Preparation method of compacted graphite cast iron

A technology of vermicular graphite cast iron and molten iron, which is applied in the field of cast iron processing and can solve problems such as poor stability, low creep rate, and high ferrite content

Inactive Publication Date: 2012-09-19
丹阳市锦雄机械制造有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are problems such as poor stability, low creep rate, high ferrite content and low tensile strength in the production of compacted graphite cast iron, which limit the wide application of compacted graphite cast iron

Method used

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Examples

Experimental program
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Effect test

Embodiment Construction

[0018] A preparation method of vermicular graphite cast iron, in weight percentage, comprises the following steps:

[0019] 1. Raw material selection: Melt conventional ordinary scrap iron into molten iron, so that the chemical composition of the molten iron is: C: 3.45-3.6%, Si: 1.45-1.7%, Mn: 0.7-1.0%, phosphorus P: 0- 0.07%, sulfur S: 0.06-0.08%, and the rest is iron.

[0020] 2. Pretreatment: add 0.4-0.7% CaC 2 Put the powder in a hollow "T" refractory tube, insert the "T" tube into the ladle, make it rotate at a speed of 60-80 rad / min, and perform mechanical stirring for 2-4 minutes to control the sulfur content. In 0.03 ~ 0.04%.

[0021] 3. Configure rare earth magnesium calcium vermicular agent: Re: 10~13%, Ca: 3~5%, Mg: 3~5%, Si: 43~47%, Cr: 1~3%, Cu: 3~ 5%, Ti: 0-1%, and the rest is iron. Adding Cr and Cu to the rare earth magnesium calcium vermicular agent can combine vermicularization and microalloying, and increase and stabilize the pearlite content in the verm...

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Abstract

The invention discloses a preparation method of compacted graphite cast iron, which is characterized by comprising the following steps of: (1) raw material selection; (2) pretreatment; (3) rare earth-magnesium-calcium vermicularizing alloy preparation; (4) vermicularizing treatment; (5) stokehole sample test and rapid metallographic test; (6) slag covering; (7) late inoculation; and (8) pouring. In the method, the sulfur content of molten iron can be controlled between 0.03% and 0.04% after the molten iron is pretreated; and after being subjected to vermicularizing treatment by using rare earth-magnesium-calcium vermicularizing alloy and late inoculation treatment by using 75 ferrosilicon alloy, the prepared compacted graphite cast iron has the vermicular graphite rate of more than or equal to 85%, the tensile strength sigmab of more than or equal to 420 Mpa, the hardness HB of 175-210 and the elongation delta of more than or equal to 1.5%, and the pearlite content in a matrix of the compacted graphite cast iron is more than or equal to 50%.

Description

technical field [0001] The invention relates to the field of cast iron processing, and adopts a rare earth magnesium calcium vermicular agent and a sulfur content control technology in front of a furnace to produce vermicular graphite cast iron castings. It specifically relates to a method of spraying powder in a molten iron ladle in front of a furnace to control the sulfur content of molten iron, using a rare earth magnesium calcium vermicular agent to perform vermicular treatment and secondary inoculation on the molten iron, and to prepare vermicular graphite cast iron castings with high strength and high wear resistance. Background technique [0002] Vermicular graphite cast iron is a new type of engineering material between gray cast iron and ductile iron, which combines the casting performance of gray cast iron with the high strength and toughness of ductile iron. Therefore, the material has good vibration damping, thermal conductivity, and wear resistance. It can be w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C37/04C22C33/10
Inventor 荆泽平付明喜张军中范萃常
Owner 丹阳市锦雄机械制造有限公司
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