Ductile iron bar for increasing number of graphite nodules with SiC and preparation method thereof

A technology of graphite balls and iron profiles, which is applied in the field of cast iron material casting, can solve the problems of small number of graphite balls, poor mechanical properties, poor structure uniformity, etc., and achieve small differences in section uniformity, good cutting performance, and improved processing performance. Effect

Active Publication Date: 2017-11-10
陕西西理华铸新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a ductile iron profile that uses SiC to increase the number of graphite balls, whic

Method used

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Examples

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Comparison scheme
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Example Embodiment

[0038] The preparation method of the large-diameter nodular cast iron profile material of the present invention has the main features that SiC is added to the electric furnace during the molten iron smelting process, which is beneficial to increase Si and C, and the addition of SiC can be used as the core of heterogeneous nucleation, which can improve graphite nucleation The core, therefore, can increase the number of graphite nodules. At the same time, due to the increase in the number of graphite spheres, it is beneficial to avoid the excessive growth of primary graphite spheres and the appearance of large-diameter graphite spheres. This is beneficial to reduce the difference between the internal and external structures of the profile, increase the hardness of the core of the profile, reduce the hardness of the surface layer, and improve the machining performance of the profile.

[0039] In addition, since the melting point of SiC is 2800°C and its density is much lower than...

Example Embodiment

[0041] Example 1

[0042] Φ142mm ductile iron profile material and its preparation.

[0043] Its composition by weight percentage is: C: 3.6%, Si: 2.4%, Mn: 0.2%, P: 0.10%, S: 0.06%, and the rest is Fe.

[0044] Use a 3T intermediate frequency induction furnace to melt molten iron. According to the above weight percentage composition, deduct the amount of silicon brought in by the long-term ferrosilicon inoculant, calculate the amount of casting pig iron, scrap steel, recycled material and 75% ferrosilicon required for the original molten iron, and the order of melting and feeding Put in a part of low-manganese cast ductile iron pig iron in order to cover the bottom of the furnace. After the batch of pig iron is melted, add SiC with a particle size of 4mm at one time. Add the remaining pig iron, scrap steel, and returned materials, and press them on the SiC until all the materials in the furnace are completely melted; the ferroalloys added to the intermediate frequency induct...

Example Embodiment

[0050] Example 2

[0051] Φ260mm ductile iron profile material and its preparation.

[0052] Its composition by weight percentage is: C: 3.3%, Si: 2.6%, Mn: 0.3%, P: 0.08%, S: 0.04%, and the rest is Fe.

[0053] Use a 5T intermediate frequency induction furnace to melt molten iron. According to the above weight percentage composition, deduct the amount of silicon brought in by the long-term ferrosilicon inoculant, calculate the amount of casting pig iron, scrap steel, recycled material and 75% ferrosilicon required for the original molten iron, and the order of melting and feeding Put in a part of low-manganese cast ductile iron pig iron in order to cover the bottom of the furnace. After the batch of pig iron is melted, add SiC with a particle size of 6mm at one time. Add the remaining pig iron, scrap steel, and returned materials, and press them on the SiC until all the materials in the furnace are completely melted; the ferroalloys added to the intermediate frequency induct...

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Abstract

The invention discloses a ductile iron bar for increasing the number of graphite nodules with SiC. The ductile iron bar comprises, by weight, 3.1%-3.6% of C, 2.4%-3.3% of Si, 0.2%-0.4% of Mn, 0-0.10% of P, 0-0.06% of S and the balance Fe. The weight percentage sum of the compositions is 100%. The invention further discloses a preparation method of the ductile iron bar. According to the ductile iron bar for increasing the number of the graphite nodules with the SiC and the preparation method thereof, surface quality of the ductile iron bar for increasing the number of the graphite nodules with the SiC is good, dimensional precision is high, and the casting defects of sand inclusion, slag inclusion, air holes, shrinkage cavities and the like are avoided; the structure is compact and even from the center to the edge, the number of the graphite nodules of a core part is increased by 20% or above compared with the number of graphite nodules without SiC, the graphite nodule diameter is about grade 6-7, and no obvious large-diameter graphite exists; and the edge hardness of the ductile iron bar is lowered by HB20 or above, the core part and surface layer hardness difference is decreased to HB20 or below, and processing performance of the ductile iron bar can be improved.

Description

technical field [0001] The invention belongs to the technical field of casting of cast iron materials, and relates to a nodular iron profile which uses SiC to increase the number of graphite balls, and also relates to a preparation method of the nodular iron profile. Background technique [0002] Ductile iron profiles are high-quality nodular cast iron blank materials produced by horizontal continuous casting. During the production process, the molten iron that has been spheroidized and inoculated is rapidly cooled and solidified in a water-cooled steel sleeve high-purity graphite mold. Graphite The rapid cooling effect of the molten iron rapidly cools down and nucleates, and the solidification speed is much faster than that of sand casting. Since the crystallizer is installed at the bottom of the holding furnace, pure molten iron enters the crystallizer from the bottom to solidify. Therefore, the horizontal continuous casting ductile iron profiles do not have the defects of...

Claims

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Application Information

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IPC IPC(8): C22C37/10C22C37/04C22C33/10C21C1/10B22D11/045
CPCB22D11/045C21C1/10C22C33/10C22C37/04C22C37/10
Inventor 徐春杰赵振张浩徐信锋马萌孙蕾张忠明
Owner 陕西西理华铸新材料科技有限公司
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