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NINGBO LARGE STONES HARDWARE & ELECTRICAL TRADING CO.,LTD
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SOMETHING ABOUT SCREWS
1. Chemical composition analysis: 304 stainless steel is composed of 18% chromium and 8% nickel, while 316 stainless steel is composed of 16% chromium, 10% nickel and 2% aluminum. A clear distinction can be made through professional chemical composition analysis.
2. Salt spray test: The neutral salt spray time of 304 stainless steel is generally 48 to 72 hours, while the neutral salt spray time of 316 stainless steel is 72 to 120 hours. It can be identified by observing the corrosion resistance in salt spray environment.
3. Appearance Observation: 304 stainless steel has a smooth surface, a thin chromium oxide film, and a hard texture. 316 stainless steel has a rough surface, light yellow powder, and soft texture. The distinction can also be made by observing the appearance.
4. Spectral detection: Each metal has its own spectrum. 316 has more molybdenum (Mo) and nickel (Ni) than 304, so it can be identified through professional spectrum detection. This method requires going to a professional organization.
5. Use stainless steel testing liquid: There are many stainless steel testing liquids online now, which are helpful in identifying stainless steel materials. If you want to distinguish between 304 stainless steel screws and 316 stainless steel screws, you can choose Ni8 testing fluid and Mo2 testing fluid. Both 304 and 316 stainless steel will turn red when using Ni8 testing liquid, which means that their Ni content has reached the standard of 304 stainless steel and above, so Mo2 testing liquid should be used to test Mo. Mo2 testing liquid The 316 stainless steel screws are the ones that turn red and do not fade.
The above are several methods for identifying 304 stainless steel screws and 316 stainless steel screws, which can be selected according to the actual situation.
