CA2200258A1 - Method of cooling steel sections which are hot from rolling - Google Patents
Method of cooling steel sections which are hot from rollingInfo
- Publication number
- CA2200258A1 CA2200258A1 CA002200258A CA2200258A CA2200258A1 CA 2200258 A1 CA2200258 A1 CA 2200258A1 CA 002200258 A CA002200258 A CA 002200258A CA 2200258 A CA2200258 A CA 2200258A CA 2200258 A1 CA2200258 A1 CA 2200258A1
- Authority
- CA
- Canada
- Prior art keywords
- cooling
- carrying
- steel
- surface layer
- shock
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000001816 cooling Methods 0.000 title claims abstract description 58
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 46
- 239000010959 steel Substances 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000005096 rolling process Methods 0.000 title claims abstract description 17
- 239000002344 surface layer Substances 0.000 claims abstract description 22
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 19
- 238000005496 tempering Methods 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 5
- 238000005275 alloying Methods 0.000 claims abstract description 4
- 230000009466 transformation Effects 0.000 claims description 13
- 229910001566 austenite Inorganic materials 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000001953 recrystallisation Methods 0.000 claims description 3
- 230000000052 comparative effect Effects 0.000 claims description 2
- 238000001556 precipitation Methods 0.000 claims description 2
- 229910000919 Air-hardening tool steel Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000639 Spring steel Inorganic materials 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/02—Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2221/00—Treating localised areas of an article
- C21D2221/10—Differential treatment of inner with respect to outer regions, e.g. core and periphery, respectively
Abstract
A method of cooling steel sections which are hot from rolling by means of shock-like cooling following the rolling process so as to form a martensitic surface layer, and by subsequently autogenously tempering this surface layer by means of core heat to obtain a tough-resistant structure with an austenitic remaining cross-section, wherein the method is used in connection with types of steel which, with uncontrolled cooling in air, would directly transform from the austenitic phase into martensite because of their alloying elements from the group Cr, Mn, Mo, Ni and other suitable elements.
Description
~ û û 2 ~ ~
BACKGROUND OF THE lN V ~:N~ ON
1. Field of the Invention The present invention relates to a method of cooling steel sections which are hot from rolling by means of shock-like cooling followlng the rolling process so as to form a martensitic surface layer, and by subsequently autogenously tempering this surface layer by means of core heat to obtain a tough-resistant structure with an austenitic remaining cross-section.
BACKGROUND OF THE lN V ~:N~ ON
1. Field of the Invention The present invention relates to a method of cooling steel sections which are hot from rolling by means of shock-like cooling followlng the rolling process so as to form a martensitic surface layer, and by subsequently autogenously tempering this surface layer by means of core heat to obtain a tough-resistant structure with an austenitic remaining cross-section.
2. Description of the Related Art Some types of steel, particularly the so-called high-grade steels, are very sluggish to transform because of the alloying elements contained therein, for example, of the group including Cr, Mn, Mo, Ni, and other suitable elements. In other words, the transformation from the austenitic phase after the hot deformation into ferrite or pearlite takes place only after long holding times at the appropriate temperature interval between 600~ and 750~C.
If these steels are not purposely cooled slowly, sometimes over several days, and are not maintained at the appropriate o ~ s ~
transformation temperature, the austenite remains during further cooling, and after reaching the martensite starting temperature, will convert directly into martensite having a high hardness.
This occurs essentially in steels having diameters of less than lOOmm during cooling after the transformation on the cooling bed in still air. This is the reason why these steels are also called air-hardening steels.
Aside from stainless heat-treatable steels containing, for example, 13~ to 17~ Cr, Mo, Ni and possible additions of other accompanying elements and carbon contents of between 0.2~ and 0.6~, belonging to this group are also tool steels (e.g., 56NiCrMoV7) and special heat-treatable steels (e.g., 45CrMoV67) in the field of high-grade structural steels. These steels have a high hardenability which is why these steels are also considered to be among the air-hardening steels.
If steels having the aforementioned chemical composition are cooled to quickly and transform martensitically as a result, a hard and brittle transformation structure is obtained which makes it possible that stress cracks will form and brittle fractures will occur during later handling. Therefore, it is known in the art to convey steels of the group of the so-called air-hardening steels as quickly as possible after the transformation process to special devices which ensure a significantly delayed cooling.
