Leading Edge Technology Solves Stress Corrosion Cracking Problem
The problem: cracking in continuous cookers
A leading U.S. hot dog manufacturer found that while Type 304 stainless steel had worked for many years in cooking meat in short-cycle batch processing, brand new Type 304 ovens quickly showed severe cracking when used on a "continuous" basis.
Engineers at Outokumpu identified the problem. When the manufacturer switched to continuous cooking (meaning that the oven operated at the cooking temperature for more than 20 hours per day) stress corrosion cracking occurred and was propagated in each daily cycle of cooking.
The solution: The solution: 254 SMO
Our engineers demonstrated with a field test that while Type 304 stainless steel could withstand years of short-cycle exposures, only a few days of long-cycle exposures were required to develop visible cracks. The results indicated that cracking was probably occurring in every cycle. Even though the chemical exposure conditions and the processing temperatures were virtually identical, Type 304 was not sufficiently resistant to stress corrosion cracking in their new processing system.
Outokumpu engineers suggested 254 SMO, which is highly resistant to pitting and crevice corrosion and can resist this kind of stress corrosion cracking for decades. The food manufacturer installed 254 SMO sheet and plate in a rebuild of their continuous cooking unit, and no cracking or corrosion of any kind has been observed in over eight years of production.
What is 254 SMO?
Outokumpu's special grade 254 SMO is our 6% Mo, high-performance, nitrogen-alloyed austenitic stainless steel. 254 SMO is 50% stronger than the common 300-series austenitic stainless steels. It was developed initially for its high resistance to pitting and crevice corrosion and to chloride stress corrosion cracking in pulp mill bleaching systems and seawater applications. Being austenitic, 254 SMO stainless steel is compatible with the common austenitic stainless steels, so this superior grade can be used in critical components and critical sections of larger constructions of Type 304 and similar grades.
Superior performance with 254 SMO
254 SMO's high levels of chromium, molybdenum and nitrogen --and its excellent fabrication characteristics -- offer superior performance in high-chloride environments.
In addition to its use in food, seawater, and paper industries, 254 SMO is now specified by engineers for applications ranging from pharmaceutical production equipment and gas desulfurization scrubbers to chemical processors.
254 SMO is available in plate, sheet and KBR wide sheet, billet, bar, pipe, tubing, fittings, forgings, castings, and welding consumables.