Tag
#welding
9 topics across all disciplines.
Pipe support standards and details — reading SP-58, SP-69 and a project detail sheet
What the support standards actually fix, why a project standard detail is a specification rather than a catalogue, the welded attachment problem on alloy and sour service, shoes and trunnions and shields, and what goes wrong when a support is left to the field.
Welding processes, WPS and NDT — what happens before an arc is struck
SMAW, GTAW, GMAW and the rest, explained by what they are good at. Then the paperwork that makes a weld legal — WPS, PQR and welder qualification — and how welds are inspected.
Reading a WPS and a PQR — what is on the sheet and what the tests proved
The practical document skill — what each field on a welding procedure specification is for, what a qualification record actually recorded, and what tensile, bend, impact, macro and hardness results each demonstrate about the joint.
Section IX essential variables — what invalidates a procedure qualification
Why a WPS can be revised freely in some respects and requalified from scratch in others. Essential, non-essential and supplementary essential variables, the ranges a PQR actually qualifies, and the low-temperature trap that turns a harmless change into a requalification.
Welder qualification and continuity — the ranges a ticket covers, and the register nobody updates
What a welder performance qualification actually establishes, the ranges it carries in thickness, diameter, position and process, how continuity lapses at six months, and why the expired ticket is always found after the weld is made.
Joint preparation and fit-up — the hold point you only get once
Bevels and root gaps, internal misalignment and the limits on it, why trimming or counterboring is allowed where grinding the bore is not, tack welds as part of the final weld, and what an inspector checks in the minutes before the root goes in.
Preheat and post-weld heat treatment — hydrogen, hardness, and reading the chart
What preheat is actually for, why interpass temperature has a ceiling as well as a floor, when PWHT is required and when it may be exempted, how to read a chart recorder trace against the specified cycle, and the hardness survey that decides it in sour service.
Non-destructive examination — choosing the method and reading the result
Why every NDE method is blind to something, what magnetic particle cannot do on stainless, why ultrasonics can miss a crack lying the wrong way, the difference between an indication and a defect, and why the examiner's qualification is part of the result.
Material degradation — sensitisation, hardness limits and galvanic attack
Why welding can ruin the corrosion resistance of stainless steel without touching the weld, what the three conditions for galvanic corrosion are and which one to break, why sour service controls hardness rather than strength, what carbon equivalent predicts, and why zinc and stainless are kept apart.