Wear resistant alloy and method of producing thereof
AssigneeGlobal Tough Alloys Pty Ltd.
InventorGraham Leonard Fraser Powell
Life of this patent
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Abstract
A wear resistant, high chromium white iron, in an unheat-treated condition has a microstructure substantially comprising austenite and M7C3 carbides. The white iron contains at least one martensite promoter and at least one austenite stabilizer which are present at respective levels to achieve a balance between their effects whereby the white iron has a microstructure characterized by at least one of: i) being substantially free of martensite at interfaces between the austenite and M7C3 carbides; and ii) having a relatively low level of interconnectivity between carbide particles; such that the white iron is substantially crack-free. The white iron may be as-cast or comprise weld deposited hardfacing.
Claims18
A wear resistant, high chromium white iron with an amount of chromium of 15-27% and of carbon of 2.5-6%, wherein said white iron in an unheat-treated condition has a microstructure including austenite and M7C3 carbides, the white iron containing a martensite promoter being silicon at a level from 0.25 to 3.5% and at least two austenite stabilizers are present, and the combined level of austenite stabilizer is not in excess of about 20%, one of the austenite stabilizers being nickel at a level of from 4 to 12% with at least one other austenite stabilizer selected from the group of manganese, copper and molybdenum at a level of from 4 to 12% for each of manganese, and copper, and an effective equivalent of molybdenum after allowance for a proportion of molybdenum taken up as carbide, and wherein the level of the martensite promoter and the level of the austenite stabilizer are selected so as to achieve a balance between their effects such that the white iron in an unheat-treated condition has a microstructure that is free of martensite at interfaces between the austenite and M7C3 carbides such that the white iron is substantially crack-free.
A wear resistant, high chromium white iron with an amount of chromium of 15-27% and of carbon of 2.5-6%, wherein said white iron in an unheat-treated condition has a microstructure including austenite and M7C3 carbides, the white iron containing a martensite promoter being silicon at a level from 0.25 to 3.5% and at least two austenite stabilizers are present, and the combined level of austenite stabilizer is not in excess of about 16%, one of the austenite stabilizers being nickel at a level of from 4 to 12% with at least one other austenite stabilizer selected from the group of manganese, copper and molybdenum at a level of from 4 to 12% for each of manganese, and copper, and an effective equivalent of molybdenum after allowance for a proportion of molybdenum taken up as carbide, and wherein the level of the martensite promoter and the level of the austenite stabilizer are selected so as to achieve a balance between their effects such that the white iron in an unheat-treated condition has a microstructure that is free of martensite at interfaces between the austenite and M7C3 carbides such that the white iron is substantially crack-free.
A method of producing a wear resistant, high chromium white iron casting with an amount of chromium of 15-27% and of carbon of 2.5-6%, the method comprising:
- casting a melt of a high chromium white cast iron, wherein said melt contains a martensite promoter being silicon at a level from 0.25 to 3.5%, and at least two austenite stabilizers are present, and the combined level of austenite stabilizer is not in excess of about 20%, one of the austenite stabilizers being nickel at a level of from 4 to 12% with at least one other austenite stabilizer selected from the group of manganese, nickel, copper and molybdenum at a level of from 4 to 12% for each of manganese, and copper, and an effective equivalent of molybdenum after allowance for a proportion of molybdenum taken up as carbide,
- cooling the melt so as to produce a casting having a microstructure which in an unheat-treated condition includes austenite and M7C3 carbides,
- wherein the level of the martensite promoter in the melt, the level of the austenite stabilizer in the melt and the cooling rate are selected so as to achieve a balance between the effects of these variables, to thus obtain a white iron casting which in an unheat-treated condition has a microstructure that is free of martensite at interfaces between the austenite and M7C3 carbides such that the white iron is substantially crack-free.
A method of producing a wear resistant, high chromium white iron hardfacing with an amount of chromium of 15-27% and of carbon of 2.5-6%, the method comprising:
- applying a high chromium white cast iron material to a substrate by weld deposition, wherein said high chromium white cast iron material contains a martensite promoter being silicon at a level from 0.25 to 3.5%, and at least two austenite stabilizers are present, and the combined level of austenite stabilizer is not in excess of about 20%, one of the austenite stabilizers being nickel at a level of from 4 to 12% with at least one other austenite stabilizer selected from the group of manganese, nickel, copper and molybdenum at a level of from 4 to 12% for each of manganese, and copper, and an effective equivalent of molybdenum after allowance for a proportion of molybdenum taken up as carbide,
- cooling the high chromium white cast iron material so as to produce on the substrate a hardfacing having a microstructure which in an unheat-treated condition includes austenite and M7C3 carbides,
- wherein the level of the martensite promoter in the high chromium white cast iron material, the level of the austenite stabilizer in the high chromium white cast iron material and the cooling rate are selected so as to achieve a balance between the effects of these variables and to thus obtain on the substrate a hardfacing which in an unheat-treated condition has a microstructure that is free of martensite at interfaces between the austenite and M7C3 carbides—such that the hardfacing is substantially crack-free.
A method of producing a wear resistant, high chromium white iron casting with an amount of chromium of 15-27% and of carbon of 2.5-6%, the method comprising:
- casting a melt of a high chromium white cast iron, wherein said melt contains a martensite promoter being silicon at a level from 0.25 to 3.5%, and at least two austenite stabilizers are present, and the combined level of austenite stabilizer is not in excess of about 16%, one of the austenite stabilizers being nickel at a level of from 4 to 12% with at least one other austenite stabilizer selected from the group of manganese, nickel, copper and molybdenum at a level of from 4 to 12% for each of manganese, and copper, and an effective equivalent of molybdenum after allowance for a proportion of molybdenum taken up as carbide,
- cooling the melt so as to produce a casting having a microstructure which in an unheat-treated condition includes austenite and M7C3 carbides,
- wherein the level of the martensite promoter in the melt, the level of the austenite stabilizer in the melt and the cooling rate are selected so as to achieve a balance between the effects of these variables, to thus obtain a white iron casting which in an unheat-treated condition has a microstructure that is free of martensite at interfaces between the austenite and M7C3 carbides such that the white iron is substantially crack-free.
A method of producing a wear resistant, high chromium white iron hardfacing with an amount of chromium of 15-27% and of carbon of 2.5-6%, the method comprising:
- applying a high chromium white cast iron material to a substrate by weld deposition, wherein said high chromium white cast iron material contains a martensite promoter being silicon at a level from 0.25 to 3.5%, and at least two austenite stabilizers are present, and the combined level of austenite stabilizer is not in excess of about 16%, one of the austenite stabilizers being nickel at a level of from 4 to 12% with at least one other austenite stabilizer selected from the group of manganese, nickel, copper and molybdenum at a level of from 4 to 12% for each of manganese, and copper, and an effective equivalent of molybdenum after allowance for a proportion of molybdenum taken up as carbide,
- cooling the high chromium white cast iron material so as to produce on the substrate a hardfacing having a microstructure which in an unheat-treated condition includes austenite and M7C3 carbides,
- wherein the level of the martensite promoter in the high chromium white cast iron material, the level of the austenite stabilizer in the high chromium white cast iron material and the cooling rate are selected so as to achieve a balance between the effects of these variables and to thus obtain on the substrate a hardfacing which in an unheat-treated condition has a microstructure that is free of martensite at interfaces between the austenite and M7C3 carbides—such that the hardfacing is substantially crack-free.
Dependencies are inferred from the claim text.