Stål

Utrustningar i stålverk som bearbetar sinter vid mycket höga temperaturer utsätts för svåra slitageförhållanden. I synnerhet sinterkrossar som måste omsätta stora materialmängder måste skyddas mot slitage för att kostnadskrävande underhåll och frekventa nedstängningar ska undvikas. Underhållschefer håller med om att standardlösningar som finns på marknaden inte uppfyller deras behov. Rotorer och brytbalkar måste regelbundet bytas ut mot nya.
Standardlösningarnas bristande slitagebeständighet beror på tre huvudfaktorer:

• materialets höga temperatur som reducerar hårda ytbeläggningars egenskaper,
• materialets nötande natur som sliter ut delar,
• de stora kraftpåkänningar som förstör spröda ytbeläggningar.

e3 är en rättighetsskyddad lösning speciellt utvecklad för stålsinterkrossars produktivitet och livslängd. Denna lösning lanserades efter fyra års laboratorietester och även på grund av verkliga funktionsförhållanden. Den baseras på Castolin Eutectics unika nötningsbeständiga legering för höga temperaturer, som erbjuder mycket höga prestanda även under påverkan av nötning och belastning. e3 lämpar sig speciellt för skydd av kritiska sinterkrosskomponenter, exempelvis rotorblad, tänder och brytbalkar. Praktiska tester har visat att e3 överträffar standardlösningar med minst en faktor tre. Utöver att livslängden ökar bevaras komponenternas geometriska form vilket garanterar bättre krosseffektivitet jämfört med standardlösningar.

Utöver att förstärka delars livslängd möjliggör e3:

• mindre frekvent underhåll av sinterkrossar och nedstängning av anläggningar,
• högre krossproduktivitet genom bevarad tandskärpa,
• mindre anskaffningskostnader för nya delar,
• undvikande av komplexa vattenkylda brytbalkar.

We offer a comprehensive range of wear-resistant sieves with round, square or oval apertures manufactured from 3 mm thick or higher, perforated sheets. We also manufacture tailor-made solutions according to specific customer requests. Our production technology uses a state-of-the-art, high power laser cladding installation. This system ensures highest quality wearfacing coatings of tungsten carbides dispersed in a nickel-based matrix to protect standard perforated steel sheets with variable mesh sizes.

The ultra hard tungsten carbide phases which are homogeneously distributed within a self-fluxing, tough nickel-based alloy matrix, provide:

• Extreme wear resistance performance against abrasion and erosion up to 10 times higher than standard, monolithic heat-treated steel alternatives.
• Withstands operating service temperatures up to 400°C. For even higher service temperature requirements, a diverse range of special alloy systems may be proposed to meet specific customer needs.

Modern Castolin Eutectic LaserClad technology uses a focused laser beam to ensure low heat input welding conditions, which translates into extremely effective, wear protective coatings on industrial parts.

After mixing the raw materials in the sinter plants (fine iron ores, additives such as limestone and olivine, recycled iron-bearing materials  from downstream operations, and coke breeze) we find a roller just underneath the charging system to constantly feed the sinter belt which is affected by abrasion. The lifetime of this feeding roller can be increased by our turnkey solutions.

In most cases after the sinter discharge, crushing and hot screening, the sintered material proceeds to a separate cooler. This is typically a rotating structure, divided into circular sectors with tipping devices, in which the sinter is placed in a layer more than 1 m thick and cooled by fresh air.

When the sinter has completed the cooling cycle, each sector is emptied via the tipping device. The cooled sinter is transferred to screens that separate the pieces to be used in the blast furnace.

Both the charge and discharge of the cooler deteriorate the surfaces whose lifetime can be increased with our CDP® wearplates.

Along the whole sinter process, several metallurgical and chemical reactions take place which produce dust and gaseous emissions apart from the sinter itself. These gases contain particles such as heavy metals that will weaken the inner surface of air suction systems.

A complete high resistance conduction system including valves and transitions circular to square section can be manufactured with our CDP® wearplates.

