GOST R 50575-93

• gost-r-50575-93.pdf (382.02 KiB)
  ГОСТ Р 50575-93

GOST R 50575−93 (ISO 7989−88) steel Wire. Requirements for zinc coating and testing methods covering

GOST R 50575−93
(ISO 7989−88)
Group В79

STATE STANDARD OF THE RUSSIAN FEDERATION
STEEL WIRE
Requirements for zinc coating and
test methods coating

Steel wire. Requirements for zinc coating
and testing methods

ISS 25.220.40
77.140.65
AXTU 1209

Date of introduction 1994−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Technical Committee for standardization TC 146 «Hardware"

2. APPROVED AND put INTO effect by the Resolution of Gosstandart of Russia from 22 June 1993 N 157

3. This standard developed by the direct application of international standard ISO 7989−88 «Zinc coatings for steel wire» with additional requirements that reflect the needs of the national economy

4. INTRODUCED FOR THE FIRST TIME

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

1. Purpose and scope

This standard specifies requirements for mass, quality and testing of zinc coatings on steel wire having a circular cross section.

Additional requirements that reflect the needs of the economy, in italics.

2. Definition

2.1. galvanized wire: Wire coated with zinc coating to protect it from corrosion. The coating can be applied by immersion in a bath of molten zinc, by electrodeposition from aqueous solutions of salts of zinc andother methods that provide protection against corrosion.

2.2. coating weight: Weight of zinc coating per unit area expressed in grams per square meter.

3. Coverage requirements

3.1. Coating mass. The minimum mass of zinc per unit of surface area shall conform to the requirements of table 1 for the appropriate coverage group.

Table 1

Allowed to get coverage groups A, AB, C, D by drawing the wire after the application of zinc.

3.2. Surface appearance

The coating must be continuous, smooth and uniform, with no gaps or cracks visible without using the magnifying devices.

Note — zinc coating applied by dipping the wire in molten zinc, it is not always smooth and devoid of irregularities. Therefore, the diameter measurement should be selected in smooth areas of the wire.

3.3. The special fine finish of the surface

By agreement between manufacturer and consumer wire manufactured with the special fine finish of the surface or a shiny surface.

3.4. The adhesion of the coating

In accordance with the requirements of section 4.3, the coating must have strong adhesion to the steel core and should not crack or flake to such an extent that the flakes of coating can be removed from the surface of the wire with your fingers.

Surface powdery peeling of the zinc coating at the test wire adhesion, by mechanical polishing the surface of galvanized wire acceptance sign is not.

3.5. Requirements of continuity and uniformity of coating shall be established, if necessary, regulatory and technical documentation for specific types of wire.

4. Test requirements

4.1. Sampling

4.1.1. The number of coils (coils) of wire selected for testing, is established in the normative-technical documentation for specific types of wireor by agreement between the manufacturer and the customer.

4.1.2. Samples of wire of a certain length for the test should be selected from one or both ends of each of the controlled coil and one end of the coil.

When damage occurs to the ends of the wire winding (coil) they should be cut before you take the samples of wire tested.

4.2. Determination of coating mass

4.2.1. Determination of the mass of the coating is carried out in one of the following methods:

a) three-getmetrics (see Annex A);

b) gravimetric (weighing) (see Annex B);

in) non-destructive methodology, approved and coordinated in the established procedure.

If there is a dispute the gravimetric method shall be used as the arbitration.

4.2.2. If a gravimetric test method for wire diameter of 3 mm and more length of the test sample should be not less than 200 mm.

Note. The length of the sample wire with a diameter of less than 3 mm should be designed such that the mass in grams numerically would be at least four diameters in millimeters.

4.3. Test for adhesion

4.3.1. Wire nominal diameter up to 7.5 mm, inclusive, shall be tested for adhesion of the coating by a helical winding of at least six tight turns around a cylindrical mandrel with a diameter equal to the specified in table 3.

Table 3

4.3.2. Wire nominal diameter of more than 7.5 mm shall withstand the bend test, 90° around the mandrel. The ratio of mandrel diameter to wire diameter shall be as given in table 3.

