Nitriding is a low-temperature surface chemical heat treatment process that diffuses nitrogen atoms into the steel surface at 500-580℃. No subsequent quenching is needed, yet it drastically boosts the workpiece’s surface hardness, wear resistance, corrosion resistance and fatigue strength—with minimal deformation. It’s a core process in high-end mechanical manufacturing, widely applied to precision load-bearing components like gears, shafts and molds.

However, nitriding performance can never be judged solely by process parameters. Metallographic analysis is the pivotal quality control method, and a mandatory inspection item specified in the industry standard GB/T 11354.

Via metallographic observation, we can accurately measure the nitrided layer depth, characterize the morphology of compound and diffusion layers, and detect fatal defects such as reticular/vein-like nitrides and surface porosity. These flaws directly cause stress concentration and sharp toughness drop in workpieces, leading to premature wear, cracking and failure in service.

Professional metallographic testing for nitrided steel not only verifies process rationality and enables timely parameter optimization, but also mitigates product quality risks from the source. It safeguards the service life and operational safety of components, making it an indispensable step in the production and quality control of nitrided steel.

🔧 Metallographic Preparation Process for Nitrided Steel

1️⃣ Grinding: Flatten the surface with P180 metallographic sandpaper disc

2️⃣ Fine grinding: POS grinding disc + 9μm PD-WT polishing suspension

3️⃣ Rough polishing: SC-JP polishing cloth + 3μm PD-WT polishing suspension

4️⃣ Final polishing: ET-JP polishing cloth + 1μm PD-WT polishing suspension

5️⃣ Etching: Corrode with 4% nitric acid alcohol solution

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