How to know if forg...
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How to know if forge weld is successful

4 Posts
2 Users
David Baranowski
Posts: 10
Member Apprentice Bladesmith
Topic starter

Hello Smiths! 

I'm a new member, so I would like to Welcome you again before I describe my problem.

If I have some scrap material I always do grain structure tests. Recently I've made San Mai billet from o2 steel (1.2842) and 75Ni8 (15n20). The test piece grain structure looks good, the HRC of the core before the tempering is 63, so exactly what Ironwork factory declares in their sheets. Thing is, that one of the scale fell off after I broke the test piece. There is no delamination on the blade and visually knife looks good. 
Question is: Is the welding good/proper? 
The nature of impact is different than bending, so I guess it can't be compared to ABS journeyman/mastersmith test.  
Additional question: If anybody ever tried 90 degree angle bend with San Mai? If Yes: is delamination  normal/expected in case of proper welded San Mai?

English is not my first language, so if something is not clear please, feel free to ask. 


Posted : 04/07/2022 5:56 pm
David Baranowski
Posts: 10
Member Apprentice Bladesmith
Topic starter

and here is the knife itself

Posted : 04/07/2022 5:58 pm
Karl B Andersen
Posts: 0
Journeyman Bladesmith Forum Moderator

There should be no delamination whatsoever.

I have bent/flexed my San-mai MORE than 90 degrees many times.

When making my stainless/simple carbon San-Mai knifes, I do considerable forging on the bias - on edge - to reduce width, forge down the ricasso, and draw out the hidden tang. Any of these action should cause the steel to delaminate if there were a bad weld. 

Posted : 05/07/2022 8:11 am
David Baranowski
Posts: 10
Member Apprentice Bladesmith
Topic starter

Hello Karl! 

Thank you for the reply and information- appreciate it a lot! 
What about the impact/strike San-mai piece clamped in the vise?

The nature of bending (even to 90 degrees) is different. The force dissolve to whole blade surface, it's constance but smaller. In case of breaking San-mai billet clamped in the vise, the striking force will acumulate in the line near vise clamps. Naturally layers will brake one after another. The last one will bend before it brakes. 
I'm very curious if the breaking test I've made proves that the forge welding wasn't good enough? 

Posted : 10/07/2022 2:42 pm