GOST 30550-98

• gost-30550-98.pdf (239.75 KiB)
  ГОСТ 30550-98

GOST 30550−98 (ISO 4496−78) Powder metal. The definition of the content of acid-insoluble substances in the powders of iron, copper, tin and bronze

GOST 30550−98
(ISO 4496−78)

Group B59

INTERSTATE STANDARD

POWDER METAL

The definition of the content of acid-insoluble substances
powders of iron, copper, tin and bronze

Metallic powders. Determination of acid insoluble content in iron,
copper, tin and bronze powders

ISS 77.160
AXTU 1790

Date of introduction 2001−07−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 150, Institute for problems of materials science I. N. Frantsevich of NAS of Ukraine

SUBMITTED to the State Committee of Ukraine for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (minutes N 13 dated 28 may 1998)

The adoption voted:

3 this standard contains the full authentic text of international standard ISO 4496−78 «Powder metal. The definition of the content of acid-insoluble residue in the powders of iron, copper, tin, bronze» with additional requirements that reflect the needs of the economy, which in the text are highlighted in italics

4 Resolution of the State Committee of the Russian Federation for standardization and Metrology dated December 19, 2000 N 384-St inter-state standard GOST 30550−98 (ISO 4496−78) introduced directly as a state standard of the Russian Federation from July 1, 2001

5 REPLACE GOST 16412.8−91

1 Scope

This standard specifies methods for determining the content of insoluble in ordinary inorganic acids of non-metallic substances (i.e., methods of determining the mass fraction of acid-insoluble residue) in powders of iron, copper, tin and bronze.

To insoluble include mainly substances which are considered insoluble in mineral acids. Such substances are, for example, silica and silicates, carbides, alumina, clay or other refractory oxides, which are either present in the raw materials from which manufactures powders, or introduced during the process.

Methods applicable to metal powders that do not contain grease. These include powders of iron, copper, tin, bronze alloys and mixtures of copper and tin with a mass fraction of acid-insoluble residue not less than 0.03%.

2 Normative references

The present standard features references to the following standards:

GOST 2053−77 Sodium sulfurous 9-aqueous. Specifications

GOST 3117−78 Ammonium acetate. Specifications

GOST 3118−77 hydrochloric Acid. Specifications

GOST 4139−75 Potassium rodanistye. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 6709−72 distilled Water. Specifications

GOST 8864−71 Sodium N, N-diethyldithiocarbamate 3-water. Specifications

GOST 10929−76 Hydrogen peroxide. Specifications

GOST 11022−95 (ISO 1171−81) solid mineral Fuel. Methods for the determination of ash content

GOST 23058−89 Gelatin-raw material for medical industry. Specifications

GOST 23148−98 (ISO 3954−77) Powders used in powder metallurgy. Sampling

GOST 25336−82 Glassware and equipment laboratory glass. The types, basic parameters and dimensions

GOST 29225−91 (ISO 1775−75) Glassware and equipment laboratory porcelain. General requirements and test methods

3 Reagents

For analysis use only analytically pure reagents qualifications not lower than «pure for analysis» (h. e. a.), distilled water according to GOST 6709, or other water, not inferior to it in purity.

Sodium sulfide according to GOST 2053.

Ammonium acetate according to GOST 3117.

Hydrochloric acid according to GOST 3118.

Nitric acid according to GOST 4461.

Potassium thiocyanate according to GOST 4139.

Hydrogen peroxide according to GOST 10929.

Sodium diethyldithiocarbamate according to GOST 8864.

Gelatin according to GOST 23058.

Density requirements of reagents and concentrations of prepared solutions for analysis of powders are given in table 1.

Table 1

4 Equipment

4.1 analytical Scale, providing a weighing error of no more than 0.0001 g.

4.2 glass Funnel for filtering with GOST 25336.

4.3 Filter paper ashless «white ribbon».

4.4 Furnace (muffle) enables operation at temperatures from 900 to 1000 °C according to GOST 11022.

4.5 Crucibles, porcelain according to GOST 29225, or of fused silica pre-calcined to constant weight at a temperature of from 900 to 1000 °C and stored in a desiccator.

5 Sampling

5.1 the Content of insoluble substances is determined on two test portions.

5.2 the Mass of the test sample should be not less than 5 g of the Sample to obtain test portions are selected according to GOST 23148.

