SE467828B - SET TO MANUFACTURE STAINLESS STEEL - Google Patents
SET TO MANUFACTURE STAINLESS STEELInfo
- Publication number
- SE467828B SE467828B SE9100294A SE9100294A SE467828B SE 467828 B SE467828 B SE 467828B SE 9100294 A SE9100294 A SE 9100294A SE 9100294 A SE9100294 A SE 9100294A SE 467828 B SE467828 B SE 467828B
- Authority
- SE
- Sweden
- Prior art keywords
- inert gas
- oxygen
- steel
- gas
- carbon content
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
- C21C7/0685—Decarburising of stainless steel
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/005—Manufacture of stainless steel
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Steel (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Glass Compositions (AREA)
- Forging (AREA)
Abstract
Description
10 15 20 25 30 35 467 828 2 komplikation av processen och därmed höjda kostnader för investering i instrument och underhåll. 10 15 20 25 30 35 467 828 2 complication of the process and thus increased costs for investment in instruments and maintenance.
Föreliggande uppfinning avser att åstadkomma ett avkol- ningsförfarande för rostfritt stål med syrgas och inertgas utan ändring av blandningsförhâllandet som funktion av kolhalten. Förfarandet ger lika låg kromoxidation som det konventionella förfarandet med olika blandningsförhållande mellan syrgas och inertgas.The present invention aims to provide a carbonization process for stainless steel with oxygen and inert gas without changing the mixing ratio as a function of the carbon content. The process gives as low a chromium oxidation as the conventional process with different mixing ratios between oxygen and inert gas.
Enligt föreliggande uppfinning sker avkolningen med enbart ett blandningsförhållande av till exempel fyra delar syrgas och en del inertgas, 4/1. Detta blandningsförhållande behålles tills kolhalten sjunkit till låga värden, exempelvis 0,2%. Under avkolningen från 1,5 till O,2% körs således samma blandning. Under denna period inblåses under korta perioder inertgas i avsevärda mängder. Dessa periodiska inertgasin- blåsningar åstadkommer i stort sett samma avkolningsförlopp som erhålles med de ändrade blandningsförhållanden enligt den konventionella tekniken. ' De korta perioder av inertgasinblåsning kan ske i ett förutbestämd periodicitet, exempelvis en tvåminuters inert- gasblåsningsperiod var femte minut. Inertgasblåsningsperiod- erna är förutbestämda och oberoende av kolhalten, varför processen kan fortgå utan stopp för provtagning och analys.According to the present invention, the decarburization takes place with only a mixing ratio of, for example, four parts oxygen and one part inert gas, 4/1. This mixing ratio is maintained until the carbon content has dropped to low values, for example 0.2%. During the decarburization from 1.5 to 0.2%, the same mixture is thus run. During this period, inert gases are blown in for short periods in considerable amounts. These periodic inert gas blows produce essentially the same decarburization process obtained with the changed mixing conditions according to the conventional technique. The short periods of inert gas injection can take place in a predetermined periodicity, for example a two-minute inert gas injection period every five minutes. The inert gas blowing periods are predetermined and independent of the carbon content, so the process can continue without stopping for sampling and analysis.
Kromoxidationen blir inte större utan snarare lägre med denna process, samtidigt som processtiden blir kortare och produk- tiviteten därför högre.Chromium oxidation does not become greater but rather lower with this process, at the same time as the process time becomes shorter and productivity is therefore higher.
Skillnaden mellan föreliggande uppfinning och den konventionella metoden är avsevärd och grundläggande. Enligt den konventionella metoden är det de ändrade blandningsför- De allt syrefattigare blandningarna skall successivt hålla tillbaka kromets oxidation och samtidigt främja kolets oxidation. hållandena som skyddar kromen från oxidation.The difference between the present invention and the conventional method is considerable and fundamental. According to the conventional method, it is the altered mixture- The increasingly oxygen-poor mixtures must gradually hold back the oxidation of chromium and at the same time promote the oxidation of carbon. the conditions that protect the chromium from oxidation.
Inertgasens uppgift är således, enligt den konventionella metoden att främja kolets oxidation jämfört med kromets oxidation.The task of the inert gas is thus, according to the conventional method, to promote the oxidation of carbon compared to the oxidation of chromium.