Based upon hundreds of successful applications approved by our clients across the globe, Castolin Eutectic can provide optimized solutions with a wide range of products and technologies to combat wear in VRM (Vertical Roller Mill) and many more. Castolin Eutectic has a detailed understanding of the industries where this equipment is used, of every major wear problem and can provide industry tested application solutions.

From the extreme cold of Russia to the heat of Brazil and Mexico, we have a deep knowledge of application solutions for the wear problems in this industry. Innovative technologies and equipment help major industrial Groups to meet their objectives in terms of increased life time and plant performance.

The fume ducts in the Steel Plants are exposed to high erosion wear or corrosion. Moreover, their internal walls are subjected to the impact of erosive particles transported at high speed by ventilation gas at high temperatures. In some applications, ventilation gas is also corrosive.

Since decades, Castolin Eutectic has been the provider of choice for service, repair and preventive maintenance of heavy-duty and industrial process equipment.

In Iron & Steel, protecting your industrial process equipment, fume ducts, tubes and walls from future corrosion and erosion while also extending your tubes’ useful life, is vital to your operation’s bottom line.

Eutronic Arc is the highest productivity and lowest running cost thermal spraying process. Due to the low heat input, there is a very low dilution during the process with limited distortion or metallurgical modification of the substrate without any dilution.

This technology can be applied both in the workshop or in the field. It does not require the use of oxygen, kerosene or combustible gas which means more economic coatings.

Enorma skador i processen på utsidan av Teyer-kylarkomponenten, som används i masugnar, är vanliga händelser som kan leda till minskad processkapabilitet och stopptider. Detta är speciellt relevant om skador på underlaget medför att Teyere-röret fastnar i det hållande huset och måste avlägsnas med kraft. Tata Steel har tillsammans med Castolin Eutectic I Monitor Coatings Ltd utvecklat en termisk sprutdepositionsmetod som skulle motverka möjliga skador på komponenten och därigenom öka dess användbarhet i tid genom att minska uppbyggnad och vidhäftning av masugnens biprodukter.

Efter omfattande försök användes ett kompositbeläggningssystem, bestående av en Ni-Cr-beläggning som beläggs genom kombination med ett snabboxiderande bränsle (High Velocity Oxy Fuel, HVOF) tillsammans med en termiskt omvandlad slamtillsats, för att skydda den påverkade yttre ytan. Denna beläggning bildar en porfri yta som förhindrar vidhäftning av processens biprodukter och skyddar samtidigt underlaget från stort slitage genom kemisk erosion.

Den hårda kompositbeläggningen CastCoat utvecklades för över 20 år sedan av brittiska Castolin Eutectics dotterbolag Monitor Coatings för tillämpningar i stålindustrin, särskilt för beläggning av kontinuerliga kopparformplåtar. Tester har visat att beläggningen är tåligare än andra beläggningar för kopparformplåtar. Den har en låg friktionskoefficient, vilket bidrar till färre larm för fastnade formar, och är okänslig för flytande stål och formpulver. Beläggningssystemet påverkar inte formnivådetektorer eller elektromagnetiska omrörare. Det har även bevisats att beläggningen obetydligt påverkar värmeöverföringshastigheten.

Med många års data från fältet bakom beläggningen, har betydande ökningar av kopparplåtarnas livslängd påvisats: tre till fyra gånger för tjocka götformar och upp till sex gånger för tunna götformars plåtar, jämte förbättrad produktform. I drift har beläggningen visat sig möjliggöra längre gjutningskörningar genom dramatisk ökning av slitagebeständigheten. Eventuell progressiv nedbrytning av beläggningen uppstår på grund av termisk utmattning i partier med höga påkänningar. CastCoat är idag en mogen teknik med kunder över hela världen och fortsätter att reducera kostnaderna per ton för användarna.

Genom beläggning av alla fyra sidorna av formen, bevaras dimensionsstabiliteten under hela förloppet, vilket ger hållbar och effektiv produktform och skaltillväxt. Uteblivet avsevärt slitage betyder att längre förlopp är möjliga mellan formbytena och högre formtillgänglighet. Det skydd som beläggningen ger betyder också ökad livslängd för kopparplåten, som medför årliga kopparbesparingar och betydande minskning av underhåll både i och utanför processen. Med den tidigare utvecklingen av en kompakt HVOF-utrustning kan kompositbeläggningen CastCoat nu appliceras på rörformar.

