GB/T 42275-2022Hardmetals—Determination of total carbon content—High frequency combustion infrared absorption or thermal conductivity method (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents" drafting.

1 Scope

This document describes a method for the determination of the total carbon content of refractory metal carbides and cemented carbides used as cemented carbide raw materials.

This document is applicable to carbides and complex carbides of refractory metals such as tungsten, tantalum, niobium, chromium, vanadium, titanium, etc., and the mixture of carbides and bonding metals Determination of total carbon content in mixtures (without forming agent) and pre-sintered or sintered cemented carbide produced from these mixtures, the determination range (mass Quantity fraction) is 4.00%~20.00%.

2 Normative references

This document has no normative references.

3 Terms and Definitions

This document does not have terms and definitions that need to be defined.

4 Principles

The sample is heated and burned in the oxygen flow of the high-frequency induction furnace, and the generated carbon dioxide is carried by the oxygen to the infrared detection cell or thermal conductivity detection In the cell, the computer system calculates the carbon content according to the quality of the sample and the signal of the detection cell.

5 Reagents or Materials

5.1 Tungsten flux. the purity is greater than 99.8%, and the carbon content (mass fraction) is not greater than 0.0005%.

5.2 Copper flux. the purity is greater than 99.8%, and the carbon content (mass fraction) is not greater than 0.0009%.

5.3 Iron flux. the purity is greater than 99.8%, and the carbon content (mass fraction) is not greater than 0.0005%.

5.4 Standard substance. a certified series of standard samples or other applicable standard samples with a carbon content similar to that of the sample to be tested.

5.6 Carbon-sulfur ceramic crucible. burn at 1100°C for at least 2 hours until the carbon blank value is constant, and store it in a desiccator after cooling.

5.5 Oxygen. the purity (volume fraction) is not less than 99.5%

6 Instruments and equipment

High-frequency induction carbon determination instrument. including high-frequency induction furnace, purification furnace, catalytic furnace, carbon dioxide infrared detection pool or thermal conductivity detection pool, computer and software control system.