Preferably used for this purpose are holding hoods, holding pits with heating means and similar devices in order to collect lots obtained after the transformation into bundles and, after the unit is filled up, to carry out a purposeful cooling which may sometimes last several days. This means that substantial technical requirements must be met, for example, for a quick transport over the cooling bed or for a separate transverse transport in front of the cooling bed, and that insulating devices and thermal protection devices in the area of the rolling mill, hot cut-off devices, additional roller conveyors and particularly the holding devices themselves must be provided.
2 S ~
SUMMARY OF THE lNv~NlION
Therefore, it is the primary object of the present invention to avoid the technical requirements mentioned above which are very expensive and, simultaneously, to ensure that, after hot transformation and cooling to room temperature, the air-hardening steels can be made available for further use in a state of their structure which is without cracks and fractures and is in a condition suitable for further processing.
In accordance with the present invention, the method of cooling steel sections which are hot from rolling by means of shock-like cooling following the rolling process so as to form a martensitic surface layer and by subsequently tempering this surface layer by means of core heat to obtain a tough-resistant structure with austenitic remaining cross-section is used in connection with types of steel which, with uncontrolled cooling in air, would directly transform from the austenitic phase into martensite because of their alloying elements from the group Cr, Mn, Mo, Ni and other suitable elements.
The product which is hot from rolling is conveyed directly after the deforming process through a cooling stretch supplied with water, wherein a thin surface layer is cooled in such a way 5 ~
that it transforms martensitically. After emerging from the cooling stretch, this martensitic surface layer is autogenously tempered as a result of the residual heat of the string of the rolled product, so that a surface layer is produced which is very tough and is capable of absorbing high tensions, wherein the surface layer prevents damage in the form of cracks or fractures during the further conversion of the still present austenite into martensite.
Preferred is shock-like cooling with a heat transmission co-efficient alpha of greater than 20 kW/m2/K, preferably up to 80 kW/m2/K.
The present invention provides the significant advantage that steels from the group of the air-hardening steels do not require the complicated devices needed in the prior art for cooling with extremely long delays. This means that the efficiency of the cooling process is significantly improved and the productivity is increased because the cooling times are decreased.
In accordance with a further development of the invention, the shock-like cooling for forming the martensitic surface layer is carried out in a water cooling stretch arranged following the rolling train at a cooling beginning exactly defined by a predetermined starting temperature after the dynamic recrystallization and with a cooling pattern predeterminable by comparative tests to a defined cooling temperature.
A continuation of the method further advantageously provides that the cooling process of the steel section is initially ended after the tempering of the martensitic surface layer, the steel section is conveyed through the other processing units, is subsequently stored and, only when requested by a customer at a later time, is transformed by a specifically elected heat treatment into a structure specified by the customer for delivery.
This is very advantageous because different structure conditions or degrees of hardness, i.e., properties determined by later use, can be produced from the same type of steel depending on the purpose of use, for example, as spring steel, as cutting steel, as structural steel, etc.
A further development of the method according to the invention provides producing partial lengths from the string of rolling stock in accordance with a specific order, collecting the partial lengths into bundles at a temperature below possible 5 ~
carbide precipitation phases, further cooling the partial lengths at a cooling speed of less than 1 K/min, and, in the transformation of the austenite which is still present, carrying out a low-stress transformation into a self-tempered martensite.
Following the cooling process, the steel may travel through the units provided for low-alloy steels and/or unalloyed steels for further processing into a defined condition as required for delivery. The advantage of this is that separate expensive additional devices are no longer required for this purpose. The steel cooled to room temperature can subsequently be subjected to the usual handling in further processing steps, without producing stress cracks or material fractures.
The method of cooling steel sections which are hot from rolling of a type of steel referred to as an air-hardening steel with alloy elements of the group Cr, Mn, Mo, Ni, V and other suitable elements is preferably suitable for use in connection with round material having diameters of less than 100 mm.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
The single Figure of the drawing is a diagram showing the pattern of temperature and cooling time for an air-hardening steel.
5 ~
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The diagram of the drawing shows the pattern of the temperature and cooling time for an air-hardening steel with temperature curves for the surface layer 1, for the core area 2, and for the average temperature 3.
