Welder — Year 3 Exam Prep
Year 3 is the final period of the welder apprenticeship and the most technically advanced. Advanced metallurgy including stainless steel and aluminum, submerged arc welding, pressure vessel and pressure piping codes, non-destructive examination, and welding procedure specifications define the third period curriculum. Completing Year 3 qualifies you to challenge the Interprovincial exam for your journeyman welder certificate. TradeBenchPrep gives you the comprehensive, curriculum-aligned practice to finish your apprenticeship at the highest level.
What a Year 3 Welder Apprentice Needs to Know
Advanced Metallurgy — Stainless Steel
Austenitic stainless steels (300 series — 304, 316, 321, 347) — austenitic structure gives them excellent corrosion resistance, good toughness, and non-magnetic properties. The key welding challenge is sensitization — when austenitic stainless is heated in the range of 425–870°C (the sensitization range), chromium carbides precipitate at grain boundaries, depleting chromium from the surrounding metal and creating zones that are susceptible to intergranular corrosion. Prevention methods: use low carbon grades (304L, 316L), use stabilized grades that contain titanium or niobium to preferentially combine with carbon (321, 347), use solution annealing after welding if possible, or minimize time in the sensitization range by limiting heat input and interpass temperature. Ferritic stainless steels (400 series — 430) — magnetic, less corrosion resistant than austenitic, susceptible to grain growth in the HAZ and sensitization. Duplex stainless steels — mixed austenitic-ferritic microstructure, higher strength than austenitic grades, excellent corrosion resistance, require controlled heat input to maintain the correct phase balance.
Advanced Metallurgy — Aluminum
Aluminum alloys — know the 4-digit designation system: 1XXX = pure aluminum, 2XXX = aluminum-copper (heat treatable, high strength), 3XXX = aluminum-manganese, 4XXX = aluminum-silicon (filler metals), 5XXX = aluminum-magnesium (strongest non-heat-treatable alloys, best for welding), 6XXX = aluminum-magnesium-silicon (heat treatable, common structural alloy), 7XXX = aluminum-zinc (highest strength, poor weldability). Oxide layer — aluminum forms a tenacious oxide layer that melts at 2050°C versus the base metal at approximately 660°C. The oxide must be removed before welding — mechanical removal or with the AC arc cleaning action in GTAW. Hot cracking in aluminum — aluminum alloys are susceptible to hot cracking (solidification cracking) depending on their composition. Filler metal selection is critical — choose a filler that shifts the weld metal composition away from the crack-susceptible range.
SAW — Submerged Arc Welding
SAW uses a continuously fed solid wire electrode and the arc is completely submerged under a layer of granular flux — no visible arc, no UV radiation. High deposition rate and deep penetration make SAW the process of choice for welding thick plate in the flat position, including pressure vessel shells, structural sections, and ship hulls. Flux types — fused and agglomerated fluxes, flux classification, and the importance of dry storage (moisture in the flux causes porosity and hydrogen cracking in the same way as a wet SMAW electrode). Wire classification — EM12K is a common SAW wire, know the classification system. Parameters — SAW uses much higher currents than other processes (600–1000A is common) and the process produces wide, deeply penetrating welds. Multiple wire SAW — tandem and twin wire configurations for maximum deposition rate.
Pressure Vessel Code — ASME Section VIII Division 1
ASME BPVC Section VIII Division 1 governs the design, fabrication, inspection, and testing of pressure vessels. For welders, the key knowledge areas are: Welding procedure qualification under ASME Section IX — the Welding Procedure Specification (WPS) and Procedure Qualification Record (PQR). Know the essential variables that, if changed, require re-qualification of the procedure (base metal P-number, filler metal F-number, significant changes in preheat, PWHT, and joint design). Welder performance qualification — how a welder qualifies to weld a specific procedure, what positions they are qualified for, and the period of effectiveness of their qualification. Code stamping — the CRN (Canadian Registration Number) system for pressure equipment in Canada and how it interfaces with ASME code requirements.
Pressure Piping Codes
CSA Z662 — Canadian standard for oil and gas pipeline systems. Welding qualification requirements, NDE requirements for different pipeline service, and the specific requirements for pipeline girth welds. B31.3 Process Piping — welding requirements for industrial process plant piping. Know how the examination category (normal, Category D, Category M) affects NDE requirements. API 1104 — welding standard for pipelines, commonly required for pipeline welders. Know the qualification test requirements and what constitutes an acceptable test weld under API 1104.
Non-Destructive Examination — Understanding What Each Method Finds
NDE is used to inspect welds without destroying them. Know the five major methods: Visual Testing (VT) — the most basic and first method applied. Know what visual inspection can and cannot detect. Liquid Penetrant Testing (PT) — a penetrant is applied to the surface, allowed to dwell, removed, and a developer applied to draw penetrant out of discontinuities. Detects surface-breaking defects only. Not effective on porous materials. Magnetic Particle Testing (MT) — a magnetic field is applied to the part and iron particles are applied. Particles concentrate at magnetic flux leakage points caused by discontinuities. Detects surface and near-surface defects in ferromagnetic materials only (not applicable to austenitic stainless or aluminum). Radiographic Testing (RT) — X-rays or gamma rays pass through the weld and expose a film or digital detector. Subsurface volumetric defects (porosity, inclusions, incomplete fusion) are detected. RT requires radiation safety precautions and is a slow, expensive method but provides a permanent record. Ultrasonic Testing (UT) — high-frequency sound waves are introduced into the weld and reflections from discontinuities are detected. Detects subsurface defects, faster than RT, and provides sizing capability. Phased array UT is increasingly replacing conventional UT and RT.
Welding Procedure Specifications
A WPS is the document that specifies all the welding variables for a production weld — base metal, filler metal, joint design, preheat, interpass temperature, PWHT, shielding gas, and welding parameters. Know every section of a WPS and what it tells you. Essential variables versus non-essential variables — essential variables are those that affect the mechanical properties of the weld and require re-qualification if changed. Non-essential variables can be changed with a simple revision to the WPS without re-qualification. Pre-qualified WPS versus a qualified WPS — under AWS D1.1 Structural Welding Code, pre-qualified joint designs and consumable combinations can be used without testing; under ASME, all procedures must be qualified by testing.
What Year 3 Welders Must Prepare for Most Carefully
Stainless steel sensitization — this is the most important and most tested stainless steel metallurgy topic. Know what it is, why it occurs, the sensitization temperature range, and all four prevention methods. An exam question on sensitization can be answered correctly in many different ways — understanding the mechanism ensures you can answer regardless of how the question is phrased.
Welding procedure qualification under ASME Section IX — know the difference between a WPS and a PQR, know the essential variables, and know the welder qualification system. This content has significant exam representation and requires systematic study.
NDE method selection — know not just what each method detects but what it cannot detect and what material or surface conditions are required. Exam questions often test the limits and requirements of each method, not just the general capability.
How to Use TradeBenchPrep for Year 3
Full Exam Mode is the most important preparation tool for Year 3 — the final period exam draws from the complete three-year curriculum and is the most comprehensive exam of the apprenticeship. Run multiple full exams in your final two to three weeks. Study Mode for stainless and aluminum metallurgy, WPS qualification, and NDE method selection ensures complete coverage of Year 3-specific content. Use your dashboard to identify and address weak areas systematically in the time you have before your exam.