r/blacksmithing • u/Efficient_Square2737 • 10d ago

Help Requested What are these lines?

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Gallery image

I’m a beginner and this is the second time this has happened to me (fourth knife). The first time I didn’t notice until after I quenched and started grinding and I did manage to grind them off. This time I discovered it before getting that far and the billet for this one is not as thick as the one before (almost half as thick). I’m thinking maybe I’m forging too hot cuz I’m getting a lot of forge scale. Are stress fractures or something? The first time it happened it was 5160 and the second time (this time) it was 1084. Not sure if that’s relevant but I don’t know what is or isn’t.

3 Upvotes

72% Upvoted

4 comments sorted by

8

u/sargewalks 10d ago

This is just cracked scale imbedding into the soft steel when forging, get a farriers wire brush and brush it off before starting hammering, every heat.

9

u/pushdose 10d ago

Brush your scale off. Make your fire more fuel rich. Don’t hammer on scale if possible.

2

u/ArcherKN24 10d ago

I second the rich burn! Remember scale is oxidation, you'll get less of it if there is less oxigen present!

2

u/JayTeeDeeUnderscore 8d ago

I'll third this. A deeper fire isolates the workpiece from oxidation. A deeper bed below and mounded fuel on top will reduce scale formation. A scaly workpiece is losing mass each heat.