Proper austenitizing temperature for 80CRV2?

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shqxk

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The label said heat treat the same as 5160 but I curious since the steel is eutectoid it should benefit from lower austenitizing temp.

I usually heat treat 5160 at 1595F and Park50 quench... (I found you will get much harder as quenched piece with fast oil quench, none distortion problem at all)

Would 1500F with fast oil quench do the trick for 80CRV2, what you guy thought?
 
If you get a harder product when going beyond the needed quenchant, there is something that is getting done to a lesser degree elsewhere. The as-quenched maximum is pretty solidly set, faster quenchants aren't going to make it harder. I suspect the temperatures or the soak time are not right. How are you determining the austenitization temp, and how long do you soak the 5160?

For 5160, the austenitizing temps are 1500-1525°F with a 5-10 minute soak. 1595° is too high for a knife blade in 5160. Medium speed oil is fine, but Parks #50 won't cause a problem.
For 80CRV2 should be austenitized at the same temps. A soak of 5-10 minutes is needed to get everything in solution.
 
I actually use Japanese SUP9 steel which has pretty similar compostion to 5155 steel.

This is how I HT this steel (I use digital control gas oven)

Heat to 1625F, equalize then air cool
Heat to 1500F, equalize then air cool
Heat to 1425F, equalize then air cool
็Heat to 1595F, 10min soak then quench in Park50
2 times tempering at 400F each.

This is the list for forge steel I usually work with at this time

Bohler'sK460 (O1) - 1500F austenitizing 15min soak, warm veg oil quench.
Bohler's R100 (52100) - 1500F austentitizing 15min soak, warm veg oil quench.
Japanese SK4 (1095) - 1470F austenitizing equalize, Park50 quench.
Japanese SK5 (1086) - 1470F austenitizing equalize then Park50 quench.
White steel #2 - 1470F same as SK4 equalize then Park50 quench.
 
Why are you using such a high austenitizing temperature on the steel? 5155 austenitizes at 1525°F. In a blade thickness with a fast quench 1500°F would work fine, too.

Perhaps you read something wrong on the HT data supplied with the steel. Also, it is hypo-eutectoid, and has a bit of alloying, thus the austenitization temp is a tad higher that the eutectoid.


1084 is the eutectoid, and the austenitization temperature for it is 1500°F. In knife thicknesses, 1475°F works fine.
 
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Thank you for the advice Stacy. I appreciate it. I think I will do 1525F as your suggest.

I have try 1525F with the steel (SUP9) before, also with 1550F and both temp I have great result... until Phd metallurgist S.Issara who have done lab experiment with this steel to find the best heat treat protocol for knife blade (SUP9 is by far the most popular steel for knife making in Thailand) suggest we to use the maximum austentizing range of the steel for better edge holding and also a tad improve in corrosion resistance (might be due to most of chromium carbide bondings have been dissolve at the temperature so we have a bit more free Cr and a bit more C to get in solution)

But I sincerely have to disagreed with you... the faster quench does reletive to as quenched hardness.

Me and my friends who knifemakers have done experiment many times that the faster quenchant will get you higher as quench hardness no matter how forgiving on cooling rate of steel are.
On kind of deep hardening steel like 52100 or O1 it would be too little difference to notice. But on steel like D2, you will have significantly difference as quenched hardness between oil and aluminium plate quench, oil will get you much harder...
 
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I agree with you that there can be different as-quenched hardness in high alloy steels depending on the media, but we are not talking about them.

Your question was on 5160.
5160 properly austenitized and then quenched properly in oil will reach the maximum hardness of around Rc65. No mater if you quenched it in liquid helium, it would only reach Rc65.
If you are getting lower hardness as-quenched, something is not right with the other HT parameters. Time, temperature, steel quality, equipment errors ( TC not reading properly), quenchant temperature, etc. All can lower the as-quenched hardness from theoretical maximum.

If you have a metallurgist working with you and your friends, and are pleased with his methods ... use his data.
 
If 80CrV2 is totally the same as our NCV1 Steel then.

For quenching in oil: Austenize in 820-830*C for 10-15 minutes.
Then quench in hot oil. ( I using 170*C hot oil ,and after this placing between two hot steel faced slabs)
You should get after tempering in 175*C something about 61HRc +/- 1HRC.

Before this 650*C for 2h and cooling with a kiln to room temperatur.

Caution: this steel is fast decarb friendly. I suggest using anti-decarb compounds.
 
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