Tough and corrosion resistant white cast irons
AssigneeWeir Minerals Australia Ltd.
InventorXinhu Tang
Life of this patent
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Abstract
An end-use casting of a high chromium white iron, i.e. a casting that has been heat-treated, includes a ferrous matrix and at least two different chromium carbides dispersed in the matrix, with at least one of the chromium carbides including a transformation product of an as-cast chromium carbide.
Claims10
A heat-treated casting of a high chromium white iron for improving toughness and corrosion resistance, includes a ferrous matrix and primary carbides including at least two different chromium carbides dispersed in the ferrous matrix, the primary carbides having a core including an as-cast chromium carbide and a shell surrounding the core including a transformation product of the as-cast chromium carbide wherein the as-cast chromium carbide is a M7C3 chromium carbide and the transformation product is a M23C6 chromium carbide, wherein the M23C6 carbide is formed during heat treatment of the casting, and wherein the composition of the casting comprises the following formula:
- Cr:
- 30-40 wt. %
- C:
- 1.5-3 wt. %
- Cr/C ratios (wt. %):
- 9:1-15:1
- Up to 3 wt. % each of any one or more than one of Mn, Si, Ni, Mo, or Cu,
- Incidental impurities
- Balance:
- Fe.
A heat-treated casting of a high chromium white iron for improving toughness and corrosion resistance, includes a ferrous matrix and primary carbides including at least two different chromium carbides dispersed in the matrix, the primary carbides having a core including an as-cast chromium carbide and a shell surrounding the core including a transformation product of the as-cast chromium carbide wherein the as-cast chromium carbide is a M7C3 chromium carbide and the transformation product is a M23C6 chromium carbide and wherein the composition of the casting is consisting of the following formula:
- Cr:
- 30-40 wt. %
- C:
- 1.5-<3 wt. %
- Cr/C ratios (wt. %):
- 9:1-15:1
- Up to 3 wt. % each of any one or more than one of Mn, Si, Ni, Mo, or Cu,
- Incidental impurities
- Balance:
- Fe;
- and
- wherein the transformation product is formed during heat treatment of the as-cast form of the casting when heated to between 800° and 1,000° C.
Dependencies are inferred from the claim text.