4.4. The continuity and uniformity of the zinc coating is controlled by the immersion method (see Appendix C).

Annex a (mandatory). Determination of mass of zinc deposited per unit area

APPENDIX A
(Required)

Volumetric-thermal method*

______________
* The title corresponds to the original. — Note the CODE.

A1. The essence of the method

The zinc coating of the wire specimen is dissolved in a solution of inhibited hydrochloric acid, inhibited solution of sulfuric acid or an aqueous solution of the mixture of acids: sulfuric and hydrochloric. The mass of zinc dissolved is thus determined by measuring the volume of hydrogen released during the dissolution of the coating (three-gasometrical method). The ratio of the mass of zinc to the surface area of the test sample measured after dissolution of the coating, determines the mass of zinc deposited per unit of surface.

A2. Reagents and measurement tools

Antimony trichloride () TU 6−09−636;

antimony oxide () on the other 6−09−3267;

sulfuric acid according to GOST 4204;

hydrochloric acid according to GOST 3118;

the technical rectified ethyl alcohol according to GOST 18300 or other normative technical documentation;

white spirit according to GOST 3134 or other normative technical documentation;

carbon tetrachloride according to GOST 20288;

cleaning material cotton;

filter paper according to GOST 12026;

micrometer according to GOST 6507;

ruler measuring metal according to GOST 427;

barometer;

thermometer with a scale division of 1 °C according to GOST 28498;

drying Cabinet with a temperature of at least 100 °C;

a device for determining mass of zinc coating (see A1 and A2).

A. 3. Solutions for coating removal

A. 3.1. A solution ingibirovannoj hydrochloric acid

2 g of antimony trioxide (a) or 3.2 g of antimony trichloride (a) was dissolved in 700 cmof hydrochloric acid () with a density of 1.19 g/cmand topped up with distilled water to 1 DM.

A. 3.2. A solution of inhibited sulphuric acid

2 g of antimony trioxide (a) or 3.2 g of antimony trichloride ( ) was dissolved in 60 cmof hydrochloric acid () with a density of 1.19 g/cmand made up to 1 DMsulfuric acid () with a density of 1.05 g/cm(concentration of 80 g/DM).

A. 3.3. A solution of the mixture of acids

In 500 cmof distilled water add 100 g of sulfuric acid (56 cmsulfuric acid density 1.84 g/cm), and then 34 g of hydrochloric acid (100 cmhydrochloric acid with a density of 1.15 g/cm). After cooling, the volume of the solution topped up with distilled water to 1 DM.

A. 3.4. The bleed solution is replaced as it is exhaustion.

A. 4. Preparation of samples to test

After careful straightening them samples of wire cut to a length:

300 mm — for wire length of less than 1.0 mm;

150 mm — for wire diameter from 1.00 to 1.49 mm;

100 mm — for wire diameter of 1.5 to 3.0 mm;

50 mm — for wire diameter over 3.0 mm.

Allowed to apply for test periods greater lengths and samples cut into any number of segments depending on the test conditions.

The length of the segments should be checked carefully. Before removing the cover samples degreased in one of the organic solvents listed in paragraph A2, or wipe dry with a clean cloth.

A. 5. The methodology of the tests

The acid solution is poured into the reservoir 3 (figure A. 1) so that completely filled the burette 1 to the highest level and part of the solution still left in reservoir 3.

Figure A. 1. A device for determining mass of zinc coating on the wire diameter of 0.7 mm (three-gasometrical method)

A device for determining mass of zinc coating
the wire diameter of 0.7 mm
(volume-gasometrical method)

1 — burette; 2 — single faucet; 3 — tank;
4 — rubber tube; 5 — vessel; 6 — tripod

Figure A. 1

For testing the height of the tank 3 is regulated so that the level of the working solution in the burette was zero and coincides with the level in the tank, the valve 2 must be opened.

Samples of certain length are placed in the burette at the top and the valve 2 quickly closes. The dissolution of the zinc coating occurs until, until no further evolution of hydrogen. Then again carry out alignment of levels of solution in the burette and the reservoir, and then record the volume of the evolved hydrogen, lower reservoir, open top faucet 2 burettes, allow solution to drain out of the burette, open the lower tap of the burette to extract the sample wire.

