NO811738L - PROCEDURE FOR AA TREATING SILICONE STEEL, CALCULATED FOR HOT DELAY - Google Patents
PROCEDURE FOR AA TREATING SILICONE STEEL, CALCULATED FOR HOT DELAYInfo
- Publication number
- NO811738L NO811738L NO811738A NO811738A NO811738L NO 811738 L NO811738 L NO 811738L NO 811738 A NO811738 A NO 811738A NO 811738 A NO811738 A NO 811738A NO 811738 L NO811738 L NO 811738L
- Authority
- NO
- Norway
- Prior art keywords
- hot
- steel
- air
- dip galvanizing
- zinc
- Prior art date
Links
- 229910000831 Steel Inorganic materials 0.000 title claims description 18
- 239000010959 steel Substances 0.000 title claims description 18
- 238000000034 method Methods 0.000 title claims description 9
- 229920001296 polysiloxane Polymers 0.000 title 1
- 239000000463 material Substances 0.000 claims description 14
- 238000005246 galvanizing Methods 0.000 claims description 12
- 238000005098 hot rolling Methods 0.000 claims description 9
- 229910052710 silicon Inorganic materials 0.000 claims description 9
- 239000010703 silicon Substances 0.000 claims description 9
- 238000005096 rolling process Methods 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000003570 air Substances 0.000 claims 4
- 229910000851 Alloy steel Inorganic materials 0.000 claims 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims 1
- 239000012080 ambient air Substances 0.000 claims 1
- 230000001680 brushing effect Effects 0.000 claims 1
- 239000007789 gas Substances 0.000 claims 1
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 16
- 239000011701 zinc Substances 0.000 description 16
- 229910052725 zinc Inorganic materials 0.000 description 16
- 239000010410 layer Substances 0.000 description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 4
- KFZAUHNPPZCSCR-UHFFFAOYSA-N iron zinc Chemical compound [Fe].[Zn] KFZAUHNPPZCSCR-UHFFFAOYSA-N 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- 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
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Coating With Molten Metal (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
Oppfinnelsen vedrører en fremgangsmåte til i forbindelse med varmvalsing å behandle kiseholdige stål-produkter således at det dårligere resultatet ved etter-følgende varmgalvanisering på grunn av kiselinnholdet i stålet unngås. The invention relates to a method for treating silicon-containing steel products in connection with hot rolling so that the poorer result of subsequent hot-dip galvanizing due to the silicon content in the steel is avoided.
Normale ulegerte eller lavlegert stål, hvor kisel bare forekommer som godtagbart forurensning, f. eks. utettet stål, er vel egnet for varm forsinkning. Da slikt stål ned-dyppes i et varmt sinkbad, belegges stål overflaten med et tett og fast sjikt av jern-sinkfaser. Tilveksten av dette sjikt skjer ved at jernet diffunderer tvers igjennom sjiktet ut til det nå smeltede sinkbad, der det forenes med sinken til ytterligere j ern-sinkf aser . Da. den bestemmende faktoren er jerntilførsélen til det befinnende sjikts ytterside, og denne bare skjer ved diffusjon^ øker sjikttykkelsen i henhold til kjente lover bare proporsjonalt med kvadratroten av tiden, innebærende en relativt hurtig forløpende tykkelses-økning. For at sjiktet skal vokse til dobbelt tykkelse, • kreves således en firedobling av tiden. Fordelene med dette er påtagelig da styringen av varmforsinkelsesprosessen vesentlig lettes. Ved opptak av stålgjenstander fra sinkbadet blir det tilbake en tynn hinne av rent sink ytterst på overflaten,som derved blir tett og blank. Meget små mengder jern passerer ut i selve sinkbadet, hvorifor tapet ved hård-sinkdannelse blir liten. Hårdsink består av en forbindelse av jern og sink som avsetter seg i sinkbadet. Normal unalloyed or low-alloy steels, where silicon only occurs as an acceptable impurity, e.g. unsealed steel, is well suited for hot dip galvanizing. When such steel is dipped into a hot zinc bath, the steel surface is coated with a dense and solid layer of iron-zinc phases. The growth of this layer occurs by the iron diffusing across the layer to the now molten zinc bath, where it combines with the zinc to form further iron-zinc phases. Then. the determining factor is the supply of iron to the outer side of the existing layer, and this only happens by diffusion^ the layer thickness increases according to known laws only proportionally to the square root of time, implying a relatively rapid gradual increase in thickness. For the layer to grow to twice the thickness, • a quadrupling of the time is thus required. The advantages of this are tangible as the management of the heat delay process is significantly facilitated. When steel objects are taken up from the zinc bath, a thin film of pure zinc is left on the outermost surface, which thereby becomes dense and shiny. Very small amounts of iron pass out into the zinc bath itself, which is why the loss due to hard zinc formation is small. Hard zinc consists of a compound of iron and zinc that is deposited in the zinc bath.
