How may rust be removed from a highly stressed metal part?

• A. Only by chemical eataway.
• B. By blasting with steel shot and applying paint.
• C. By glass bead blasting, careful polishing with mild abrasive paper, or using a fine buffing compound.
• D. By heating to red-hot and quenching.

Answer: (C)

Removing rust from highly stressed metal parts requires a cleaning method that removes oxide without damaging the surface or altering the metal’s strength. Glass bead blasting is gentle enough to strip rust without creating deep scratches or changing the metal’s hardness, which helps preserve fatigue life. After blasting, careful polishing with mild abrasive paper or a fine buffing compound removes residual oxide and yields a smooth finish, reducing potential crack initiation sites.

In contrast, using steel shot blasting is more aggressive and can leave deeper scratches or introduce surface damage that acts as stress risers, which is undesirable for high-stress components. Heating the part to red-hot and quenching induces thermal stresses and can alter the microstructure or warp the part, degrading strength. Chemical removal methods can also attack the base metal or coatings, leading to unpredictable changes in properties. Painting after harsher cleaning doesn’t fix underlying surface damage.

So, the best approach is glass bead blasting followed by careful polishing with mild abrasive paper or a fine buffing compound, as it cleanly removes rust while maintaining surface integrity.