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Abstract

Content

Introduction

At the present time, with a rather difficult economic conditions, the market of metallurgical industry of one of the products is the rolling production. To ensure high quality of hire need to efficiently and economically remove the scale from the surface. Scale formed on the castings and in the rolling process by reacting under heating the product surface with ambient air.

Scale – a product of high-temperature oxidation of metal or gas corrosion. On the final semi-finished steel it is usually a scale thickness of less than 20 microns (usually 7–15 microns). The outer layer scale usually FeO (hematite), the inner layer adjacent to the metal, – Fe2O3 (wustite). On the surface of alloyed steels formed complex oxides (NiO * Fe2O3, FeO * Cr2O3, and others.) [4].

An urgent problem is to find solutions for safe, effective removal of scale from a metal with low energy consumption.

Cтроение слоев окалины

Figure 1 - The structure of the layers of scale

1. Theme urgency

The problem of cleaning the surfaces of large products (in my case, large diameter pipes) from scale, rust, dirt, etc. before the final operations, such as applying different coatings, painting enterprises are facing a long time.

The presence of scale on the workpiece and reduces the rolled sheet grade products cause additional material costs, significant additional labor and reduces production costs. Scale on the physical properties different from the parent metal, however, it complicates further processing of the product and makes practically impossible processes such as pressing, stamping, coating on the metal surface, and reduces its quality and stability when using the finished product [6].

2. Goal and tasks of the research

Completed experimental and experimental studies of a number of scientific research organizations have shown the effectiveness of pulsed jets compared to the same fixed parameters. Results achieved generating devices, pulsed jet developed in the Donetsk National Technical University, on the destruction of the coal array gives an indication of the possibility of using them for the destruction of the scale.

Optimization of the parameters of these devices will achieve lower power consumption to perform this operation.

To achieve this goal the following tasks:

  1. Analysis of the existing methods and means for the destruction of the scale;
  2. Development of a mathematical model of the processes in the mud pulse setting;
  3. Modeling processes;
  4. Development of recommendations for the definition of rational parameters hydropulse method of cleaning metal from dross.

3. Hydropulse way to clean the pipes from scale

The advantage of the purification method hydroimpulse rolled economically compared with other methods of purification is to lower energy consumption. Note also other advantages hydroimpulse purification method as shape retention and surface roughness of machined (no removal of the base metal); environmentally friendly techniques (closed loop operation); fire safety and explosion safety.

The result of years of work employees DonNTU in the development of devices has been the creation of hydropulse generator pulse jets (GPJ) [8].

Принципиальная гидравлическая схема генератора импульсных струй

Figure 2 – Schematic hydraulik diagram of the generator of pulsed jets

GPJ consists of a main hydro pneumo accumulator (GPA) 1, drive 2, executive body 3, the control valve 4, and 5 additional GPA.

Figure 3 – The principle of operation of GPJ
(animation: the number of frames – 6, the number of repetitions in not limited, size 25,0 КB)

Conclusion

Obtaining a priori information gives an indication of the possibility of using GPA to improve hydraulic method of cleaning rolling of scale.

In writing this essay master's work is not yet complete. Final completion: December 2015. The full text of work and materials on the topic can be obtained from the author or his manager after that date.

References

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  2. Марочник сталей и сплавов : [Электронный ресурс]. – Режим доступа: http://www.manual-steel.ru/term52116.html
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