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GOST 22598-93

GOST 22598−93 low-alloy Nickel and Nickel alloys. Method of determining oxygen


GOST 22598−93

Group B59


INTERSTATE STANDARD

NICKEL AND LOW-ALLOY NICKEL ALLOYS

Method of determining oxygen

Nickel and low nickel base alloys. Method of determination of oxygen


AXTU 1709

Date of introduction 1995−01−01

Preface

1 was DEVELOPED by Gosstandart of Russia

SUBMITTED by the Technical Secretariat of the Interstate Council for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification 21 October 1993

The adoption voted:

   
The name of the state The name of the national authority
standardization
The Republic Of Belarus Belstandart
The Republic Of Kyrgyzstan Kyrgyzstandard
The Republic Of Moldova Moldovastandart
Russian Federation Gosstandart Of Russia
The Republic Of Tajikistan Tajikstandart
Turkmenistan Turkmengeologiya
Ukraine Gosstandart Of Ukraine

3 INTRODUCED TO REPLACE GOST 22598−77

INFORMATION DATA


REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

   
The designation of the reference document referenced Section number, paragraph, sub-paragraph
GOST 8.315−91 2.2, 3.2.2, 5.5
GOST 8.326−89 2.1
GOST 61−75 2.2
GOST 492−73 Chapeau
GOST 1465−80 2.2
GOST 3118−77 2.2
GOST 4461−77 2.2
GOST 6709−72 2.2
GOST 10988−75 2.2
GOST 13083−77 2.2
GOST 18300−87 2.2
GOST 19241−80 Chapeau
GOST 25086−87 1, 5.5



This standard establishes the procedure for determination of oxygen by the method of reductive melting in the low-alloy Nickel and Nickel alloys according to GOST 492* and GOST 19241 in the range of mass fraction from 0.0005 to 0.30%.
_______________
* On the territory of the Russian Federation GOST 492−2006. — Note the manufacturer’s database.

The method is based on reaction of interaction of dissolved and bound oxygen with carbon of the graphite crucible at high temperature. The oxygen from the molten sample is released in the gas phase in the form of carbon monoxide. Carbon monoxide is supplied to the analyzer that provides quantitative analysis of the extracted gas.

The method of reductive melting has two options: restorative melting in vacuum method (vacuum melting), and melting of the recovery current of inert gas (the carrier gas).

1. GENERAL REQUIREMENTS


General requirements for method of analysis according to GOST 25086.

2. APPARATUS, MATERIALS AND REAGENTS

2.1. The devices based on the method of reductive melting in a vacuum:

-911М1;-1403М1 design Giredmet and their modifications.

Express oxygen analyzers based on the method of reductive melting under a stream of neutral carrier gas: RO-16; RO-116; RO-316, AK-7516 and their modifications.

Equipment must undergo metrological certification in accordance with GOST 8.326*.
_______________
* On the territory of the Russian Federation there are PR 50.2.009−94. — Note the manufacturer’s database.


Note: you may apply a different design with similar metrological characteristics.

2.2. For preparing samples for analysis and carrying out analysis used the following materials and reagents:

nitric acid according to GOST 4461;

acetic acid according to GOST 61;

hydrochloric acid according to GOST 3118;

the technical rectified ethyl alcohol according to GOST 18300;

distilled water according to GOST 6709;

bars of Nickel GOST 13083;

copper rods GOST 10988;

standard samples of composition of metals according to GOST 8.315*;
_______________
* On the territory of the Russian Federation GOST 8.315−97, here and hereafter. — Note the manufacturer’s database.

files GOST 1465.

2.3. The list of materials and reagents required for the operation of specific brands of equipment are shown in the relevant production structures.

3. PREPARATION FOR ASSAY

3.1. Sample preparation

3.1.1. Samples must not have cracks, burrs, pits.

3.1.2. The mass of samples is determined depending on the mass fraction of oxygen at the table.1.

Table 1

   
The mass fraction of oxygen, % The mass of sample, g
From 0.0005 to 0.001 incl.
3,0−1,2
SV. 0,001 «0,003 «
1,2−1,0
«Of 0.003» to 0.01 «
1,0−0,7
«0,01» 0,3 «
0,7−0,3

3.1.3. Compact the surface of the samples subjected to mechanical Stripping (a file with a fine-cut or cutter of high speed steel on a lathe), washed in alcohol and dried in air.

3.1.4. Samples with a mass fraction of oxygen less than 0,003%, as well as samples of complex configuration or thickness (diameter) of less than 3 mm regardless of the mass fraction of oxygen in them is further subjected to etching in a freshly prepared Etchant solution consisting of 700 parts of glacial acetic acid, 300 parts of nitric acid and 5 parts of hydrochloric acid. Etching conditions: freshly prepared solution was heated to 70−80 °C, is immersed in the sample and etched for 40 s. Then the sample is washed in running and distilled water and alcohol. Allowed to poison the samples of the same batch of metal simultaneously in the same volume of Etchant. After etching, the specimen should have a bright shiny surface without spots.

