KR101674091B1 - Method of manufacturing steel sheet and apparatus of manufacturing steel sheet - Google Patents
Method of manufacturing steel sheet and apparatus of manufacturing steel sheet Download PDFInfo
- Publication number
- KR101674091B1 KR101674091B1 KR1020150140959A KR20150140959A KR101674091B1 KR 101674091 B1 KR101674091 B1 KR 101674091B1 KR 1020150140959 A KR1020150140959 A KR 1020150140959A KR 20150140959 A KR20150140959 A KR 20150140959A KR 101674091 B1 KR101674091 B1 KR 101674091B1
- Authority
- KR
- South Korea
- Prior art keywords
- slab
- heating
- copper
- heating device
- rolling
- Prior art date
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
- B21B1/24—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
- B21B1/24—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process
- B21B1/26—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process by hot-rolling, e.g. Steckel hot mill
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/004—Heating the product
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B2261/00—Product parameters
- B21B2261/20—Temperature
Abstract
Description
TECHNICAL FIELD The present invention relates to a method of manufacturing a steel material and a steel material manufacturing apparatus, and more particularly, to a method of manufacturing a steel material and a steel material manufacturing apparatus capable of reducing occurrence of surface cracks in manufacturing a steel material containing copper (Cu).
Copper (Cu) -containing or copper (Cu) -containing steels are excellent in corrosion resistance and are used as materials for marine structure and the like which require excellent corrosion resistance. However, in the case of a hot-rolled steel sheet to which copper (Cu) is added, a surface crack easily occurs during hot rolling. This is because when a slab is reheated in a reheating apparatus, a concentrated liquid phase of copper (Cu) is formed at the interface between iron and scale by oxidation of iron (Fe), which causes surface cracking .
To solve this problem, there has been used a method of reducing surface cracking by increasing the solubility of copper (Cu) in austenite by adding nickel (Ni). However, Ni is an expensive element and a circulating element which is not removed by conventional oxidation scouring, and its use is restricted in terms of environment.
The present invention provides a method of manufacturing a steel material and a steel material manufacturing apparatus capable of reducing surface cracking.
The present invention provides a method of manufacturing a steel material and a steel material manufacturing apparatus capable of preventing surface cracking during hot rolling in producing a steel material containing copper (Cu).
The present invention relates to a method of manufacturing a steel material to which copper (Cu) is added, comprising the steps of: preparing a slab to which copper (Cu) is added; A first heating step of heating the slab by using a first heating device; A second heating step of moving the slab heated first through the second heating device disposed on one side of the first heating device to heat the surface of the slab to a temperature higher than the first heating temperature; Moving the secondary heated slab to a roughing mill disposed at one side of the second heating apparatus and subjecting the slab to rough rolling; And moving the hot rolled material, which is a slab rough-rolled in the roughing mill, to a finishing mill located at one side of the roughing mill, and finishing the hot rolled material.
The temperature at which the surface of the slab is secondarily heated is 1500 占 폚 to 1550 占 폚.
In the second heating of the slab, the temperature from the surface of the slab to the depth of 5 mm inward from the surface of the slab is set to 1500 to 1550 ° C.
And the moving speed at which the slab passes through the second heating device is adjusted to be 0.35 m / min to 0.65 m / min.
The secondary heating is preferably an induction heating method.
The copper (Cu) is contained in an amount of 0.2 wt% to 0.4 wt% with respect to the entire slab.
The present invention relates to a steel material producing apparatus for producing a copper (Cu) added steel by hot rolling a copper (Cu) added slab, comprising: a first heating device for first heating the slab; A second heating device located at one side of the first heating device and secondarily heating the surface of the slab heated first by the first heating device to a temperature higher than the first heating temperature; A roughing mill located at one side of the second heating apparatus for rough rolling the slab heated secondarily; And a finishing mill located at one side of the roughing mill and finishing hot rolled material as a rough-rolled slab.
The second heating device includes a coil part in a spiral shape, and the slab moves so as to pass through the inside of the coil part.
The second heating apparatus heats the surface of the slab and the inner surface to a depth of 5 mm from the surface of the slab so that the temperature is 1500 캜 to 1550 캜.
The slab preferably passes through the second heating device at a speed of 0.35 m / min to 0.65 m / min.
A steel material containing copper (Cu) is prepared by using a slab containing copper (Cu) in an amount of 0.2 wt% to 0.4 wt% with respect to the entire slab.
