×
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

HAZ High in One Area

HAZ High in One Area

HAZ High in One Area

(OP)
625-4130. I am trying to redo a procedure using a different gas and a faster travel speed. 1G on a 12 OD coupon in a spiral toward the center using GTAW-P. The HAZ came back 251,254,274. What would cause that one area to be so much harder?

RE: HAZ High in One Area

Technique regarding bead placement and heat input.

RE: HAZ High in One Area

A fluctuation in welding conditions, speed, feed, or power.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: HAZ High in One Area

Also preheat (minimum interpass temp.)
Also were the hardness measurements made across the HAZ or at the 6:00, 9:00 and 12:00 locations about the circumference? There will always be variation across the width of the HAZ. The variation shown is not abnormal when taken at the previously stated circumferential locations.

RE: HAZ High in One Area

Do you mean the variance between the three hardness numbers? If these are distictly different locations then they should not be reported as a group.
You should do 3-5 tests at each location of interest and report the mean of each.
The range of numbers you report is quite normal for HAZ variation. The end point of your weld will be considerably hotter once the arc has travelled one circumference. Having said all that, apparent fluctuation in HAZ hardness readings is also very much down to variation by the technician in locating the hardest sub-zone immediately adjacent to the fusion line.

In general, HAZ hardness in carbon and alloy steels will decrease if preheat and interpass temperature increase, all other parameters being equal.
In general, HAZ hardness in carbon and alloy steels will decrease if heat input increases, all other parameters being equal.
Increased travel speed will decrease the heat input, all other parameters being equal.

It sounds to me like you have put the cart of pretty appearance ahead of the horse of mechanical properties.
Or perhaps distortion is your issue; with GTAW you have chosen just about the most severe process in that respect. Playing with parameters won't change it that much.
.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

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