Describe the following metallurgical tests and explain why each is carried out: impact test, hardness test, endurance test, tensile test?
Short answer
| Test | Measures | Purpose |
|---|---|---|
| Impact | Energy to fracture notched bar | Assess toughness; detect ductile-to-brittle transition at low temperature |
| Hardness | Resistance to indentation | Correlates with tensile strength; quick QC for strength and wear resistance |
| Endurance | Cycles to failure under cyclic stress | Find endurance limit for components under fluctuating loads |
| Tensile | Yield/UTS, elongation, modulus | Define static strength, ductility and stiffness for load-bearing design |
- Impact test: Charpy/Izod notched-bar fracture, measures absorbed energy; assesses toughness and detects ductile-to-brittle transition at low temperature
- Hardness test: Brinell/Vickers/Rockwell indentation, measures resistance to plastic deformation; correlates with tensile strength, quick QC check
- Endurance test: Fatigue test with cyclic stress below UTS; determines endurance limit for infinite life under fluctuating loads
- Tensile test: Stress-strain curve to fracture; yields yield strength, UTS, elongation, reduction of area, elastic modulus
- Requirement: IACS UR W2, W7, W8, W11, W28 mandate tensile, impact and hardness tests for material approval
- EOOW role: Verify material properties against certificates, understand fitness for service, report discrepancies
Full answer
The full answer explains each point step by step, with the regulations and figures behind it and the discussion from other candidates. It is in the MEO Class IV section of the Marine One forum, open to members enrolled for the MEO Class IV exam.