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I am trying to find out what temperature steel is required to be heated at in order to meet the technical delivery conditions in PD 970.
So to achieve T or V condition what temperature does the steel need to be heated to? I thought there would be a standard for this but I cant find one. Anyone able to help?
It depends on the "steel" grade...
T and V are size related also. So it depends on the size.
PD970 is a standard. Current version is 2005.
is it in [url= https://drive.google.com/file/d/1HjTlGp4u96YHFo9FsStw3oW5k5VcnV_O/view?usp=sharing ]here[/url]
So how does the heat treatment company know what temperature to apply the heat treatment at to achieve T or V condition. Is this just based on experience and down to the individual heat treatment company?
This is not a one line answer.
T and V are in essence the required mechanical properties after mechanical/ heat treatment
The temperatures required to achieve these properties will be down to the chemistry of the material and the size.
PD 970 does give some guidance about normalizing temperatures however if the "steel" you have is to be delivered in the QT condition then there is no guidance in the spec.
Alternatively, contact a steel supplier to see if they can get you material that is already certified to the required grade.
Most of the T/ V grades are high strength, which suggests that by design its critical ( high loads).. probably shouldn't be looking for answers on STW 🙂
I haven't got the material properties I require and I think the material hasn't been heated to a high enough temperature during the process hence not achieving the required mechanicals.
As a designer it is easy just to specify what you want but it is important to have an understanding of how it is achieved. After a lot of googling and looking through standard etc I couldn't find a clear answer so thought STW might have some people who work in heat treatment and therefore able to assist.
I assumed there would be a BS specification that advised the heat treatment company what the correct temperature etc was to achieve the required mechanicals but it would appear that isn't the case.
It's an impossible problem to resolve without knowing the material properties. Heat treatment varies massively over different grades of steel. What properties where you trying to achieve? A certain UTS or a hardness? May give a clue to what you've got.
If you don't think you have the properties then either test the material ( mechanically ) or ask the supplier to re-heat-treat a sacrificial using the same parameters. Assuming these are recorded. Most HT facility's will have a means of recording time and temperature.
There is no silver bullet sorry.
Not looking for a silver bullet. The manufacturer has got to remake the component so that isn’t an issue. I just want to understand why it hasn’t met the required properties and I think the component was not treated at the right temperature (at least 20 degrees too low) so I was trying to understand where they got the temperatures from and there didn’t seem to be a consistent source for these temperatures.
H/T can be hit and miss. The steel might be borderline with one of the alloying elements that enables the property that's wrong. The oven may have not made temperature or time was insufficient for the cross sectional area of the component. This is the reason tensile and impact test pieces are used for critical components