I stål inneholdende kisel, dannes ved varmforsinkning ikke den fine overflate som er omtalt tideligere. Overflaten blir i stedet ofte gråmatt og ujevn på grunn av dårlig vedhengning mot underliggende lag av jern- sinkfase. In steel containing silicon, hot-dip galvanizing does not produce the fine surface mentioned earlier. Instead, the surface often becomes dull gray and uneven due to poor adhesion to the underlying layer of iron-zinc phase.
• Dette beror sannsynligvis på at den dannede jern-sinkfase er porøs og ujevn. Belegningens vekst skjer her proporsjonelt med neddypningstiden, hvilket gjør prosessen vanskelig å styre, og mere følsom for ••øvrige betingelser i bad, frem-for alt temperaturvariasjoner innen badet og i den ned-dyppede stålgjen stand. Betydelige mengder sink går dessuten • This is probably due to the iron-zinc phase formed being porous and uneven. The growth of the coating here occurs proportionally to the immersion time, which makes the process difficult to control, and more sensitive to ••other conditions in the bath, above all temperature variations within the bath and in the submerged steel condition. Significant amounts of zinc also go
tapt som hårdsink. Allerede innhold under 0, 05 vekt$ kisel i stålet, fremkommer disse ufordelaktige effekter. De kraftigste effekter har imidlertid blitt konstatert innen området 0,05 - 0,10 vekt$ kisel. lost as hard zinc. Already below 0.05 wt% of silicon in the steel, these disadvantageous effects appear. However, the most powerful effects have been found within the range of 0.05 - 0.10 wt% silicon.
Man har på forskjellig-:måte forsøkt å unngå disse ulemper, dels ved å endre betingelsene i sinkbadet, eksempel-vis ved å variere temperaturen og sammensetningen, dels ved å på forskjellige måte å forbehandle ståloverflaten. Den første type forhåndsregler har ikke ført til praktiske løs-ninger, og den andre typen forholdsregel har vært alt for kostnadskrevende til å utgjøre praktiske løsninger. Various attempts have been made to avoid these disadvantages, partly by changing the conditions in the zinc bath, for example by varying the temperature and composition, partly by pre-treating the steel surface in different ways. The first type of precautionary measures has not led to practical solutions, and the second type of precaution has been far too costly to constitute practical solutions.
Det har nå overraskende vist seg at man kan få meget gode varmforsinkningsegenskaper hos ulegerte og lavlegert stål inneholdende for varmforsinkning kritiske kiselinnhold ved at direkte etter den endelige varmvalsning å drøye av-kjølingen innen temperaturområdet som ikke underskrider 650°C. Forutsetningen for et godt resultat er også at det ved slutt-valsingen dannede glødeskallet får sitte tilbake, og at lufttilgangen til valseoverflåtene under den forsinkede avkjøling umuliggjøres. It has now surprisingly been shown that very good hot-dip galvanizing properties can be obtained in unalloyed and low-alloy steels containing silicon content critical for hot-dip galvanizing by delaying the cooling directly after the final hot-rolling within the temperature range that does not fall below 650°C. The condition for a good result is also that the glow shell formed during the final rolling is allowed to sit back, and that air access to the rolling surfaces during the delayed cooling is made impossible.
Oppfinnelsen skal forklares nærmere ved hjelp av noen eksempler. The invention will be explained in more detail with the help of some examples.
