Tag
#fabrication
13 topics across all disciplines.
Plate materials — what vessels and tanks are actually made from
A516, A240, Monel, Hastelloy and titanium — why a plate specification is not a pipe specification, what each alloy is bought to survive, and why you almost never buy a solid exotic vessel.
Fittings and branch connections — how a pipe changes direction
Elbows, tees, reducers and caps, and the branch fittings that take a small line off a big one. What each is for, why the dimensions are fixed, and why a branch needs reinforcement.
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.
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.
Examination extent and progressive sampling — what five per cent actually obliges
How fluid service sets the amount of examination, why the sample has to represent each welder on each procedure, and the progressive sampling rule that turns one rejected weld into a widening scope — the part of Chapter VI taught almost nowhere.
Inspection and test plans — hold, witness, review, and who signs
What an ITP actually is, how it is built line by line from the code and the specification, what each of the four intervention levels obliges, why a document full of hold points is worse than a short one, and the notification failure that turns a witness point into nothing.
Non-conformance and corrective action — the four dispositions, and why NCRs repeat
Writing an NCR somebody can act on, the difference between rework, repair, use-as-is and reject, who may grant a concession, and why closing non-conformances one at a time without ever raising a corrective action guarantees the same defect next week.
From isometric to installed line — fabrication, erection and testing
How to read a piping isometric, why spool breaks decide what happens in the shop and what happens at height, and the test and reinstatement sequence that gets a line handed over.
Structural steel — sections, connections and why it must be fireproofed
How to read a steel section designation, what makes each shape good at its job, bolted versus welded connections, and why unprotected steel fails in a hydrocarbon fire in about ten minutes.