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US 5,778,714 AGranted
Method for manufacturing seamless pipe
AssigneeNKK Corporation
InventorsTatsuro Katsumura, Takashi Ariizumi, Motoharu Yamazaki, Masahiko Yasukawa
Life of this patent
Estimating the term…
Abstract
A method for manufacturing a seamless pipe, comprises: preparing a billet made of an alloy steel or an alloy; joining a steel plate to an end surface at which piercing of the billet is commenced; preparing a piercing plug made of Mo, a Mo alloy or a heat-resisting steel; hot-piercing the billet by using the piercing plug to produce a hollow shell; and rolling the hollow shell to produce a seamless pipe.
Claims22
A method for manufacturing a seamless pipe, comprising the steps of:
- (a) preparing a billet made of an alloy steel or an alloy having a main component selected from the group consisting of Cr, Ni and Mo;
- (b) joining a steel plate at least to an end surface of the billet at which a piercing of the billet is to be commenced;
- (c) preparing a piercing plug, the piercinc plug comprising (i) a main body made of Mo, a Mo alloy or a heat resisting steel and (ii) a hard laver formed on the surface of the main body, wherein said hard layer is made of any one selected from the group consisting of stellite, a ceramic obtained by adding tungsten carbide to stellite, a ceramic obtained by adding a mixture composition of tungsten carbide and cobalt to stellite and a ceramic obtained by adding a compound of chromium and carbon to stellite;
- (d) hot-piercing the billet at a hot-piercing temperature, to which the steel plate is Joined, with the piercing plug by a Mannesmann piercing to produce a hollow shell, an oxide scale being formed from said steel plate, at the hot-piercing temperature, the oxide scale lubricating the piercing plug during the hot-piercing;
- and
- (e) rolling the hollow shell to produce a seamless pipe.
3 more elements
A method for manufacturing a seamless pipe, comprising the steps of:
- (a) preparing a billet made of an alloy steel or an alloy having a main component selected from the group consisting of Cr, Ni and Mo;
- (b) joining a steel plate at least to an end surface of the billet at which a piercing of the billet is to be commenced;
- (c) preparing a piercing plug, the piercing plug comprising (i) a plug body made of Mo, a Mo alloy or a heat-resisting steel and (ii) a plug head formed at a leading end of the plug body, the plug head being made of Mo, a Mo alloy or a heat resisting steel, the plug body having a hard layer formed on a surface of the plug body, wherein said hard layer is made of any one selected from the group consisting of stellite, a ceramic obtained by adding tungsten carbide to stellite, a ceramic obtained by adding a mixture composition of tungsten carbide and cobalt to stellite and a ceramic obtained by adding a compound of chromium and carbon to stellite;
- (d) hot-piercing the billet at a hot-piercing temperature, to which the steel plate is joined, with the piercing plug by a Mannesmann piercing to produce a hollow shell, an oxide scale being formed from said steel plate, at the hot-piercing temperature, the oxide scale lubricating the piercing plug during the hot-piercing;
- and
- (e) rolling the hollow shell to produce a seamless pipe.
3 more elements
A method for manufacturing a seamless pipe, comprising the steps of:
- (a) preparing a billet made of an allov steel or an alloy having a main component selected from the group consisting of Cr, Ni and Mo;
- (b) joining a steel plate at least to an end surface of the billet at which a piercing of the billet is to be commenced;
- (c) preparing a piercing slug, the piercing plug comprising (i) a plug body made of Mo, a Mo alloy or a heat-resisting steel and (ii) a plug head formed at a leading end of the plug body, the plug head being made of Mo, a Mo alloy or a heat resisting steel, the plug head having a hard layer formed on a surface of the plug head, wherein said hard layer is made of any one selected from the group consisting of stellite, a ceramic obtained by adding tungsten carbide to stellite, a ceramic obtained by adding a mixture composition of tungsten carbide and cobalt to stellite and a ceramic obtained by adding a compound of chromium and carbon to stellite;
- (d) hot-piercing the billet at a hot-piercing temperature, to which the steel plate is joined, with the piercing plug by a Mannesmann piercing to produce a hollow shell, an oxide scale being formed from said steel plate, at the hot-piercing temperature, the oxide scale lubricating the piercing plug during the hot-piercing;
- and
- (e) rolling the hollow shell to produce a seamless pipe.
3 more elements
A method for manufacturing a seamless pipe, comprising the steps of:
- preparing a billet made of an alloy steel or an alloy having a main component selected from the group consisting of Cr, Ni and Mo;
- joining a steel plate at least to an end surface of the billet at which a piercing of the billet is to be commenced, the steel plate being subjected to an oxidation treatment;
- heating the billet to which the steel plate is joined;
- hot-piercing the heated billet at a hot-piercing temperature with a piercing plug by a Mannesmann piercing to produce a hollow shell;
- an oxide scale being formed from said steel plate, at the hot-piercing temperature, the oxide scale lubricates the piercing plug during the hot-piercing;
- and
- rolling the hollow shell to produce a seamless pipe.
4 more elements
A method for manufacturing a seamless pipe, comprising the steps of:
- preparing a billet made of an alloy steel or an alloy having a main component selected from the group consisting of Cr, Ni and Mo;
- heating the billet in a heating furnace;
- joining a steel plate at least to an end surface of the billet at which a piercing of the billet is to be commenced, the steel plate being subjected to an oxidation treatment;
- hot-piercing the heated billet at a hot-piercing temperature, to which the steel plate is joined, with a piercing plug by a Mannesmann piercing to produce a hollow shell;
- an oxide scale being formed from said steel plate, at the hot-piercing temperature, the oxide scale lubricates the piercing plug during hot-piercing;
- and
- rolling the hollow shell to produce a seamless pipe.
4 more elements
A method for manufacturing a seamless pipe, comprising the steps of:
- preparing a billet made of a high alloy steel or a high alloy;
- preparing a piercing plug having a plug rolling portion and a plug reeling portion, the plug reeling portion is adjacent to the plug rolling portion, the piercing plug satisfies the following equation:
- 0.80.degree..ltoreq..alpha.-.beta..ltoreq.1.51.degree., wherein .alpha. is an angle of the plug reeling portion and .beta. is an angle at an outlet portion of a piercing roll;
- hot-piercing the billet with the piercing plug to produce a hollow shell;
- and
- rolling the hollow shell to produce a seamless pipe.
3 more elements
Dependencies are inferred from the claim text.