Piercer Plug and Method of Manufacturing the Same
AssigneeNippon Steel Corporation
InventorsYasuyoshi Hidaka, Naoya Shirasawa, Tatsuya Miyai
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Abstract
A piercer plug with increased recyclability is provided. A piercer plug (1) has a chemical composition of, in mass %: 0.15 to 0.30% C; 0.4 to 1.2% Si; 0.2 to 1.5% Mn; 0.1 to 2.0% Ni; 0 to 4.0% Mo and 0 to 4.0% W, where the total content of Mo and W is 1.0 to 6.0%; higher than 1.0% and not higher than 4.0% Cr; 0 to 0.2% B; 0 to 1.0% Nb; 0 to 1.0% V; 0 to 1.0% Ti; and balance Fe and impurities, the plug including a tip portion (2) and a trunk portion (3) made of the same material as the tip portion (2) and contiguous to the tip portion (2). The trunk portion (3) includes a cylindrical portion (5) having a hole used to mount a bar. The tip portion (2) is harder than the cylindrical portion (5).
Claims4
A piercer plug having a chemical composition of, in mass %:
- 0.15 to 0.30% C;
- 0.4 to 1.2% Si;
- 0.2 to 1.5% Mn;
- 0.1 to 2.0% Ni;
- 0 to 4.0% Mo and 0 to 4.0% W, where a total content of Mo and W is 1.0 to 6.0%;
- higher than 1.0% and not higher than 4.0% Cr;
- 0 to 0.2% B;
- 0 to 1.0% Nb;
- 0 to 1.0% V;
- 0 to 1.0% Ti;
- and
- balance Fe and impurities,
- the plug comprising:
- a tip portion;
- and
- a trunk portion made of the same material as the tip portion and contiguous to the tip portion,
- the trunk portion including a cylindrical portion having a hole used to mount a bar,
- the tip portion being harder than the cylindrical portion.
A method of manufacturing a piercer plug, comprising the steps of:
- preparing a piercer plug having a chemical composition of, in mass %:
- 0.15 to 0.30% C;
- 0.4 to 1.2% Si;
- 0.2 to 1.5% Mn;
- 0.1 to 2.0% Ni;
- 0 to 4.0% Mo and 0 to 4.0% W, where a total content of Mo and W is 1.0 to 6.0%;
- higher than 1.0% and not higher than 4.0% Cr;
- 0 to 0.2% B;
- 0 to 1.0% Nb;
- 0 to 1.0% V;
- 0 to 1.0% Ti;
- and balance Fe and impurities, the plug including a tip portion and a trunk portion made of the same material as the tip portion and contiguous to the tip portion;
- and
- heating the piercer plug in such a manner that the tip portion is at a temperature not lower than an AC3 point and a cylindrical portion of the trunk portion having a hole used to mount a bar is at a temperature below the AC3 point.
Dependencies are inferred from the claim text.