Equipment line for manufacturing heavy-walled steel products

Patent metadata

Field	Value
Publication number	US-2016236249-A1
Application number	US-201415031247-A
Country	US
Kind code	A1
Filing date	Sep 25, 2014
Priority date	Oct 21, 2013
Publication date	Aug 18, 2016
Grant date	—

Abstract

An equipment line for manufacturing heavy-walled steel products having excellent low-temperature toughness, the equipment line including a heating device, a cooling device, and a hot working device in this order. The working device includes plurality of hot working devices, and the cooling device is arranged on an entrance side of at least one of the plurality of hot working devices. Furthermore, a thermostat equipment is arranged on an exit side of the hot working device. The equipment line provides a steel product with a finer microstructure with a relatively small amount of working.

First claim

1 . An equipment line for manufacturing heavy-walled steel products, the equipment line comprising:
a heating device for heating a steel, a hot working device for hot working the heated steel into a heavy-walled steel product, and a cooling system is-arranged between the heating device and the hot working device.

2 . The equipment line for manufacturing heavy-walled steel products according to claim 1 , wherein the cooling system has a cooling power capable of cooling a surface of the steel at an average cooling rate of 1.0° C./s or more.

3 . The equipment line for manufacturing heavy-walled steel products according to claim 1 , further comprising a thermostat equipment arranged on an exit side of the hot working device.

4 . The equipment line for manufacturing heavy-walled steel products according to claim 1 , wherein the hot working device includes a plurality of hot working devices, and the cooling system is arranged on an entrance side of at least one of the plurality of hot working devices.

5 . The equipment line for manufacturing heavy-walled steel products according to claim 4 , wherein:
the heavy-walled steel product is a heavy-walled seamless steel pipe, the hot working device includes a piercing device and a rolling device, the piercing device being configured to pierce the heated steel to form a hollow piece, and the rolling device being configured to form the hollow piece into a seamless steel pipe having a predetermined shape, and the cooling system is arranged either (i) between the heating device and the piercing device or (ii) between the piercing device and the rolling device.

6 . A method of manufacturing heavy-walled high-strength steel products using the equipment line according to claim 3 , the method comprising:
heating a steel in the heating device at a heating temperature within a range from an Ac 4 transformation point to less than a melting point of the steel, cooling the heated steel in the cooling system such that the heated steel is subjected to cooling at an average cooling rate of 1.0° C./s or above on a surface of the of 50° C. or more between a cooling start temperature and the cooling stop temperature, and hot working the cooled steel in the hot working and optionally further passing the hot worked steel through the thermostat equipment so that the hot worked steel has a predetermined size, wherein the steel has a chemical composition comprising:
0.050% or less C,by mass %,
0.50% or less Si, by mass %,
0.20 to 1.80% Mn, by mass %,
15.5 to 18.0% Cr, by mass %,
1.5 to 5.0%
3.5% or less Mo, by mass %,
0.02 to 0.20% V, by mass %,
0.01 to 0.15% N, by mass %,
0.006% or less O, by mass %, and
Fe and unavoidable impurities.

7 . The method of manufacturing heavy-walled high-strength stainless steel products according to claim 6 , wherein the hot worked steel is cooled at an average cooling rate of 20° C./s or less by passing the hot worked steel through the thermostat equipment.

8 . The method of manufacturing heavy-walled high-strength stainless steel products according to claim 6 , wherein the chemical composition further comprises at least one group selected from the following element groups A to D:
Group A: 0.002 to 0.050% Al, by mass %, Group B: 3.5% or less Cu, by masse %, Group C: at least one element selected from 0.2% or less Nb, 0.3% or less Ti, 0.2% or less Zr, 3.0% or less W, and 0.01% or less B, by mass %, and Group D: at least one element selected from 0.01% or less Ca, and 0.01% or less REM, by mass %.

Assignees

• Jfe Steel Corp

Inventors

• Sasaki Shunsuke
• Katsumura Tatsuro
• Kato Yasushi

Classifications

• B21B45/0203

  Cooling · CPC title

• C21D8/10 Primary

  during manufacturing of tubular bodies · CPC title

• C22C38/58

  with more than 1.5% by weight of manganese · CPC title

• B21B45/02

  for lubricating, cooling, or cleaning {(in particular in combination with forging or pressing devices B21B15/005, control of flatness or profile using lubricating or cooling B21B37/44)} · CPC title

• B21B19/04 Primary

  Rolling basic material of solid, i.e. non-hollow, structure; Piercing {, e.g. rotary piercing mills} · CPC title