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plating, anodizing, & finishing Q&As since 1989




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Nitriding and Shot Peening

2000

Recently, a failure of an H13 gas nitrided part was experienced. The failure apparently originated at the nitride white layer and propagated through the diffusion layer and base material.

1. Has anyone experienced similar failures?
2. Does anyone know of an easy way to remove the white layer formed during gas nitriding besides secondary machining?
3. Finally, has anyone shot peened a nitrided surface with success? This last question addresses the question of possibly removing the white layer and introducing residual compressive stress to enhance fatigue properties.

Alan Simon
Dynisco HotRunners - Gloucester, MA USA

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2005

I've just read that citric acid will remove the white layer. Or abrasive blasting. If the white is not removed From the surface it can cause fatigue problems in the future. I guess it did.

George Allen
- Harrisburg, Pennsylvania, USA