×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

B16.5 Stud vs Nut Material Selection

B16.5 Stud vs Nut Material Selection

B16.5 Stud vs Nut Material Selection

(OP)
For flange bolting B16.5 lists suitable stud and nut materials in Table 1B. Intermediate Strength materials are required to cover our services.

We have selected ASTM 320 B8M Cl 2 studs and ASTM 194 8MA S1 heavy hex nuts. Both are Carbide solution treated and strain hardened as suggested by Notes 6 and 11 below Table 1B.

An enquiry to Australian bolt suppliers has indicated that while the stud material is readily avaiable the nuts will need to be specially imported. Only non strain hardened ASTM A194 8M nuts are readily available. They advise that this mixed combination has been the normal supply in Australia for the last 20 years.

A review of A194 and A320 did not clarify whether the higher grade nuts are required.

I would like to seek advice regarding whether plain 8M nuts are typically used in other places?

Can someone advise if there is a good reason for this mixed material combination (e.g. to avoid galling)?

Can someone advise if this mixed material combination has been subjected to proof tesing to determine if the full strength of the botls can be used without a risk of failure of the nuts?

Dennis Kirk Engineering
www.ozemail.com.au/~denniskb

RE: B16.5 Stud vs Nut Material Selection

dennis...

Why did you select the "ASTM 320 B8M Cl 2 studs and ASTM 194 8MA S1 heavy hex nut" combination ?

-MJC

  

RE: B16.5 Stud vs Nut Material Selection

(OP)
The studs are directly from Table 1B for SS316 material. They are Carbide Solution Treated and Strain Hardened.

The nuts were selected based on Note 11 to be "of corresponding material".

I think now that the 8MA S1 nuts may not be available and that I should have refered to either 8MA (Carbide Solution Treated) or 8M S1 (Strain Hardened)

Dennis Kirk Engineering
www.ozemail.com.au/~denniskb

RE: B16.5 Stud vs Nut Material Selection

Your suppliers are not far from the truth about the strain hardened nuts.

Situation in the States:
A strain hardened SS nut of any description is going to be hard to procure.  Even if you can find someone to make the nut you are talking about time and a lot of money.  A colleague in the bolt business told me today that two suppliers that use to make a strain hardened nut are now no quoting.  
He routinely sees a lot of orders for strained hardened studs/bolts with threaded nuts.  He says that nearly all his customers that use Austenitic fasteners are now calling out Cl 2 or strain hardened studs/bolts with the threaded nut.
I know when we started using Cl 2 studs there was no thought of using a strained hardened nut for the simple reason the nuts weren't available due to the difficulty in manufacturing them.  I cannot recall any problem with this approach on our piping system.  Any Austenitic SS stud/bolt under 1 1/4" , whether set in, low temperature or high temperature is a Cl 2 with a threaded nut.     

RE: B16.5 Stud vs Nut Material Selection

(OP)
Great information thanks so now I will pose two questions to group members to take this a little further:

Given that ASTM 320 B8M Cl 2 studs are required what, in your experience, are the required nuts to go with these and what reference points you to this material?

Can you advise whether ASTM 194 8MA S1 (Carbide Solution Treated and Strain Hardened) heavy hex nuts or 8M S1 (Strain Hardened) heavy hex nuts are available in your area?

Dennis Kirk Engineering
www.ozemail.com.au/~denniskb

RE: B16.5 Stud vs Nut Material Selection

Somewhere, in a previous life in valveland, it usta say that strainhardened nuts are required for strain hardened bolts [old A-193 or A-194? maybe it was that note 11 of Table 1B in B16.5 - need a spec-lawyer with a better memory. We had many nerd battles on the subject.]

These guys list 'em:
http://www.goasf.com/SpecShts/2NutsStk.html

I think we usta get them from these guys:
Robbins Manufacturing Co
1200 Airport Rd,  Fall River,  MA  02720
Phone: 508-675-2555
or maybe it was:
http://www.fallrivermfg.com/products_nuts.html

RE: B16.5 Stud vs Nut Material Selection

(OP)
Thanks Arto, I have sent a qury to Goasf for thier advice.

On the basis that a bolt should fail in tension before the threads in a nut begin to shear (otherwise you might not detect a failure) I have just completed a calculation of bolt tensile capacity compared to nut proof load using the data from ASTM A320 and A194.

For 5/8" size bolt from B8 Cl 2 (Strain Hardened) material the minimum failure load is 28,250 lb.

The A194 8 nut has a proof load of only 18,080 lb.

The A194 8 S1 (Strain Hardened) nut has a proof load of 28,250 lb.

It certainly appears that strain hardened nut will be required to go with the strain hardened bolts?

Dennis Kirk Engineering
www.ozemail.com.au/~denniskb

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources