Ferrous: iron-based (steel, cast iron) — structural components, shafts, gears. Non-ferrous: aluminum, copper, titanium — lightweight structures, electrical conductors, corrosion-resistant parts. Show you know when weight, conductivity, or corrosion drives the choice.

Annealing: soften for machining. Quenching: rapid cooling to harden. Tempering: reheat after quenching to reduce brittleness. The goal is to achieve a specific hardness-toughness balance for the application.

Steps: visual inspection → fracture surface analysis (brittle vs ductile) → hardness testing → chemical composition verification → microstructure examination (metallography) → compare to design spec → identify root cause. Use terms like fractography, SEM, inclusion content.

Processes: MIG, TIG, stick (SMAW), flux-core, spot welding. Different heat inputs create different HAZ (heat-affected zone) widths and microstructures. TIG = precise, low heat input. MIG = faster, more spatter. Show awareness of post-weld heat treatment needs.

Types: uniform, galvanic, pitting, crevice, stress corrosion cracking. Protection: coatings (paint, galvanizing, epoxy), cathodic protection, selecting corrosion-resistant alloys, controlling the environment. Galvanic corrosion happens when two dissimilar metals contact in an electrolyte — a common mistake in design.

Collect: service history, load conditions, environment, material certifications (MTRs), manufacturing records. Then proceed to physical analysis. Show you treat it as a forensic investigation — gather facts before drawing conclusions.

Methods: ultrasonic testing (UT), magnetic particle (MT), dye penetrant (PT), radiography (RT), visual (VT). Be specific: "I used UT to detect internal porosity in a weld that wasn't visible externally." NDT saves lives — show you take it seriously.

Check: chemical composition vs. spec, tensile/yield strength, elongation, Charpy impact (for toughness), hardness, heat number traceability. Show you don't just accept material — you verify it meets the design requirement before it enters production.

Common standards: ASTM A36 (structural steel), ASTM A516 (pressure vessel), SAE 4140 (alloy steel), ASTM B209 (aluminum sheet). Show you can navigate the standard to find the allowable properties and testing requirements — not just name it.

Document: NCR (Non-Conformance Report) with part number, heat number, the specific failure, test data, and corrective action request (8D or CAPA). Clear, fact-based communication protects the company and improves supplier quality over time.

Fatigue: crack initiation and propagation under cyclic loading, below the yield strength. Prevention: remove stress concentrations (sharp corners → radii), improve surface finish, shot peening, reduce mean stress, use higher strength material with good fatigue resistance.

QMS means documented processes, controlled records, calibrated equipment, and a formal corrective action process. Show you see it as a tool to ensure consistent quality — not just paperwork. IATF 16949 is critical for automotive supply chains in the U.S.