Search Results for UNS S30300

Cold-drawn type 303 stainless steel wire sections, 6.4 mm (0.25 in.) in diameter, failed during a forming operation. All of the wires failed at a gradual 90 deg bend. Investigation (visual inspection and 5.3x/71x/1187x SEM views) supported the conclusion that the wires cracked due to ductile overload. The forming stresses were sufficient to initiate surface ruptures, suggestive of having exceeded the forming limit. Recommendations included examining the forming process, including lubrication and workpiece fixturing.

After about two years in service, a 303 stainless steel valve in contact with a carbonated soft drink in a vending machine occasionally dispensed a discolored drink with a sulfide odor. According to the laboratory at the bottling plant, the soft drink in question was strongly acidic, containing citric and phosphoric acids and having a pH of 2.4 to 2.5. Investigation (visual inspection, chemical analysis, immersion testing in the soft drink, and 100x unetched micrographs) supported the conclusion that the failure was caused by the size and distribution of sulfide stringers in the alloy used in the valve. Manganese sulfide stringers in the valve were exposed at end-grain surfaces in contact with the beverage. The stringers, which were anodic to the surrounding metal, were subject to corrosion, producing a hydrogen sulfide concentration in the immediately adjacent liquid. Recommendations included changing the valve material to type 304 stainless steel.