The diagram corresponds to the thermal treatment of a sample according to the present invention and was carried out with a round section having a diameter of 62mm and the chemical composition: C=0.40~; Mn=1.45~; Cr=2.0~; Mo=0.2~. The martensitic transformation of the surface layer was carried out by travel through a water cooling stretch with Tw=30~C and a speed V=1.13m/s.
The sample leaves the last roll stand with a rolling temperature of about 960~C. By the time the sample enters the cooling stretch, the dynamic recrystallization has been completely concluded.
The shock-like cooling of the sample begins in the cooling stretch at the 14th second, wherein the surface temperature (1) cools within about 2 seconds from 920~C to about 200~C and s ~
fur~her to about 70~C between the 15th second and the 23rd second.
The core temperature (2) drops much more slowly and is about 870~C at the 35th second and about 640~C at the 80th second.
The average temperature (3) drops from the 14th second to the 23rd second from 940~C to about 640~C and then drops approximately steadily to about 620~C.
After leaving the cooling stretch, the temperature of the surface layer (1) increases rapidly in accordance with an exponential function as a result of heat supplied from the core and reaches a temperature of about 610~C up by the 80th second.
This results in a very tough and resistant surface layer as a result of a tempering process in the surface layer, wherein this tough and resistant surface layer surrounds like a protective layer the initially still austenitic remaining cross-section and prevents damage to the material, such as cracks or fractures during the later transformation of the residual austenite into martensite.
The method according to the invention is uncomplicated and merely requires an exactly reproducible and controlled accelerated cooling of air-hardening alloy steels while not requiring the complicated devices for cooling with significant delay which in the past were necessary for air-hardening steels.
~ccordingly, the object of the present invention described above is met in an optimum manner.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
If these steels are not purposely cooled slowly, sometimes over several days, and are not maintained at the appropriate o ~ s ~
transformation temperature, the austenite remains during further cooling, and after reaching the martensite starting temperature, will convert directly into martensite having a high hardness.
This occurs essentially in steels having diameters of less than lOOmm during cooling after the transformation on the cooling bed in still air. This is the reason why these steels are also called air-hardening steels.
Aside from stainless heat-treatable steels containing, for example, 13~ to 17~ Cr, Mo, Ni and possible additions of other accompanying elements and carbon contents of between 0.2~ and 0.6~, belonging to this group are also tool steels (e.g., 56NiCrMoV7) and special heat-treatable steels (e.g., 45CrMoV67) in the field of high-grade structural steels. These steels have a high hardenability which is why these steels are also considered to be among the air-hardening steels.
If steels having the aforementioned chemical composition are cooled to quickly and transform martensitically as a result, a hard and brittle transformation structure is obtained which makes it possible that stress cracks will form and brittle fractures will occur during later handling. Therefore, it is known in the art to convey steels of the group of the so-called air-hardening steels as quickly as possible after the transformation process to special devices which ensure a significantly delayed cooling.
Preferably used for this purpose are holding hoods, holding pits with heating means and similar devices in order to collect lots obtained after the transformation into bundles and, after the unit is filled up, to carry out a purposeful cooling which may sometimes last several days. This means that substantial technical requirements must be met, for example, for a quick transport over the cooling bed or for a separate transverse transport in front of the cooling bed, and that insulating devices and thermal protection devices in the area of the rolling mill, hot cut-off devices, additional roller conveyors and particularly the holding devices themselves must be provided.
2 S ~
SUMMARY OF THE lNv~NlION
Therefore, it is the primary object of the present invention to avoid the technical requirements mentioned above which are very expensive and, simultaneously, to ensure that, after hot transformation and cooling to room temperature, the air-hardening steels can be made available for further use in a state of their structure which is without cracks and fractures and is in a condition suitable for further processing.
In accordance with the present invention, the method of cooling steel sections which are hot from rolling by means of shock-like cooling following the rolling process so as to form a martensitic surface layer and by subsequently tempering this surface layer by means of core heat to obtain a tough-resistant structure with austenitic remaining cross-section is used in connection with types of steel which, with uncontrolled cooling in air, would directly transform from the austenitic phase into martensite because of their alloying elements from the group Cr, Mn, Mo, Ni and other suitable elements.
