GB/T 2972-2016Test method for uniformity of zinc coating on zinc-coated steel wire by the copper sulphate dip (English PDF)

Foreword

This Standard is drafted as per provisions specified in GB/T 1.1-2009.

This Standard replaces GB/T 2972-1991 "Zinc-coated steel wire - Test method

for uniformity of zinc coating on wire by the copper sulphate dip". Compared

with GB/T 2972-1991, this Standard makes significant changes in the respect

of the following technical contents.

-- for application scope, add "Zn-Al alloy coated steel wire can refer to this

Standard";

-- add normative references;

-- modify the sample preparation requirements; sample length is modified to

about-250mm;

-- modify reagent preparation requirements; modify crystal of copper

sulphate to analytical pure; modify amount to 314g/L and temperature to

20°C ± 2°C; heating during dissolution is not allowed;

-- delete copper hydroxide and copper carbonate in the neutralization

reagents;

-- delete specific gravity requirements of test solution;

-- add Annex A "Test method of zinc content in copper sulfate test solution".

This Standard is drafted by adopting the re-drafting method and referencing to

ISO 7989-2.2007 "Steel wire and wire products - Non-ferrous metallic coatings

on steel wire - Part 2. Zinc or zinc-alloy coating". This Standard is not equivalent

to ISO 7989-2.2007.

This Standard was proposed by China Iron and Steel Industry Association.

This Standard shall be under the jurisdiction of National Technical Committee

for standardization of steel (SAC/TC 183).

Drafting organizations of this Standard. National Quality Supervision and

Inspection Center for Wire Rope Products; China Metallurgical Information and

Standardization Institute; Institute of Quality and Quantity Supervision Center

of Yuhang District of Hangzhou.

1 Scope

This Standard specifies the testing principle, sample preparation, reagent

preparation, testing procedure and judgment principle for test method for

uniformity of zinc coating on zinc-coated steel wire by the copper sulfate dip.

This Standard is applicable to the uniformity test of zinc coating of hot-dip zinc-

coated steel wire. For zinc-aluminum alloy coated steel wire and zinc-

electroplated steel wire, it can also refer to this Standard.

2 Normative references

The provisions of the following documents, through reference of this document,

constitute the provisions of this document. For dated documents, only the dated

editions are applicable to this document. For undated documents, the latest

editions (including all amendments) are applicable to this document.

GB/T 603 Chemical reagent - Preparations of reagent solutions for use in

test methods

GB/T 665 Chemical reagent - Copper (II) sulfate pentahydrate

GB/T 674 Chemical reagent - Copper (II) oxide powder

3 Test Principle

During the pre-determined time, the zinc-coated steel wire sample is dipped

into the copper sulphate solution once or several times, for carrying out the

replacement reaction; the zinc coating is gradually dissolved. And finally,

defects are revealed on the surface; judge the uniformity of the zinc coating.

Note. This test is to reflect that the coating thickness may exist non-uniformity, therefore, even

if the coating on unit area complies with relevant requirements, defects on coating

surface can also be revealed.

6 Test Procedure

6 samples can be tested at the same time.

7 Principle for accessing result

Carry out the operation of Chapter 6. The products are deemed as qualified if

......