S+C's centrifugally cast rotary kilns are our first choice in the high temperature range >1200°C. Their lifetime, dimensional stability and abrasive wear resistance is very good.
Indirectly heated rotary kilns with added values.
Higher working temperature. Extended service life. Improved product quality.
At S+C, we base our activities on decades of experience in the production of high-quality stainless steel products for industrial furnace construction. We are continuously working to expand our wide range of in-house developed materials to extend our product portfolio in line with industry's requirements.
Our rotary tubes made from Centralloy® centrifugally cast materials have many economic advantages compared to sheet metal tubes. Among other applications, they are used in indirectly heated rotary kilns for the thermal treatment of inorganic pigments, refractory metal powders, high-purity alumina and other bulk materials. Our proposed materials are highly heat-resistant and can be used continuously up to a working temperature of 1,250 °C, which is neccessary in some cases. They offer extremely high functional reliability and a long, trouble-free operation. A significantly increased service life by a factor of 2-3* should be emphasized compared with conventional rotary kilns made of sheet metal. (* depending on the operating conditions)
At S+C rotary kilns can be produced in diameters between Ø50 and Ø1,100 mm and in lengths of up to 20 meters.
All rotary kilns are manufactured at S+C by using the centrifugal casting process. Add-on-parts such as flanges as well as built-in parts such as inlet screws, flippers and dams are re professionally welded to the kiln and usually consist of hot rolled or forged stainless steels. Rotary kilns are usually delivered ready for installation.
We at S+C also fully meet the requirements of your rotary kiln.
Indirectly heated rotary kilns made by S+C.
Tailor made tubes for your rotary kilns.
Which stresses rotary kilns have to withstand?
Indirectly heated rotary kilns have to withstand various stresses, such as oxidation or corrosion in different types as well as high-temperature creep that may lead into deformation. In operation, the combination of corrosion and high-temperature creep in particular leads into damages that quickly results in repairs and, in worst-case into premature replacement.
The centrifugal casting process is particularly well suited for the production of indirectly heated rotary kilns, due to its directional solidification with uniform material structure, as well as the wide range of materials. This is why this manufacturing process is exclusively used at S+C for rotary kiln manufacture.
Why rotary kilns made by S+C?
Tubes for indirectly heated rotary kilns require best quality materials to comply with the set requirements. Due to many years of experience in the field of industrial furnaces, our experts are always at hand to select the most suitable material, tailor-made for your application. Centrifugal casting provide excellent material properties that are better compared to tubes made of sheet metal. This leads into a longer service life and higher functional reliability under identical process conditions. The benefits are lower maintenance and operating costs.
With Centralloy® 60 HT R, a special alloy is available that is characterized by improved structural strength and excellent creep strain values. This allows operational temperatures of up to 1250°C, which is higher than recommended with all other metallic heat-resistant alloys and materials. The formation of a material-own Al2O3 protective layer with ceramic properties also ensures an optimum resistance to oxidation and corrosion. This enables a particularly long service life and protects the production material from contamination with chromium oxide particles that detach from the inner surface of tubes made of conventional materials.
Learn more about rotary kilns.
What is a rotary kiln?
A rotary kiln is a thermoprocessing plant for continuous heat treatment in the process engineering of bulk materials. The rotary kiln tube is slightly inclined in longitudinal direction in order to bring about a transport of the material inside the tube with rotation of the tube, i.e. from the inlet side to the outlet side.
A rotary kiln is a costly investment that is particularly suitable for continuous operation, which is why rotary kilns are usually operated 24 hours a day, 7 days a week.
What types of rotary kilns are available?
In terms of construction type, a major difference is made between directly and indirectly heated rotary kilns:
The common feature of directly fired rotary kilns is the firing system, which is a burner tube fitted to the hood at the hot end of the kiln that heats the kiln inside with a flame. The production material is in direct contact with the resulting flue gas. Directly heated rotary kilns consist of a welded sheet metal tube and a lining with refractory bricks. Rotary kilns of this construction type are not included in S+C’s product range.
The heat of indirectly heated rotary kilns is transferred from outside to inside via the rotary kiln wall. Indirectly heated rotary kilns allow precisely specified atmospheres, for example oxidizing or defined gas atmospheres (inert or reducing). The metallic tube is made of heat-resistant-steel or special alloys, made from longitudinally welded sheet metal or centrifugally cast tubes, whereby rotary kilns of S+C are exclusively made of particularly resistant centrifugally cast tubes.
An indirectly heated rotary kiln usually consists of the following components:
- Inlet housing, usually just an inlet screw
- Rotary tube (possibly with attachments and installations such as flanges, flippers and dam)
- Discharge housing
- Sealing systems (if necessary for sealing against air, also using sealing gas)
- Drive system(by girth gear or by friction on driven rollers)
- Bearing (traditional with race and rollers)
- Furnace / combustion chamber with refractory lining and heating system (heat is usually provided by gas burners or electrical heating elements)
What is the application of rotary kilns?
Indirectly heated rotary kilns are used in a variety of applications. Examples are the production of inorganic color pigments, calcination of ultra-high purity alumina, reduction of refractory metals, graphite and activated carbon treatment, heat treatment of steel abrasives and the pyrolysis of plastic waste. Rotary kiln applications are increasingly expanding to meet new processing requirements.
Typical processes are thus calcining, pyrolysis, oxidizing and reducing.
Why rotary kilns
made by S+C?
Rotary kilns for the high temperature range.
Industrial Furnace Construction / Thermal process Engineering.
More than 40 years.
Centralloy® 60 HT R, Centralloy® Micro alloys, CrNi steels, nickel-based alloys.