When working with the device (figure A. 2) do the same, only the sample is dipped into the tank 5, quickly closed with a stopper (valve 2 open) and then close the valve. The volume of the evolved hydrogen determined by the rise of the solution in the burette 1 of the original. After removing the coating the test specimen is washed in running water and carefully wiped before measuring the diameter.

Figure A. 2. A device for determining mass of zinc coating on the wire diameter up to 0.7 mm (three-gasometrical method)

A device for determining mass of zinc coating
the wire diameter up to 0.7 mm
(volume-gasometrical method)

1 — burette; 2 — crane; 3 — tube; 4 — rubber tube;
5 — tank; 6 — tripod

Figure A. 2

The test is conducted on only one sample, the temperature in the burette is maintained at (20±2) °C.

Allowed the determination of mass of zinc coating for wire diameter 0.7 mm St. to spend on the device, depicted in figure A. 2, given the mass coverage and the amount released at the same time hydrogen.

A. 6. Processing of the results

The results determined after testing of all samples.

The mass of zinc deposited per unit surface area , g/m, determined by the formula

where  — the average amount of hydrogen released during each test, cm;

the diameter of the wire without coating, mm;

 — the length of the test sample wire, mm.

If the barometric pressure is outside of 740−780 mm Hg.St., the right side of the above formula must be multiplied by a factor , where is the barometric pressure in mm Hg.St. (mm Hg =133,322 PA).

If the ambient temperature is outside 20 °C, and the pressure goes outside of 760 mm Hg.St., the mass of zinc deposited per unit surface area, determined by the formula

where  — coefficient taking into account the effect of temperature and pressure during the reduction of volume of the evolved hydrogen to the conditions of: barometric pressure 101,310PA (760 mm Hg.St.), temperature of 20 °C. the Coefficient is selected from table 4.

Table 4

The value of the coefficient , considering the influence of temperature and atmospheric pressure

In practice, the mass of zinc per unit of surface area can be directly determined from tables depending on the wire diameter and the volume of evolved hydrogen gas.

ANNEX b (mandatory). Determination of mass of zinc deposited per unit surface area Gravimetric (weight) method

THE APP
(Required)

V. 1 the essence of the method

The zinc coating from the surface of a certain area is dissolved in the inhibited acid. The loss of mass due to the dissolution of the coating is determined by weighing the test sample before and after coating removal.

B. 2 Reagents and measuring instruments

antimony (III) oxide THAT 6−09−3267, antimony trichloride THAT 6−09−636;

sulfuric acid according to GOST 4204;

hydrochloric acid according to GOST 3118;

the technical rectified ethyl alcohol according to GOST 18300 or other normative technical documentation;

white spirit according to GOST 3134 or other normative technical documentation;

carbon tetrachloride according to GOST 20288;

cleaning material cotton;

filter paper according to GOST 12026;

micrometer according to GOST 6507;

ruler measuring metal according to GOST 427;

laboratory scales for General purpose according to GOST 24104* the second class of accuracy with the greatest weighing limit of 200 g or other scales that meets the specified requirements for their metrological characteristics;
__________________
* In July 2002, put into effect GOST 24104−2001.

drying Cabinet with a temperature of at least 100 °C.

B. 3 Solutions for removing zinc coating

V. 3.1 3.2 g of antimony chloride () or 2 g of antimony oxide () was dissolved in 500 cmof concentrated hydrochloric acid (density 1,19 g/cm). The resulting solution was diluted with distilled water to 1 DM.

V. 3.2 To 500 cmof distilled water add 100 g of sulfuric acid (56 cmsulfuric acid density 1.84 g/cm), and then 34 g of hydrochloric acid (100 cmhydrochloric acid with a density of 1.15 g/cm). After cooling, the volume of the solution topped up with distilled water to 1 DM.

V. 3.3 2 g of antimony oxide () was dissolved in 60 cmof hydrochloric acid (density 1,19 g/cm) and made up to 1 DMsulfuric acid (density 1.05 g/cm) concentration of 80 g/DM.

Warning! When working with a solution to remove the cover, caution should be exercised due to the toxicity of the compounds of antimony.

