Equipment Engineering Fundamentals and Manufacturing Technology
Domain 1 - Equipment Engineering Fundamentals and Manufacturing Technology
This domain tests whether you can read a manufacturing sequence and say where quality is created or destroyed: material selection, forming, welding, heat treatment, machining accuracy and non-destructive testing (NDT). Items are usually framed as "which process, which test, which acceptance criterion applies", so you need process logic rather than memorised lists.
Core rules
- Material selection balances 力学性能 (yield, tensile, creep rupture, fatigue limit), 工艺性能 (weldability, castability, machinability, hardenability) and 环境适应性 (corrosion, low-temperature toughness, hydrogen service). A steel that meets strength but not weldability is the wrong choice for a welded shell.
- Welding is a special process (特殊过程). Output cannot be proven by later inspection alone, so control rests on 焊接工艺评定 (e.g. per NB/T 47014), welders qualified for the exact item range, consumable control, preheat and interpass temperature, and post-weld heat treatment (PWHT) where thickness or hardness demands it.
- Heat treatment. 退火/正火/淬火/回火 change structure; 消除应力退火 is required, for example, for carbon and low-alloy steel vessels above roughly 32 mm wall thickness under GB/T 150.4 unless an exemption applies.
- NDT follows defect geometry. RT detects volumetric defects (porosity, slag); UT/TOFD/PAUT detects planar defects (lack of fusion, cracks); MT only ferromagnetic surfaces and near-surface flaws; PT any non-porous surface, surface-breaking only.
- Machining accuracy has four elements: dimensional, form (圆度, 圆柱度), positional (同轴度, 垂直度) and surface roughness. Errors arise from machine tool, fixture, cutter, workpiece stiffness, thermal distortion and residual stress.
Worked example
A 60 mm Q345R nozzle-to-shell weld passes 100 % RT, but later UT reveals lack of fusion. The RT result is not false - it is insensitive. Lack of fusion is planar, tight and orientation-dependent; radiation crosses the plane with little attenuation change. Reasoning chain: (1) infer the likely defect from the process (SMAW, poor sidewall fusion); (2) match defect geometry to detection principle; (3) specify UT/TOFD as the governing method for that joint, with RT as a supplementary volumetric check. Acceptance must rest on the method capable of detecting the governing defect.
Traps that cost marks
- Treating "100 % NDT" as "all defects found", or expecting PT to reveal buried flaws.
- Forgetting that a procedure qualification covers a range of thickness and positions, not a single value.
- Confusing 返修 with 返工, and omitting re-inspection at the original method after repair.
- Quoting PWHT thickness thresholds without the exemptions.