Centrifugal casting, if necessary combined with static cast and forged components.
Machining, assembly, welding.
Full-service partner - R+D, failure investigation, materials + application consulting, fabrication, assembly, commissioning, repair.
Repair service of rotary kilns.
Ensure functional reliability and trouble-free operation.
Repair service of rotary kilns. Ensure functional reliability and trouble-free operation. In order to ensure the continuous production as well as the functional reliability of your rotary kiln made by S+C, we offer the following repair service.
We of S+C, have not only the target to meet the requirements of your centrifugally cast rotary kiln, we also want to give you constantly a good feeling of safety by using our products. Repairs are often more cost-effective compared to the purchase of new rotary kilns and conserve resources due to lower consumption of raw materials. Our service consists of the following operations:
- Examination of the used rotary kiln.
- Evaluation of the results and decision on parts for reuse.
- Cutting of the worn parts.
- Centrifugal casting of new tube segments.
- Machining, preparation and welding of a new tube sections with the existing parts.
- Manufacture and welding of flanges.
- Inspection of the weld seams.
We warm up where others break a sweat.
Innovative stainless steel casting solutions up to 1,250 °C.
Expertise for your products.
We are continuously expanding our expertise in innovative stainless steel products,
helping customers to achieve groundbreaking customized solutions.
Reduce costs with
high-performance materials made by S+C.
We reduce your energy costs and improve your environmental audit.
Heat-resistant nickel/aluminum alloys made by S+C
Together with S+C and our patented heat resistant nickel/aluminum alloys, Centralloy® HTE and Centralloy® 60 HT R, you will take your next step forward towards "Green Manufacturing". The proprietary high-performance material Centralloy® 60 HT R, with which application temperatures of up to 1,250 °C are possible, convinces with its exceptional properties compared to conventional materials.
This optimum material is the industry's most temperature-resistant metallic material for furnace rollers. It is particularly creep resistant and retains its shape even at highest temperatures. Customers who previously used water-cooled furnace rollers in their furnaces switched over to "dry" furnace rollers made of Centralloy® 60 HT R after getting detailed advice of S+C.
35% lower energy costs.
Up to $2.3 million savings per year*
* Model calculation. Furnace-specific benefits must be considered specifically.
Heat-resistant alloys made by S+C.
The optimization of heat-resistant components for a longer service life and better sustainability is now one of the main topics in the equipping of new and existing furnaces. Important aspects in our consulting are operating temperatures, furnace atmospheres, heating, heating curves, product quality, service life expectancy, material selection, etc.
The optimum price-performance ratio is achieved above all by solutions tailored to the individual application.
In the field of heat resistant alloys S+C supplies the following materials:
- Nickel/chromium alloys
- Nickel-chromium-tungsten alloys
- Microalloyed nickel-chromium-tungsten alloys
- Nickel-chromium-tungsten-cobalt alloys
Heat-resistant stainless steel castings made by S+C.
Whether corrosion resistant, heat resistant or wear resistant, our experts will always find the right solution to ensure that your products perform best. In addition, S+C is certified according to ISO 50001:2018 for energy management systems. This means that energy-saving potentials are identified and leveraged in the manufacturing plant, all in the spirit for a more sustainable production, which includes also recycling.
Customers can offer S+C used stainless steel components so that they can be directly returned to the material cycle or can be professionally recycled.
In the area of heat-resistant stainless steels, S+C supplies the following materials:
- Ferritic-austenitic cast steel (duplex)
- Austenitic cast steel (chromium/nickel steels)
- Microalloyed austenitic cast steel
Economic added value
furnace rollers in a heat equlization furnace.
A customer who had previously used water-cooled furnace rollers in his furnaces switched to "dry" furnace rollers made of Centralloy® 60 HT R ,after detailed advice from S+C. The higher initial cost compared to conventional water-cooled rollers paid off in lower operating costs and other benefits: By switching to dry furnace rollers made of Centralloy® 60 HT R (360 mm or 425 mm), energy consumption and thus energy costs were reduced by up to 35% annually.
Based on our customer's entire furnace (capacity 4 million tons/year) and taking the longer service life of our furnace rollers into account (50 to 125%), this results in savings of between USD 1.8 and 2.5 million per year.
The lower energy consumption and the lower raw material requirements for the production of the furnace rollers also have another advantage: both protect the environment, which is of increasing importance for companies that are operating sustainably.
Area Sales Manager - Western Europe | Special Products
Rotary kilns made of Centralloy® 60 HT R at our customer
XERION BERLIN LABORATORIES GmbH.
Special requirements for rotary kilns in the high-temperature range.
Challenge: XERION manufactures electrically heated rotary kilns for the high-temperature range. If the working temperatures reach continuously a range between 1200°C to 1250°C, the requirements on the tubes become particularly high. The challenges on rotary kilns are high temperature stability, good abrasive wear resistance, the requirement for purity of the production materials and the possibility of good machinability / weldability.
Solution: Rotary kilns made of Centralloy® 60 HT R. Due to the excellent temperature stability of this alloy, rotary kilns made of Centralloy® 60 HT R are u. a. particularly suitable for setting up gas-tight plants, e.g. for vacuum or inert gas technology. In addition, build-in parts such as flippers can be easily welded to the rotary kilns, which is not possible with tubes made of mineral glass or ceramics. S+C’s rotary kilns made of Centralloy® 60 HT R centrifugal castings are also far superior to those made of longitudinally welded tubes in terms of service life and dimensional stability, and have proved successful at our customer XERION BERLIN LABORATORIES GmbH since their first use.