Why Multi shot should be conducted for Radiography Examination..?

Abstract

Ultrasonic pulse echo method is approved for planar defect in the weld joint against radiography examination. The most important point in this evaluation is planar defects are effectively traced in radiography. Due to its excellent weldability, carbon steel is suitable for submerged arc welding. Ultrasonic and Radiography inspection is conducted for weld joint. During radiography method, planar defect (Lack of fusion) is detected and as verification ultrasonic pulse-echo method is also conducted to grasp planar defect. Primarily a demerit in radiography is shown as plus point in ultrasonic method. Secondarily, Lack of fusion is very common type of defect in weld defects. Lack of fusion is not notice as weld defect, as they are characterized as planar defect. As a final point, lack of fusion is not noticed by radiography examination, and may probably determine by ultrasonic method. The merits of Ultrasonic evaluation over X-ray Radiography inspection are discussed in these studies. Radiographic Testing (RT) or industrial radiography is a nondestructive testing (NDT) method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation (high energy photons) to penetrate various materials. Principle of radiography is differential absorptionand X-ray radiography can be used as source for detection of defectSince the amount of radiation emerging from the opposite side of the material can be detected and measured, variations in this amount (or intensity) of radiation are used to determine thickness or composition of material. Penetrating radiations are those restricted to that part of the electromagnetic spectrum of wavelength less than about 10 nanometer. Radiography defects such as planar cracks are difficult to detect using radiography; hence Ultrasonic is the preferred method for detecting this type of discontinuity.Ultrasonic pulse-waves of short wave length with center frequencies [3] ranging from 0.1-15 MHz and occasionally up to 50 MHz are launched into materials to detect internal flaws or to characterize materials.Radiography and ultrasonic inspection are the two generally non-destructive methods used in these investigations Non-destructive inspection methods that can [1] detect embedded flaws that are located well below the surface of the test part. Neither method is limited to the detection of specific types of internal flaws. In order to evaluate the stability of a casting component, the shape of a defect inside it is discriminating for the evaluation and acceptance criteria which shall be adopted. Defect shape is usually classified in two types; in volumetric defects, which the ratio between height and width is next to unity, and [7] in planar defects, whose width is indeed, very small with respect to the height. Radiography capability allows the inspection of internal mechanisms and enhances the detection of cracks and planar defects by manipulating the part to achieve the proper orientation for flaw detection. Sample preparation Surface preparation of weld According to the American Iron and Steel Institute (AISI) standards the series of steel used in this study is 10XX. So that low carbon steel contains [8] about 0.1%Carbon and microstructure consists of Pearlite and ferrite. Due to its excellent [9] weldability, sub-merged arc welding is used to join two carbon steel pieces. Typical uses of carbon steel are connecting rods, automobile body panels etc. The complete surfaces of the welds are examined by X-ray. It has to be adequately free from irregularities that may mask or interfere with the X-rays.