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A Control Method of Graphite Morphology in the Core of Large-Section Silicon Solid-solution Strengthened Ferritic Nodular Cast Iron

A technology of solid solution strengthening and nodular cast iron, which is applied in the field of cast iron, can solve problems such as the method of guaranteeing the shape and performance of graphite at the center of large-section castings, and the thickness of nodular cast iron.

Active Publication Date: 2017-10-03
JIANGSU JIXIN WIND ENERGY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] Chinese invention patent 201310368533.0, the title of the invention is "a full ferritic nodular cast iron and its production method", the wall thickness of the nodular cast iron produced by this method is not mentioned, and there is no mention of solving the shape and performance of graphite in the center of large-section castings Guarantee method

Method used

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  • A Control Method of Graphite Morphology in the Core of Large-Section Silicon Solid-solution Strengthened Ferritic Nodular Cast Iron
  • A Control Method of Graphite Morphology in the Core of Large-Section Silicon Solid-solution Strengthened Ferritic Nodular Cast Iron
  • A Control Method of Graphite Morphology in the Core of Large-Section Silicon Solid-solution Strengthened Ferritic Nodular Cast Iron

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Example 1: Prepare a stepped ingot of 300mm×300mm×300mm+200mm×200mm×200mm+150mm×150mm×150mm with the material of EN-GJS-450-18. For the structure and size of the stepped ingot, see figure 1 .

[0037] The composition of control elements is: C: 3.4~3.7wt%, Si: 2.8~3.3wt%, Mn≤0.3wt%, P≤0.04wt%, S: 0.01~0.03wt%, Sb: 0.001~0.006wt%, Mg : 0.03~0.06wt%, Re≤0.001wt%, and the rest are Fe and impurities brought in during the preparation process.

[0038] According to the method steps of this invention are as follows:

[0039] A) Material selection and ingredients: pig iron: 60wt%, scrap steel: 20wt%, return material: 20wt%, pig iron selection high-purity pig iron (Mn≤0.15wt%, P≤0.035wt%, S:≤0.03wt%, harmful alloy The sum of elements≤0.08wt%), low-carbon steel is selected for scrap steel (C≤0.03wt%, Mn≤0.15wt%, P≤0.03wt%, S:≤0.03wt%); the nodulizer selects rare earth-free magnesium-silicon-iron alloy balls As the covering agent, choose a low-silicon, high-iron, Ba-containing s...

Embodiment 2

[0048] Example 2: A square ingot of 400mm×400mm×400mm was prepared with the material of EN-GJS-600-10.

[0049] According to the method of the invention, the elemental composition of the ductile iron material:

[0050] C:3.0~3.4wt%, Si:3.1~4.0wt%,, Mn≤0.3wt%, P≤0.04wt%, S:0.01~0.03wt%, Sb: 0.001~0.006wt%, Mg:0.03~0.06 wt%, Re≤0.001wt%, the rest is Fe and impurities brought in during the preparation process;

[0051] The nodular cast iron material of the above formula is smelted first, and the temperature of the molten iron is controlled to be 1420-1460°C for nodularization treatment. The formula of the nodulizer is Mg 5-7wt%, Si 40-50wt%, Re≤0.01wt%, and the rest Iron, the addition amount of the nodulizer is 1.2wt%. A covering agent is added on the nodulizer. The covering agent is a low-silicon, high-iron and Ba-containing ferrosilicon covering agent. All the other are with embodiment 1.

[0052] Production shows that the performance of the square ingot of 400mm×400mm×400mm...

Embodiment 3

[0053] Example 3 Prepare a square ingot of 400mm × 400mm × 400mm with the material of EN-GJS-500-14

[0054] Control of graphite morphology in the core of large-section (wall thickness greater than 60mm) high-strength and high-toughness silicon solid-solution strengthened ferritic nodular cast iron EN-GJS-450-18 wind power castings. The 2.5MW wind power bearing cover plate casting is selected for trial production. The bearing cover plate has a single weight of 0.8 tons and a main wall thickness of 100-220mm. Follow the steps below:

[0055] Control element composition: C: 3.2~3.5wt%, Si: 2.9~3.5wt%, Mn≤0.3wt%, P≤0.04wt%, S: 0.01~0.03wt%, Sb: 0.001~0.006wt%, Mg: 0.03-0.06wt%, Re≤0.001wt%, and the rest are Fe and impurities brought in during the preparation process.

[0056] Select pig iron: 60wt%, steel scrap: 20wt%, recycle materials: 20wt%; first smelt, pig iron, scrap steel, and recycle materials are melted together, and the temperature of molten iron out of the furnace is ...

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Abstract

The invention belongs to the technical field of cast iron, and particularly relates to a technological method of ensuring the graphite shape and performances of the core of large-cross section silicon solid solution strengthening ferritic nodular cast iron. The technical scheme of the invention is to provide a method of ensuring the graphite shape of the core of a large-cross section silicon solid solution strengthening ferritic nodular iron casting. The method comprises the following steps of: dissecting the core of an ingot bar with the wall thickness of larger than 300mm and trepanning a large casting body with the wall thickness of larger than 60mm by selecting raw materials, controlling compositions of molten iron, optimizing a nodulizing agent, a covering agent and treatment technologies thereof and determining an inoculant and a treatment technology thereof as well as the addition amount of trace alloying elements and an addition method thereof, so that on the premise of meeting requirements on related properties of materials, chunky graphite does not occur in the core of the ingot bar and the large casting body, a graphite nodule is round and complete, the nodularity is greater than or equal to 80%, the content of ferrite in a matrix structure is greater than 95%, and the content of pearlite in the matrix structure is less than 5%.

Description

technical field [0001] The invention belongs to the technical field of cast iron, and in particular relates to a process method for ensuring the shape and performance of graphite in the core part of large-section silicon solid-solution strengthened ferritic nodular cast iron. Background technique [0002] In the current national standard "GBT 1348-2009 Ductile Iron Castings", there are two grades of QT500, QT500-7A and QT500-10A, for the performance of QT500 with attached casting test block, the former is ferrite-pearlite mixed base ductile iron, The latter is a new type of ductile iron: silicon solid solution strengthened ferritic ductile iron. The performance indexes of the two materials are shown in Table 1. Under the condition that the strength reaches 500Mpa, the maximum elongation is 10%. [0003] Table 1 Performance indicators of QT500-7A and QT500-10A in GBT 1348-2009 [0004] [0005] In March 2012, when the German and European ductile iron standard DIN EN1563 ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C37/10C22C37/04C22C33/08C21C1/10
CPCY02P10/20
Inventor 王星王美喜史学勇闫兴义陈柏林
Owner JIANGSU JIXIN WIND ENERGY TECH
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