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Hydromechanical Descaling

The increasing quality requirements of steel products, stainless steel products, copper products, aluminum and forged products simultaneously increase the requirements for the descaling process. In order to meet these stringent requirements today and in the future, hydromechanical descaling is widely used in the production of high quality hot-rolling products.

Hauhinco develops turnkey hydromechanical descaling systems for scale-free results of hot-rolled products. Many decades of practical work experience by our employees in descaling as well as in water hydraulics in the field of pump-, valve- and system-technology in a large number of applications provide the basis for the development of our customized solutions.

Efficient descaling systems from a single source

At Hauhinco the high pressure pumps, valves, descaling valves and components as well as the entire descaling system engineering come from a single source. We know the particularities involved in the descaling of rings, blocks, rods and pipes, slabs and billets as well as sectional steels and the related high quality requirements for their production. In addition to the high quality, Hauhinco provides for a large number of additional advantages and savings with an efficient and intelligent system design as well as by low maintenance and operating costs.


Why descaling?

An efficient descaling system is indispensable in all hot rolling mills because scaled surfaces interfere with the forming process for several reasons:

  • Scales contaminate the environment of the rollers and frequently cause problems and disturbances in the rolling process.
  • Rolling-in effects on the surface lead to the formation of cavities and thus to a lamination in the further forming process.
  • Rolled-in scales must be removed before any subsequent cold forming by expensive and work-intensive processes such as pickling, brushing or mechanical machining.
  • If a machined surface is required, then up to 20% of material must be removed, depending on the coat thickness of the scales.
  • A scale-free surface protects tools and materials.

How does scale occur? What are the elements of scale?

Scale occurs if the oxygen partial pressure in the atmosphere exceeds the low decomposition pressure of the oxides produced. For temperatures up to approx. 560° Celsius, blank steel surfaces show the typical annealing colours. For temperatures above 560° Celsius, a so-called oxide coat forms on the steel surface, also known as scale. In addition to iron oxides, also mixed oxides form from existing alloy and accompanying elements, which significantly influence the adhesion of the scale to the steel surface. In particular, elements such as silicon, nickel and copper lead to a significantly higher adhesion of the scale. Naturally, the furnace temperature and the steel grade also have an influence on the scale and the adhesion of the scale.

Hydromechanical Descaling:
Always at the correct pressure, angle and distance

The hot-rolling process is one of the forming processes subsequent to the ingot casting or continuous casting processes. For this purpose, the cooled-down rolling material in the raw material stock is reheated to temperatures of approx. 1,250° Celsius, that is, above the recrystallisation temperature. Just after leaving the furnace the red-glowing slab is descaled, i.e. freed from the oxide coating formed in the glowing state. Hydromechanical descaling is particularly suitable for this purpose. For hydromechanical descaling a water jet in a defined form and with the correct volume flow and pressure is directed at a defined spraying distance and work angle to the surface of the workpiece.

The water or the water jet plays the decisive role in descaling. Due to the high kinetic energy of the water droplets, the scale is broken up, detached from the material surface and then removed from the workpiece. The effectiveness of the descaling process depends significantly on the impact (contact force) and the spraying characteristics, with which the water hits the surface of the scale.

The objective here is always:

  • to remove the scale completely
  • as well as to achieve a high and even product quality

For this efficient type of high pressure descaling, Hauhinco provides turnkey plant and system solutions with own water-hydraulic components.

Intelligent system engineering provides for efficient descaling systems

With decades of water hydraulics experience and knowledge in the area of high-pressure pumps, valves and system engineering, Hauhinco is your partner for hydromechanical descaling systems. From individual descaling pumps and valves to complete turnkey descaling systems with automation and workpiece manipulation, Hauhinco always has the perfect solution for your requirements. The experience from a large number of projects realised, in combination with Hauhinco's own pumps, valves and components, allows the development of optimised and energy-efficient descaling systems. The process-related system engineering in dependence of the actual material and process parameters is important. With an optimal nozzle design, Hauhinco descaling systems are future-proof in modernisation projects and also for complete new systems.



Hauhinco descaling systems comprise the following main components:

  • Filter technology
  • Pressure supply
  • High pressure piping made of stainless material (1.4571/1.4541)
  • Nozzle bar
  • Descaling box / descaling equipment
  • Automation

Reduction in maintenance costs

For system operators, efficient maintenance is a significant competitive factor. A maintenance measure is always efficient if it is carried out at defined intervals and at an optimum point in time. Maintenance on all Hauhinco products and systems can be executed easily and fast during shutdowns, e.g. during summer or winter shutdowns.

Additionally, the design of the Hauhinco descaling system does not include any pressure accumulators. By not using pressure accumulators, annual maintenance costs can be reduced by up to 50%. The advanced technological development state of our descaling systems provides the basis for the production of high-quality products and the long-term reduction in life-cycle costs. This sustainably assures the competitiveness of your company.

Contact

Udo Hertel
Engineering Solutions
Descaling
Phone: +49 2324 705-164
udo.hertel(at)hauhinco.de

Steve DeMar
Engineering Solutions, Hauhinco LP
Telefon +001-724-789-7050 ext. 316
sdemar(at)hauhinco.com