304L versus 316L in pulp/paper environment
304L versus 316L in pulp/paper environment
(OP)
316L seems to be the preferred material in the pulp/paper industry. Water, wear, and often caustic chemicals are the norm. 304L is significantly cheaper; what are the limitations of using 304L versus 316L in this environment?





RE: 304L versus 316L in pulp/paper environment
316 was originally developed for the pulp/paper industry -- the Mo alloying combats pitting corrosion.
RE: 304L versus 316L in pulp/paper environment
Since these alloys are at least twice as strong as 316L you can save a lot of metal and get good CSCC resistance at the same time.
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RE: 304L versus 316L in pulp/paper environment
I agree that duplexes are a better choice in many applications if CSCC is a concern, which is not always the case. Also, there aplications where the duplex strength does not help. Vessel internals such as screen backing bars in a digester or loose lining in a pulp storage tank, are a good examples of this; they are not stressed, therefore no CSCC possibility and no advantage for strength.
I have heard several complaints, basically, from fabrication shops that wanted to use LDX2101 in lieu of 2205 but it was not available unless they ordered a large quantity. This has been a reported problem on relatively small shop fabricated vessels.
Depending on your application, 304L may be better than 316L (if you stay w/ the austenitic path). Cooking and white liquor plants seem to be this case. There are alot of papers discussing the techanical reasons for this claim. In many applications, it is really a marginal concern.
RE: 304L versus 316L in pulp/paper environment
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: 304L versus 316L in pulp/paper environment
When looking into using duplex grades you have to throw away old asssumptions about how equipment is built and what thicknesses to use.
The min order quantity is a red hering. If I need to run a job in 304L or 316L the min order quantities are at least 40,000lb. The duplex grades are the same. If you want 317L or a special chemistry then be prepared to take 100T of material.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: 304L versus 316L in pulp/paper environment
Designs are often driven by stiffness requirements, not strength, so higher yield doesn't always result in less required material.
I will look into more of the duplex stainless steels, esp. cost comparison for new designs.
Thanks,
acurat