Austenitic Alloy—Allegheny Ludlum

The following table Illustrates the corrosion resistance of AL-6X in various solutions in comparison to AISI stainless steel grades. Tests were performed in boiling acid (concentrations in weight percent) for five 48-hour periods. The listed values are corrosion rates in IPM (inches per month)  

including the boiling acid tests above, show that AL-8X is generally more corrosion resistant than Type 316. In environments such as sulfuric acid, concentrations and temperatures have a marked influence on corrosion rate, and specific conditions should be carefully determined. The following data determined for 2-hour coupon tests are illustrative  

Typical Weight Changes and Sample Conditions Resulting From 10 Percent Ferric Chloride Exposure Tests— 

45 Gram Weight Loss Severe Crevice Attack 0.45 Gram Weight Loss Severe Pitting 

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Also, relatively new are the 6% molybdenum super-austenitic stainless steels, which possess the strength of duplex stainless steels and corrosion resistances about midway between the duplex stainless steels and the high-nickel-based alloys. Welding super-austenitic stainless is not a problem with molybdenum-enriched filler metals. Examples of high-molybdenum alloys are AL-6XN (Allegheny Ludlum Corp.) and 254 SMO (Avesta Sheffield, Inc.). Sorell (1994) and Kane (1993) present concise reviews of the various alloy groups. 

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