Föreliggande uppfinning använder sig av en helt annan mekanism. De periodiskt återkommande inertgasinblåsningarna åstadkommer en reaktion mellan kolhalten i badet och syret 10 15 20 25 30 35 .[2- cm sa CO m CO 3 bundet till krom i form av kromoxid. Kromoxiden reduceras således med kol under inertgasinblåsningen.The present invention uses a completely different mechanism. The periodic inert gas blows cause a reaction between the carbon content of the bath and the oxygen [2 cm 2 CO m CO 3 bonded to chromium in the form of chromium oxide. The chromium oxide is thus reduced with carbon during the inert gas injection.
Ovanstående torde förklara det överraskande förhållandet att processen kan genomföras utan ändring av förhållandet mellan syrgas och kvävgas i den inblåsta gasblandningen. Det skall dock påpekas att denna förklaring icke behöver utgöra den vetenskapliga sanningen. En annan förklaring kan vara att den konventionella metoden med de varierande förhållanden syrgas/inertgas helt enkelt är onödig och således kan undvaras utan egentlig olägenhet.The above should explain the surprising fact that the process can be carried out without changing the ratio of oxygen to nitrogen in the blown gas mixture. It should be noted, however, that this explanation need not constitute the scientific truth. Another explanation may be that the conventional method with the varying oxygen / inert gas ratios is simply unnecessary and thus can be dispensed with without any real inconvenience.
I praktisk mening viktigaste skillnaden är dock den rationaliseringsvinsten som erhålles då de vid bestämda kolhalter införda växlingen av blandningsförhållandet mellan syre och inertgas med stopp, provtagning och väntetider som trots stor insats av tid och investering i mätutrustning inte alltid kan utföras med tillfredsställande noggrannhet.In practical terms, however, the most important difference is the rationalization gain obtained when the change of the mixing ratio between oxygen and inert gas introduced at certain carbon contents with stop, sampling and waiting times which, despite great effort of time and investment in measuring equipment, can not always be performed with satisfactory accuracy.
Exempel 1.Example 1.
Ett råstål hade följande analys: C Si Mn Cr Ni 1.21 0.31 1.13 17.21 8.95 Det flytande råstålet behandlades i en 5 tons konverter genom insprutning av syrgas och kvävgas. Behandlingen skedde i tre steg: först med 4 delar syre och en del kvävgas sedan med IL del syre och en del kvävgas och slutligen med en blandning innehållande en del syre och tre delar argon. Väx- lingspunkterna mellan de olika stegen var 0.53 % C respektive 0.18 % C. Slutkolhalten blev 0.041 %.A crude steel had the following analysis: C Si Mn Cr Ni 1.21 0.31 1.13 17.21 8.95 The liquid crude steel was treated in a 5 ton converter by injecting oxygen and nitrogen. The treatment took place in three steps: first with 4 parts oxygen and one part nitrogen gas then with IL part oxygen and one part nitrogen gas and finally with a mixture containing some oxygen and three parts argon. The change points between the different steps were 0.53% C and 0.18% C, respectively. The final carbon content was 0.041%.
Tidsutnyttjandet blev: Steg 1 32 min Steg 2 9 min Steg 3 12 min Prov 1 5 min Prov 2 4 min Prov 3 5 min Reduktion inklusive slaggdragning 17 min Justering 11 min Tappning 3 min Sza _ 98 min 10 15 20 25 30 35 467 828 4 Materialförbrukningen blev: Syrgas 29.04 Nm3/t Kvävgas 18.10 " Argon 10.07 " Kisel 20.32 kg/t Kalk 70.28 " Exempel 2.The time utilization was: Step 1 32 min Step 2 9 min Step 3 12 min Sample 1 5 min Sample 2 4 min Sample 3 5 min Reduction including slag drawing 17 min Adjustment 11 min Draining 3 min Sza _ 98 min 10 15 20 25 30 35 467 828 The material consumption was: Oxygen 29.04 Nm3 / h Nitrogen gas 18.10 "Argon 10.07" Silicon 20.32 kg / h Lime 70.28 "Example 2.
Ett råstâl behandlades i en 5 tons konverter, varvid råstålet hade följande analys: C Si Mn Cr Ni 1.24 0.37 1.32 18.3 9.01 Behandlingen skedde enligt föreliggande uppfinning.A crude steel was treated in a 5 ton converter, the crude steel having the following analysis: C Si Mn Cr Ni 1.24 0.37 1.32 18.3 9.01 The treatment took place according to the present invention.
Först inblåstes en gasblandning bestående av 4 delar syrgas och en del kvävgas. 7 minuter efter blåsningens början utfördes en kvävgasblåsning under 30 sekunder varvid kväv- gasflödet uppgick till 0.81 Nm3/min,ton. Därefter återupptogs blåsningen med fyra delar syrgas och en del kväve. Vid 12 minuters total blåstid utfördes ytterligare en 30 sekunders kvävgasblâsning med 0.81 IMF/min,ton. Därefter upprepades kväveinblåsningsperioden efter var femte minut. Sammanlagt utfördes Efter 38 minuters blåsning togs ett kolprov som visade O.I7 % C; Därefter inblåstes enbart argon i 7 minuter, varvid flödet var 0.73 NnP/minpcon. slutkolnalten blev o.os9 2.First, a gas mixture consisting of 4 parts of oxygen and one part of nitrogen gas was blown in. 7 minutes after the start of the blowing, a nitrogen gas was blown for 30 seconds, the nitrogen gas flow amounting to 0.81 Nm3 / min, ton. Then the blowing was resumed with four parts oxygen and one part nitrogen. At a total blowing time of 12 minutes, a further 30 seconds of nitrogen blowing was performed at 0.81 IMF / min, ton. Thereafter, the nitrogen injection period was repeated after every five minutes. In total, performed After 38 minutes of blowing, a carbon sample was taken showing O.I7% C; Thereafter, only argon was blown in for 7 minutes, the flow being 0.73 NnP / minpcon. the final colnal became o.os9 2.
Tidsutnyttjandet blev: Steg 1. inkl. kväveblåsningar 38 min Steg 2. 12 min Prov 1 5 min sex kväveblâsningsperioder.The time utilization was: Step 1. incl. nitrogen blowing 38 min Step 2. 12 min Sample 1 5 min six nitrogen blowing periods.
Reduktion inkl. slaggdragning 18 min Justering 11 min Tappning 4 min Sza 88 min Materialförbrukningen blev: syrgas 27 . 22 NnP/t Kvävgas 17.10 " Argon 11.02 " Kisel 18.02 kg/t Kalk 62.31 " _10 15 467 82 CO 5 Av de båda exemplen framgår att en tidsbesparing på 10 minuter, vilket utgör en c:a 10 procentig produktivitets- vinst. Kiselförbrukningen är också lägre med föreliggande metod, medan de övriga förbrukningssiffrorna är i stort sätt oförändrade.Reduction incl. slag drawing 18 min Adjustment 11 min Bottling 4 min Sza 88 min Material consumption was: oxygen 27. 22 NnP / h Nitrogen gas 17.10 "Argon 11.02" Silicon 18.02 kg / h Lime 62.31 "_10 15 467 82 CO 5 The two examples show that a time saving of 10 minutes, which constitutes an approximately 10 percent productivity gain. The silicon consumption is also lower with the present method, while the other consumption figures are largely unchanged.
Av de framförda exemplen framgår således att förfarandet enligt uppfinningen leder till produktivitetsökning och besparing av förbrukningsmaterial.The examples given thus show that the method according to the invention leads to an increase in productivity and a saving of consumables.
I föreliggande beskrivning och patentkrav avses enligt föreliggande uppfinning med en oxygenrik gas en gasblandning bestående av minst 50 volymprocent oxygen, varvid återstoden utgöres av en inert gas, t ex nitrogen eller argon. Gasbland- ningen innehåller företrädesvis minst 70 % oxygen. Ett föredraget intervall för oxygenhalten är 75-90 %. Med inertgas avses en gasblandning innehållande minst 70 volym- procent av en inert gas, t ex nitrogen. Enligt föreliggande definition är även luft att betrakta som en inert gas.In the present description and claims, according to the present invention, with an oxygen-rich gas is meant a gas mixture consisting of at least 50% by volume of oxygen, the remainder being an inert gas, for example nitrogen or argon. The gas mixture preferably contains at least 70% oxygen. A preferred range for the oxygen content is 75-90%. By inert gas is meant a gas mixture containing at least 70% by volume of an inert gas, eg nitrogen. According to the present definition, air is also to be regarded as an inert gas.
