Weld defects laminations

Welding Defects Visual, radiographic and/or ultrasonic Indications. Any welded joints. Basic welding problem laminated steel can cause trouble. Electrode manipulation. Control of welding speeds, procedures, careful inspection and nondestructive testing to locate defects for cutting out or repair. 

Most defects can be detected using one or more appropriate nondestructive testing techniques. However, in the absence of routine nondestructive testing inspections, identification of defects in installed equipment is generally limited to those that can be observed visually. Defects such as high residual stresses, microstructural defects such as sensitized welds in stainless steel, and laminations will normally remain undetected. Defects that can be detected visually have the following features ... 

Figure 15.13 Cracking in weld deposit caused by lamination in steel base metal. (Reprinted with permission from Helmut Thielsch, Defects and Failures in Pressure Vessels and Piping, New York, Van Nostrand Reinhold, 1965.)...

Locations. Locations of defects of this type are essentially unpredictable but can occur wherever laminated metal is welded. 

Identification. Defects in welds due to laminations may be difficult to identify based solely on a visual examination. Typically, cracks from welding laminated metal cause jagged, stepwise tears in the base metal. The crack may propagate into the weld itself. 

Surface defects There are numerous substrate surface defects that occur during either the forming of the metal or the fabrication of the metal into a structure. These include hackles, laminations, needles, and weld splatter, among others. 

Defects revealed by visual inspection, possibly enhanced by DP and MP, include cracks, undercutting, surface porosity, surface slag inclusions, craters, residual slag, incorrect weld reinforcement profile and misalignments. Defects detected through the weldment thickness by volumetric techniques can include cracks, lack of penetration, lack of fusion, porosity, slag inclusions and laminations. 

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