×
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

Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts
2

Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts

Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts

(OP)
Hi all,

For duplex stainlees steel flanged joints, we had specified ASTM A453 Gr. 660 bolts and ASTM A194 Gr. 2HM nuts (as per API 6A). However, we propose to change the nuts to a corrosion-resistant alloy (CRA) material. Can someone let me know any CRA material grades for nuts that are compatible with Gr. 660 bolts ? The main concern here is galling. Can we use nuts to A453 Gr. 660 (same grade as bolts)?

Would appreciate if you could share your experiences/observations on CRA nuts on Gr. 660 bolts.

Thanks,

Balvendra Pal

RE: Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts

2
Consider indicating your service, min Tensile Strength req and temp ranges

ASTM A453 specification covers standards for Grade 660 (Class A, B, C, and D) , Grade 651 (Class A and B), Grade 662 (Class A and B), and Grade 665 (Class A and B) of bolting materials,with ten classes of yield strength ranging from 50 to 120 ksi [345 to 827 MPa], for use in high-temperature service such as fasteners, for pressure vessels and valve flanges. Bolting materials in ASTM A453 are covered rolled, forged, or hot-extruded bars, and also bolts, nuts, screws, washers, studs, and stud bolts. Grade 660 (A286, UNS S66286) has a PREN of 16.8. Grade 660 nuts used with 660 bolts will gall at a low threshold galling stress (see link).
http://www.nickelinstitute.org/~/Media/Files/Techn...


RE: Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts

Excellent link provided by boo1. TABLE XII on page 25 shows two data points for A286: self-mated and A286 vs. Nitronic 60.

RE: Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts

(OP)
Thanks boo1 and TVP. So as per Table XII, A286 self-mated has low threshold galling stress, which is markedly improved by using Nitronic 60 with A286. These are the only combinations mentioned in this link and all other sources I have since found. If anyone has information or experience regarding use of nuts of any other stainless steel / Nickel alloy material with Gr. 660 bolts, please share.

For example, can we use ASTM A194 Gr. 8MA (SS316) nuts with Gr. 660 bolts ? Is there data available for threshold galling stress for this material combination ? Service is non-sour, low temperature (up to 40 deg. C) and 300 lb. pressure rating.

RE: Nuts Material Grades Compatible with ASTM A453 Gr. 660 Bolts

Conventional austenitic stainless steels like 302, 304, 316, etc. will have low threshold for galling too. Your best option will be special grades like Nitronic 60. If the joint doesn't require high preload/torque, you might be able to use a more common grade together with a thread lubricant optimized for stainless steels. LOCTITE 771 Nickel Anti-Seize, Fastorq FastLUBE, and Bostik Never-Seez® are examples of suitable products.

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