Tag Archives: galvanizing


BTU: Exact setting of strip back-tension – at any position in the processing line

Umlauf Bridles can build up very high back-tension in strip processing lines – even when dealing with thick gages and high-strength grades.

BTU: Exact setting of strip back-tension - at any position in the processing line

Two Umlauf Bridles arranged up and downstream of a stretch-leveler can build up any back-tension

Umlauf Bridles designed by BTU Bridle Technology GmbH can be installed at virtually any position of strip processing lines where they ensure gentle strip transport without any deflection of the strip. Umlauf Bridles can build up strip back-tension exactly where and as high as needed. Also thick strips or strips made of high-strength materials can be handled with ease. The Bridle units have proven highly successful in numerous strip processing applications, such as in pickling, annealing, rolling, side trimming, galvanizing and leveling or, in steel service centers, in slitting or cut-to-length lines.

The Umlauf Bridles“ capabilities are not limited to building up or reducing strip back-tension. They are also employed to decrease residual stresses in the strip, optimize strip flatness and correct rolling effects such as camber. Moreover, they minimize cropping scrap at the head and tail ends as well as side trimmings. The crawler-type Bridle units transport the strip in a most gentle manner without any risk of strip surface damage as their contact surfaces come with an elastic coating.

Michael Umlauf, Commercial Manager of BTU Bridle Technology, sees clear cost advantages for his customers: „Operators of strip processing lines may use our Bridle units at virtually any position of their lines to build up or reduce back-tension in a highly controlled way. Our Bridles provide numerous possibilities to operate strip processing equipment in a most efficient way. As a result, more sellable meters are obtained from every coil.“

Leveling without rollers

In conventional leveling arrangements, the forces required to push the strip forward are almost exclusively generated by the leveler. A disadvantage of such arrangement is the risk of roller slippage which may result in longitudinal scratches on the strip surface. What is more, the drives of leveling rollers are often not powerful enough to handle thicker gage strip or universal shafts may break due to local overloading.

If an Umlauf Bridle is arranged behind the leveler, the strip can be pulled through the leveler in a controlled manner, relieving a major part of the load from the drives of the leveling rollers. The effect of the Bridle unit may even be so high that some of the leveling rollers can be dispensed with or regular drives can be replaced by auxiliary ones. Under certain conditions, it may even be possible to do entirely without driven rollers. The Umlauf Bridles can build up back-tensions high enough to also level thick strips and strip made of high-strength steels. Any damage of the strip surface is ruled out because neither the leveling rollers nor the crawler tracks of the Umlauf Bridle will slip on the strip.

An even greater effect can be achieved by combining two Umlauf Bridles in one application. With one unit arranged before and one behind the leveler, it is possible to apply – in a precisely controlled manner – a longitudinally acting force of several thousand kN on the strip. Through this arrangement, leveling is performed primarily by stretching and only to a minor degree by bending. Actually, stretching may take over up to 90% of the leveling work. It may also be possible to use larger rollers in the leveler, resulting in a marked reduction of residual stresses and hence improved flatness of the strip. Due to the high strip back-tension of up to 6,000 kN achievable by the Umlauf Bridle, it has eventually become possible to continuously stretch-level strip without requiring any leveling rollers. Calculations have shown that this is not only much more economical than conventional stretch-leveling. It also provides a better result.

Scale breaking without conventional bridle rolls

For scale breaking and strip leveling ahead of pickling lines, Umlauf units can be used instead of conventional bridle rolls.

As the Umlauf Bridles guide the strip linearly, i.e. without any deflection, no strain energy is required. This is an important cost factor, especially when dealing with thick strips. Additionally, the tensile strength distribution is more homogeneous as the Umlauf Bridle applies the tensile force uniformly over the entire width of the strip.

Norbert Umlauf, founder and Managing Director of BTU explains: „We installed two Umlauf Bridles in a leveling line in which high-strength steel strip of premium quality in terms of shape and flatness is produced. In that application, our Bridle units build up a strip back-tension of 1,200 kN and adjust the elongation rate with an accuracy of 0.1 percent. The equipment, designed for strips of up to about 4 mm thickness, also reduces strip camber in the process. Additionally, we measure the flatness of the strip in a tension-free state during the running process.“

Background: The principle of the Umlauf technology – more sellable meters per coil

Umlauf Bridles consist of two crawler-type units covered by an elastic coating. One unit is arranged above and one below the strip. They guide and transport the strip linearly, i.e. without any deflection, at different stages of strip processing lines. Thanks to their extreme compactness, they can be arranged at virtually any position in the line.

By applying the force over an area – and not concentrated in one point – any local concentrations of forces or relative movements between the crawler unit and the strip surface are avoided. Therefore, surface damage is ruled out, making this technology highly suitable for delicate strip surfaces.

A single Bridle unit may be used to apply large forces to the strip, for example, in order to pull it through side trimmers or levelers. This aspect is of particular interest especially when processing thick strips. The unit may also be installed to decouple the back-tension of a line section from upstream processes or even reduce the back-tension to „zero“. By reducing strip back-tension to „zero“, an Umlauf Bridle makes it possible, for example, to measure the flatness of the strip without any interfering effects.