Eksempel 1Example 1
Det første■eksempel er tatt fra undersøkelse i laboratorie skala. The first■example is taken from an investigation on a laboratory scale.
Fra et bredbånd, som på vanlig måte opphasples ved 600°C direkte etter varmvalsningen, klippes kuponger, 95 x 25 mm. Stålet hadde følgende analy seve kt% : 0, 05% C, 0,05$ Si, 0,515? Mn, 0,0105? P, 0,017$ S, 0,006$ N, 0,05$ Al, samt resten Fe og normale forurensninger. Coupons, 95 x 25 mm, are cut from a wide strip, which is normally wound up at 600°C directly after hot rolling. The steel had the following analy seve kt% : 0.05% C, 0.05$ Si, 0.515? Mn, 0.0105? P, 0.017$ S, 0.006$ N, 0.05$ Al, as well as the rest Fe and normal impurities.
Kupongene ble tatt fra de indre av båndrullen, og oksydsjiktes tykkelse ble målt til 8 -10 um. Et antall slike kuponger, slåes inn i tynne platehull som lukkes ved sammenvikling, og denne pakke ble oppvarmet til forskjellige temperaturer under varierende trykk, hvorpå de ble tatt ut, beiset, dyppet i flussmiddel, og innhengt i et bad av smeltet" sink ved 460°C i 8 minutter. Etter uttagning og fri avkjøling i luft, ble det undersøkt et tverrsnitt gjennom den respek-tive kupong. Det fantes da at tykke porøse belegningssjikt (330 - 4-4-0<y>m) med gråmatt overflate var oppnådd på The coupons were taken from the inside of the tape roll, and the thickness of the oxide layer was measured to be 8-10 µm. A number of such coupons are struck into thin plate holes which are closed by folding, and this package is heated to different temperatures under varying pressures, whereupon they are taken out, stained, dipped in flux, and suspended in a bath of molten zinc at 460 °C for 8 minutes. After removal and free cooling in air, a cross-section through the respective coupon was examined. It was then found that thick porous coating layers (330 - 4-4-0<y>m) with a gray matte surface were achieved on
i.;: ikke varmebehandlede kuponger,i.;: not heat-treated coupons,
varmebehandlede kuponger der oksydsjiktet er fjernet før varmebehandlingen, heat-treated coupons where the oxide layer has been removed before the heat treatment,
kuponger som med bibeholdt bksydsjikt ble holdt ved 675°C i 60 minutter. coupons which, with the bx layer retained, were held at 675°C for 60 minutes.
Tynne, tette belegningssj ikt (100 um, nær uav-hengig av dypptiden) med blank overflate ble dannet derimot i kuponger som med bibeholdt oksydsjikt ble oppnådd ved 750°C i 15 - 120 minutter.. Thin, dense coating layers (100 µm, almost independent of the immersion time) with a glossy surface were, on the other hand, formed in coupons which, with a retained oxide layer, were obtained at 750°C for 15 - 120 minutes.
Eksempel 2Example 2
Også dette eksemplet er tatt fra en undersøkelseThis example is also taken from a survey
i laboratorieskala.on a laboratory scale.
Fra et varmvalset bredbånd som etter varmvalsing ble oppviklet ved 750°C og deretter tillatt uhindret av-kjølt i luft, ble det klippet kuponger på samme måte som i foregående eksempel. Stålet hadde følgende analyse i vekt% : 0, 09% C, 0,05$ Si, 0,61$ Mn, 0,011$ P, 0,014$ S, 0,006$ N, 0. 004. Al, samt resten Fe av normale forurensninger. Coupons were cut from a hot-rolled wide strip which, after hot-rolling, was wound up at 750°C and then allowed to cool unimpeded in air, in the same way as in the previous example. The steel had the following analysis in weight%: 0.09% C, 0.05$ Si, 0.61$ Mn, 0.011$ P, 0.014$ S, 0.006$ N, 0.004. Al, as well as the rest Fe of normal impurities .
