B16 Bolt&nut Torque - CR4 Discussion Thread

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subbharao Associate Join Date: Aug 2010 Posts: 42	B16 Boltνt Torque 07/10/2013 2:26 AM
	Can someone beam me out? I have 4" Class 900 flange connected to a PRV ( 60bar , 485 C to 27 bar- De Super heater to Sat.Steam. ) . Connecting gasket is an oval metal ring grade SS 316. While waiting for B16 1 1/8" , it was recommended that I can use SS316 , which has been installed yesterday and it was working well at 51bar. 1) What could be the initial torque setting for 1 1/8" B16 Nuts and SS 316? - We set the 1" SS316 at 250 lbf.ft ( Immediately available size is 1" ) 2) Do I need to re-torque ? Any suggestion for intervals ? For both B16 and SS316 I could not get much info from seal and bolts suppliers. Any links can help me? Regards .
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bigg Guru Join Date: Jun 2010 Posts: 1296 Good Answers: 104	#1 Re: B16 Boltνt Torque 07/10/2013 7:52 AM
	So you installed under-sized, substituted-material studs/bolts in a high-pressure steam system and your only concern is how to torque the bolts? Sheesh
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#2 In reply to #1 Re: B16 Boltνt Torque 07/10/2013 8:04 AM
	Quite. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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subbharao Associate Join Date: Aug 2010 Posts: 42	#3 In reply to #1 Re: B16 Boltνt Torque 07/10/2013 9:01 AM
	Yes Sheesh, I don't have much 1st hand experience on re torque high temperature bolts. It is still holding until now. We will replace the 1"SS316 with 1 1/8" B16 bolts this weekend. 250lbf.ft is OK? Which was set at ambient temperature.
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Anonymous Poster #1	#4 Re: B16 Boltνt Torque 07/10/2013 10:05 AM
	Subaru, ASTM A193-Gr B7 bolts are acceptable to 400C. ASTM A193- B16 bolts were SPECIFICALLY DEVELOPED for applications where the operating temperature exceeds the limitations of the B7 Bolting. Maximum operating temperature for the B16s are 540C. (Also, the recommended nut material for a B16 stud is A 194 Gr 7) "it was recommended that I use SS316".... This statement has no meaning. I suggest that you and the person you solicit advice from stand very close to the PRV during startup if you use anything other that the B16/B7 bolting combination...
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subbharao Associate Join Date: Aug 2010 Posts: 42	#5 In reply to #4 Re: B16 Boltνt Torque 07/10/2013 11:01 AM
	Thank You Very Much. Actually I am very sorry to say that 'it was recommended' , In fact SS316 is the best option available to me and the advice- Do Not Insulate and use a blower fan until I get the replacement. Guys , what is torque I should apply on 1 1/8" B16? Do I need any re torque? Of course we are not going to do Hot re torque.
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HeHound Commentator Join Date: Oct 2012 Posts: 75 Good Answers: 7	#6 Re: B16 Boltνt Torque 07/10/2013 11:12 PM
	Sometimes you just have to do it right now, rather than doing it right. We don't all live and work down the road from the bolt supplier or have overnight delivery. IMHO 250 ft/lbs is fine for now and till the weekend. You might want to stick some barriers around the PSV and keep people away. When your new bolts arrive are you going to use any lube? Always should so you can account for friction. Recommended Bolt Stress for a 4" 900# would be 45,000 psi, which is fine for a B16. Using a good bolt lube with a known co-efficient of friction recommended torque figures are µ = 0.08 - 359 lbf/in2 µ = 0.11 - 474 lbf/in2 µ = 0.13 - 550 lbf/in2 µ = 0.15 - 626 lbf/in2 If you dont know the friction factor of the lube, ask, or look at the manufacturers website. Copper Slip will be fine if you have any around. While using the next size down of bolts is not good, I will give you credit for keeping the PSV online and not isolating it off! Please come back on Monday and tell us everything was ok.
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Mechanicalmark Commentator Join Date: Jul 2008 Posts: 97 Good Answers: 2	#7 Re: B16 Boltνt Torque 07/11/2013 9:57 AM
	DO NOT substitute SST316 for A193 B16 Bolts/Studs and A194 Grade 7 Nuts !!! I recommend you consult the pages starting at page 48 of: http://flexitallic.com/uploads/files/broDesignCriteria.pdf
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subbharao Associate Join Date: Aug 2010 Posts: 42	#8 In reply to #7 Re: B16 Boltνt Torque 07/13/2013 12:37 AM
	Dear M.Mark and Guys! Thank you very much for this link. Sorry i can't thank you in time as my internet has been very slow lately. Regards, Rao
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Anonymous Poster (1); bigg (1); HeHound (1); Mechanicalmark (1); PWSlack (1); subbharao (3)

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B16 Boltνt Torque