GB/T 223.89-2019Iron, steel and alloy - Determination of tellurium content - Hydride generation-atomic fluorescence spectrometric method (English PDF)

1 Scope

GB/T 223.89-2019 is the Chinese national standard on iron, steel and alloy - determination of tellurium content - hydride generation-atomic fluorescence spectrometric method, in the field of metallurgy. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 30 August 2019 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 July 2020. Classification: ICS 77.080.01, CCS H11. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This Part of GB/T 223 specifies a method for the determination of tellurium content by hydride generation-atomic fluorescence spectrometric method. This Part applies to the determination of tellurium content in iron, steel and alloy. The determination range is 0.00001 % ~ 0.005 % of mass fraction.

2 Normative references

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

GB/T 6379.1 Accuracy (trueness and precision) of measurement methods and results - Part 1: General principles and definitions

GB/T 6379.2 Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method

GB/T 6682 Water for analytical laboratory use - Specification and test methods

GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition WEIGH 10 g of potassium borohydride; DISSOLVE in potassium hydroxide solution (5 g/L) and DILUTE to 500 mL. Prepare before use.

4 Reagents...

5 Instruments

Non-dispersive atomic fluorescence spectrometer, fitted with hydride generator and special tellurium hollow cathode lamp. After optimization, the non-dispersive atomic fluorescence spectrometer used shall achieve the following indicators:

a) Short-term precision: Measure the fluorescence intensity of the tellurium 5 %, precipitate will occur at the bottom of the beaker. The precipitate may be crushed with a glass rod and then ammonium fluoride solution (see 4.9) is added. Table 2 -- Acid used to dissolve different types of samples Sample type Amount of hydrochloric acid and nitric acid used Medium and low alloy steels of which the mass fraction of pure iron, pure nickel and chromium is less than 5 % Add 5 mL of nitric acid (see 4.6) to decompose the sample, and then add

7.5 mL of hydrochloric acid (see 4.3) Stainless steel 10 mL of hydrochloric acid, nitric acid mixed acid (see 4.7) Superalloy 10 mL of hydrochloric acid, nitric acid mixed acid (see 4.8)

7 Analysis steps...

9 Precision

The precision of this Part is determined by a joint test of 9 levels of tellurium in 11 laboratories. Each level is tested twice in each laboratory under the repeatability conditions specified in GB/T 6379.1. The samples used and the precision test results are listed in Annex A. The test results reported by each laboratory are statistically analyzed according to GB/T 6379.2. The correlation between the obtained tellurium content and the repeatability limit r and the reproducibility limit R is shown in Table 5. Table 5 -- Repeatability and reproducibility of tellurium Element Range/% Repeatability limit r Reproducibility limit R Tellurium 0.00001 ~

0.005 m in the formulas is the average value of the two measured values, expressed in % (mass fraction). The repeatability limit r and the reproducibility limit R are obtained according to the formulas given in Table 5. Under repeatability conditions, the absolute difference between the two independent test results is not greater than the repeatability limit r, on the premise that the repeatability limit r is greater than 5 %. Under reproducibility conditions, the absolute difference between the two independent test results is not greater than the reproducibility limit R, on the premise that the reproducibility limit R is greater than 5 %.

10 Test report

The test report shall include the following: