Heating the base metal to a specific desired temperature before welding is called as preheating. The temperature at which the base metal is heated is called as the preheat temperature. Preheat temperature can be determined by the applicable code. Please see table 1 to know how to find the preheat temperature in the respective code: In absence of code, the following factors shall be considered for determining the preheat temperature;….
Submerged Arc Welding (SAW) is an arc welding process in which arc is generated between a bare electrode and the workpiece. The arc and the molten weld pool are submerged in a blanket of granular fusible flux on the workpiece. Flux covers the arc and prevents fumes, sparks, spatter, and intense ultra violet radiation from escaping, which makes this process very different from other arc welding processes. Submerged arc welding….
Flux cored arc welding (FCAW) is a welding process that uses the heat produced by an arc generated between a continuous tubular filler metal (electrode) and the work piece. The filler metal is hollow with flux at the core. Flux present at the core of the filler metal shields the molten weld pool from atmospheric contamination. Flux Cored Arc Welding are mainly of two types: Self-Shielded (FCAW – S) Gas….
High frequency sound waves (frequency > 20000 HZ) also known as ultrasonic waves are introduced in a test object through a probe, these waves travel through the material on a predictable path. The waves are reflected at interfaces or other interruptions or discontinuity. The reflected waves are detected and then analysed for the possibility of any discontinuity in the test object. Sound beam is emitted through a probe. The probe….
SELECTION OF PROBE ANGLE: There are three methods for selecting a probe angle, these are: Based on groove angle: Probe Angle (Ø) = 90 – α/2 Where, α – Groove angle and Ø- Probe Angle As per AWS: 0 – 30 mm Thickness – 700 Probe 30 – 40 mm Thickness – 600 Probe > 40 mm Thickness – 450 Probe As per approved procedure:….