B. 4 Method of test

The test specimen is degreased by one of the organic solvents indicated in V. 2 that do not affect the coating, then dried or wiped with a clean cloth.

Before removing the cover, the test sample is weighed.

The amount of solution for coating removal is taken from the calculation at least 10 cm on each square centimeter of the surface of the test sample.

The test specimen is completely immersed in the solution at room temperature and left in it until complete dissolution of the coating.

The end of the dissolution process is determined by cessation of an initial intensive hydrogen evolution. Then the test specimen is washed in running water and, if necessary, clean brush to remove adhering to the surface of the particles, immersed in alcohol, rapidly dried or washed with distilled water and wipe with a clean cloth to remove moisture; dried and weighed.

The surface area is determined by measuring the dimensions of the test specimen after removal of the coating.

B. 5 calculation of the coating mass

The loss of mass , g, is calculated by the formula

where is the mass of the test specimen prior to removal of the coating, g;

 — mass of test sample after removing the cover,

Coating mass per unit surface area , g/m, is calculated by the formula

where  — mass loss, g;

 — surface area, mm.

Note — steel wire, is convenient to calculate the mass of zinc coating per unit area , g/m, by the formula

where is the wire diameter after coating removal.

Take the density of steel is 7,850 kg/m. In this case, the length of the wire is not determined.

The margin of sampling error is ±5% to ±10% of the average value (due to different coating methods, different researchers, different devices and different operating conditions).

APPLICATION (required). The immersion method

APPLICATION
(Required)

C. 1 the essence of the method

Samples of galvanized wire immersed in a solution of copper sulphate with subsequent visual inspection of the samples surface.

C. 2 Reagents

Copper (II) sulfate 5-water according to GOST 4165 or copper sulfate according to GOST 19347, 3% and 17%-nye solutions, distilled water, sodium hydroxide according to GOST 4328 1% solution;

the technical rectified ethyl alcohol according to GOST 18300 or other normative technical documentation;

white spirit according to GOST 3134 or other normative technical documentation;

carbon tetrachloride according to GOST 20288;

cleaning material cotton;

ruler measuring metal according to GOST 427;

the container glass.

C. 3 Solutions

P.3.1 Hydroxide copper

To 3% solution of copper sulphate poured a 1% sodium hydroxide solution. The precipitate of the hydroxide of copper is washed by decantation several times, then filtered off and washed on the filter with distilled water.

P.3.2 Solution of copper sulfate

17% solution of copper sulfate neutralized with an excess of freshly precipitated hydrate of copper oxide, which in a solution of copper sulphate add a pasty precipitate of hydrate of copper oxide, stirring until small excess on the bottom of the container, and then the solution was filtered. The density of the filtered neutralized solution should be 1,114−1,116 g/cm.

P.3.3. The same solution of copper sulphate with a volume of 200 cmcan be used for testing samples, the number of which depending on the diameter of the wire is given in tthe table 5.

Table 5

P. 4. The samples

Length of core samples of wire — 150 mm.

C. 5 Method of testing

Samples of degreased wire is one of the organic solvents specified in paragraph C. 2, is then dried or wiped with a clean cloth. If the samples are degreased with benzene, then in addition, they are washed with distilled water, dry or wipe with a clean cloth, the samples were then immersed in a glass vessel filled with solution of copper sulphate to a depth of not less than 100 mm.

The solution temperature during the test must be (18±2) °C.

After each immersion in the solution, samples were washed with distilled water and wiped with a clean cloth. The samples must take exactly 1 min. If set to dip to 30, it should be carried out after immersion of 1 min. Samples of wire shall be in the solution is stationary, not in contact with each other and with the walls of the vessel.

C. 6 test Results

Consider samples without the use of a magnifying device (visual).

On the surface of the wire specimen after the test are allowed:

a) redness of the surface of the wire specimen at the site, located at a distance of 10 mm from the solution level and at a distance of 20 mm from the immersed in the solution the lower end of the sample;

b) brown color and the redness of point character, disappearing or increasing in size and brightness with additional immersion of the sample in the solution for 1−2 s.

On the surface of the wire specimen after the test by immersion is not allowed places, covered with copper, not coming down when wiping with cotton wool or a clean cloth.