×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

API 6A hardness issue

API 6A hardness issue

API 6A hardness issue

(OP)
Dear Experts,

We placed an order for Wellhead equipment (Material AISI 75 KSI, Design pressure/Working Pressure: 7,000 psi; Test Pressure: 10,000 psi, API 6A standard). As per API 6A standard "minimum hardness" for 75 KSI material is 197 BHN. But, during the raw material testing, hardness is found to be 180 BHN. As per my interpretation of API 6A, this is not acceptable. However, our vendor now justifies that material with 180 BHN still can be acceptable from design point of view and also it can still withstand test pressure of 10,000 psi. Please advise if I can accept the material though with less hardness. If yes, can I ask for any additional docs (such as design calculation or any other analysis)?

RE: API 6A hardness issue

If this equipment has 7,000psi rated working pressure and 10,000psi test pressure, then it is not to API 6A per API 6A 21st Edition 4.3.1.1 (and is not API monogrammable). Therefore, the supplier can do whatever the customer and supplier agree on. You can ask for whatever you want; it is up to you and the supplier to negotiate what they will give you.

Note that per API 6A Table 7, 60K material is acceptable for 10,000psi rated bodies, bonnets, integral end connectors, and loose connectors. Per API 6A Table 20, 60K material only has 174 HBW minimum hardness. Therefore, API 6A allows lower hardness material for use in higher pressure applications than in your example.

If the supplier is responsible for the design (and is competent as a wellhead equipment designer), then they should be able to determine whether or not it is safe to use this material for this application. If you trusted them to do the initial design without reviewing their calculations, then you should be able to trust them to do this calculation without reviewing it.

If this is the customer's design, then the customer's engineer should review the situation to ensure it will be safe.

RE: API 6A hardness issue

(OP)
Thank you jmec87 for your advice.
The original rating is 5K; but, uprated to 7K (7000 psi). Based on the measured hardness, it is closer to 60K material. Can we accept 60K material for 7,000 psi working pressure and test pressure 1.5 x WP i.e. 10,500 psi for integral connection?

RE: API 6A hardness issue

Again, this is no longer a 6A product because of the 7,000 psi rating, so you can do whatever you and the supplier agree on. Based on the API 6A hardness requirements alone, I would not be concerned.

However, uprating from 5K to 7K pressure rating is weird (downrating from 10K to 7K would be more normal), and this raises significant concerns regardless of hardness. Are you using type 6B flanges on this design? How are you justifying the 7K pressure rating on a 5K-rated flange? If there is any relevant external authority (i.e. government regulator), how are you justifying this to them?

RE: API 6A hardness issue

What is the yield strength from the MTRs? What type of wellhead equipment?

Petrotrim Services, LLC
www.petrotrim.com

RE: API 6A hardness issue

(OP)
Original rating was 5K; but, as per OEM's design analysis, it is being uprated to 7K for intended service application.
In MTR, yield strength and tensile strength values are meeting 75K criteria. There is only issue with hardness value. Type of Wellhead equipment: Drilling adapter (as per API 6A) to connect two different sizes of Wellhead equipment.

RE: API 6A hardness issue

We have used 5k equipment for 7,500 psi rated equipment in the past. We hydro tested at 1.5 W.P. I would make sure the hardness test is being done correctly and the tools are calibrated.

Petrotrim Services, LLC
www.petrotrim.com

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! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close