According to the embodiment of the present invention, the slab is heated (primary heating) to a temperature at which hot rolling is easy (primary heating), and then the slab surface is rapidly heated (secondary heating) to 1500 to 1550 占 폚. As a result, copper (Cu) precipitated between iron (Fe) and scale interface is re-dissolved and diffused by secondary heating during the first heating for hot rolling, Is removed. Therefore, in the production of steel by hot rolling a slab to which copper (Cu) is added, it is possible to produce a steel material in which surface cracks due to copper (Cu) are not generated or reduced compared with the prior art.
Also, the method of manufacturing steel according to the present invention has an advantage of preventing the occurrence of surface cracks even when expensive nickel is not applied as in the prior art.
1 is a view conceptually showing a hot rolling apparatus according to an embodiment of the present invention.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.
The steel material to be produced by the manufacturing method according to the embodiment of the present invention is a steel material excellent in corrosion resistance due to addition of copper (Cu). A method of manufacturing a steel material according to an embodiment of the present invention is a method of manufacturing a hot rolled material by hot rolling a slab to which Cu is added to minimize or prevent surface cracking caused by copper during hot rolling And more particularly, to a method of manufacturing a steel material.
1 is a view conceptually showing a hot rolling apparatus according to an embodiment of the present invention. 2 is a view conceptually showing a heating state of the slab by the second heating apparatus of the present invention. 3 is a view conceptually showing a heating region of the slab by the second heating device.
1, a hot rolling apparatus according to an embodiment of the present invention includes a heating apparatus (hereinafter referred to as a first heating apparatus 10) for heating a slab S1 to a temperature at which rolling is easy, (Second heating device 200 (hereinafter, referred to as "
According to this hot rolling apparatus, the
Since the
The
The rough rolling
The
On the other hand, when the slab to which copper (Cu) is added is heated to 1100 ° C to 1300 ° C using a first heating apparatus for hot rolling, iron (Fe) on the surface of the slab is oxidized but copper (Cu) by dissolving in pure water. The concentrated liquid copper (Cu) precipitates at the interface between the scale and iron, particularly, an oxide film produced by oxidation of iron, and penetrates between crystal grains. More specifically, it penetrates between the austenite grains. When the precipitated copper (Cu) penetrates into the austenite grains, deformation is caused to weaken the grain boundary strength, thereby causing surface cracking in the subsequent rolling process.
The above-mentioned slab surface crack is particularly generated in the hot rolling of a slab to which 0.2 weight% or more of copper (Cu) is added.
Therefore, in the embodiment of the present invention, the slab heated in the
The
Heating the area from the surface of the slab S1 to the depth of 5 mm from the surface of the slab S1 by the
When the heating temperature of the surface of the slab S1 in the
Therefore, in the present invention, it is possible to easily dissolve and diffuse the precipitated copper (Cu) and to prevent the problem from occurring when bending or moving, and to a region of 5 mm inward from the surface of the slab S1 And then heated to 1500 to 1550 占 폚.
The
For example, when the moving speed of the slab S 1 passing through the
Therefore, in the present invention, the slab heated to a temperature at which the rolling can be easily performed by the first heating device, that is, 1100 to 1300 ° C, is heated by the second heating device while the moving speed of the slab is 0.35 to 0.65 m / min . Thus, it is possible to heat the slab surface and the slab surface to an inner depth of 5 mm to 1500 ° C to 1550 ° C, thereby allowing copper (Cu) precipitated from the iron-scale interface to be re-dissolved and diffused.
Hereinafter, a method of manufacturing a steel material according to an embodiment of the present invention will be described with reference to FIGS.
The steel material produced according to the embodiment of the present invention is a copper (Cu) added steel containing copper (Cu) in an amount of 0.2 wt% to 0.4 wt% with respect to the entire steel material.
First, a slab containing copper (Cu) in an amount of not less than 0.2% by weight and not more than 0.4% by weight with respect to the entire steel is cast. The slab contains carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), aluminum (Al) and unavoidable impurities in addition to iron (Fe) and copper (Cu).
In the embodiment of the present invention, a steel material containing 0.4% by weight or less of copper (Cu) is prepared as described above. This is because even if the surface of the slab S1 is rapidly heated to 1500 占 폚 to 1550 占 폚 by using the
The slab S1 is charged into the
When the heating of the slab S1 is completed in the
In the present invention, the slab S1 having the copper (Cu) precipitated between the iron and scale interface heated by the
The slabs heated by the
Cracks due to the copper (Cu) concentrate are not generated during rough rolling and finishing rolling. This is because even if liquid iron (Cu) precipitates at the interface between the iron (Fe) and the scale of the slab S1 by the normal reheating, that is, by the
Also, the method of manufacturing steel according to the present invention has an advantage of preventing the occurrence of surface cracks even when expensive nickel is not applied as in the prior art.