Kupongene ble behandlet på stort sett sammen måte. Glødningstemperaturen og glødningstidene varierte dog på annen måte. Som i foregående eksempel fremkom to forskjellige be-legningstyper: 1. Tykk, omtrent 400 um, porøst belegg med gråmatt overflate på kuponger som ikke hadde, glødet. 2. Tynne, omtrent 8 um, kompakt belegg med blank overflate på material som hadde glødet ved 750°C i 15 minutter The vouchers were treated in largely the same way. However, the annealing temperature and annealing times varied in a different way. As in the previous example, two different types of coating appeared: 1. Thick, approximately 400 µm, porous coating with a gray matt surface on coupons that had not been annealed. 2. Thin, approximately 8 µm, compact coating with a glossy surface on material that had been annealed at 750°C for 15 minutes
725°C » 30 " 725°C » 30 "
675°C " 4 timer675°C " 4 hours
De kuponger som ble glødet ved 700°C i to timer, viste overgangsutseende med begge ovenfor nevnte belegnings- The coupons that were annealed at 700°C for two hours showed a transitional appearance with both of the above-mentioned coating
typer representert.types represented.
Eksempel 3Example 3
Forsøksserien i eksempel 2 ble gjentatt. Imidlertid slipes en sideoverflate. av kupongene ned 1 mm under den opprinnelige overflate før innhegningen i sinkbadet. På samtlige nedslipede overflater oppnås samme tykke, porøse belegg som på ubehandlede kuponger i henhold til punkt 1 i eksempel 2. The test series in example 2 was repeated. However, one side surface is ground. of the coupons down 1 mm below the original surface before the enclosure in the zinc bath. On all sanded down surfaces, the same thick, porous coating is obtained as on untreated coupons according to point 1 in example 2.
Eksempel 4Example 4
Et antall bånd med stort sett samme analyse som i eksempel 2, ble sluttvalset i et varmvalseverk ved ca. 750°C samt opprullet meget tett på en båndhaspel. Båndrullene ble deretter nedført i en varmeisolert lufttett beholder, og holdt der i minst 15 minutter. Temperaturen sank derved ikke i noen del av båndrullene under 700°C. Etter løsing ble de varmfor sinket hvorved de fikk en meget tett og hård og helt godtagbar overflate. A number of strips with largely the same analysis as in example 2 were final rolled in a hot rolling mill at approx. 750°C and wound very tightly on a tape reel. The rolls of tape were then lowered into a heat-insulated airtight container, and held there for at least 15 minutes. The temperature therefore did not drop below 700°C in any part of the tape rolls. After loosening, they were hot dipped galvanized, which gave them a very dense and hard and completely acceptable surface.
Eksempel 5Example 5
I stedenfor som i eksempel 4»hvor båndet ble oppviklet meget tett for å unngå kontakt med omgivende luft, oppviklés et antall bånd meget løst. For å senke oksygen-potensialet i omgivende atmosfære, spyltes gjennom beholderen hydrogengass og under den forsinkede avkjøl ingstid. Samme gode egenskaper på belegningssjiktet ble oppnådd ved etter-følgende var mf or sinkning . Instead of, as in example 4, where the tape was wound very tightly to avoid contact with the surrounding air, a number of tapes were wound very loosely. To lower the oxygen potential in the surrounding atmosphere, hydrogen gas is flushed through the container and during the delayed cooling time. The same good properties of the coating layer were achieved by subsequent var mf or zinc.
Eksempel 6Example 6
For å oppnå spesielle mekaniske egenskaper hosTo achieve special mechanical properties of
det ferdige bånd, senktes sluttvalsningstemperature.n. Hen-sikten var at etterfølging av oppvikling skulle skje ved en temperatur hos båndet som skulle ligge så nær 700°C som mulig. En del av de tett oppviklede bånd ble lagt i en beholder for kontrollert avkjøling der temperaturen ikke sank under-650°C. De bånd som beholdes i beholderen minst 2 timer, the finished strip, the final rolling temperature was lowered. The aim was that subsequent winding should take place at a temperature of the strip which should be as close to 700°C as possible. A portion of the tightly wound bands was placed in a container for controlled cooling where the temperature did not drop below -650°C. The bands that are kept in the container for at least 2 hours,
fikk .etterfølgende varmgalvanisering en helt godtagbar overflate på tross at kisel innholdet i utgangsmaterialet lå ved 0, 06$ Si. subsequent hot-dip galvanizing gave a completely acceptable surface despite the fact that the silicon content in the starting material was 0.06$ Si.
