Nitriding hardness depth
Nitriding hardening depth is the thickness of the case layer where hardness is higher than in the core due to nitriding. This increases strength and toughness but makes the material harder to weld.
Physicochemical Mechanism of Action
Nitriding is a chemical process where nitrogen diffuses into the steel surface, changing the crystal structure of the edge layer and increasing its hardness.
Metallurgical Relevance & Welding Risks
A high nitriding depth can cause poor weldability because the material is harder in this zone. This increases the risk of cracks and adds stress to the weld pool. If welded too hard, the steel can suffer hot cracks or uneven distortion.
Workshop Practice & Instructions
To minimize the risk of cracks and uneven welding, consider the nitriding depth when selecting steel. For heavily nitrided materials, careful pre-treatment and slow cooling are required. The maximum hardness in the weld zone should be below 500 HV to maintain toughness.