The product which is hot from rolling is conveyed directly after the deforming process through a cooling stretch supplied with water, wherein a thin surface layer is cooled in such a way 5 ~
that it transforms martensitically. After emerging from the cooling stretch, this martensitic surface layer is autogenously tempered as a result of the residual heat of the string of the rolled product, so that a surface layer is produced which is very tough and is capable of absorbing high tensions, wherein the surface layer prevents damage in the form of cracks or fractures during the further conversion of the still present austenite into martensite.
Preferred is shock-like cooling with a heat transmission co-efficient alpha of greater than 20 kW/m2/K, preferably up to 80 kW/m2/K.
The present invention provides the significant advantage that steels from the group of the air-hardening steels do not require the complicated devices needed in the prior art for cooling with extremely long delays. This means that the efficiency of the cooling process is significantly improved and the productivity is increased because the cooling times are decreased.
In accordance with a further development of the invention, the shock-like cooling for forming the martensitic surface layer is carried out in a water cooling stretch arranged following the rolling train at a cooling beginning exactly defined by a predetermined starting temperature after the dynamic recrystallization and with a cooling pattern predeterminable by comparative tests to a defined cooling temperature.
A continuation of the method further advantageously provides that the cooling process of the steel section is initially ended after the tempering of the martensitic surface layer, the steel section is conveyed through the other processing units, is subsequently stored and, only when requested by a customer at a later time, is transformed by a specifically elected heat treatment into a structure specified by the customer for delivery.
This is very advantageous because different structure conditions or degrees of hardness, i.e., properties determined by later use, can be produced from the same type of steel depending on the purpose of use, for example, as spring steel, as cutting steel, as structural steel, etc.
A further development of the method according to the invention provides producing partial lengths from the string of rolling stock in accordance with a specific order, collecting the partial lengths into bundles at a temperature below possible 5 ~
carbide precipitation phases, further cooling the partial lengths at a cooling speed of less than 1 K/min, and, in the transformation of the austenite which is still present, carrying out a low-stress transformation into a self-tempered martensite.
Following the cooling process, the steel may travel through the units provided for low-alloy steels and/or unalloyed steels for further processing into a defined condition as required for delivery. The advantage of this is that separate expensive additional devices are no longer required for this purpose. The steel cooled to room temperature can subsequently be subjected to the usual handling in further processing steps, without producing stress cracks or material fractures.
The method of cooling steel sections which are hot from rolling of a type of steel referred to as an air-hardening steel with alloy elements of the group Cr, Mn, Mo, Ni, V and other suitable elements is preferably suitable for use in connection with round material having diameters of less than 100 mm.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
The single Figure of the drawing is a diagram showing the pattern of temperature and cooling time for an air-hardening steel.
5 ~
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The diagram of the drawing shows the pattern of the temperature and cooling time for an air-hardening steel with temperature curves for the surface layer 1, for the core area 2, and for the average temperature 3.
The diagram corresponds to the thermal treatment of a sample according to the present invention and was carried out with a round section having a diameter of 62mm and the chemical composition: C=0.40~; Mn=1.45~; Cr=2.0~; Mo=0.2~. The martensitic transformation of the surface layer was carried out by travel through a water cooling stretch with Tw=30~C and a speed V=1.13m/s.
The sample leaves the last roll stand with a rolling temperature of about 960~C. By the time the sample enters the cooling stretch, the dynamic recrystallization has been completely concluded.
The shock-like cooling of the sample begins in the cooling stretch at the 14th second, wherein the surface temperature (1) cools within about 2 seconds from 920~C to about 200~C and s ~
fur~her to about 70~C between the 15th second and the 23rd second.
The core temperature (2) drops much more slowly and is about 870~C at the 35th second and about 640~C at the 80th second.
The average temperature (3) drops from the 14th second to the 23rd second from 940~C to about 640~C and then drops approximately steadily to about 620~C.
After leaving the cooling stretch, the temperature of the surface layer (1) increases rapidly in accordance with an exponential function as a result of heat supplied from the core and reaches a temperature of about 610~C up by the 80th second.
This results in a very tough and resistant surface layer as a result of a tempering process in the surface layer, wherein this tough and resistant surface layer surrounds like a protective layer the initially still austenitic remaining cross-section and prevents damage to the material, such as cracks or fractures during the later transformation of the residual austenite into martensite.
