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Discontinuities in Ultrasonic Testing in NDT

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 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...
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NDT on Shafts

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  Non Destructive Testing,NDT on Shafts is considered essential , because the shafts are mostly made as load bearing structures, any defects such as cracks will propagate more during acting of load and eventually will cause failure. The most possible defects in shafts are Cracks and Pipes , which is shown below The Non Destructive methods preferred for defect detection on raw material shafts are Ultrasonic Testing, Magnetic Particle testing / Eddy Current Testing / Magnetic Flux Leakage method. We have not discussed about other NDT methods such as Liquid Penetrant testing & Radiographic testing because for raw material inspection. These methods will be cost effective for raw material testing  ( i.e. most costly and labor intensive, also there is possibility of missing out the cracks in radiography testing due to orientation of crack ) The Defect wise identification method is given as below  , Internal Defect ( Piping ) – Ultrasonic Testing Surface Defects  (C rac...
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Standards for Welding Positions

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  Standards for Welding Positions : It is very important for the Weld Inspector  to know the position , or location of a joint relative to the horizon, because it may determine what welding process, methods, and techniques can be used. Welding is usually easiest when the welder can work on a joint located on a flat, horizontal surface, such as on a table or bench. However, joints in the field may be located in a variety of positions relative to the welder and to the horizon, as shown below.  1)  Welding positions – AWS D1.1, European Welding Standard EN 287 – 1, ASME IX: 2) Welding Positions – Butt, Fillet and Piping Welds: Flat Butt Weld Position – 1G In this position, the axis line of the weld must  not incline more than 15°  from the horizon and the face of the weld must be on top. Welders often refer to the flat-position welding by the nonstandard term  downhand welding. Horizontal Butt Weld Position – 2G In this position, both plates are perpendic...
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