Non-destructive tests of weld commonly used in industries are summarised in Table 10.1. They include Visual examination, Dye-penetrant inspection, Magnetic-particle inspection. Radiography and ultrasonics. The last three tests are more common and will be described in the following paragraphs. 10.3.1 Magnetic Particle Inspection Magnetic particle inspection, as the name implies, requires the use of a […]

Bend tests on corner, but, lap and tee welds are shown in Fig. 10.8(a). Final bend for free-bend У//////Л I/////K Initial bend for free-bend specimens Fig. 10.8 (b) Typical fixtures for free bend testing (top) and guided bend (bottom). (for SI equivalents U. S. customary values) 10.2.1 Procedures of Preparing Test Sample Procedure for butt […]

Tension-Shear Test. The tension-shear test is the most widely used method for determining the strength of resistance spot welds. It is also used for evaluation of weld schedules for fer­rous and nonferrous alloys. The test specimen in Fig. 10.4 is made by overlapping suitable size coupons and making a spot weld in the center of […]

All types of welded structures from jet engines to metal trash cans are expected to perform some function. The joints comprising these structures must possess some service related capa­bilities. To test that the required function will be met some tests are conducted. The ideal test is the observance of the structure in actual practice. This […]

A welded specimen may corrode uniformly over its entire surface (Fig. 9.8a). The weld metal may corrode less than the base metal (Fig. 9.86) or more than the base metal (Fig. 9.8c) de­pending upon the composition of weld metal during solidification. In addition the base metal may corrode adjacent to weld metal in the HAZ. […]

Different types of corrosion common in metals and alloys are shown in Fig. 9.6. Some of these are related to welds. Their causes and remedies will be briefly discussed in the following para­graphs. i. Selective leaching j. Intergranular k. Stress cor — l. Corrosion rosion cracking fatigue Fig. 9.6 Types of corrosion commonly found in […]

This term is used to describe the oxides and other nonmetallic solid materials that are entrapped in weld metal or between weld metal and base metal. Slag inclusion may be caused by contamination of the weld metal by the atmosphere, however, they are generally derived from electrode-covering materials or fluxes employed in arc welding operations; […]

As the welded joints are finding applications in critical components where the failure results into a catastrophy, the inspection methods and acceptance standards are increasing. Acceptance standards represent the minimum weld quality and are based upon test of welded specimens containing some discontinuities, usually a safety factor is added to yield the final acceptance standard. […]

As with other arc welding procedures, a good MIG/CO2 welding procedure starts with correct edge preparation and joint fit-up. The joint surfaces must be free from rust, scale grease, oil, paint and other foreign materials. For making full penetration joints by welding with spray transfer technique from both sides, it is necessary to gouge out […]

SAW, semi-automatic and fully-automatic, is used for making butt joints in the downhand position and for making fillet welds in T and lap joints in the downhand and horizontal-verti­cal positions as shown in Fig. 8.27. Normally this process cannot be used in vertical and overhead position, because of the difficulty of preplacing the flux. It […]