Damascus delaminate after quenching

[kaplak]

Greetings all. My damascus blade delaminate after quenching. This happened more than 10 times since I started making damascus knife 2 years ago as part time. I am using gas forge and using O1 and L6. Used motor oil for quenching. No sign of delamination while forging and grinding. Please see picture and all delamminated blade was at same place ( at center and usually happen with thick blade) . I wonder if I overheat the blade before quenching or actually the blade was not weld perfectly. Please help me.

I am sorry for my bad English. Its not my everyday language.
Please click this link for image https://imgur.com/a/D2xFTd5

 

[John mc c]

Can't see that pic kaplak

 

[kaplak]

Can't see that pic kaplak

I already edited and put an image link thanks

 

[John mc c]

Can see now.
I wouldn' know enough to comment tho
They are tricky steels to make damascus from so id say regular failures are common for any smith but someone here will know the probable cause

 

[DevinT]

I would recommend using simpler steels. 1075 or 1084 and 15n20. The problem could be inadequate normalizing and annealing prior to quenching. Other problems could be weak welds or forging too hot. O1 and L6 have some chrome in them making them difficult to forge weld and will harden from forging temperatures causing internal stress. Most knife steels grow when quenched, O1 and L6 will grow at different rates causing stress.

Switch to 1084 and 15n20 and it will fix the problem. With more experience you can go back to the original mix.

Hoss

 

[Tom Lewis]

Hoss gave excellent advice. Some steels weld easier than others. Start with the easy steels like 1084 and 15N20.

 

[Stacy E. Apelt - Bladesmith]

I get that with san-mai occasionally. Billets with a thicker center layer have this issue more often.

Use lower temps in HT. If you are using a forge for HT, that is also an issue. Cycle the billet before grinding to get the steel in proper condition.

As already said, switch to 1084 and 15N20 and the problem will likely disappear.

 

[Kentucky]

L6/O1 is my favorite mix for Damascus . It’s so even and uniform in hardness and great performance. The problem is L6 or some of it (with molybdenum)can cause a lot of problems in the heat treat if it’s not ran through a cycle to get it ready. I’ve used L6 for axe bits for years and I found out the hard way unless you do a full normalization cycle or a fine spheroid it will split the core sometimes during heat treat. Not the weld but the L6 itself will tear itself in two..great steel but can be tricky to work with

 

[kaplak]

I would recommend using simpler steels. 1075 or 1084 and 15n20. The problem could be inadequate normalizing and annealing prior to quenching. Other problems could be weak welds or forging too hot. O1 and L6 have some chrome in them making them difficult to forge weld and will harden from forging temperatures causing internal stress. Most knife steels grow when quenched, O1 and L6 will grow at different rates causing stress.

Switch to 1084 and 15n20 and it will fix the problem. With more experience you can go back to the original mix.

Hoss

Thanks do you mean too hot when I forge into knife shape or too hot when I weld them? I always use same hot from start to finish. Its welding heat.

 

[kaplak]

L6/O1 is my favorite mix for Damascus . It’s so even and uniform in hardness and great performance. The problem is L6 or some of it (with molybdenum)can cause a lot of problems in the heat treat if it’s not ran through a cycle to get it ready. I’ve used L6 for axe bits for years and I found out the hard way unless you do a full normalization cycle or a fine spheroid it will split the core sometimes during heat treat. Not the weld but the L6 itself will tear itself in two..great steel but can be tricky to work with

I normalized 2 times before quenching. I like both steel to. They can cut nail without chipping. This problem occur only some times. Maybe 1 every 7 blade that I forge. Unluckily this time was competition chopper 7.5mm thickness 15 inch total long!!. Two days forging 288 layers. A bit frustrated.

 

[Kentucky]

I normalized 2 times before quenching. I like both steel to. They can cut nail without chipping. This problem occur only some times. Maybe 1 every 7 blade that I forge. Unluckily this time was competition chopper 7.5mm thickness 15 inch total long!!. Two days forging 288 layers. A bit frustrated.

I hate that. Bad luck buddy sorry

 

[kaplak]

I get that with san-mai occasionally. Billets with a thicker center layer have this issue more often.

Use lower temps in HT. If you are using a forge for HT, that is also an issue. Cycle the billet before grinding to get the steel in proper condition.

As already said, switch to 1084 and 15N20 and the problem will likely disappear.

Thanks for reply. I will try lower temp and yes it usually occur on thicker blade. I've got two knife from one billet kneck knife 3.5mm thick and chopper 7.5mm thick. The chopper delaminate and no problem with the neck knife.

 

[kaplak]

Hoss gave excellent advice. Some steels weld easier than others. Start with the easy steels like 1084 and 15N20.

I cannot buy 15n20 and 1085 in my country Malaysia. Sometimes the problem happened when I used 4340 for replace L6. Its only option in my contry 4340 and L6 or band saw blade.

 

[DevinT]

I cannot buy 15n20 and 1085 in my country Malaysia. Sometimes the problem happened when I used 4340 for replace L6. Its only option in my contry 4340 and L6 or band saw blade.

Most large saw mill type band saws in the US are made from 15n20. 99% of all damascus in the US that has 15n20 comes from used band saw blades.

And yes, lower your forge welding temperature and increase your soak time.

Hoss

 

[John mc c]

I'm no expert but forging shape all at welding heat is too hot
Welding heat for welding then lower forging heat when it's all welded

Thanks do you mean too hot when I forge into knife shape or too hot when I weld them? I always use same hot from start to finish. Its welding heat.