Eksempel 7Example 7
Deler av materialpartiet ifølge eksempel 6, dels beiset på vanlig måte, dels stålbørstet før varmforsinkningen for å få bort resten av glødeskall dannet ved varmvalsningen. Resultatet ble at varmforsinkningen ga et ennå bedre resultat enn ved det material som ikke var overflatebahandlet på denne måte. Parts of the material part according to example 6, partly stained in the usual way, partly steel brushed before the hot-dip galvanizing to remove the rest of the glow scale formed during the hot rolling. The result was that the hot-dip galvanizing gave an even better result than with the material that had not been surface-treated in this way.
Eksempel 8Example 8
Forutsetningen for et godt varmforsinknings-resultat er at det kiselholdige material holdes ved minst 675 C ved en viss tid etter varmvalsingen og uten lufttil-gang fra omgivelsene. Når det gjelder varmvalset bredbånd, har det vist seg at hvis båndene er oppviklet tett, ute-stenger dette luften så effektivt at man kan holde på full-gode varmf orsinknifigsresultat. Når det g jelder material i e k sempelvis stangform, er man derimot henvist til lukkede beholdere, hvor materialet lagres etter varmvalsning for forsinket avkjøling. Eksperiment er utført idet stang-materialet ble lagret i oksygenavskjermede hyller, i luft-tette tunneller og lommer med godt resultat. Hyllene er gjort varmeisolerende for å nedbringe varmetap til aksept-able verdier. The prerequisite for a good hot-dip galvanizing result is that the siliceous material is kept at at least 675 C for a certain time after hot rolling and without air access from the surroundings. In the case of hot-rolled wide strip, it has been shown that if the strips are wound tightly, this shuts out the air so effectively that you can maintain excellent hot-sinking results. When it concerns material in simple bar form, on the other hand, you are referred to closed containers, where the material is stored after hot rolling for delayed cooling. Experiments have been carried out where the rod material was stored in oxygen-shielded shelves, in air-tight tunnels and pockets with good results. The shelves are made heat-insulating to reduce heat loss to acceptable values.
Claims (5)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8003830A SE446882B (en) | 1980-05-22 | 1980-05-22 | Method for production of non-alloy and low-alloy steel with carbon levels not exceeding .30 weight percent and containing 0.05 to 0.20 weight percent silicon |
Publications (1)
Publication Number | Publication Date |
---|---|
NO811738L true NO811738L (en) | 1981-11-23 |
Family
ID=20341017
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
NO811738A NO811738L (en) | 1980-05-22 | 1981-05-21 | PROCEDURE FOR AA TREATING SILICONE STEEL, CALCULATED FOR HOT DELAY |
Country Status (4)
Country | Link |
---|---|
DK (1) | DK218581A (en) |
FI (1) | FI72278C (en) |
NO (1) | NO811738L (en) |
SE (1) | SE446882B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107185969B (en) * | 2017-05-27 | 2019-10-29 | 内蒙古包钢钢联股份有限公司 | Medium carbon cold heading steel wire rod scale on surface component and method for controlling thickness |
-
1980
- 1980-05-22 SE SE8003830A patent/SE446882B/en not_active IP Right Cessation
-
1981
- 1981-05-14 FI FI811486A patent/FI72278C/en not_active IP Right Cessation
- 1981-05-18 DK DK218581A patent/DK218581A/en unknown
- 1981-05-21 NO NO811738A patent/NO811738L/en unknown
Also Published As
Publication number | Publication date |
---|---|
FI72278C (en) | 1987-05-11 |
SE8003830L (en) | 1981-11-23 |
FI72278B (en) | 1987-01-30 |
SE446882B (en) | 1986-10-13 |
DK218581A (en) | 1981-11-23 |
FI811486L (en) | 1981-11-23 |
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