GOST 25599.1-83

• gost-255991-83.pdf (273.81 KiB)
  ГОСТ 25599.1-83

GOST 25599.1−83 (ST SEV 2948−81) sintered hard Alloys. Methods for determination of total carbon (Change No. 1)

GOST 25599.1−83
(CT CMEA 2948−81)

Group B59

STATE STANDARD OF THE USSR

SINTERED HARD ALLOYS

Methods for determination of total carbon

Sintered hardmetals. Methods for the determination of total carbon

OKP 19 6100

Date of introduction 1984−01−01

Resolution of the USSR State Committee on standards of January 20, 1983 N 291 validity period is set with 01.01.84 to 01.01.89*
______________
* Expiration removed by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS No. 5/6, 1993) — note the manufacturer’s database.

REPRINTING. August 1984

The Change N 1, approved and introduced with effect from 01.01.89 by the resolution of Gosstandart of the USSR from 27.04.88 No. 1184

Change No. 1 made by the manufacturer of the database in the text ICS N 7, 1988


This standard sets by a gas-volume, potentiometric, coulometric and infrared methods for the determination of total carbon at a mass fraction of from 3 to 20% in hard sintered alloy, carbide carbide mixtures of simple and complex carbides.

Standard is fully consistent with CT CMEA 2948−81.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 14339.0−82.

2. BY A GAS-VOLUME METHOD

2.1. The essence of the method

The method is based on the combustion of the sample in flowing oxygen with subsequent absorption of the formed carbon dioxide with a solution of potassium hydroxide. The carbon content is determined by difference between the initial volume of the mixture gases (co+O) and the volume of gas obtained after absorbing carbon with a solution of potassium hydroxide.

2.2. Apparatus, materials and reagents

Setup for determination of carbon by a gas-volume method (Fig.1).

1 — steel cylinder with oxygen, equipped with a pressure reducing valve; 2 — flowmeter; 3 — rinse bottle filled with Astarita; 4 — resistance furnace with silicon carbide heaters, providing heat to the furnace (1350±50) °C; 5 — dust filter, which is a glass tube with a spherical thickenings, filled with cotton wool; 6 — glass tube filled with granular manganese dioxide; 7 — by a gas-volume analyzer for carbon audiometros 4.5%

Damn.1

Boat porcelain with GOST 9147−80.

Porcelain tubes of internal diameter from 20 to 21 mm.

Potassium hydroxide, 40% solution according to GOST 24363−80.

Methyl orange (indicator).

Of manganese dioxide.

Rectified ethyl alcohol technical — according to GOST 18300−87.

2.3. Preparation for assay

Before the analysis, the installation drive. With tubes and rubber tubes washings of the flask and connect the detector with a tube furnace, and then check all connection for tightness.

Oxygen flow rate — 300 cm/min.

Set the furnace temperature from 1250 to 1350 °C.

Pumps calcined in flowing oxygen at a temperature of from 1300 to 1350 °C for 3−4 min.

Samples cleaned of contamination by washing with 5−10 cmof alcohol.

2.2, 2.3. (Changed edition, Rev. N 1).

2.4. Analysis

Depending on the mass fraction of total carbon take a charge in accordance with table.1, calcined placed in a porcelain boat and the oxygen is introduced into the tubular furnace for burning.

Table 1

2.5. Processing of the results

2.5.1. Mass fraction of total carbon () in percent is calculated by the formula

,

where is the indication of the scale of audiometry corresponding to the mass fraction of carbon in the sample, %;

 — indication of the scale of audiometry corresponding to the mass fraction of carbon in a control experiment, %;

 — correction factor for temperature and pressure according to GOST 22536.1−77*;
_________________
* On the territory of the Russian Federation GOST 22536.1−88. — Note the manufacturer’s database.

 — the weight of the portion of the sample,

2.5.2. Permissible differences between results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.

Table 2

3. POTENTIOMETRIC METHOD

3.1. The essence of the method

The method is based on combustion in a current of oxygen, the formed carbon dioxide is absorbed absorption solution with a particular initial pH value.

The volume of the titrated solution is used for restoring the original pH value, is proportional to the content of total carbon in the sample test.

3.2. Apparatus, materials and reagents

Installation for determining the carbon content by the potentiometric method (Fig.2).

1 — steel cylinder with oxygen and a reducing valve; 2 — flowmeter; 3 — rinse bottle filled with Astarita; 4 — loading gate or plug; 5 — dubtronica resistance furnace with silicon carbide heaters, providing heat to the furnace (1350±50) °C; 6 — dust filter; 7 — capillary flow restrictor, creates a pressure of the gas in the furnace 5 kPa; 8 — glass tube filled with granular manganese dioxide; 9 — absorption vessel with a capacity of 300 to 400 cmand a height of 15 to 16 cm; 10 — mixer; 11 — electrode system, which consists of a measuring electrode (glass) and minor (any running silver chloride); 12 — IV fluids to enter into the cell titrant; 13 — block of automatic titration; 14 — normal; 15 — pH-meter; 16 — magnetic valve or burette-pipette; 17 — burette with a capacity from 10 to 25 cm; 18 — motor

Damn.2

Boat porcelain with GOST 9147−80.