As the Umlauf Bridles are arranged within the strip processing line, they build up strip back-tension before the coiler bites the strip head. This significantly increases the usable coil length, in some strip processing lines the yield per coil may be increased by up to 20 m.

The Bridle units may be swiveled through their vertical axis, for example, in order to reduce strip camber and adjust the strip position during side trimming. At cut-to-length lines, they position the strip edge perfectly perpendicular to the shear. The result is an exact, rectangular cut.

About BTU Bridle Technology

BTU was founded in 1985 by Norbert Umlauf who had developed a technology capable of flexibly building up or reducing the back-tension of strip in strip processing lines while adjusting strip travel in a highly precise manner. That technology helped operators of strip processing lines in cold rolling mills or steel service centers to increase the efficiency and flexibility of their operations.

Since then, Umlauf Bridles have been in use all over the world at leading producers of steel or NF metals strip. The Bridles have proven their worth in pickling, hot-dip galvanizing and annealing lines as well as in finishing facilities such as cut-to-length or slitting lines. More than 30 units are in use worldwide. Several new installations are currently underway.

Since 2016, Norbert Umlauf“s sons, Christian and Michael, have taken up active roles in the company, which today is based in Hagen, Germany.

BTU Bridle Technology GmbH & Co. KG
Christian Umlauf
Sedanstraße 41
58089 Hagen / Germany
+49 2331.34008-00
+49 2331.34008-02

Regina Reinhardt
Dennewartstraße 25-27
52068 Aachen / Germany


New patenting furnace saves ten percent on energy

Resource-saving wire production: New measuring technique enables control of furnace atmosphere.

New patenting furnace saves ten percent on energy

Patenting furnace – side view

At Wire 2014, Wire Körner will exhibit the new series of directly heated patenting furnaces fitted with automatic furnace atmosphere control and burner with heat recuperation. With these new energy-saving furnaces, Wire Körner further expands its range of efficient and eco-friendly heat treatment plants for wire. Based on his good experience with the furnace, a German customer has already ordered an extension to the existing unit.

The first unit of this new furnace generation has been in operation for two years. Designed for a throughput of 2,000 t per hour, it processes wire in diameters from 1.5 to 5.5 mm. The plant expansion is expected to be commissioned in April 2014.

By implementing a wide array of innovative features, Wire Körner has increased the efficiency of patenting furnaces for wire and achieved savings on energy consumption of some eight to ten percent compared to conventional furnaces. The very first furnace of this new generation has already been in production for more than two years.

With an innovative sensor, Wire Körner has for the first time realized a system for controlling the furnace atmosphere. Via the furnace control system the air/combustion gas ratio is exactly set within a specified range. The high control precision and stability of the gas/air ratio makes the new furnaces superior to Pre Mix systems. In addition to the savings on energy, controlling the air/gas ratio keeps NOx emissions low and prevents decarburization of the wire. The furnace temperature is adjusted with a precision of +/- 2 °C.

A central recuperator installed in the waste gas duct preheats the combustion air for the high-speed burners to 200 – 250 °C, while reducing the waste gas temperature at the stack from 600 °C to 400 – 500 °C. Already in the preheating zone Wire Körner exploits the thermal energy of the waste gas to heat up the wire entering the furnace. This reduces the energy demand for preheating.

In contrast to previously used burners, the high-speed burners employed by Wire Körner can be adjusted in several steps. This ensures that the burners consume exactly the amount of energy they need, not more.
Wire Körner has brought down heat losses via the furnace wall by optimizing the layout of the wall, among others by means of insulating ceramic fibers. An additional coating ensures a long service life of the furnace wall even under conditions of high CO contents and high flow velocities. An additional, 2.5-cm-thick Microtherm® insulating layer behind the refractory brick lining brings down heat losses even further.

The furnace is directly heated. The heat is transferred into the wire by convection, at flow velocities of up to 120 m/s. This provides much better energy efficiency than heating by radiation.

Wire Körner at Wire 2014 in Düsseldorf, April 7 to 10, 2014:
Hall 9, booth F 51
Bildquelle:kein externes Copyright

About Wire Körner

Wire Körner GmbH designs and manufactures plant and equipment for the complete process chain of wire and narrow strip heat treatment, from the drawn wire through to the finished end product. The range of heat treatment plants comprises bell-type, chamber and channel furnaces for patenting, annealing, galvanizing, hardening, tempering and chemical treatments. The company provides design, engineering, manufacture, erection, commissioning and after sales service. Wire Körner maintains a worldwide network of branches and licensees.

Wire Körner’s numerous quality and efficiency-enhancing innovations regularly attract the industry“s attention. For example, the recently developed wire patenting furnace with an innovative atmosphere control system achieves substantial energy savings, or the recuperative immersion burner for ceramic galvanizing furnaces has been designed for very long service lives, just to mention a few examples.

