Sample Welding Heat Input Formula from ASME
Welding Heat Input Calculation
BPVC . IX 2017 , QW‐409 Electrical Characteristic
Travel Speed for a pipe can be determined as follows :
Travel Speed
= Circumference of Pipe / t = 2πr / t = πD / t
Pictorial Illustration ( Sketch Not to Scale )
d
Base Metal
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For simplicity , “ D ” can be considered as the Nominal Diameter of Pipe . However , for accuracy one may utilise this formula : D = OD – 2d
Welding Bead
Figure 3
Legend : r = Pipe radius D = Pipe diameter OD = Outer Diameter of Pipe d = depth measured after each weld layer t = Welding time
Remarks : In some European systems , “ Thermal Efficiency ”, ranging from 0.6 to 1.0 depending on the welding processes , is included into the Heat Input calculation , but not for ASME BPVC IX .
Figure 3 : Welding heat input calculation .
is a recipe for the welding to produce the desired quality weldment . Once the WPS is ready , the next aspect to consider is the qualification of Welders or Welding Operators for the job .
The qualification of Welders or Welding Operators is simpler compared to the WPS process . It begins by selecting a potential candidate to undergo the Welder Qualification Test ( WQT ), whereby the test coupon is subjected to Visual Inspection followed by a Non-Destructive Test ( mostly Radiographic Test ) and / or Bend Test . Like WPS , an “ Essential Variable ” exists in the WQT process but with fewer criteria . Once the Welders or Welding Operators pass the test , they will be considered qualified and a Certificate and Pass may be issued based on the Company ’ s Quality Assurance Programme . Furthermore , Welders or Welding Operators who have taken part in the WPQT process and meet the desired outcome will automatically be qualified .
In general , the intention of the Welding Procedure Specification ( WPS ) process is to ensure that the recipe for welding is fit for use , meeting the usage purpose . Similarly , the Welder Qualification
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