Type 304L stainless resists SCC in chloride

Citation

(1999), "Type 304L stainless resists SCC in chloride", Anti-Corrosion Methods and Materials, Vol. 46 No. 1. https://doi.org/10.1108/acmm.1999.12846aab.006

Type 304L stainless resists SCC in chloride

Type 304L stainless resists SCC in chloride

Keywords Armco, Corrosion, Stainless steel

No evidence of stress corrosion cracking or pitting was found in welded U-bend specimens of AISI Type 304L stainless steel that were tested in oxygenated, chloride-containing petroleum, according to a report from Armco Inc., Ohio.

Welded U-bend specimens were prepared by TIG welding the ends of strips measuring 2.5 × 10 × 0.07cm (1 × 4 × 0.03in). The presence of residual stress was shown by the fact that the U-bend sprang open when the weld was cut away. The weld oxide was left untouched as a "worst case scenario".

The samples were shipped to the BP Oil Technical Centre in Cleveland, Ohio, where they were exposed to oxygenated petroleum containing 50ppm copper and 100ppm chlorides for periods as long as 1,000 hours. Six U-bend samples were immersed in this fuel blend in vessels that were pressurized to 690MPa (100 psi) with oxygen. The vessels were placed in a 100°C water bath for 250, 500 and 1,000 hours.

According to Armco, no evidence of stress-corrosion cracking or pitting was observed after 1,000 hours. The surfaces of the samples developed a dark "gum", which was easily removed with solvent.

The tests were conducted to address concerns about the possibility of stress-corrosion cracking in the austenitic stainless steels being considered for car petrol tanks. Results indicate that chloride stress-corrosion cracking should not be a concern with welded austenitic stainless steels of the 300 series.