Table 1 shows a comparison between the steel material produced by the method according to the embodiment of the present invention and the steel material produced by the method according to the comparative example.
The steel material according to the first to third embodiments contains 0.2 to 0.4% by weight of copper (Cu), the moving speed of the slab through the second heating device is 0.35 m / min to 0.65 m / min, And a steel material produced by heating the surface of the slab by a heating device to 1500 to 1550 占 폚. On the other hand, in the first comparative example, copper (Cu) is 0.2 to 0.4 wt%, but the rate at which the slab passes through the second heating device exceeds 0.65 and the second heating temperature of the second heating device is less than 1500 ° C It is a manufactured steel. In the second comparative example, the heating temperature by the second heating device and the second heating device passing speed of the slab satisfy the manufacturing method of the present invention, but the steel material is more than 0.4% by weight of copper (Cu).
(° C)
(m / min)
occurrence condition
Referring to Table 1, the copper-added steel material produced by the method according to the embodiment of the present invention did not crack on the surface. However, it was confirmed that the surface condition of the first comparative example and the first comparative steel having an addition amount of copper (Cu) of more than 0.4 wt% caused a surface crack.
In the case of the steel material according to the first to third embodiments, copper (Cu) is 0.4 wt% or less and heated to 1,500 캜 to 1,550 캜 inside the slab surface and the inside of the slab surface 5 mm by the second heating device Since the rolling was performed, surface cracks were not generated during the rolling process because the factors causing surface cracks were minimized or eliminated. That is, even when liquid copper (Cu) precipitates at the interface between iron (Fe) and scale at the time of the first heating by the first heating device, as the surface of the slab is heated to 1500 ° C to 1550 ° C, The precipitated copper between the interface between Fe and the scale is diffused.
However, in the case of the first comparative example, as the speed at which the slab passes through the second heating device exceeds 0.65, the heating rate is too fast, and the temperature from the slab surface and the surface to the depth of 5 mm is less than 1500 ° C. As a result, the precipitated copper between the interface between iron (Fe) and scale was not diffused, which caused surface cracking during rolling.
As another example, in the case of the second comparison, the temperature of the slab surface was heated to 1500 ° C to 1550 ° C at a passing speed of 0.35m / min to 0.65m / min for the second heating device. However, 0.4% by weight, it is insufficient to dissolve and diffuse all precipitated copper (Cu) even if the slab is heated to 1500 ° C to 1550 ° C using the second heating apparatus.
As described above, in the present invention, after the slab is firstly heated, the surface of the slab is heated to 1500 to 1550 占 폚 by using the second heating device to diffuse copper (Cu) precipitated between the iron and the scale. (Cu) -containing steel material in which cracks caused by precipitated copper (Cu) are removed and cracks are not generated during rolling can be produced.
10: first heating device 200: second heating device
30: rough rolling mill 40: finishing mill
50: cooler 60: winder
Claims (11)
Preparing a slab to which copper (Cu) is added;
A first heating step of heating the slab by using a first heating device;
A second heating step of moving the slab heated first through the second heating device disposed at one side of the first heating device to heat the surface of the slab to a temperature higher than the first heating temperature;
Moving the secondary heated slab to a roughing mill disposed at one side of the second heating apparatus and subjecting the slab to rough rolling; And
Rolling the hot rolled material, which is a slab rough-rolled in the roughing mill, to a finishing mill located at one side of the roughing mill;
/ RTI >
Wherein the copper (Cu) is contained in an amount of 0.2 wt% to 0.4 wt% with respect to the entire slab.
And the temperature for secondary heating the surface of the slab is 1500 ° C to 1550 ° C.
Wherein a temperature from the surface of the slab to a depth of 5 mm inward from the surface of the slab is 1500 占 폚 to 1550 占 폚 in the second heating of the slab.
And the moving speed of the slab through the second heating device is adjusted to be 0.35 m / min to 0.65 m / min.
Wherein the secondary heating is an induction heating method.
A first heating device for firstly heating the slab;
A second heating device located at one side of the first heating device and secondarily heating the surface of the slab heated first by the first heating device to a temperature higher than the first heating temperature;
A roughing mill located at one side of the second heating apparatus for rough rolling the slab heated secondarily; And
A finishing mill located at one side of the roughing mill and finishing the hot rolling material as the rough-rolled slab;
Lt; / RTI >
Wherein the slab containing copper (Cu) is contained in an amount of 0.2 wt% to 0.4 wt% with respect to the entire slab, to produce a steel material containing copper (Cu).
Said second heating device comprising a coiled portion of a helical shape,
And the slab moves so as to pass through the inside of the coil portion.
