Adjusting aust. time per thickness, Magnacut

[Scaniaman]

I heat treated this steel successfully at 3.5 mm thickness. I am now going to use some thin stock at 1.65 mm.
Should I reduce the time at aust temp? I went with 35 min at 1120 C, with 3.5 mm.

Edit: that was 25 min, not 35

 

[DanF]

Watching

 

[Natlek]

The main difference is that they need different times to reach the set temperature, after that the time can be the same. At least I think so

 

[Seedy Lot]

Data sheet has 1120 C for 20 minute soak. I have used this with 2.7 mm material and hit target hardness goals.

 

[DevinT]

I heat treated this steel successfully at 3.5 mm thickness. I am now going to use some thin stock at 1.65 mm.
Should I reduce the time at aust temp? I went with 35 min at 1120 C, with 3.5 mm.

No

 

[Alex Topfer]

A lot of the discussion seems to be an hour per inch, to ensure that the entire piece is up to temperature and in a uniform state. Looking around this appears to be longer than necessary
We're dealing with 3mm stuff, if you do a linear projection that's a ~7 minute soak. For something 1.6mm thick I would be more worried about cold spots longitudinally than getting the inside hot, like the tip being in a cold spot in your furnace.
As Seedy said the datasheet says 20 minutes at 1120c, so i would do that

(Note: I don't mess with that chromium stuff )

 

[Larrin]

A lot of the discussion seems to be an hour per inch, to ensure that the entire piece is up to temperature and in a uniform state. Looking around this appears to be longer than necessary
We're dealing with 3mm stuff, if you do a linear projection that's a ~7 minute soak. For something 1.6mm thick I would be more worried about cold spots longitudinally than getting the inside hot, like the tip being in a cold spot in your furnace.
As Seedy said the datasheet says 20 minutes at 1120c, so i would do that

(Note: I don't mess with that chromium stuff )

Yes often datasheets will give a time per inch but then say that there is a minimum soak time to use below one inch. In this case with MagnaCut going thinner than 3.5mm I would treat the recommended hold times as minimums.

 

[Seedy Lot]

In this case with MagnaCut going thinner than 3.5mm I would treat the recommended hold times as minimums.

So Larrin, the 20 minute soak for 1120 C per data sheet would be minimum amount of soak time? If this is the case what might be the maximum amount of hold time at 1120 C

 

[Larrin]

So Larrin, the 20 minute soak for 1120 C per data sheet would be minimum amount of soak time? If this is the case what might be the maximum amount of hold time at 1120 C

The datasheet says minimum on it, or actually “Min Aust time.” What the maximum could be I don’t know since technically people could be heat treating very thick pieces. But I would guess much longer times than the minimum could be used without significantly affecting the properties. Temperature matters more than time.

 

[Seedy Lot]

The datasheet says minimum on it, or actually “Min Aust time.” What the maximum could be I don’t know since technically people could be heat treating very thick pieces. But I would guess much longer times than the minimum could be used without significantly affecting the properties. Temperature matters more than time.

Thanks Larrin. I have been thinking about this for some time and me stressing soak times is silly. Time to buy more quench plates.