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Undercut created during welding. In welding, undercutting is when the weld reduces the cross-sectional thickness of the base metal. This type of defect reduces the strength of the weld and workpieces. One reason for this defect is excessive current, causing the edges of the joint to melt and drain into the weld; this leaves a drain-like ...
The poor overlap does not allow the slag from the previous weld to melt out and rise to the top of the new weld bead. It can also occur if the previous weld left an undercut or an uneven surface profile. To prevent slag inclusions, the slag should be cleaned from the weld bead between passes via grinding, wire brushing, or chipping. [21]
Name N AWS Characteristics Applications Air acetylene welding (321) AAW Chemical welding process, not popular Limited Oxyacetylene welding: 311: OAW Combustion of acetylene with oxygen produces high-temperature flame, inexpensive equipment Maintenance, repair Oxygen/Propane welding 312: Gas welding with oxygen/propane flame Oxyhydrogen welding ...
Welding is the joining together of materials (typically metals or thermoplastics), ... Undercut (welding) Upset welding; W. Weld access hole; Weld pool; Weld purging;
During the welding process, residual stresses can present themselves in the area of the weld, either in the heat affected zone or fusion zone. The mean stress a welded joint may see in application, can be altered due to the welding processes implementing residual stresses, changing the fatigue life and can render S-N laboratory testing results. [2]
Welding - Studs and ceramic ferrules for arc stud welding: ISO 13919-1: Welding - Electron and laser-beam welded joints - Guidance on quality level for imperfections - Part 1: Steel ISO 13919-2: Welding - Electron and laser-beam welded joints - Guidance on quality level for imperfections - Part 2: Aluminium and its weldable alloys ISO 13920
Arc blow tends to occur if the material being welded has residual magnetism at a certain level, particularly when the weld root is being made, and the welding current is direct current (DC positive or negative). Magnetic arc blow is popularly attributed to a change in the direction of current as it flows into and through the workpiece.
Position welding is complicated by a tendency for molten metal to run out of the puddle (“weld drip”), especially a problem with overhead joints. Weld drip will result in cratering and undercutting where the bead should blend into the base metals, resulting in a weak weld and a risk of cracking at the edge of the bead.