Soft tang but hardened blade..?

[Shanghai McCoy]

I was messing around with a funky old butcher styled knife, taking remains of the scales off, and it appears that the tang is just soft but the blade portion was hardened.
It's just an old unmarked knife so I'm wondering if this was a standard thing for the cheaper of the cheap old knives?
I'm thinking that older knives I've encountered in the past were heat treated full length. But now I'm not so sure...?

 

[DMW1116]

It wasn’t unheard of to heat treat knives by hanging them from the tang and heating them in a bath of molten lead. Thats before we learned how bad of an idea that was. It would however explain a hardened blade and soft handle.

 

[hso]

It is easy to get a hard blade/soft tang.

Was the spine soft too?

 

[Shanghai McCoy]

It is easy to get a hard blade/soft tang.

Was the spine soft too?

There's really not much difference in hardness that I can tell. But I'm just testing it with a file.
It may just be a cheap, old, not very well made kitchen knife..?

 

[hso]

There's really not much difference in hardness that I can tell.

Between the spine and the tang or spine and edge?
IOW, if the spine is soft and edge hard, it was edge quenched instead of the blade having been quenched as a whole. The tang apparently wasn't quenched since it is soft.

 

[Shanghai McCoy]

Between the spine and the edge.
The tang is downright "bendy"...

 

[hso]

Between the spine and the edge.

The blade is through hardened instead of edge hardened and the tang isn't hardened at all. Be careful "bending" the tang since it could be stub with a mild steel extension that can break at the forge/weld line.

 

[Slamfire]

Can't see a reason why you would want a hard tang. Hardening steel makes it brittle. So, do you plan to sharpen your tang? There can be a lot of stress right at the ricasso, having a softer steel may prevent the blade from snapping.

 

[DMW1116]

For some thinner blades in the 0.05” range, leaving the tang completely soft can allow the blade to bend just in front of the handle with any accidental torquing or lateral force.

 

[Show Me]

The tang on a file is soft for the same reason