×
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

UK low alloy steel stress relief - effect on props?
2

UK low alloy steel stress relief - effect on props?

UK low alloy steel stress relief - effect on props?

(OP)
We have a supplier who wants to stress relieve a machined component made of UK low alloy steel 817M40 (see BS 970-3).

They want to do so at 570 deg C (1060 deg F) for 5 hours. (This is to keep dimensional control tight, as they feel it will move a bit when they machine it.)

The material's minimum tempering temperature is 600 deg C (1110 deg F) and it's not supposed to be tempered above 660 deg C (1220 deg F).

a) would this change the mechanical properties much?

b) what sort of time is 817M40 (and/or similar alloys) usually tempered for?

Alloy composition (from the mill assay):

C: 0.38.
Mn: 0.55.
Cr: 1.03.
Ni: 1.4.
Mo: 0.26.
Si: 0.28.
S: 0.008.
P: 0.009.
Cu: 0.08.

Here's the nominal (if it helps):

C: 0.36 to 0.44.
Mn: 0.45 to 0.70.
Cr: 1.00 to 1.40.
Ni: 1.30 to 1.70.
Mo: 0.20 to 0.35.
Si: 0.10 to 0.40.
S: 0.040 max.
P: 0.035 max.
 

RE: UK low alloy steel stress relief - effect on props?

As long as you are below the temperature that you steel was actually tempered there will be no measurable change in properties. The norm is to stay at least 20F, better 50F, below the actual tempering temperature.

Unless this component has a very thick cross section your time seems to be a little long as something like 90% of the stress relief for a specific temperature is accomplished in the first few minutes when the part is at that temperature.

One approach to a problem like yours is to double or triple temper, rough machine, stress relieve and finish machine.  

RE: UK low alloy steel stress relief - effect on props?

Syd answered a).  Here is the answer to b):

Alloy steels like these typically are temepered for around 1 to 2 hours.

Regards,

Cory

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.

RE: UK low alloy steel stress relief - effect on props?

(OP)
Many thanks to both unclesyd and corypad.

Unclesyd: these are quite thick parts, at least by my standards; the original billet could be up to 8" thick and the part to be stress relieved could have a maximum effective thickness of about 4".
 

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