Welded joints

To prepare simulated free-of-noise 3D images of a complex body For this target the image of an internal pore in the real welding joint with extracted noise was used. The ray tracer model was applied for the simulation of five projections of the selected image. 

Nondestructive testing techniques for welded joints usually include visual, radiographic, magnetic particle, liquid penetrant, and ultrasonic testing methods. Of interest in this paper is the radiographic testing (RT) technique. 

It allows to save the radiographic film in computer for an eventual digital processing. In our case welded joints radiographic films are digitized in 256 gray levels. 

We present in this paper an invariant pattern recognition method, applied to radiographic images of welded joints for the extraction of feature vectors of the weld defects and their classification so that they will be recognized automatically by the inspection system. 

We present in table 1 and table 2 the results of the application of tlie DHT on two edge images of two welded Joints radiographic films containing a lack of penetration in the first and a... 

Figure 3 A radiographic image of a welded joint (defect lack of penetration), a Original image, b Edge image (only the defect is maintained).

Szydiik W Economic - technical test conditions presented hy CJD and RTG for welded joints. Materials of the 21 st. National Conference on Non-destroying methods, Szczyrk 1992, p. 127-132. 

GOST 23055-78. Russian standard. "Classification of welded joints by results of radiography testing and corresponding production forms and records". 

The first stage in any inspection is to generate a proeedure which is specific to the component being examined in many instances, such a procedure will be based on a standard such as CEN J5I/-EN1714 Non-Destructive Testing of Welds - Ultrasonic Examination of Welded Joints . CamuS incorporates a tool ProcGen to provide assistance with this task. 

A. Gurvich und G. Passi Comparison of non automated systems for the acoustic nondestructive testing of welded joints, Defektoskopiya, 1991, No 2, p 3-9 (in Russian)... 

Often repair of the found defects is extremely undesirable. Therefore, for discontinuities which are potentially hazardous, it is very important to have a onfirmation of their stability. In this case monitoring of potentially hazardous discontinuities is well supported by automated UT systems and based on the comparative analysis results, the actual data from examination of a section of the welded joint of a (hydrogen) separator are given in Figures 5,6. 

Figures 5 presents the results of scanning of the same section of a welded joints with approximately one year interval. Figures 6 shows the same section in the mode of representation of the amplitudes of UT signals reflected from discontinuities in the...

Fig.5,a. The actual data from examination of a section of the welded joint of a (hydrogen) separator. 

The pulser/receiver HILL-SCAN 30XX boards satisfy DIN 25450. Typical applications are ultrasonie imaging systems for nuclear power stations and for aircraft, material characterization, transducer qualification, replacement of portable flaw detectors (inspections of welded joints), inspection of new materials, measurement systems with air eoupling. ... 

To provide the better inspection of welded joints the parameters of crawlers, working in low temperatures up to - 40°C, and X-ray television introscopes are improved, etc. 

Besides large-diameter pipes, ultrasonic testing is used for checking the welded joints of drill bits, components of wind-driven electric plants, welded joints of light alloys and non-metallic materials, for an integrated inspection of various objects. A range of training aids developed at the Institute allows the operators to be trained effectively. 

In the field of radiation methods of control, development work was performed in order to create the X-ray detectors with a low content of silver. X-ray TV systems with improved performance for automatic interpretation of the X-ray TV images, portable radiometers and dosimeters, creation of portable equipment for radioscopy of the welded joints of pipelines, etc. 

In order to control the tightness of welded joints on various products and structures, a range of units and complexes for control of pipes, pipelines, tanks, protective casings were developed, in particular, a set of put-on vacuum chambers for sheet structures. 

Thus, the metallurgy of welds, comprising the weld metal and surrounding heat-affected zone, is influenced not only by the composition of the materials involved, but also by the welding process, the specific procedures for applying the process, and the heat-transfer characteristics (deterrnined by material, mass, and geometry) of the welded joint (9—12). 

Stress and Distortion. The forces acting on a stmcture are transmitted through the welded joints that is, the joint is subjected to simple tension (or compression), bending, shear, or torsional stresses, or to combinations of these stresses owing to combined loading situations. Weldments must be of a proper size, length, and location to withstand the loads imposed during service. 

In gas metal-arc, also called metal inert gas (MIG) welding, the arc is stmck between the workpiece and a metal electrode that is consumed as it is transferred in the form of molten droplets across the arc into the weld joint. Using a predominantiy argon shield gas, the droplets are transferred with Httie radial dispersion. Using pure helium, on the other hand, the droplets are larger and have more of a tendency to spray radially from the arc s axis. 

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