Wherein the second heating device heats the surface of the slab and the inner surface to a depth of 5 mm from the surface of the slab so that the temperature is 1500 占 폚 to 1550 占 폚.
Wherein the slab passes the second heating device at a speed of 0.35 m / min to 0.65 m / min.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020150140959A KR101674091B1 (en) | 2015-10-07 | 2015-10-07 | Method of manufacturing steel sheet and apparatus of manufacturing steel sheet |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020150140959A KR101674091B1 (en) | 2015-10-07 | 2015-10-07 | Method of manufacturing steel sheet and apparatus of manufacturing steel sheet |
Publications (1)
Publication Number | Publication Date |
---|---|
KR101674091B1 true KR101674091B1 (en) | 2016-11-08 |
Family
ID=57527847
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
KR1020150140959A KR101674091B1 (en) | 2015-10-07 | 2015-10-07 | Method of manufacturing steel sheet and apparatus of manufacturing steel sheet |
Country Status (1)
Country | Link |
---|---|
KR (1) | KR101674091B1 (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100573589B1 (en) | 2003-12-23 | 2006-04-24 | 주식회사 포스코 | Manufacturing Method Of Hot Rolled Steel Sheet With No Surface Crack |
WO2014163089A1 (en) * | 2013-04-01 | 2014-10-09 | 新日鐵住金株式会社 | Titanium slab for hot rolling and method for manufacturing same |
-
2015
- 2015-10-07 KR KR1020150140959A patent/KR101674091B1/en active IP Right Grant
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100573589B1 (en) | 2003-12-23 | 2006-04-24 | 주식회사 포스코 | Manufacturing Method Of Hot Rolled Steel Sheet With No Surface Crack |
WO2014163089A1 (en) * | 2013-04-01 | 2014-10-09 | 新日鐵住金株式会社 | Titanium slab for hot rolling and method for manufacturing same |
KR20150131288A (en) * | 2013-04-01 | 2015-11-24 | 신닛테츠스미킨 카부시키카이샤 | Titanium slab for hot rolling and method for manufacturing same |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5646643B2 (en) | Method for producing directional electrical steel strip and directional electrical steel produced thereby | |
KR101617288B1 (en) | Non-oriented Electrical Steel Plate and Manufacturing Process Therefor | |
MX2021012807A (en) | Steel sheet and method for manufacturing same. | |
KR20190077201A (en) | Hot-rolled steel sheet for non-oriented electrical steel sheet, non-oriented electrical steel sheet and method for manufacturing the same | |
KR101665795B1 (en) | Method for manufacturing soft steel wire rod | |
JP4923650B2 (en) | Method for preventing surface cracks in continuous cast slabs | |
KR101674091B1 (en) | Method of manufacturing steel sheet and apparatus of manufacturing steel sheet | |
US20120305212A1 (en) | Process and device for producing hot-rolled strip from silicon steel | |
JP5626792B2 (en) | Rolling method of high strength steel sheet | |
KR20190078395A (en) | Non-oriented electrical steel sheet having excellent shape property and method of manufacturing the same | |
KR101795871B1 (en) | Mathod for manufacturing high copper stainless steel with twin roll strip casting apparatus | |
KR102452598B1 (en) | Softening method of high-strength Q&P steel hot-rolled roll | |
KR101203647B1 (en) | Method for manufacturing hot rolled steel sheet including high carbon contents using minimill process | |
KR101879103B1 (en) | Method for manufacturing hot-rolled steel sheet for electrical steel sheet | |
JP4665417B2 (en) | Method for producing grain-oriented electrical steel sheet | |
KR20110046674A (en) | Method for manufacturing hot rolled steel sheet | |
KR102462023B1 (en) | Cooling method for reducing coil collapse in hot rolling mill of extra strength coil rolled steel | |
KR20190078401A (en) | Non-oriented electrical steel sheet having low deviation of mechanical property and thickness and method of manufacturing the same | |
JP2020007580A (en) | Manufacturing method of checkered steel plate | |
KR102631770B1 (en) | Ethod of manufacturing cold-rolled steel sheet | |
KR101239460B1 (en) | method of manufacturing martensitic stainless steel | |
JP4265054B2 (en) | Method for producing hot-rolled steel sheet with excellent surface properties | |
KR101736629B1 (en) | High manganese steel having excellent resistance to crack by hot rolling and method for manufacturing the same | |
JPH0257128B2 (en) | ||
JP3445993B2 (en) | Manufacturing method of hot-rolled steel sheet with small deformation after cutting |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
E701 | Decision to grant or registration of patent right | ||
GRNT | Written decision to grant |