US 11,772,154 B1Granted

Plunger for die casting and method of making the same

AssigneesGM Global Technology Operations LLC, Easyforming Steel Technology Co., Ltd.

InventorsZhou Wang, Hongliang Yi, Jianfeng Wang, Lianqian Liu

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Abstract

A plunger for die casting may include a front injector end made of an iron alloy including, by mass: about 1% to about 6% nickel, about 0.1% to about 5% copper, about 0.2% to about 2.5% aluminum, about 0.5% to about 2% manganese, and about 0.05% to about 0.2% carbon. The iron alloy may be formed into an initial shape of the front injector end, heated to a temperature greater than or equal to about 900° C. and then cooled to form a supersaturated solid solution of iron and dissolved alloying elements. Then, the iron alloy may be heated at a temperature sufficient to precipitate intermetallic nanoparticles from the supersaturated solid solution to form an intermetallic precipitate phase dispersed throughout an iron-based matrix phase. A chemical compound layer may be formed at and along a surface of the iron alloy by exposing the iron alloy to an oxygen-containing and/or nitrogen-containing environment.

Claims20

Dependent claims

A plunger for die casting, the plunger comprising:

a front injector end including a front wall, a cylindrical sidewall extending from the front wall, and an outer peripheral surface at least partially defined by a front face of the front wall and an outer circumferential surface of the cylindrical sidewall, the front injector end being made of an iron alloy comprising, by mass:
nickel in an amount greater than or equal to about 1% to less than or equal to about 6%;
copper in an amount greater than or equal to about 0.1% to less than or equal to about 5%;
aluminum in an amount greater than or equal to about 0.2% to less than or equal to about 2.5%;
manganese in an amount greater than or equal to about 0.5% to less than or equal to about 2%;
carbon in an amount greater than or equal to about 0.05% to less than or equal to about 0.2%;
and
greater than or equal to about 78% iron;
and
a chemical compound layer disposed at and along the outer peripheral surface of the front injector end, wherein the chemical compound layer comprises a relatively high concentration of at least one of metal oxides, metal nitrides, and metal oxynitrides, as compared to a bulk volume of the front injector end,
wherein the chemical compound layer has a thickness extending from the outer peripheral surface of the front injector end of greater than or equal to about 2 micrometers to less than or equal to about 15 micrometers.

8 more elements

A method of manufacturing a plunger for die casting, the method comprising the following steps in the sequence set forth:

(i) forming an iron alloy into an initial shape of a front injector end of a plunger for a die casting machine, the iron alloy comprising, by mass:
nickel in an amount greater than or equal to about 1% to less than or equal to about 6%;
copper in an amount greater than or equal to about 0.1% to less than or equal to about 5%;
aluminum in an amount greater than or equal to about 0.2% to less than or equal to about 2.5%;
manganese in an amount greater than or equal to about 0.5% to less than or equal to about 2%;
carbon in an amount greater than or equal to about 0.05% to less than or equal to about 0.2%;
and
greater than or equal to about 78% iron;
(ii) heating the iron alloy to a temperature greater than or equal to about 900° C. to form a solid solution of iron and dissolved alloying elements;
(iii) cooling the iron alloy at a cooling rate of greater than or equal to about 5° C. per second to form a supersaturated solid solution of iron and dissolved alloying elements;
(iv) heating the iron alloy at a temperature sufficient to precipitate intermetallic nanoparticles from the supersaturated solid solution and form an intermetallic precipitate phase dispersed throughout an iron-based matrix phase;
and
(v) exposing the iron alloy to an oxygen-containing environment and/or a nitrogen-containing environment to form a chemical compound layer disposed at and along an outer peripheral surface of the front injector end, wherein the chemical compound layer comprises a relatively high concentration of at least one of metal oxides, metal nitrides, and metal oxynitrides, as compared to a bulk volume of the front injector end,
wherein steps (iv) and (v) are performed substantially simultaneously.

11 more elements

Dependencies are inferred from the claim text.