Steel Problem

[Tom Militano]

I ground eight blades last week, four from one piece of bar stock, and four from another. They were both supposed to be 1084. Two normalizing cycles, one quench, two temper cycles. Four of them came out fine, no problems. The other four came out super hard. I dropped one on the concrete floor of my shop and it broke, so I checked the other three and shattered all three of them. All the bad ones came from the same piece of stock. Any ideas? The bad ones came out harder than a woodpeckers lips. I don't know what I got a hold of, but I don't want anymore of it. Has anyone run into this problem? I got the steel from a supplier I use a lot and never had a problem with, so I won't say where it came from.

 

[ysforge]

did it grind harder too? Try tempering at a higher temp.

 

[Tom Militano]

I couldn't tell any difference when I was grinding it.

 

[Pete Allan]

Your supplier might not be at fault either. Some time back I ordered in a batch of 12L14 screw stock and one piece in the batch was VERY hard -- not 12L14 at all as that stuff is as soft as brass. It looked like all the rest and was color coded the same. ???

 

[ragnoor]

Tom, sounds to me that you had not tempered the blades, yet. If so, sure sounds like 1095 to me. I can do a water quench and if I am not careful will crack the 1095, before I can get a draw on the blade.

Ken Beatty

 

[Tom Militano]

Thanks everybody. Ken, I tempered all eight blades at the same time. I've never run into anything like this before.

 

[AwP]

Since the carbon amount in the steels is a range, not an exact amount, both bars could have been the same kind of steel but at opposite ends on the range. I donno if this is the case, but it's a possibility.

 

[Stacy E. Apelt - Bladesmith]

Another possibility is that the hardening was not the same.Lets assume that you started quenching in room temperature oil,in an undersized quench tank.The first four blades would have raised the quench bath temp to a higher temp.The last four could end up a lot softer than the first.If the temper cycle was also a bit low,say 350F,it would not draw down the extra hard blades,and they would still break like glass.
Stacy