Nondestructive Testing service providers

  What is an Alloy? Since metals are insoluble in water, alcohol; they are mixed with other metals in molten state which upon cooling solidifies to a solid mixture called an Alloy. This solid state mixture is also referred as a homogeneous liquid mixture. Alloys are formed by mixing a metal with metal or a metal with a non metal. From the above explanation it is clear that an alloy contains atleast one metal. What are the properties of an alloy? Alloys are harder, less malleable. They possess low melting points, low electrical conductivity. They resist corrosion and actions of acids. What is the purpose of alloying metals? To increase the hardness of the metal To lower the melting points of metals. To resist the corrosion of the metal. To modify the chemical activity of the metal. To modify the colour of the metal. To get good casting of metal. Effects or Functions of Alloying Elements: Addition of small amount of certain metals imparts some special properties like hardness, tensil...

 A study on the couplant effects in contact ultrasonic testing. The primary purpose of a couplant is to provide a suitable sound path between the transducer and the test surface.Ultrasonic Testing couplants usage can be seen here A couplant must effectively wet or totally contact both surfaces of the transducer and the test part. The couplant must exclude all air from between the surfaces as air is a very poor conductor of sound. The couplant fills in and smoots out irregularities on the surface of the part. The couplant aids in the movement of the transducer over the surface in contact testing. The practical couplant must be easy to apply and easy to remove. It must also be harmless to the part surfaces. How to Pick the Right Ultrasonic Couplant for Your Application? Oil or water mixed with Glycerin (2 parts water and 1 Part glycerin) are commonly used couplants. Even wallpaper paste has advantages as couplant. Heavier couplants, such as Grease or heavy Oil can be ...

  Non destructive testing for concrete Non Destructive Testing is the process of detecting the quality without destructing the material or without changing its actual properties. Rebound Hammer is also called as Schmidt hammer or Swiss Hammer or Concrete hammer test. This NDT method is used to detect the strength of Concrete Slab or rock, by identifying the hardness or elastic property. Principle of Rebound Hammer Test. Schmidt’s hammer test is based on the principle of “rebound of a spring loaded mass depends on the hardness of the concrete mass on which the mass strikes”. This rebound distance of the rebounded Plunger mass is noted down in the graduated scale as Rebound number / rebound  index. The graph in the body of hammer is used to found out the respective compressive strength. The concrete with low energy and low stiffness absorbs more energy from plunger and produces a low rebound value on the scale. Objective of Hammer rebound test...

  Welding is a process of joining metals by process of heating.  Most of the weld made are manual. It is possible that the weld may have various defect formation due to parameters of welding and poor workmanship. Why is Welding Inspection Methods  important? Therefore the weld made should be tested for defects and quality of weld metal. To ensure the joint is strong and suitable for the purpose the product is designed for. The Welding inspection methods can be broadly divided into two types Destructive Testing and Non Destructive Testing   Destructive Testing otherwise called as Mechanical Testing. It is a qualitative analysis process, which identifies the qualities like Tensile Strength, % of elongation, Hardness, Toughness, Chemical Content of metal and Micro Structure formed during welding process. But destructive testing cannot be done on all the weld joints made. Instead it is carried out on a sample per lot. Mostly the a...

  LIQUID PENETRANT EXAMINATION (PT) Pentrant Testing is surface defects detection method, the method can be used on any material ( i.e: Ferrous/ non-ferrous, conductive/ non conductive, metals/ non metals) But PT is limited to materials having porous surface or very rough surface. PT can be carried out on castings, raw material, machined faces and weld joints. It is more often used in Austenitic Stainless Steels, where MPI inspection is not practically possible.   Most standards insist that the penetrant materials used, should not contain contaminants that spoil the quality of weld and metals.( contaminants such as Sulphur, Chlorine & halogens )   Penetrant materials are mostly suitable for materials with surface temperature less than 52°C. Therefore the weld has to allowed to cool before carrying out PT test on it. Liquid penetrant testing principle Any PT inspection on elevated temperature (temperature other than 4°C to 52°C), should have special ...

  What is an Eddy Current? Eddy currents are currents that circulate in conductors like swirling eddies (a whirlpool) in a stream. They are induced by changing magnetic fields and flow in closed loops, perpendicular to the plane of the magnetic field. How is Eddy current used in Non-Destructive Testing? It is one of the electromagnetic methods of non-destructive testing. It is used for identifying surface and subsurface defects in conducting materials. Principle of Eddy Current Testing: Electromagnetic Induction is the basic principle of ECT. How is Eddy Current used for identifying a defect? When eddy current is induced to an object/material which is being tested, by varying the electromagnetic field alternatively, there will be a change in pattern of the current flow when a defect is present in an object.   Eddy Current Testing   Properties of Eddy Currents: They are induced in closed loops. They normally travel parallel to the coils windings. ...

 This blog will discuss types of discontinuities that can be evaluated with the ultrasonic testing in NDT method. Discontinuities can be divided into three general categories inherent, processing and service Inherent discontinuities are usually formed when the metal is molten. Inherent wrought discontinuities relate to the melting and solidification of the original ingot before it is formed into slabs, blooms and billets. Inherent cast discontinuities relates to the melting, casting and solidification of a cast article. Usually caused by inherent variables such as inadequate feeding, gating, excessive pouring temperature or entrapped gases. Processing discontinuities are usually related to the various manufacturing process such as machining, forming, extruding, rolling, welding, heat treating and plating. Service discontinuities are related to the various service conditions such as stress, corrosion, fatigue and erosion. During the manufacturing process, many d...