3.1.5. The ground is prepared for the analysis of samples is determined with an error not more than 0.01 g.

3.1.6. Not allowed prepared to analyze the samples stored in air more than 2 hours.

3.2. Preparation of units for testing shall be in accordance with technical description and instruction on exploitation.

3.2.1. The prep plants based on the method of reductive melting in a vacuum includes:

check the unit for leaks and degassing of the crucible for 2000−2100 °C for 1.5−2 h. the End of the degassing is characterized by the correction value in the reference experiment, which should not exceed 3.5 micrograms of carbon monoxide for 3 min extraction at a temperature of 1600 °C;

the formation in the crucible a bath of molten metal, in which there will be analysis of samples.

For the analysis of pure Nickel in the crucible is loaded 2−3 g of Nickel and degassed for 4−5 minutes at a temperature of 1600 °C, followed by a blank experiment and measure the correction that 3 min extraction at a temperature of 1600 °C must not exceed 3.5 micrograms of carbon monoxide.

For the analysis of low-alloyed Nickel alloys using copper-Nickel bath. The order of its formation are the following: reduce the temperature to 1100 °C, is loaded into the crucible first 3−4 g of copper, and then 2−3 g of Nickel slowly over 10−15 min to increase the temperature 1700−1750 °C and the melt is degassed for 10−15 min, after which conduct control experience and measure the level of compensation, which shall not exceed 4,5 µg of carbon monoxide for 3 min extraction at a temperature of 1700−1750 °C.

Note. As bath use Nickel and copper with a mass fraction of oxygen is not more than 0.005%.

3.2.2. The prep plants based on the method of reductive melting in a stream of neutral carrier gas includes:

holding in a row of at least two control experiments with consistently interchangeable crucibles-capsules and determination of the difference between the highest and lowest values was obtained with this amendments the reference experiment. The device is considered ready for analysis if this difference is not more than 2 mg of oxygen. In this case, the calculated average correction in the reference experiment and entered into the storage device;

calibration of the measuring cell of the instrument either in the lap of known amounts of calibration gases, either by certified by GOST 8.315 standard samples with known mass fraction of oxygen (of the same order as in the analyzed sample).

4. ANALYSIS

4.1. Sample through a gateway is introduced into the furnace space, and then into the crucible where it is melted and oxygen interaction of the melt with carbon. The extracted gas is transported to the measuring part of the installation. Depending on the type of apparatus used are transported using a vacuum pump or carrier gas stream.

4.2. In installations based on the method of reductive melting in a vacuum, the analysis of Nickel is carried out in a Nickel bath at a temperature of 1600 °C and low-alloyed Nickel alloys — copper-Nickel bath at a temperature of 1700−1750 °C. the maximum ratio of the masses of Nickel and of copper in the melt should be 1:1. It is the periodic replenishment of the bath with pieces of copper. The duration of extraction in both cases is 3−5 min.

4.3. In installations based on the method of reductive melting in a stream of neutral carrier gas, the analysis is conducted without the use of baths in a disposable graphite crucible-capsule. The duration of the extraction varies automatically depending on the mass fraction of oxygen and is 20−30 C. monitoring experience perform every 5−6 definitions.

5. PROCESSING OF THE RESULTS

5.1. For applications based on the method of reductive melting in a vacuum, as a rule, is a direct measure of the amount of extracted gas in a closed volume by the equation of Clapeyron-Mendeleev

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода, (1)


where ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — mass fraction of oxygen, %;

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — pressure carbon monoxide emitted from the sample, mm Hg. St;

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислородаanalytical volume, cmГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода;

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — room temperature, °C;

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — mass of test sample, g;

0,026 — the value of the constant quantities in the equation of Clapeyron-Mendeleev.

5.2. When using the modern Express oxygen analyzers based on melting in flowing neutral carrier gas, the results of the analysis are displayed on the scoreboard of the digital voltmeter or printed on paper tape in parts per million (1 ppm=1·10ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода% by mass). The mass of the sample is calculated automatically.

5.3. For the results analysis be the arithmetic mean of results of two individual parallel definitions ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислородаif the absolute value of the difference between them does not exceed the permissible values ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода, calculated for a confidence probability of 0.95 from the equation

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода(2)


where ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — an indicator of convergence.

5.4. The absolute value of the difference between the results of the analysis of the same sample must not exceed the permissible differences, calculated from the equation

ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода(3)


where ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — an indicator of reproducibility.

5.5. Control the accuracy of the results of the analysis should correspond to GOST 25086. The control accuracy is performed by analyzing standard samples of composition of Nickel GOST 8.315 — two parallel definitions. The results of the analysis are considered accurate if the absolute value of the difference between the results of parallel measurements of oxygen in the standard sample does not exceed calculated according to the equation (2) the magnitude of the rate of convergence ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода, and the difference between the reproduced and certified mass fraction of oxygen in the standard sample does not exceed 0,71ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислородаwhere ГОСТ 22598-93 Никель и низколегированные сплавы никеля. Метод определения кислорода — an indicator of reproducibility, defined by the equation (3).