×
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

How to compare percentage elongation of steel

How to compare percentage elongation of steel

How to compare percentage elongation of steel

(OP)
Hi,

I'm trying to compare the mechanical properties of aisi 8620 steel against a British Standard. All of the data sheets list a percentage elongation using a gauge length of 2 inches (typically 16%). However the British Standard gives a minimum requirement of 19% with a gauge length of 5.65√s0. What is the effect of the different gauge length? Can i directly compare the two?

Thanks

RE: How to compare percentage elongation of steel

First of all, it appears that you are trying to compare a data sheet stating typical properties with a spec that has minimum properties. You can't do that. Second, I don't understand the units you have provided for the gauge length in the British Standard.

RE: How to compare percentage elongation of steel

(OP)
The data sheets are giving actual (not typical) elongation values and the British Standard gauge length is defined as: Gauge length = 5.65 √So (i.e. 5.65 x square root of the original cross-sectional area).

RE: How to compare percentage elongation of steel

The stated values are not directly comparable between gage length values and values obtained by formula based on sample geometry.

RE: How to compare percentage elongation of steel

Gauge length of 2 inches is normally 4D, while 5.65√s0 is 5D. In this case, the specimen is machined to .5'', 4D=2'', 5D=2.25''. Normally 4D will give you a bit higher elongation.

RE: How to compare percentage elongation of steel

5.65√So = 5D, which makes it a standard DP5 round test bar. A longer gauge length might give you a bit longer elongation.

RE: How to compare percentage elongation of steel

Generally speaking, shorter gauge length leads to a higher percentage of elongation, reason being the portion near breaking always deformed /elongated more, while the measured elongation is the average of the whole gauge length.

RE: How to compare percentage elongation of steel

Ben you are right of course. my mistake.

RE: How to compare percentage elongation of steel

A conversion of elongation values on various gauge length (proportional or non-proportional) to other gauge lengths is given in ISO 2566. Part 1 applies to carbon and low-alloy steels with tensile strength from 300 to 700 MPa.
To compare values obtained on non-proportional to proportional gauge lengths the cross section of the test specimen has to be considered.

RE: How to compare percentage elongation of steel

(OP)
Thanks everybody. Your replies have been very helpful.

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


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