Sunday, July 28, 2013

Central Process Laboratory ( Pakistan Steel ).


Central Process Laboratory of Pakistan Steel provides an array of material test  methods help select raw materials, evaluate production processes, investigate root cause of any failure and verify the quality of end products for customers satisfaction.

Process testing laboratory is equipped with the essential testing facilities mentioned below:

   Spectrometric Analysis.
   X-Ray Fluorescence Spectrometric Analysis.
   Chemical Analysis.
   Instrumental Analysis.
   Refractory Physical Testing.
   Cement and Concrete Testing.
   Lubrication Oil Testing.
   Water Testing.
   Mechanical Testing.
   Non-destructive Testing.

 Few of the test facilities may be discussed as under:

 Spectrometric Analysis.
An electrical arc is passed through a metal sample, under an argon atmosphere, heating and exciting the atoms within the sample of the material.
While discharging energy the atoms give off a characterstic wavelength of light that is detected and measured to obtain an accurate weight percentage of the elements like Carbon, Silicon, Manganese, Phosphorous and Sulphur etc. present in the steel sample.

To keep harmony in fast pace of production cycle and quality requirements, a similar  spectrometer is provided in express laboratory of steelmaking department to get  prompt analysis of pig iron (hot metal), ready steel and cast steel samples.

X-Ray Fluorescence Spectrometric Analysis.
XRF is a proven technique for material analysis in a broad range of applications.
This is performed for quantitative analysis of major, minor, and trace elements in Rocks, Minerals, and Meteorites by using Wavelength-Dispersive X-Ray Fluorescence Spectrometry.

A stable atom comprises a nucleus and the electrons orbiting it. Orbiting electrons are organized into shells: each shell is made up of electrons with the same energy. When a high energy incident (primary) X-ray collides with an atom it disturbs this stability. An electron is ejected from a low energy level (eg K shell: see diagram) and a space is created. As a result an electron from a higher energy level (e.g L shell) falls into this space.

The difference in energy produced as the electron moves between these levels is released as secondary X-rays which are characteristic of the element. This process is called XRF.
Each of the elements present in a sample produces a unique set of characteristic x-rays that is a “fingerprint” for that specific element. XRF analyzer determines the chemistry of a sample by measuring the spectrum of the characteristic x-rays emitted by the different elements in the sample when it is illuminated by x-rays.   

Ultrasonic Testing.
Ultrasonic Test is used to find internal and external defects or to measure wall thickness discontinuities in materials and mechanical parts. The process is nondestructive, which means the test item is not damaged during testing.

The Ultra sound testing’s are also performed on large equipments/ vessels like 1300 Tonne  Mixer and 130 Tonne LD-Converter at site during capital repairs to check the soundness of equipments to continue onward operation.

Metallographic analysis.
.Metallographic analysis is performed with optical microscopy, electron microscopy, and X-ray diffraction to identify and characterize different crystalline phases and other critical materials properties that are invisible to the naked eye.

The execution of metallographic analysis enables very precise analysis of metallographic elements, such as: shape and size of crystal grains, orientation of crystal grains, length and type of micro cracks, extracted carbides, non metallic inclusions and other material defects. All these elements significantly affect the desired mechanical characteristics of the final products.

Metallographic analysis helps in developing solutions to identify the root causes of failures of materials and improve the integrity of the production processes.  

Mechanical Testing Facilities:-

Electrically operated analogue Tensile Testing Machine is used for testing tensile strength and elongation of ferrous and non-ferrous materials in Pakistan Steel. 

Notch toughness (Charpy v notch test) is the ability that a material possesses to absorb energy in the presence of a flaw. The quantitative result of the impact test, the energy needed to fracture a material can be used to measure the toughness of the material and the yield strength.

This test is used for testing building and construction materials used in the construction of pressure vessels, bridges and to see how storms will affect engineering materials used in building.

Hardness is related to the strength of a material and is a measure of a material’s resistance to plastic deformation by scratching or indentation.

Mechanical testing facilities at central laboratory of Pakistan steel encompass Analogue Brinell, Rockwell and Vicker hardness tests as shown above.

Bend test.
A bend test is used to determine whether a specific piece of metal in query will break or fracture under pressure. The bend test essentially measures a metal’s ductility. Ductility defines how easily a metal can bend without breaking. The higher the ductility of a metal, the more it can bend without breaking or becoming deformed from its original shape.

By performing regular tensile and bending tests along with metallographic test for uniform crystallized structure, the favorable mechanical properties of products are controlled and conformity of required standards are guaranteed.

More accurate & computer controlled mechanical testing instruments have been developed and implemented in advanced steel production plants, tied with testing accuracy and  higher quality products demand. Up-gradation of above devices, especially mechanical testing instruments may be deemed with future revamping of steel making and rolling facilities in Pakistan Steel for acquiring greater accuracy in testing facilities of future superior quality products demand.

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