Test Method For Nitrogen in Carburizer

1 Scope

This standard specifies the principle, reagents and materials, instruments, sample preparation, analysis steps, and result calculation for the determination of nitrogen content in low-nitrogen carburizers by oxygen and nitrogen analyzers.

2. Normative reference standards

Due to the detection and analysis of nitrogen content in carburizers, the national standard has not been formulated, and the inert gas fusion thermal conductivity method for nitrogen content in steel (conventional method) GB/T20124-2006 is cited.

3. Principle

Oxygen and nitrogen analyzer, using pulse thermal conductivity method to measure nitrogen in low nitrogen carburizer. The sample is wrapped in a nickel capsule with a lid and pressed by hand and mechanically, heated and melted in a helium flow in a high-temperature electrode furnace, and nitrogen is released in the form of molecular N2, which is quantitatively detected by a thermal conductivity detector. And directly displayed by the computer in the form of nitrogen percentage content or ppm level content.

4. Reagents and materials

Unless otherwise stated, only reagents confirmed to be analytically pure were used in the analysis, and distilled water or water of equivalent purity was used in the water cooling unit.

5. Instrument Leco Nitrogen and Oxygen Analyzer

6. Sample preparation

Put 120g of the sample into the fully-sealed laboratory pulverization sample machine, vibrate and pulverize for 40s-60s, take out, sieve with 0.125mm sample size, take out the material on the sieve, put it into the bowl and continue to pulverize for 45s, take it out and sieve, If there is still material on the sieve, take it out and put it into the bowl and crush it for 45 seconds, then sieve it, mix all the material under the sieve, and pack it into a bag. Place the sample in a drying oven at 105±5℃ for 30min, take it out, and cool it to room temperature in a desiccator.

7. Analysis steps

<1> Weighing sample size Weigh 0.0200g - 0.0300g sample, accurate to 0.0001;

<2> Determination of the sample

Put it in a nickel-capped capsule that has been tared on the electronic balance in advance, cover the nickel capsule, and use a special pressing tool to flatten the nickel capsule to drive out the air, and be careful not to break it. The nickel capsule was weighed on an electronic balance and entered into the oxynitrometer software weight library. The heating power was adjusted to 4000w, and the upper sample injection method was used for detection. After the detection, the melting state of the sample was checked, and the validity and accuracy of the detection results were judged.