Gray cast iron and preparation method thereof

A gray cast iron and cast iron technology, applied in the field of gray cast iron preparation, can solve the problems of casting shrinkage cavity, shrinkage porosity, increased deformation, poor casting performance of cast iron, high cost pressure of castings, etc., to achieve shrinkage porosity and deformation, small, High yield and good casting performance

Active Publication Date: 2015-12-30
浙江杭机铸造有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, when producing high-strength gray iron castings, copper, molybdenum, nickel, vanadium and other precious metals are usually added for alloying to improve the strength and hardness of gray iron castings. The casting performance of castings deteriorates, and the tendency of shrinkage cavity, shrinkage porosity and deformation of castings increases; in addition, due to the high price of precious metals, the production of castings faces very high cost pressure

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0021] The preparation method of the gray cast iron comprises the following steps:

[0022] The first is the smelting process. The metal charge is mainly scrap steel, mainly including 25% to 40% of ordinary steel scrap; 10% to 15% of chromium-containing scrap; 28% to 45% of returned furnace iron; 5% to 25% of pig iron; 0.5% to 1% ferrosilicon; 0.5% to 1.5% ferromanganese and 8% to 11% layer coke (layer coke is casting coke with a carbon content ≥ 88%) to smelt metal charge into molten iron. And detect and adjust the composition of molten iron, so that the carbon content in the molten iron is 3.0% to 3.2%, the silicon content is 1.35% to 1.55%, the manganese content is 0.85% to 1.10%, the chromium content is 0.08% to 0.15%, and the phosphorus content is ≤ 0.065%, sulfur content ≤ 0.11%, after adjusting to meet the standard, let stand and remove slag.

[0023] Then inoculation treatment: in the process of tapping molten iron after smelting, quantitatively add an inoculant befor...

Embodiment example 1

[0030] The main components of gray cast iron include: 3.031% carbon; 1.783% silicon; 1.080% manganese; 0.112% chromium; 0.034% antimony; 0.098% sulfur and 0.060% phosphorus.

[0031] The preparation method of the gray cast iron comprises the following steps:

[0032] The first is the smelting process. The metal charge includes 35% ordinary steel scrap; 15% chromium-containing scrap; 40% returned iron; 10% pig iron; 0.6% ferrosilicon; 0.5% ferromanganese and 11% layer coke. Firstly, the metal charge is smelted in the cupola. The temperature of the process is required to be controlled above 1450°C, and then the molten iron is returned to the heat preservation electric furnace to raise the temperature. After analyzing the composition of the molten iron through the spectrum, the composition is determined according to the composition percentage of gray cast iron. Adjust, then stand still, remove slag, tap iron, and the iron tapping temperature is controlled at 1435-1460°C.

[0033...

Embodiment example 2

[0037] The preparation method of the gray cast iron of this embodiment is similar to that of Embodiment 1. The main difference is that the metal charge includes: 35% ordinary steel scrap; 15% chromium-containing scrap; 40% returned iron; 10% pig iron; 0.9% ferrosilicon; 1.3% ferromanganese and 10% layer coke.

[0038] The amount of inoculant in front of the furnace is 0.4% of the total mass of molten iron; the amount of inoculant with flow is 0.1% of the total mass of molten iron.

[0039] The main chemical components in the final shaped casting include: 3.065% carbon; 1.757% silicon; 1.120% manganese; 0.105% chromium; 0.028% antimony; 0.096% sulfur and 0.056% phosphorus.

[0040] The tensile strength of the casting is 332MPa; the casting body hardness HB is 198; the graphite form is type A; the graphite size is 4-5 grades, pearlite ≥ 98%; cementite ≤ 1%.

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Abstract

The invention discloses gray cast iron and a preparation method thereof, and belongs to the field of metal casting. The gray cast iron and the preparation method solve the technical problems that existing gray cast iron is high in production cost and insufficient in performance. According to the gray cast iron and the preparation method, precious metal such as copper, molybdenum, nickel and vanadium is not added, strength and hardness of castings are improved through chromium and antimony, the manufacturing cost is reduced, and performance of the gray cast iron can be improved by conducting microalloying on antimony and chromium together.

Description

【Technical field】 [0001] The invention relates to a preparation method of gray cast iron. 【Background technique】 [0002] Cast iron is a traditional structural material with a long history, especially gray cast iron, because of its good wear resistance, heat resistance, oxidation resistance and shock absorption, it also has a lower melting point than other alloy materials, good casting performance and processing performance, It is easy to organize production and other characteristics, so it has been widely used in various industries such as machine tools and general machinery for a long time. With the development of casting technology and the improvement of customers' requirements for castings, high strength and stable and reliable materials of iron castings are the goals pursued by the foundry industry. [0003] At present, when producing high-strength gray iron castings, copper, molybdenum, nickel, vanadium and other precious metals are usually added for alloying to impro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C37/10C22C33/08
Inventor 陈建国方毅王海君桑迪樊智勇钱银锋
Owner 浙江杭机铸造有限公司
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