Since a very long time we are successfully applying a partnership program, focused on cost reductions. This smart Maintenance and Repair program can be summarized in six steps:

1. Analysis: The first step to a good solution is a correct analysis.
2. Technical Report: With the information provided, our Technical Department prepares a report.
3. Job development: Once the client considers the repair to be feasible, Castolin Eutectic puts at your service all the Technical Department for the development of the procedure outlined above.
4. App registration: Always subject to the customer’s approval, we first propose to register the job done in our confidential “FAR” database where the short application summary remains on hold until confirmation  of service results.
5. EcoTest: At the end of the service life of the part involved, we are ready to establish a detailed cost analysis to evaluate the practical direct savings achieved through mutual collaboration.
6. Terolink: Finally we propose to submit the complete application as verified in our Terolink Database.

Iron ore, coal, limestone, fluxes and scrap are unloaded in the raw material area. They are classified, stored, crushed, grinded and handled for transport into the next production process. All these activities produce a combination of wear phenomena in the different machines and parts involved. Their service lifetime can be extended with different solutions, thanks to the cost reduction program from Castolin Eutectic.

After processing the respective raw materials, they pass through the blast furnace, electric arc furnace (EAF) or basic oxygen furnace (BOF) to get pig iron or Steel. The first step for a good solution is a correct analysis. To facilitate this, we have created an analysis document that can easily be completed in collaboration with our technical delegate. The document reflects the most important parameters to be considered to develop in-house solutions to your wear problems.

Continuous casting rolls are critical parts that are used for making the slabs, blooms or billets just after the tundish and moulds, at a very high temperature. The extreme working loads as well as the high temperature wear-out the rolls surface and, as a result, parts are damaged. Maintenance managers regularly have to decide to either scrap these expensive parts or try to repair them according to OEM specifications.

The semifinished products obtained after the continuous casting process have to be shaped before being comercialized. The first of these processes is hot rolling, from which sometimes final products are obtained and other times semifinished products intended for cold rolling or coating.

In all rolling processes, cooling the steel is a critical factor. The speed at which the rolled product is cooled will affect the mechanical properties of the steel. Cooling speed is controlled normally by spraying water on the steel as it passes through and/or leaves the mill, although occasionally the rolled steel is air-cooled using large fans.

Since the installation of laser cladding technology in the Castolin Eutectic Services Centers the wear protection of key tools such as rolls and guides has been raised to a new level. The utilization of 8kW High Power Direct Diode (HPDD) with automation leads to flexible production and superior quality. In addition, the powerful laser enables high deposition rates that can reduce the cost of the cladding operation. Compared to standard welding techniques, the dissolution of the carbides and the dilution of the cladding material are the lowest that can be achieved. As a result, the wear-resistance is maximized and the service-life is longer. The unique broad beam (up to 23mm wide) produces a flat coated surface that minimizes subsequent machining or grinding. Rolls can often be used as welded without further processing. The low heat input of the laser process means the lowest distortion of large and thin wall parts that can easily be cladded.

OEMs usually provide parts that have the surface coated with high wear resistant alloys such as Eutalloy® RW 12496. This coating is applied first by spraying a powder on the roller surface and then by fusing it just above the liquidus temperature. The process allows the coating to offer its best wear resistant properties and to perfectly bound on the steel substrate. On long and heavy parts, fusion is extremely difficult to be done correctly. Just after the spraying step, the part must be pre-heated homogeneously and kept in temperature while several torches fuse the powder all along the roll. In 2m long massive rolls, fusion may require up to 7 hours and any variation in temperature may result on an irregular surface quality. Since the part is exposed to very high temperature, deformation is also critical, especially on rolls made with thin wall tubes. Finally, if cooling is not well managed, thermal stresses can be so high that cracks may appear on the overlay. Our well-equipped service workshops as well as more than 10-years experience  allow us to offer high quality overlays. Parts are coated by highly skilled operators that follow strict manufacturing methods. They regularly apply several powders according to what has been defined by OEMs.