bevel pipe weld joints

NARROW PIPE BEVELS? Note: In order to use a "narrow pipe bevel", the weld inspection may require "shear wave ultrasonic examination". This mode of inspection is necessary so the NDT equipment can size the weld flaw, and determine if the flaw is acceptable based on CTOD and fracture mechanic equations. Pipe line companies are aware of this complex inspection criteria and the issues generated, and therefore may only consider the narrow bevel welds or low fusion MIG modes for small pipe line projects. Narrow gap and compound pipe joints require field machining and the pipe roundness deviation is always a concern. 

Note: When using narrow, bevel pipe weld joints, or weld processes such as pulsed MIG that provide minimum side wall weld fusion, extraordinary weld inspection methods may be required. What you save on the narrow weld prep is often lost on the additional weld inspection required and the consequences of that magnified inspection.

CERAMIC BACKING AND VEE GROOVE PLATE EDGE PREPS. 
When making all position flux cored welds on vee groove welds on carbon steel plate with ceramic backing, two interesting questions would be, what would the minimum vee groove angle and weld gap be? 

In ship yards where the typical steel thickness plate is 9 to 25 mm, when welding that vee groove with ceramic backing, the optimum root weld gap size is 5-6 mm. The minimum, "combined" vee groove angle should be 40 degrees.

Date: 2023-04-10     hits: 657    Return