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

HAZ - Heat Affect Zone for Spot Welds

HAZ - Heat Affect Zone for Spot Welds

HAZ - Heat Affect Zone for Spot Welds


How can I determine the HAZ for 5.5mm diameter spot welds?


RE: HAZ - Heat Affect Zone for Spot Welds

Two methods frequently used are Visual inspection and Hardness Traverse.

If the metal is steel, etching with Ammonium persulfate (10 mL (NH4)2S2O8 with 90 mL water) will give excellent contrast of the various microstructures-- base metal, HAZ, weld metal.  The surface should be rubbed with absorbetn cotton during etching.  Time depends on the desired contrast.

Perform a hardness traverse of the area in question, going from base metal, through the HAZ, into the weld, and then back through the opposite side HAZ, and then into the opposite side base metal.  The hardness will drop as you go from base metal into the HAZ.  There are a number of standards that cover this sort of testing.  One example is the following:

DIN EN ISO 14271  Vickers Hardness Testing of Resistance Spot, Projection and Seam Welds (Low Load and Mirohardness)

RE: HAZ - Heat Affect Zone for Spot Welds

Sorry, I guess I wasn't specific enough.  Is there a "rule of thumb" to determine the approximate HAZ when designing spot welds in a tightly spaced configuration?


RE: HAZ - Heat Affect Zone for Spot Welds

Why do you want to measure the HAZ ? Are you concerned about HAZ's are overlapping ? Shouldn't you be more concern about producing an acceptable spot weld of required strength. How about a detructive test ? There are a few different types of destructive tests you can perform.



RE: HAZ - Heat Affect Zone for Spot Welds

TVP > nailed it dead on from a metallurgical view.

RE: HAZ - Heat Affect Zone for Spot Welds


Yes, I am concerned with HAZ's overlapping.  I know that I can create a satisfactory and repeatable spot weld under certain conditions, but if I want to create a group of them, I am concerned that the effect of the HAZ will degrade the quality of the joint.

If I create two spot welds very far apart then I expect the strength of the joint to be twice as strong as with a single spot weld.  But as I move the two welds closer and closer together, at some point, the "second" spot weld (and/or surrounding region) won't be as strong as the first and so my joint strength is no longer double what it was with one weld.

Am I missing something else here?


RE: HAZ - Heat Affect Zone for Spot Welds

ASM HANDBOOK Volume 6 Welding, Brazing, and Soldering recommends a minimum spacing of ~ 15 to 25 times the sheet thickness.  Handbook of Product Design for Manufacturing edited by J. Bralla is the reference cited.  Other automotive process standards have similar recommendations.

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


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