GB/T 20975.30-2019Methods for chemical analysis of aluminium and aluminium alloys—Part 30: Determination of hydrogen content—Heating extraction-thermal conductivity method (English PDF)

Foreword

GB/T 20975, Methods for chemical analysis of aluminium and aluminium alloys, is divided into 31 parts:

-- Part 1: Determination of mercury content;

-- Part 2: Determination of arsenic content;

-- Part 3: Determination of copper content;

-- Part 4: Determination of iron content - Orthopenanthroline photometric method;

-- Part 5: Determination of silicon content;

-- Part 6: Determination of cadmium content - Flame atomic absorption spectrometric method;

-- Part 7: Potassium periodate spectrophotometric method;

-- Part 8: Determination of zinc content;

-- Part 9: Determination of lithium content - Flame atomic absorption spectrometric method;

-- Part 10: Determination of tin content;

-- Part 11: Determination of tin content;

-- Part 12: Determination of titanium content;

-- Part 13: Determination of vanadium content - N-bezoyl-Nphenylhydroxylamine spectrophotometric method;

-- Part 14: Determination of nickel content;

-- Part 15: Determination of boron content;

-- Part 16: Determination of magnesium;

-- Part 17: Determination of strontium content - Flame atomic absorption spectrometric method;

-- Part 18: Determination of chromium content;

-- Part 19: Determination of zirconium content;

Caution -- The personnel who uses this Part shall have hands-on experience in formal laboratory work. This Part does not address all possible security issues. It is the responsibility of the user to take appropriate safety and health measures and to ensure compliance with the conditions which are set by the relevant national regulations.

1 Scope

This Part of GB/T 20975 specifies the method for the determination of hydrogen content in solid aluminum and aluminum alloys by heating extraction-thermal conductivity method.

This Part applies to the determination of hydrogen content in solid aluminum and aluminum alloys. Determination range: 0.05 µg/g ~ 1.0 µg/g.

Note: This method only performs inter-laboratory test on the specified measurement range. However, the laboratory can extend the measurement range of this method through experiments such as method sensitivity, precision and bias in method validation.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 8170-2008, Rules of rounding off for numerical values & expression and judgement of limiting values

3 Method summary

Place the sample in a high-purity graphite crucible; heat to just below the melting point to drive off the surface hydrogen; then, continue to heat under a […]

6 Sample

Weigh a certain mass of the sample (6.1); accurate to 0.001 g. The sample mass for pulse heating method should be 1 g ~ 4 g; the sample mass for high-frequency heating method should be 2 g ~ 6 g.

7 Test steps

Under the same test conditions as the sample, use aluminum alloy standard sample or quality control sample (5.1) that is approved by both parties to calibrate the working standard, according to the instrument analysis software.

8 Result calculation

8.1 The instrument automatically displays the test results. The test results are expressed to three decimal places; the rounding-off value is according to 3.2, 3.3 of GB/T 8170-2008.

8.2 Take the average of the two test results. If the two test results are not within the repeatability limit, it should be retested. […]

9 Precision