General Inspection Principles, Methods, and Quality Control
This domain tests inspection as a controlled process: how a plan is built, which method answers which question, how results are judged against acceptance criteria, and how the organisation keeps that judgement traceable and defensible.
Principles and the inspection plan
Every inspection starts from a written 检验方案 derived from the applicable TSG: scope, item list, methods, sampling proportion, instruments, acceptance criteria, and safety measures. Items are graded - 重要项目 (major items) must all conform for a 合格 conclusion; a nonconforming 一般项目 may still permit 合格 if safety is unaffected. Distinguish 检测 (testing), which produces data, from 检验 (inspection), which issues the conformity judgement.
Method selection
- Macroscopic/visual examination and dimensional measurement - geometry, alignment, corrosion mapping.
- Wall-thickness measurement by ultrasonic gauging on a defined grid.
- NDT: RT for volumetric defects, UT for planar internal defects, MT for ferromagnetic surface/near-surface, PT for non-porous surface-breaking.
- Physical-chemical checks (hardness, spectrographic alloy ID, metallography).
- Pressure/leak tests and functional tests of safety accessories and interlocks.
Quality control
Accredited body plus CMA; qualified personnel (检验员/检验师); instruments calibrated and traceable, with intermediate checks; records completed on site; report passes three levels - inspector, reviewer, approver - and carries the inspection seal.
Worked example
A vessel's nameplate minimum thickness is 8 mm and ultrasonic readings cluster at 7.4 mm on one barrel course. Reasoning: confirm instrument calibration and couplant, re-grid that course at closer spacing (cross pattern per section, not fewer than the plan requires), check whether the low zone is local pitting or general thinning, then compare measured thickness against the minimum required by strength calculation with corrosion allowance. General thinning below calculated minimum means a strength re-rating or rejection; isolated pits need depth and density assessment. One reading is never a conclusion.
Traps that cost marks
Concluding from a single method; using out-of-calibration instruments; signing a report without review; forgetting that safety accessories are inspection items, not optional extras; confusing 检测报告 with 检验报告.