Porcelain tubes of internal diameter from 20 to 21 mm.

Lime soda according to GOST 6755−73*.
_________________
* On the territory of the Russian Federation GOST 6755−88. — Note the manufacturer’s database.

Potassium chloride saturated solution according to GOST 4234−77.

Rectified ethyl alcohol, 96% GOST 18300−87.

Barium chloride according to GOST 4108−72.

Barium hydroxide according to GOST 4107−78.

A standard sample of cast iron 23Ж; use industry standard samples and standard samples of the enterprise, certified in accordance with GOST 8.315−78.

The absorption solution of barium chloride; prepared as follows: 10 g of barium chloride dissolved in 1000 cmof water. To the obtained solution poured 15 cmof ethanol.

A titrated solution of barium hydroxide; prepared as follows: saturated solution of barium hydroxide is diluted 10 times with water previously boiled for 1 h, cooled to 20 °C. the Titrated solution is stored in bottles fitted with tubes with soda lime. The caption is set according to the standard model.

A buffer solution with a pH of 9.18, made of fiksanala 0.01 g·equiv. of a solution of sodium tetraborate or dissolution of 3.81 g of the reagent in 1000 cmof water.

(Changed edition, Rev. N 1).

3.3. Preparation for assay

pH meter set up according to the instructions attached to it. The electrode system set up in the buffer.

To the output of the pH meter is connected to the block automatic titration series using normal element.

Pumps calcined in flowing oxygen at 1300−1350 °C for 3 min.

The absorption cell is poured from 250 to 300 cmof absorption solution, which, after the analysis of 50 samples should be replaced by a new one. Set the oxygen flow rate is 700 cm/min.

Include the block of automatic titration in the titration and the pH adjusted to 10.

To conduct the calibration standard burn the sample and measure the volume of the titrated solution is used for the recovery of the original pH.

3.4. Analysis

Depending on the expected content of the total carbon take a portion of the sample in accordance with table.3, calcined placed in a porcelain boat, and introduced into the tubular furnace, and enable the automatic titration. After the end of the titration read the buret on the amount spent titrated solution. To control the correctness of the results it is necessary to burn a standard sample every three samples.

Table 3

3.5. Processing of the results

3.5.1. Mass fraction of total carbon () in percent is calculated by the formula

,

where  — the volume of the titrated solution of barium hydroxide, spent on titration, sm;

 — the volume of the titrated solution of barium hydroxide used for the blank experiment, cm;

the titer of the solution of hydroxide of barium, expressed in grams of carbon per 1 cmof solution;

 — weight of sample, g

.

3.5.2. Permissible differences between results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.

4. COULOMETRIC METHOD

4.1. The essence of the method

The method is based on combustion in a current of oxygen. The resulting carbon dioxide is absorbed absorption solution with a particular initial pH value.

The number of pulses of electricity to restore the original pH value, is proportional to the content of total carbon in the sample test.

4.2. Apparatus, materials and reagents

Coulometric analyzer.

Pumps porcelain — GOST 9147−80.

A porcelain tube with an inner diameter from 20 to 21 mm.

Rectified ethyl alcohol technical — according to GOST 18300−87.

Potassium chloride — according to GOST 4234−77.

Potassium genesisintermedia — GOST 4207−75.

Boric acid — according to GOST 9656−75.

Strontium chloride, 6-water according to GOST 4140−74.

Standard samples, and industry standard samples of the enterprise, certified in accordance with GOST 8.315−78.

(Changed edition, Rev. N 1).

4.3. Preparation for assay

4.3.1. The analyzer is set up according to the instructions attached to it.

Samples cleaned of contamination by washing with 5−10 cmof alcohol.

(Changed edition, Rev. N 1).

4.4. Analysis

A sample taken in accordance with table.3, is placed in a burnt boat, is introduced into the combustion tube and close the tube. The analysis is considered successful if the instrument reading for 1 min is changed to the value not exceeding the value of the idling score of the instrument.

To control the correctness of the results it is necessary to burn a standard sample every nine definitions.

Table 3

(Changed edition, Rev. N 1).

4.5. Processing of the results

4.5.1. Mass fraction of total carbon () in percent is determined on the digital display of the analyzer.

(Changed edition, Rev. N 1).

4.5.2. Permissible differences between results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.

5. THE METHOD OF IR-SPECTROSCOPY

5.1. The essence of the method

The method is based on burning the sample in oxygen in an induction furnace. Formed FROMaverages closed closed system and the IR detector is determined by the percentage FROM.

In the absence FROMthe infrared detector receives the maximum energy.

5.2. Apparatus, materials and reagents

The analyzer IR.

Standard samples according to claim 4.2.

The technical rectified ethyl alcohol GOST 18300−87.

5.3. Preparation for assay

5.3.1. Analyzer set by the user to the device.

5.3.2. Samples cleaned of contamination by washing with 5−10 cmof alcohol.

5.4. Analysis

The analysis is conducted depending on the type of analyzer.

Mass fraction of total carbon percentage determined on the display.

5.5. Processing of the results

The absolute discrepancies in the results of parallel measurements at a confidence level =0.95 does not exceed the values specified in table.2.

Section 5. (Added, Rev. N 1).