Class of ductile iron, and process of forming same
AssigneeIndustrial Materials Technology, Inc.
InventorsRobert Widmer, Daniel H. Zick, Jane L. LaGoy
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Abstract
A new class of ductile iron is formed by the hot isostatic pressing of a ductile iron casting, followed by austempering of the ductile iron casting. Hot isostatic pressing can be carried out at a pressure in the range of 10,000 to 17,000 psi at a temperature above 1600.degree. F., and usually in the range of 1850.degree. F. to 2050.degree. F. Austempering of the material is carried out by heating to the austenitizing temperature (about 1500.degree. F. to 1800.degree. F.), maintaining the austenitizing temperature for a suitable time period, and rapidly cooling to an austempering temperature (about 400.degree. F. to 750.degree. F.) to form ausferrite within the sample.
Claims11
A process of forming wrought ductile iron, comprising the steps of
- casting a ductile iron sample;
- HIP processing the sample at a temperature in excess of 1650.degree. F. and at a pressure in the range of about 10,000-17,000 psi;
- and
- austempering the sample.
A ductile iron material characterized as having mechanical properties of tensile strength of at least about 190,000 psi, yield strength of at least about 150,000 psi and about 9% total elongation.
Dependencies are inferred from the claim text.