Eddy Current Testing is a nondestructive method of locating discontinuities in a product. Signals can be produces by Discontinuities located either on the external or internal surface of the tube or by discontinuities totally contained within the walls. Testing is usually performed by passing the tube lengthwise through a coil energized with alternating current at one or more frequencies. The electrical impedance of the coil is modified by the proximity of the tube, the tube dimensions, electrical conductivity and magnetic permeability of the tube material, and metallurgical or mechanical discontinuities in the tube. During passage of the tube, the changes in electromagnetic response caused by these variables in the tube produce electrical signals which are processed so as to actuate an audio or visual signaling device or mechanical marker which produce a record.
In optical Emission Spectroscopy Technique, energy of spark, formed between sample and electrode, caused the electrons in the sample to emit light which is converted into a spectral pattern. Detectors (photo-multiplier tubes) measure the presence or absence of the spectrum extracted for each element and the intensity of the spectrum to perform qualitative and quantitative analysis of the elements. We adapt advanced Magellan optical emission spectrometer made by Quantron which is pioneer a German company. The machine is composed of optical system and equipped with powerful functions, windows and calibrating systems. The optical emission spectrometer has merit of good stability, high precision, low limit of inspection and good accuracy. It is the only vacuum spectrometer with channel photomultipliers, digital plasma generator, unlimited single spark and time resolution and high-resilient, low-maintenance spark stand with co-axial argon leadership. Extremely low-maintenance systems and consistently tailored to specific software requirements underline the exceptional quality of this unconditional high-end product for elemental analysis in the metal producing and processing industry.
These tests cover the tension of metallic materials in any form at room temperature, specifically; the methods of determination of yield strength, yield point elongation, tensile strength, cognition, and reduction of area.
Tension tests provide information on the strength and ductility of materials under uni-axial tensile stresses. This information may be useful in comparisons of materials, alloy development, quality control, and design under certain circumstances.
Testing Machines: Machines used for tension testing shall conform to the Standard requirements. The forces used in determining tensile strength and yield strength shall be within the verified force application range of the testing machine.
Yield stress has been calculated by the following methods through tensile test:
Optical Microscope has been applied for measuring both Grain Size and Inner Grooved Tube dimensions. Grain Size tests cover the measurement of average grain size and include the comparison Procedure, planimetric (or Jeffries) Procedure, and the intercept Procedures. This test may also be applied to nonmetallic materials with structure having appearances similar to those of the metallic structure. Methods for Determining Grain Size 1- Comparison Procedure: The Comparison Procedure does not require Counting of either Grains, intercepts, or intersections but, as the name suggests, involves comparison of the grain structure to a series of graded images, either in the form of wall chart, clear plastic overlays, or an eyepiece reticle.There appears to be a general bias in that comparison grain size raising claim that the grain size is somewhat coarse that is actually is. 2- Planimetric Procedure: The planimetric method involves an actual count of the number of grains within a known area. The number of grains per unit Area is uses to determine the ASTM grain size number. 3- Intercept Procedure: The intercept method involves an actual count of the number of grains intercepted by a test line or the number of grain boundary intersections with a test line, per unit length of test line, used to calculate the mean lineal intercept length.