Spheroidal graphite cast iron, cast article and automobile structure part made thereof, and method for producing spheroidal graphite cast iron article
AssigneeProterial, Ltd.
InventorLin Wang
Life of this patent
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Abstract
A spheroidal graphite cast iron meeting N(5-)≥250, N(5-20)/N(5-)≥0.6, and N(30-)/N(5-)≤0.2, wherein N(5-) represents the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more, N(5-20) represents the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more and less than 20 μm, and N(30-) represents the number (/mm2) of graphite particles having equivalent-circle diameters of 30 μm or more, among graphite particles observed in an arbitrary cross section of at least 1 mm2.
Claims13
A method for producing a cast article of spheroidal graphite cast iron meeting the following conditions:
- N(5-)≥250,
- N(5-20)/N(5-)≥0.6, and
- N(30-)/N(5-)≤0.2,
- wherein N(5-), N(5-20), and N(30-) are the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more, the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more and less than 20 μm, and the number (/mm2) of graphite particles having equivalent-circle diameters of 30 μm or more, respectively, among graphite particles observed in an arbitrary cross section of at least 1 mm2;
- comprising
- pouring a melt into a gas-permeable casting mold by gravity-casting,
- pressing a surface of the melt in the gas-permeable casting mold by a gas at a pressure of 1-100 kPa, before said melt starts eutectic solidification;
- and
- solidifying said melt while supplying said gas into said casting mold,
- wherein said method meets
- 0<dtpE/dtE≤1/2,
- wherein dtE represents a time period from the start of eutectic solidification of said melt to the completion of the eutectic solidification, and dtpE represents a time period from the start of eutectic solidification of said melt to the completion of said pressing.
A method for producing a cast article of spheroidal graphite cast iron meeting the following conditions:
- N(5-)≥250,
- N(5-20)/N(5-)≥0.6, and
- N(30-)/N(5-)≤0.2,
- wherein N(5-), N(5-20), and N(30-) are the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more, the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more and less than 20 μm, and the number (/mm2) of graphite particles having equivalent-circle diameters of 30 μm or more, respectively, among graphite particles observed in an arbitrary cross section of at least 1 mm2;
- comprising
- pouring a melt into a gas-permeable casting mold by gravity-casting,
- pressing a surface of the melt in the gas-permeable casting mold by a gas at a pressure of 1-100 kPa, before said melt starts eutectic solidification;
- and
- solidifying said melt while supplying said gas into said casting mold,
- wherein said method meets
- 0<dtpE/dtE≤1/1.9,
- wherein dtE represents a time period from the start of eutectic solidification of said melt to the completion of the eutectic solidification, and dtpE represents a time period from the start of eutectic solidification of said melt to the completion of said pressing.
Dependencies are inferred from the claim text.