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Gray pig iron and production process thereof

A production process, the technology of gray cast iron, applied in the field of gray cast iron and its production process, can solve the problems of poor casting performance, large tendency of casting shrinkage and porosity, increased leakage of castings, etc., to achieve superior casting performance, low cost, and avoid shrinkage porosity Tendency to large effect

Inactive Publication Date: 2011-09-14
WEICHAI POWER CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, molybdenum alloyed HT300 is commonly used as engine material. Adding copper, chromium and molybdenum to HT300 gray cast iron for alloying can significantly improve the strength of gray cast iron, but the use of molybdenum for alloying will cause shrinkage of the casting. The tendency is large, making the casting performance poor, increasing the risk of casting leakage, and the casting rejection rate is high

Method used

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  • Gray pig iron and production process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] a) Using a cupola to melt the mixed pig iron, scrap steel and returned iron into molten iron, the content of pig iron is 30% by weight, the steel is 40%, the returned iron is 30%, and the furnace temperature is 1500 degrees.

[0038] b) The melted molten iron is transferred to the heat preservation electric furnace for heat preservation, and the heat preservation temperature is 1440 degrees.

[0039] C) take out molten iron, carry out pre-stove treatment simultaneously, the weight percent composition that the molten iron after processing contains is:

[0040] C: 3.3%, Si: 1.7%, Mn: 0.6%, P: 0.03%, S: 0.09%, Cr: 0.3%, Cu: 0.5%, Sn: 0.08%, Ni: 0.4%, Fe: 93%.

[0041] d) Transfer the molten iron treated before the furnace to the pouring machine for pouring.

Embodiment 2

[0043] a) Using an electric furnace to melt the mixed pig iron and scrap steel into molten iron, the weight percentage of pig iron is 30%, steel is 70%, and the furnace temperature is 1520 degrees.

[0044] b) The molten iron is transferred to the heat preservation electric furnace for heat preservation, and the heat preservation temperature is 1450 degrees.

[0045] C) take out molten iron, carry out pre-stove treatment simultaneously, the weight percent composition that the molten iron after processing contains is:

[0046] C: 3.1%, Si: 2.0%, Mn: 0.5%, P: 0.04%, S: 0.07%, Cr: 0.19%, Cu: 0.6%, Ni: 0.3%, Fe: 93.2%.

[0047] d) Transfer the molten iron treated before the furnace to the pouring machine for pouring.

Embodiment 3

[0049] a) Using a cupola to melt the mixed pig iron and scrap steel into molten iron, the pig iron content is 60% by weight, the steel product is 40%, and the furnace temperature is 1550 degrees.

[0050] b) The molten iron is transferred to the heat preservation electric furnace for heat preservation, and the heat preservation temperature is 1430 degrees.

[0051] C) take out molten iron, carry out pre-stove treatment simultaneously, the weight percent composition that the molten iron after processing contains is:

[0052] C: 3.4%, Si: 1.8%, Mn: 0.7%, P: 0.05%, S: 0.1%, Cr: 0.2%, Cu: 0.4%, Sn: 0.1%, Ni: 0.5%, Fe: 92.75%.

[0053] d) Transfer the molten iron treated before the furnace to the pouring machine for pouring.

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Abstract

The invention provides a gray pig iron, which comprises the following elements in percentage by weight: 3.1 to 3.4 percent of C, 1.5 to 2.1 percent of Si, 0.5 to 0.8 percent of Mn, 0 to 0.06 percent of P, 0.05 to 0.15 percent of S, 0.15 to 0.50 percent of Cr, 0.3 to 0.8 percent of Cu, 0 to 0.12 percent of Sn, 0.20 to 0.60 percent of Ni, and the balance of Fe. In the production process of the gray pig iron, the Cu, the Cr, the Ni and the Sn are added into molten iron to perform alloying, so the defect of large shrinkage porosity tendency caused by using molybdenum to perform the alloying can be overcome, the obtained gray pig iron has excellent casting property, shrinkage cavities are not generated on casts, the requirements on materials of key casts of cylinder bodies and cylinder covers of high-performance engines at present can be met; and the price the Ni and the Sn is lower than that of the molybdenum, so the cost of the casts is low.

Description

technical field [0001] The invention relates to the field of casting, in particular to gray cast iron and a production process thereof. Background technique [0002] The cylinder block and cylinder head of the engine are generally made of gray cast iron, which has excellent castability and can be used to manufacture various products. [0003] At present, due to the development of engine technology, product upgrading, engine emission standards are becoming more and more stringent, and diesel engine explosion pressure is getting higher and higher. Therefore, it is urgent to improve the quality, reliability and stability of casting materials. The current HT250 material is far from meeting the requirements. Therefore, it is urgent to develop a cast iron material with higher performance than HT250 and good overall performance. [0004] At present, molybdenum-alloyed HT300 is commonly used as the engine material. Adding copper, chromium, and molybdenum to the HT300 gray cast iro...

Claims

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Application Information

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IPC IPC(8): C22C37/10C22C33/08
Inventor 李明刘庆义房夺李娜张行河乔进国张敏之许景峰
Owner WEICHAI POWER CO LTD
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