4140mod Forged bar -Normalizing - is it still done?

[acrmnsm]

We have a company mats spec that requires forged bar that we buy in to have been normalised before Q+T.
In my structural steel experience, normalising has been pretty much superceded these days. Eg in Rolled structural steels, controlled rolling is used where lower temps in the last stages of hot rolling are employed to control austenite grain size so that it transforms to a fine grained ferrite.
So do they do they same thing in forged bar?
We have been offered some 6inch 80ksi 4140mod but the supplier has noted that it does not meet our mat spec to be normalized prior to Q+T.

 

[acrmnsm]

PS Maquaid EHN is 6-8 so i guess its all good.

 

[CoryPad]

Controlled cooling after forging is used to adjust microstructure (e.g. grain size) and therefore mechanical properties. Normalizing also is used.

 

[acrmnsm]

Ok so they do it on forging too. Great thanks.

 

[Tmoose]

We specify normalizing on 1045 and 4140 shafts we have made as a nice upgrade in material specs from hot formed or sometimes forged, depending what is available.
Also Timken seems to list better properties to the core than q&t, which we need because we whittle the shaft down pretty far for bearings and couplings.

It seems we have to ask and pay for it these days.

 

[acrmnsm]

Yeah thats what I've just been told by Tata UK, its an optional extra.
We are going to bore it out..

 

[OGMetEngr]

Normalizing, in general, will give more consistent properties as the temperature is much better controlled (assuming calibrated and uniform furnaces/instruments) as well as uniform through thickness. Forging temperature, if monitored at all besides color, will be much less uniform through thickness. Rolling mills can control these working temperatures better than say a forging shop, but normalizing in properly setup batch furnaces will provide the most consistent properties and microstructure.

 

[tbuelna]

6" dia normalized 4140 bar should have a UTS higher than 80ksi. So your supplier was probably correct to note that the material was likely not in a normalized condition.