Does washer needed for flange connection?
Does washer needed for flange connection?
(OP)
Hello all,
would you please do me a favor to answer the question?
Dose washer needed for flange connection? In my experience, we never asked for washer in piping material specifications for chemical engineering. While I looked a PMS for FLNG, I found the washer required. I did not found any standard or practice required for washer even for the cryogenic service. (I assumed that the Belleville washers may help on bolt tension on cryogenic flange connection)
Does the washer required for offshore marine engineering?
Thanks a million in advance.
would you please do me a favor to answer the question?
Dose washer needed for flange connection? In my experience, we never asked for washer in piping material specifications for chemical engineering. While I looked a PMS for FLNG, I found the washer required. I did not found any standard or practice required for washer even for the cryogenic service. (I assumed that the Belleville washers may help on bolt tension on cryogenic flange connection)
Does the washer required for offshore marine engineering?
Thanks a million in advance.





RE: Does washer needed for flange connection?
https://www.linkedin.com/groups/Flange-washers-is-...
http://www.eng-tips.com/viewthread.cfm?qid=223700
http://www.eng-tips.com/viewthread.cfm?qid=301302
http://www.eng-tips.com/viewthread.cfm?qid=364145
http://www.eng-tips.com/viewthread.cfm?qid=134091
http://www.eng-tips.com/viewthread.cfm?qid=98238
http://www.eng-tips.com/viewthread.cfm?qid=165408
http://www.eng-tips.com/viewthread.cfm?qid=81706
http://www.eng-tips.com/viewthread.cfm?qid=314597
RE: Does washer needed for flange connection?
RE: Does washer needed for flange connection?
RE: Does washer needed for flange connection?
RE: Does washer needed for flange connection?
RE: Does washer needed for flange connection?
I also noticed that (while perhaps not directly related to piping joints) some detailed research half a century ago at https://www.google.com/url?sa=t&rct=j&q=&a... stated even hardened washers didn't appear to make much of a bolt tension difference when the "turn of the nut" method was used, whether or not even these washers were used, in those structural connections (see Figure 5 etc.) I saw however, that hardened washers would protect softer flange surface from "galling" in the substantial preload of harder/high strength bolt wrenching e.g. in that testing program, it this were objectionable in the application, and per their Figure 6 etc. while preload was achieved with or without washers at least hardened washers did indeed reduce some the torque required to get a proof tension load for at least some mild steel structural connections with this high strength (some harder) steel bolts/nuts.
With regard particularly to "hardened washers," it is however interesting as well that some manufacturers e.g. at
http://www.portlandbolt.com/products/washers/harde... now say with regard to these washers, "They are the recommended washer for any fastener other than a low carbon steel bolt." Also, I know the scope to ASTM F436 Standard Specification for Hardened Steel Washers per http://www.astm.org/Standards/F436.htm states, "These washers are suitable for use with fasteners covered in Specifications A325, A354, A449, and A490." (I see for whatever reason all of these spec numbers are for high strength, not even mentioning their application to quite common lower strength e.g. ASTM A307 Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60 000 PSI Tensile Strength that have been traditionally specified for a whole lot of low and mid-pressure joining of steel and ductile iron flanged plant etc. piping).
Finally, while I believe most joints are still "wrenched", there are of course now also other means to tension some critical joint bolting e.g. with variously designed "tensioners", as opposed to conventional wrenches.
In the end, this may well be one of those "it depends" type questions (with perhaps a lot of things to consider
RE: Does washer needed for flange connection?
That said, I usually only start recommending through-hardened washers on bad-actor flange joints as one of variety of improvement measures. I also highly recommend them on joints in cyclic service, especially if the cycles include thermal variation.
So, yes - it depends indeed.