High strength and high thermal conductivity gray cast iron and manufacturing method thereof

Abstract

A method for manufacturing gray cast iron includes: preparing an alloy material comprising: carbon: 3.2 to 4.0 wt%, silicon: 1.0 to 1.5 wt%, manganese: 0.5 to 1.0 wt%, and copper: 0.1 to 0.5 wt%, with the remaining weight percentage being iron and unavoidable impurities; melting the alloy material to form an alloy molten metal; adding a silicon-containing inoculum to the alloy molten metal; cooling the alloy molten metal to form a gray cast iron billet; heating the gray cast iron billet to a Voss tempering temperature and holding it at that temperature for a first predetermined time; salt quenching the gray cast iron billet to control its temperature at a Voss tempering temperature and holding it at that temperature for a second predetermined time; and then air cooling it to room temperature to form gray cast iron. Therefore, this invention can achieve the purpose of improving the strength and thermal conductivity of gray cast iron.

Claims

1. A method for manufacturing gray cast iron, comprising the following steps: An alloy material preparation step: preparing an alloy material, the composition of which, by weight percentage, includes the following elements: carbon: 3.2 to 4.0 wt%, silicon: 1.0 to 1.5 wt%, manganese: 0.5 to 1.0 wt%, and copper: 0.1 to 0.5 wt%, with the remaining weight percentage being iron and unavoidable impurities; A process for preparing and solidifying an alloy molten metal: heating the alloy material to a melting temperature for melting to form an alloy molten metal; adding a silicon-containing inoculant to the alloy molten metal at the inoculation temperature during an inoculation process for graphite nucleation and refinement treatment; cooling the alloy molten metal to form a gray cast iron billet; and a heat treatment process: heating the gray cast iron billet to a Voss tempering temperature and holding it at that temperature for a first predetermined time; controlling the temperature of the gray cast iron billet at a Voss tempering temperature by salt quenching and holding it at that temperature for a second predetermined time; and then air cooling to room temperature to form gray cast iron.

2. The method for manufacturing gray cast iron as described in claim 1, wherein, In the preparation step of the alloy material: the composition of the alloy material also includes the following elements: phosphorus: 0.15 to 0.20 wt% and sulfur: 0.049 to 0.066 wt%.

3. The method for manufacturing gray cast iron as described in claim 1, wherein, In the preparation and solidification steps of the alloy molten metal: the inoculation temperature is 1450 to 1480 °C.

4. The method for manufacturing gray cast iron as described in claim 1, wherein, In the alloy melt preparation and solidification steps: the silicon-containing inoculant is a silicon-barium inoculant, whose composition by weight percentage includes the following elements: silicon: 68 to 72 wt%, strontium: 0.9 to 1.2 wt%, calcium: 1.1 to 1.3 wt%, and barium: 2.0 to 2.3 wt%.

5. The method for manufacturing gray cast iron as described in claim 1, wherein, In this heat treatment step: the ferroplating temperature is 850 to 950 °C, and the first predetermined time is 1 to 1.5 hours.

6. The method for manufacturing gray cast iron as described in claim 1, wherein, In this heat treatment step: the Voss tempering temperature is 240 to 300 °C, and the second predetermined time is 1.5 to 3 hours.

7. The method for manufacturing gray cast iron as described in claim 1, wherein, The ratio of the alloy material to the silicon-containing inoculant is between 96:4 and 98:

2.

8. The method for manufacturing gray cast iron as described in claim 1, wherein, The gray cast iron has a tensile strength greater than 323 MPa and a thermal conductivity greater than 55 W / m·K.

9. A gray cast iron, comprising, by weight percentage, the following elements: carbon: 3.2 to 4.0 wt%, silicon: 1.0 to 1.6 wt%, manganese: 0.5 to 1.0 wt%, and copper: 0.1 to 0.5 wt%, with the remaining weight percentage being iron and unavoidable impurities.

10. Gray cast iron as described in claim 9, wherein, The gray cast iron also contains the following elements: phosphorus: 0.15 to 0.20 wt% and sulfur: 0.049 to 0.066 wt%.

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