6 analysis

6.1 iron Powder

6.1.1 Sample (a) weight not less than 5 g, weighed with accuracy to 0.0001 g, place in a glass beaker.

6.1.2 Carefully poured into a glass 100 cmof hydrochloric acid (3.1) and cover it over the watch glass. The reaction must pass before the end of hydrogen evolution at room temperature.

Note — If necessary, dissolution of carbides, which is part of the insoluble substances, hydrochloric acid (3.1) add 20 cmof nitric acid (3.4) and act in accordance with 6.1.2.


The need to dissolve the carbides must be specified in the regulations for a specific powder.

6.1.3 Solution is heated on a tile to a boil and boil until complete dissolution of the sample. The duration of the boil — at least 1 min. Then add 150 cmof hot water, bring to a boil again and boil for about 1 min. the Solution was cooled and defend at least 5 min.

Allowed to improve the discharge of sediment to add to the solution before sedimentation is not less than 2 cmgelatin solution (3.5).

6.1.4 Filter the solution through ashless filter paper. The filter cake was washed alternately with hot water and hot hydrochloric acid (3.2). Washing is repeated until the termination detection in the wash water with iron salts with potassium thiocyanate (3.3) (allowed use of ammonium thiocyanate).

6.1.5 preheated crucible is weighed () accurate to 0.0001 g and placed in a filter with the sediment. The precipitate is dried prior to charring of the filter and calcined in a furnace at a temperature of from 900 to 1000 °C for as long as the difference between two successive weighings of the cooled crucible is no more than 0.0001 g.

6.1.6 Weigh crucible with residue () with an accuracy of 0,0001 g.

6.2 the Powders of tin, copper and bronze

6.2.1 the sample (a) weight not less than 5 g, weighed with accuracy to 0.0001 g, place in a glass beaker.

6.2.2 Carefully poured into the beaker 50 cmhydrochloric acid (3.6) and cover it over the watch glass. Cautiously evaporated on the tile contained in the glass solution at least 30 min.

6.2.3 the Glass is slightly cooled, carefully added to 50 cmof nitric acid (3.7) and waiting for the start of the reaction, which starts after about 10 min. After the reaction, add 50 cmof nitric acid (3.7).

6.2.4 solution in the beaker is heated to the boil and boil to reduce the volume by half.

Note — If the precipitate, black in color, the glass carefully add a few cubic centimeters of hydrogen peroxide (3.8) and boiled for 2 min. Treatment with hydrogen peroxide was repeated until the disappearance of the black precipitate.

6.2.5 Slowly added to the beaker 50 cmof hot water and again bring the solution to boil. Boil for about 1 min.

Cool the solution and stand for at least 5 min.

6.2.6 Filter the solution through a paper filter, wash the precipitate on the filter first with hydrochloric acid (3.6), and then hot water.

Washing with water is repeated:

a) for powders of copper and bronze — before the termination detection in the wash water with salts of copper, such as diethyldithiocarbamate sodium (3.10);

b) for powders of the tin — before the termination detection in the wash water of tin salts, such as sodium sulfide (3.11) or hydrogen sulfide (3.12).

Note — If the powder contains lead sulfate, the precipitate should be washed once or twice with a hot solution of ammonium acetate (3.9), and then with water.

6.2.7 preheated crucible () is weighed with accuracy to 0.0001 g and placed in a filter with the sediment. The residue dried on the tile before the charring of the filter and calcined in a furnace at a temperature of from 900 to 1000 °C until the difference between two successive weighings of the cooled crucible is no more than 0.0001 g.

6.2.8 Weighed crucible (a) with sediment with a precision of 0.0001 g.

7 Processing of analysis results

7.1 the Content of acid-insoluble substances , i.e. mass fraction of acid-insoluble residue, % by mass, calculated by the formula

, (1)

where is the mass of the crucible with the sediment, g;

the preheated mass of empty crucible, g;

 — mass of test sample, g.

7.2 calculate the results of each determination with a precision of 0.01%.

7.3 Maximum allowable difference between the two definitions should be no more than 10% from their average value and not more than 0.02% in absolute value from the greater of the definitions.

7.4 Record the arithmetic mean of the two determinations, rounding it up to 0.02%, if the content of insoluble substances is equal to or less than 0.25% and up to 0.05%, if the content of insoluble substances more than 0.25%.

8 making the results of the analysis

The results of the analysis draw up a Protocol which should contain:

— reference to this standard;

— all necessary data for identification of the test sample (sample);

— the obtained results analysis.

— all operations that are not covered by this standard are optional;

— description of all factors that could affect the outcome.