the graphite cast iron pr...

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Abstract

The invention discloses a fragmented graphite prevention large-section nodular cast iron sectional material. The large-section nodular cast iron sectional comprises, by mass, 3.40%-3.50% of carbon, 2.45%-2.55% of silicon, 0.35%-0.40% of manganese, 0.010%-0.014% of bismuth, 0.015%-0.025% of antimony, and the balance iron. The obtained large-section nodular cast iron sectional material is good in graphite form and graphite nodulizing grade, graphite nodules are complete and fine, and a metallographic structure is free of fragmented graphite. The invention further discloses a process of the fragmented graphite prevention large-section nodular cast iron sectional material. Alloys bismuth and antimony are added at the inoculation stage after nodulizing treatment so as to obtain the nodular cast iron sectional material with the fine crustal particles. The number of the graphite nodules is increased, a fracture surface is free of fragmented graphite, attenuation of nodulizing and inoculation is delayed, and the nodulizing rate is increased. The roundness of the sectional material is higher, the uniformity, compactness and comprehensive performance of the fracture surface are improved, and the high-quality nodular cast iron sectional material is obtained.

Description

technical field [0001] The invention belongs to the technical field of cast iron materials and foundry metallurgy, and in particular relates to a large-section ductile iron profile that prevents the formation of fragmented graphite, and also relates to a process for preventing the formation of fragmented graphite. Background technique [0002] Spheroidal graphite cast iron is obtained through spheroidization and inoculation treatment. When the horizontal continuous casting process is used to produce large-section (diameter greater than 250mm) nodular cast iron profiles, because the eutectic solidification time is long, the decline of spheroidization and inoculation is prone to occur. It is often accompanied by fragmented graphite, which seriously affects the roundness of the profile and the compactness of the section and other comprehensive properties. Contents of the invention [0003] The object of the present invention utilizes in the rapid cooling process, adds alloy b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C37/04C22C37/10C21C1/10C22C33/08
CPCC21C1/105C22C33/08C22C37/04C22C37/10Y02P10/20
Inventor 魏志勇王敬民孔令伟
Owner HANDAN HENGGONG METALLURGICAL MACHINERY CO LTD
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