Föreliggande inerta gas innehåller minst 90 %, speciellt ' minst 99% inert gas, t ex argon eller nitrogen.The present inert gas contains at least 90%, especially at least 99% of inert gas, eg argon or nitrogen.
Claims (9)
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9100294A SE467828B (en) | 1991-01-31 | 1991-01-31 | SET TO MANUFACTURE STAINLESS STEEL |
AT92904055T ATE154647T1 (en) | 1991-01-31 | 1992-01-28 | METHOD FOR PRODUCING STAINLESS STEEL |
PCT/SE1992/000053 WO1992013975A1 (en) | 1991-01-31 | 1992-01-28 | A method of manufacturing stainless steel |
JP4504096A JPH06505056A (en) | 1991-01-31 | 1992-01-28 | How to make stainless steel |
ES92904055T ES2104896T3 (en) | 1991-01-31 | 1992-01-28 | A METHOD FOR THE PRODUCTION OF STAINLESS STEEL. |
DE69220479T DE69220479T2 (en) | 1991-01-31 | 1992-01-28 | METHOD FOR PRODUCING STAINLESS STEEL |
EP92904055A EP0569448B1 (en) | 1991-01-31 | 1992-01-28 | A method of manufacturing stainless steel |
FI933417A FI97626C (en) | 1991-01-31 | 1993-07-30 | Procedure for manufacturing stainless steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9100294A SE467828B (en) | 1991-01-31 | 1991-01-31 | SET TO MANUFACTURE STAINLESS STEEL |
Publications (3)
Publication Number | Publication Date |
---|---|
SE9100294D0 SE9100294D0 (en) | 1991-01-31 |
SE9100294L SE9100294L (en) | 1992-08-01 |
SE467828B true SE467828B (en) | 1992-09-21 |
Family
ID=20381765
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
SE9100294A SE467828B (en) | 1991-01-31 | 1991-01-31 | SET TO MANUFACTURE STAINLESS STEEL |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP0569448B1 (en) |
JP (1) | JPH06505056A (en) |
AT (1) | ATE154647T1 (en) |
DE (1) | DE69220479T2 (en) |
ES (1) | ES2104896T3 (en) |
FI (1) | FI97626C (en) |
SE (1) | SE467828B (en) |
WO (1) | WO1992013975A1 (en) |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3854932A (en) * | 1973-06-18 | 1974-12-17 | Allegheny Ludlum Ind Inc | Process for production of stainless steel |
DE2710577A1 (en) * | 1977-03-11 | 1978-09-14 | Thyssen Edelstahlwerke Ag | METHOD OF REFRESHING STEEL |
CA1333663C (en) * | 1987-09-09 | 1994-12-27 | Haruyoshi Tanabe | Method of decarburizing high cr molten metal |
-
1991
- 1991-01-31 SE SE9100294A patent/SE467828B/en not_active IP Right Cessation
-
1992
- 1992-01-28 EP EP92904055A patent/EP0569448B1/en not_active Expired - Lifetime
- 1992-01-28 JP JP4504096A patent/JPH06505056A/en active Pending
- 1992-01-28 ES ES92904055T patent/ES2104896T3/en not_active Expired - Lifetime
- 1992-01-28 WO PCT/SE1992/000053 patent/WO1992013975A1/en active IP Right Grant
- 1992-01-28 AT AT92904055T patent/ATE154647T1/en not_active IP Right Cessation
- 1992-01-28 DE DE69220479T patent/DE69220479T2/en not_active Expired - Fee Related
-
1993
- 1993-07-30 FI FI933417A patent/FI97626C/en active
Also Published As
Publication number | Publication date |
---|---|
DE69220479D1 (en) | 1997-07-24 |
SE9100294L (en) | 1992-08-01 |
SE9100294D0 (en) | 1991-01-31 |
DE69220479T2 (en) | 1997-10-16 |
JPH06505056A (en) | 1994-06-09 |
FI97626B (en) | 1996-10-15 |
WO1992013975A1 (en) | 1992-08-20 |
ATE154647T1 (en) | 1997-07-15 |
FI933417A0 (en) | 1993-07-30 |
ES2104896T3 (en) | 1997-10-16 |
FI97626C (en) | 1997-01-27 |
EP0569448B1 (en) | 1997-06-18 |
EP0569448A1 (en) | 1993-11-18 |
FI933417A (en) | 1993-07-30 |
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