The method according to the invention is uncomplicated and merely requires an exactly reproducible and controlled accelerated cooling of air-hardening alloy steels while not requiring the complicated devices for cooling with significant delay which in the past were necessary for air-hardening steels.
~ccordingly, the object of the present invention described above is met in an optimum manner.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
Claims (9)
1. In a method of cooling steel sections which are hot from rolling in a rolling process, the method including carrying out a shock-like cooling following the rolling process so as to form a martensitic surface layer and subsequently tempering the surface layer by means of core heat into a tough-resistant structure with an austenitic remaining cross-section, the improvement comprising carrying out the method in types of steel which, due to alloying elements from the group Cr, Mn, Mo, Ni and other suitable elements, are transformed when subjected to uncontrolled cooling in air directly from the austenitic phase into martensite.
2. The method according to claim 1, comprising carrying out the shock-like cooling without substantial delay in a controlled cooling step in devices provided therefor.
3. The method according to claim 1, comprising carrying out the shock-like cooling in a water cooling stretch arranged following a rolling train for forming the martensitic surface layer at a cooling beginning exactly defined by a predetermined starting temperature after dynamic recrystallization in a cooling pattern predeterminable by comparative tests to a defined cooling temperature.
4. The method according to claim 3, comprising carrying out the shock-like cooling with a heat transmission coefficient alpha of greater than 20 kW/m2/K.
5. The method according to claim 3, comprising carrying out the shock-like cooling with a heat transmission coefficient alpha of up to 80 kW/m2/K.
6. The method according to claim 1, comprising initially ending the cooling process of a steel section after autogenously tempering the martensitic surface layer thereof, conveying the steel section through additional processing units, subsequently storing the section, and carrying out a heat treatment to produce a desired structure in accordance with a specific order.
7. The method according to claim 6, comprising producing predetermined partial lengths from rolled stock in accordance with a specific order, collecting the partial lengths into bundles at a temperature below possible carbide precipitation phases, further cooling the partial lengths with a cooling speed of less than 1 K/min, and carrying out a further transformation of still present austenite into autogenously tempered martensite by a low-stress transformation.
8. The method according to claim 6, further comprising conveying the steel section following the cooling process through units provided for low-alloy steels and/or unalloyed steels for further processing into a defined final state.
9. The method according to claim 1, wherein the steel section is of an air-harding steel and has a diameter of less than 100mm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19612818A DE19612818C2 (en) | 1996-03-30 | 1996-03-30 | Process for cooling warm-rolled steel profiles |
| DE19612818.8 | 1996-03-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2200258A1 true CA2200258A1 (en) | 1997-10-01 |
Family
ID=7790032
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002200258A Abandoned CA2200258A1 (en) | 1996-03-30 | 1997-03-18 | Method of cooling steel sections which are hot from rolling |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5830293A (en) |
| EP (1) | EP0798390A1 (en) |
| JP (1) | JPH1024317A (en) |
| KR (1) | KR970065739A (en) |
| CN (1) | CN1067111C (en) |
| CA (1) | CA2200258A1 (en) |
| DE (1) | DE19612818C2 (en) |
| TW (1) | TW346506B (en) |
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|---|---|---|---|---|
| NL1007739C2 (en) | 1997-12-08 | 1999-06-09 | Hoogovens Staal Bv | Method and device for manufacturing a high strength steel strip. |
