the reason that we consider it something other than normal causes like furnace uniformity and ... is the fact that material passes the UTS comfortably but fails 0.2%PS. so PS/UTS ratio changes when we get failure.
Thanks metengr.
material is low alloy steel and it is hardened and temepred and as i mentioned it is 0.2% proof stress failure.
the location of the test is fixed and sometimes we get test failure on these parts not always, so we rule out the design issue.
what i am looking for, is scinetific...
I have been always told that if you get proof failure one of the main reasons can be slack quenching.
my questions are:
- is this true?
- what else can be involved?
- can we explain the reasons scinetifically (by dislocation theory or...)?
thank you evryone for your help.
If you don t mind some theoretical discussion, I know polymer has reversible solubility but can you please let me know why it is so sensitive to the temperature range? why 25 to 40 can be different from 40 to 50C?
Thanks guys for the information.
we check concentration by refractometer on daily basis and by viscometer on weekly basis. I know none of them are accurate enough to tell you if the polymer is in good condition or not so our supplier test the polymer on monthly basis.
RP mantioned a good point...
I will post more details tomorrow morning (UK time), but my main question is can quench cracks be curved?
Regarding polymer, we use them on daily basis. By ageing I mean the loss of effectiveness due to repeated use.
Recently we heat treated some extruded steel(low alloy steel) tubes (hardening, polymer quench and temper) and they cracked in the bore. refractomere and viscometer tests shows that our polymer concentration is in the range. We think it may be due to the aged polymer. but the thing which has...
thanks for the reply guys, the heating mechanism is gas furnace, the time is different as we forge diameters as small as 90 mm to diameters as big as 450 mm.
Wrenchbender, our billets are not necessarily big to maintain the heat loss due to the air blast, do you probably know how much is the...
Hi all,
we are looking for an effective method of billet de-scaling or protecting coating to minimise the scaling of the billets before forging.
our forging temp is normally around 1200C (steel). currently we are using rotary de-scaler which same as the coatings we use is not very efficient...
Thanks guys.
Time asked for homogenising and aging are not long around 2 hrs.
unfortunately all the customers are not same and asking question here was purely for my own information. we do not have much historical data to prove homogenising is not necessary but definitely we will consider it...
Thanks RP, we have chosen 1080 as forging temp based on previou trial but as you said they are nearly in the same range. what you think about forging temp?
we have an order for forging some maraging steel and the customer has asked for 3 stages heat treatment. one at nearly 940 one at nearly 790 and one aging op.
am I right to think the first one is some kind of annealing or stress reliving op? as normally they have two stages heat treatment...