Wire Körner is a company of the Körner Group, which was established in 1928. Thus the company builds on more than 80 years of experience in industrial furnace technology and auxiliary equipment. Within the group, Zink Körner GmbH specializes in plants for piece galvanizing. TVT Kordt GmbH develops plants for thermal process technology, with a focus on industrial furnaces for the heat treatment of steels, special steels and non-ferrous metals.

Wire Koerner GmbH
Peter Kordt
Profilstraße 9
58093 Hagen/Germany

Regina Reinhardt
Süsterfeldstraße 83
52072 Aachen/Germany


Zink Körner starts up high-efficiency galvanizing plant in Russia

Eco-conscious batch galvanizing: Follow-up order from Tochinvest demonstrates successful cooperation

Zink Körner starts up high-efficiency galvanizing plant in Russia

The new furnace is designed for an annual production of 80,000 t.

In 2012, Tochinvest Zinc, a leading manufacturer of steel parts in Russia, installed a new hot-dip galvanizing furnace from Zink Körner. Last February, Zink Körner received the FAC for the plant.

The successful operation of the first galvanizing shop was reason for JSC Tochinvest to establish the Tochinvest Zinc division in 2011. This event also marked the kick-off of a new project, namely the construction of a further galvanizing plant in Ryazan, some 100 km to the southeast of Moscow.

For this project, Zink Körner supplied the galvanizing furnace, complete with the housing, and the drying furnace. The tank is 13.0 m long, 1.8 m wide and 3.2 m deep. The new facilities were started up at the beginning of 2013. With trial operation running smoothly, already in February Tochinvest issued the Final Acceptance Certificate for the new plant.

Tochinvest Zinc specializes in the manufacture of crash barriers and bridge railings. The company also offers job galvanizing services for steel parts as diverse as lamp posts, traffic signs, barriers and customized steel structures for use in road construction.
The new furnace can galvanize up to 15 t/h. Assuming three-shift operation during 250 days of the year, Tochinvest Zinc will be able to produce 80,000 t annually. This makes Tochinvest Zinc the most productive galvanizing plant in Russia.

Already in 2007, Tochinvest, a leading manufacturer of steel parts in Russia, had built a hot-dip galvanizing plant. Also for that plant, Zink Körner had supplied the galvanizing furnace, including the housing, and the drying furnace. That furnace is 7.0 m long, 1.5 m wide and 2.5 m deep. Right from the first day of operation, the galvanizing quality had been in compliance with the Russian GOST 9.307-89 standard and the international standard ISO 9001:2000.

The recently built furnace features flat flame burners of the FL 20/50 type, which Körner developed specifically for batch galvanizing. These burners use natural gas as fuel, which is available at relatively moderate cost. Their design allows them to provide the same smooth and mild heating as previously only achievable by electrically heated furnaces.

The burners achieve an efficiency of 75 percent. This makes Zink Körner a market leader also in terms of energy efficiency. Unlike burners commonly used in the past, they operate in a modulating mode that makes them infinitely adjustable within a range of 1:10.
Diffusor plates mounted on the burners direct the gas flow along the inner furnace wall. This produces a combination of radiant and convective heat, which has the positive effect that a high input of heat into the liquid zinc is achieved at relatively low furnace temperatures.

Throughout furnace operation, the output of the burners is infinitely adjusted to the throughput of the furnace. Thus the temperature drop in the zinc bath caused by the dipping of a new batch is minimized. Another positive feature is that the furnace always consumes just the amount of energy needed in a certain situation. This regulating mode also avoids abrupt temperature changes, which otherwise would cause strain in the galvanizing tank structure. Thanks to these features, furnaces from Körner achieve long service lives.

Bildrechte: Zink Körner

About Zink Körner

Zink Körner GmbH designs and manufactures the complete array of hot-dip galvanizing equipment for bulk material, tubes and pipes, miscellaneous small parts and centrifugal parts.

The supply range encompasses complete galvanizing plants, including pretreatment and handling equipment. The company provides design, engineering, manufacture, erection, commissioning and after sales service. Zink Körner maintains a worldwide network of branches and licensees.

Zink Körner has launched many pioneering developments during its company history. For example, as early as at the beginning of the 1970s the company built the first automated centrifugal galvanizing plants, which have markedly enhanced the quality of the end products and the energy efficiency of the galvanizing process. The company took another innovative move when it developed dedicated burner technology for hot-dip galvanizing applications.

Zink Körner is a company of the Körner Group, which was established in 1928. Thus the Group builds on more than 80 years of experience in industrial furnace technology and auxiliary equipment.

Within the Group, Wire Körner GmbH designs heat treatment equipment for wire and narrow strip. TVT Kordt GmbH develops plants for thermal process technology, with a focus on industrial furnaces for the heat treatment of steels, special steels and non-ferrous metals.

Zink Körner GmbH
Peter Kordt
Profilstrasse 9
58093 Hagen / Germany
49.2331.800 6-0

Regina Reinhardt
Süsterfeldstrasse 83
52072 Aachen /Germany