| DE102009015862A1 (en) * | 2009-04-01 | 2010-10-07 | Siemens Aktiengesellschaft | Gear compressor rotor for cold gas applications |
| US9822422B2 (en) | 2009-09-24 | 2017-11-21 | Ati Properties Llc | Processes for reducing flatness deviations in alloy articles |
| DE102011051682B4 (en) * | 2011-07-08 | 2013-02-21 | Max Aicher | Method and apparatus for treating a steel product and steel product |
| US10047416B2 (en) | 2012-09-13 | 2018-08-14 | Jfe Steel Corporation | Hot rolled steel sheet and method for manufacturing the same |
| CN104619876B (en) * | 2012-09-13 | 2016-12-21 | 杰富意钢铁株式会社 | Hot rolled steel plate and manufacture method thereof |
| CN105618481B (en) * | 2016-03-15 | 2017-04-26 | 石家庄钢铁有限责任公司 | Equipment and process for conducting protruding roller rolling through continuous casting slab waste heat |
| CN110763612B (en) * | 2018-07-25 | 2022-10-11 | 中国石油化工股份有限公司 | Method for researching influence of martensite on stress corrosion cracking performance of austenitic steel |
| DE102019215053A1 (en) * | 2019-09-30 | 2021-04-01 | Thyssenkrupp Steel Europe Ag | Method for producing an at least partially tempered sheet steel component and at least partly tempered sheet steel component |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE715141C (en) * | 1937-08-13 | 1941-12-16 | Hoesch Ag | Process to improve the deep-drawability of non-air-hardening stainless chrome steels |
| US3298827A (en) * | 1963-09-13 | 1967-01-17 | Timken Roiler Bearing Company | Air hardening bearing steel and bearings made therefrom |
| DE2242388B1 (en) * | 1972-08-29 | 1974-03-07 | Stahlwerke Suedwestfalen Ag, 5930 Huettental-Geisweid | Process for the treatment of steel bars from the rolling heat |
| US4180418A (en) * | 1973-09-11 | 1979-12-25 | Stahlwerke Peine-Salzgitter A.G. | Method of making a steel wire adapted for cold drawing |
| IT1090143B (en) * | 1975-01-29 | 1985-06-18 | Centre Rech Metallurgique | PROCESS FOR MANUFACTURING LAMINATED STEEL PRODUCTS |
| DD119270B1 (en) * | 1975-04-02 | 1987-10-14 | Florin Stahl Walzwerk | PROCESS FOR PRODUCING ROLLED STEEL PRODUCTS WITH DEFINED EDGE ZONE AND HIGH-FIXED CORE |
| JPS55107734A (en) * | 1979-02-14 | 1980-08-19 | Sumitomo Metal Ind Ltd | Manufacture of high tensile steel wire rod |
| JPS57126913A (en) * | 1981-01-27 | 1982-08-06 | Kobe Steel Ltd | Production of high-toughness high-strength wire or rod steel |
| DD234281B1 (en) * | 1984-12-21 | 1989-06-21 | Florin Stahl Walzwerk | METHOD FOR PRESSURE WATER TREATMENT OF ROLLING STEEL PRODUCTS |
| NL193218C (en) * | 1985-08-27 | 1999-03-03 | Nisshin Steel Company | Method for the preparation of stainless steel. |
| JPH076713B2 (en) * | 1987-07-15 | 1995-01-30 | 三洋電機株式会社 | Operation circuit for multiple low-temperature shows |
| DE3927276A1 (en) * | 1989-08-18 | 1991-02-21 | Schloemann Siemag Ag | METHOD FOR HARDENING STEEL WITH THE AID OF LIQUID COOLING MEDIA |
| JPH04154921A (en) * | 1990-10-16 | 1992-05-27 | Nisshin Steel Co Ltd | Manufacture of high strength stainless steel strip having excellent shape |
-
1996
- 1996-03-30 DE DE19612818A patent/DE19612818C2/en not_active Expired - Fee Related
-
1997
- 1997-03-14 EP EP97104338A patent/EP0798390A1/en not_active Ceased
- 1997-03-14 JP JP9061279A patent/JPH1024317A/en not_active Withdrawn
- 1997-03-18 CA CA002200258A patent/CA2200258A1/en not_active Abandoned
- 1997-03-19 KR KR1019970009260A patent/KR970065739A/en not_active Application Discontinuation
- 1997-03-22 TW TW086103634A patent/TW346506B/en active
- 1997-03-27 US US08/826,302 patent/US5830293A/en not_active Expired - Fee Related
- 1997-03-30 CN CN97109587A patent/CN1067111C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| KR970065739A (en) | 1997-10-13 |
| US5830293A (en) | 1998-11-03 |
| JPH1024317A (en) | 1998-01-27 |
| EP0798390A1 (en) | 1997-10-01 |
| DE19612818A1 (en) | 1997-10-02 |
| DE19612818C2 (en) | 1998-04-09 |
| CN1172858A (en) | 1998-02-11 |
| CN1067111C (en) | 2001-06-13 |
| TW346506B (en) | 1998-12-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |