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BS 729 PDF

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British Standard BS also applies to hot zinc there is no danger of corrosion at these. Fasteners dip galvanizing of small components with the points. Description. This British Standard specifies requirements for hot dip galvanized coatings on steel articles galvanized after fabrication and on grey and mallcable . BS EN. Incorporating. Amendment No. 1. Quality requirements The European Standard EN has the status of a.


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BRITISH STANDARD SPECIFICATION FOR HOT DIP GALVANIZED COATINGS ON IRON AND STEEL ARTICLES BS B R I T I S H STANDARDS INSTITUTION Incorporated by Royal Charter 2 PARK STREET. BSI B S * 7 2 7 71 bbî b BS BS Hot-Dip Galvanized Coatings on Iron & Steel Articles. Table 1. Coating Weight*. Category. Minimum average coating weight for any individual test. Galvanized Coatings On Iron Steel [PDF] [EPUB] MIG-MARUICHI - Hot-Dip Galvanizing Service. Hot-Dip Galvanizing Service BS

Weldable structural steels. British Standards are subject to periodical review. Suggestions for improvements will be recorded and in due. BS Third revision May.

If either of these fails to meet the requirement, the consignment shall be deemed not to comly with the standard. In this case the consignment may be re-galvanized and again submitted for testing and inspection. The coating shall withstand four one-minute dips in the standard copper sulphate solution without the formation of an adherent red spot of metallic copper upon the basis metal.

The following areas are exempt from the requirements of this clause: less than 25 mm from any cut edge, less than 13 mm from threads of over 10 mm diameter cut or brushed after galvanizing, less than 6 mm from such threads up to 10 mm diameter.

The solution is then diluted to 1 litre with distilled water.

Pdf bs 729

The samples are degreased with a suitable organic solvent, e. The sample shall be completely immersed in the stripping solution at room temperature until the coating has completely dissolved, i. The sample shall then be rinsed in running water and, if necessary, brushed to remove any loose substances, dipped in alcohol, dried and re-weighed. The surface area of the sample is then determined. The weight of zinc coating per unit surface area is obtained by dividing the difference in weight by the surface area.

Appendix B Copper sulphate preece dip test for uniformity of coating B. The reagent used is copper sulphate solution, made by dissolving approximately 36 g of crystalline copper sulphate CuSO4. The water may be heated to facilitate solution of the crystals, but if it is heated the solution must be allowed to cool before neutralizing. Adjustment may be made by adding distilled water or solution of higher relative density, as appropriate. The volume of the solution in millilitres shall be numerically at least eight times the approximate surface area in square centimetres of the immersed portion of the articles being tested.

The solution shall be discarded when these have been tested. The container used for the test shall be made of a material inert to copper sulphate solution.

BS_(hot dip galvanized coating on irons and steeel articles)_百度文库

Its internal dimensions shall be such as to allow a clearance of at least 25 mm between the container and any article immersed in the solution. Finally, they shall be wiped dry with a clean soft cloth.

The samples shall be subjected to four successive dips in the solution, each lasting 1 minute. If possible they shall be completely immersed, but they shall not touch each other. While they are immersed, neither they nor the solution shall be agitated. After each dip the samples shall be withdrawn, rinsed immediately in clean running water, and any black deposit removed with a fibre brush, care being taken to clean out all holes and pockets.

The samples shall then be wiped dry with a clean, soft cloth and, except after the final dip, returned immediately to the solution. If the copper has been removed and zinc appears underneath, the sample does not fail the test. BSI 5 BS Appendix C Transport and storage of galvanized articles The purchaser should pay particular attention to the conditions of transport, shipment and storage to avoid the possibility of wet storage staining.

The susceptibility to wet storage staining can be reduced by applying a post-treatment see Clause Galvanized articles should never be stored on clinkers or ashes. A galvanized coating has excellent resistance to rough treatment. Nevertheless, some damage may occur in the course of transit and erection; small areas damaged in this way may be renovated by the procedures described in Appendix D. Appendix D Renovation of damaged areas Small areas of galvanized coating damaged by welding, cutting or by excessively rough treatment during transit and erection may be renovated either by the use of low melting point zinc alloy repair rods or powders made specifically for this purpose, or by the use of at least two coats of good quality zinc-rich paint5.

Sufficient material should be applied to provide a zinc coating at least equal in thickness to the galvanized layer. The maximum size of the areas for which such repairs are acceptable will depend, to some extent, on the article and the application but for general guidance an area of 40 mm2 is suggested as being suitable.

For large structures it may well be acceptable to renovate larger areas. Appendix E Embrittlement E. For steel to be in an embrittled condition after galvanizing is rare, and its occurrence depends on a combination of factors.

Under certain conditions, some steels can lose their ductile properties and become embrittled. There are several different types of embrittlement which can occur and one only, strain age-hardening, can be aggravated by the hot dip galvanizing process. The following information is given as guidance in critical applications. The following factors may contribute to the embrittlement of galvanized steel.

Strain age-hardening is principally caused by the nitrogen content of the steel which in turn is largely dependent on the steel-making process.

As a general guide the open hearth, electric or oxygen processes are preferable to the Bessemer process in this respect and the aluminium-killed steels are the least susceptible to strain age-hardening.

BS permits the customer to specify the steel-making process and proscribes the use of air, and mixed air-oxygen, bottom-blown basic converter processes. The degree of strain introduced into a fabrication will depend on the cold forming operations carried out and on the thickness of the steel.

Cold working operations carried out before galvanizing which may give rise to embrittlement of susceptible steels include the punching of holes, severe bending and shearing. No steels are likely to be severely affected in thicknesses less than 3 mm.

No other aspect of the galvanizing process is significant. Oversize tapping or re-tapping of nuts or female threads is required when the bolt or male thread is hot dip galvanized. Although this procedure results in an uncoated female thread, this will be protected by the coating on the male thread when the fastener is assembled.

Under some circumstances the whole coating may consist of zinc-iron alloy layers 3 Information to be supplied by the downloadr to the galvanizer The following information, when appropriate, shall be supplied by the downloadr to the galvanizer: BS ; 2 the nature of the material to be galvanized; 3 the method of sampling to be adopted; 4 if a post-treatment is required, the type of treatment, e. The galvanizer shall not be responsible for changes in the mechanical properties of the basis metal as a result of hot dip galvanizing, except where these changes can be shown to be due to faulty processing.

The standard does not apply to semi-finished products such as galvanized wire, tube or sheet which are suitable for subsequent fabrication.

Where particular galvanized articles are covered by other standards, reference should be made to these standards for any special qualification, which should take preference over BS Any tests for adhesion shall be agreed between the downloadr and the galvanizer.

Higher or lower weights can be agreed between the downloadr and the galvanizer in particular defined cases. For example, heavier coatings may be obtained by grit-blasting before galvanizing or by using fully-killed silicon steels. In some instances it may be necessary to grit-blast before galvanizing in order to achieve the coating weights specified in Table 1.

For large articles, e. Bolts which are to be fitted with nuts are screwed to the tolerance laid down in the appropriate specification without allowance being made for galvanizing.

The nuts are tapped up to 04 mm oversize after galvanizing and the threads are oiled. Where required by the downloadr, treatments such as chromating or phosphating may be applied to reduce the risk of wet storage staining or to assist subsequent painting. The weight before galvanizing shall be determined after pickling and drying, the weight after galvanizing when the article has cooled to ambient temperature.

In cases of dispute the stripping test, where practicable, shall be the referee test. If any test area fails to comply with the standard, two further areas shall be tested. If either of these fails to meet the requirement, the consignment shall be deemed not to comly with the standard.

In this case the consignment may be re-galvanized and again submitted for testing and inspection. The coating shall withstand four one-minute dips in the standard copper sulphate solution without the formation of an adherent red spot of metallic copper upon the basis metal. The following areas are exempt from the requirements of this clause: The solution is then diluted to 1 litre with distilled water. The samples are degreased with a suitable organic solvent, e.

The sample shall be completely immersed in the stripping solution at room temperature until the coating has completely dissolved, i.

729 pdf bs

The sample shall then be rinsed in running water and, if necessary, brushed to remove any loose substances, dipped in alcohol, dried and re-weighed.

The surface area of the sample is then determined. The weight of zinc coating per unit surface area is obtained by dividing the difference in weight by the surface area. Appendix B Copper sulphate preece dip test for uniformity of coating B. The reagent used is copper sulphate solution, made by dissolving approximately 36 g of crystalline copper sulphate CuSO4.

Category «British Standard»

The water may be heated to facilitate solution of the crystals, but if it is heated the solution must be allowed to cool before neutralizing. Adjustment may be made by adding distilled water or solution of higher relative density, as appropriate. The volume of the solution in millilitres shall be numerically at least eight times the approximate surface area in square centimetres of the immersed portion of the articles being tested.

The solution shall be discarded when these have been tested. The container used for the test shall be made of a material inert to copper sulphate solution. Its internal dimensions shall be such as to allow a clearance of at least 25 mm between the container and any article immersed in the solution. Finally, they shall be wiped dry with a clean soft cloth.

The samples shall be subjected to four successive dips in the solution, each lasting 1 minute. If possible they shall be completely immersed, but they shall not touch each other. While they are immersed, neither they nor the solution shall be agitated. After each dip the samples shall be withdrawn, rinsed immediately in clean running water, and any black deposit removed with a fibre brush, care being taken to clean out all holes and pockets.

The samples shall then be wiped dry with a clean, soft cloth and, except after the final dip, returned immediately to the solution. If the copper has been removed and zinc appears underneath, the sample does not fail the test. The susceptibility to wet storage staining can be reduced by applying a post-treatment see Clause Galvanized articles should never be stored on clinkers or ashes.

A galvanized coating has excellent resistance to rough treatment. Nevertheless, some damage may occur in the course of transit and erection; small areas damaged in this way may be renovated by the procedures described in Appendix D. Appendix D Renovation of damaged areas Small areas of galvanized coating damaged by welding, cutting or by excessively rough treatment during transit and erection may be renovated either by the use of low melting point zinc alloy repair rods or powders made specifically for this purpose, or by the use of at least two coats of good quality zinc-rich paint5.

Sufficient material should be applied to provide a zinc coating at least equal in thickness to the galvanized layer. The maximum size of the areas for which such repairs are acceptable will depend, to some extent, on the article and the application but for general guidance an area of 40 mm2 is suggested as being suitable. Bolts are galvanized after screwing unless otherwise specified.

729 pdf bs

B o b which arc? The nuts are tapped up to 0. The weight before galvanizing shall be determined after pickling and drying, the weight after galvanizing when the article has cooled to ambient temperature. In cases of dispute the stripping test, where practicable, shall be the referee test. Where agreed between the purchaser and the galvanizer, the copper sulphate Prccce test described in Appendix B for uniformity of coating shall be applied to suitable articles.

The coating shall withstand four one-minute dips in the standard copper sulphate solution without the formation of an adlierent red spot of metallic copper upon the basis metal. The following arcas are exempt from the requirements of this clause: less than 25 mm from any cut edge, Icss than 13 nim froin threads of over IO mm diameter cut or brushed after golvaniziiig, less than h mm from such threads up to 10 mm diameter.

Where required h y the piirchnser, treatments such as chromating or phosphating may be applied [ o reduce the risk of wet storage staining or to assist subsequent painting. TESTING Unless agreed in writing between the purchaser and the galvanizer, inspection niid testing for conipliance with this standard shall take place at the galvani- x r ' s works prior to despatch. If iiny test area fails to comply with the standard, two further areas shall IIC:tcsicd.

I f either of these fails to meet the requirement, the consignment shall Iw dccnied not to comly with the standard.

729 pdf bs

In this case the consignment may he re-galvanized and again submitted for testing and inspection. The solution is then diluted to 1 litre with distilled water. The samples are degreased with a suitable organic solvent, e. The sample shall be completely immersed in the stripping solution at room temperature until the coating has completely dissolved, i.

BS 731-1:1952 pdf free download

The sample shall then be rinsed in running wafer and, if necessary, brushed to remove any loose substances, dipped in alcohol, dried and re-weighed. The surface area of the sample is then determined. The weight of zinc coating per unit surface area is obtained by dividing the difference in weight by the surface area. The reagent used is copper sulphate solution, made by dissolving approximately 36 g of crystalline copper sulphate CUSOJ.

The water may be heated to facilitate solution of the crystals, but if it is heated the solution must be allowed to cool before neutralizing. The relative density of the test solution shall be 1. Adjustment may be made by adding distilled watcr or solution of higher d a t i v e density, as appropriate. The volume of the solution in millilitres shall be numerically at least eight tinies the :ipproxiiiinte surface area i n square centiiiictres of the ininicrcd portion of the articles being tcited.

The solution shall be discardcd when these have been tcsteJ. The container used for the test shall be made of a material inert to copper sulphate solution. Its internal dimensions shall be such as to allow a clearance of at least 25 mm between the.

Finally, they shall be wiped dry with a clean soft cloth. At the commencement and during the progress of the test, the tempcrature of the samples and of the solution shall not vary outside the limits of 18 2C. The samples shall be subjected to four successive dips in the Folution, each lasting I minute. If possible they shall be completely inimersed, but they shall not touch each other.

While they are immersed, neither they nor the solution shall be agitated I After each dip the samples shall be withdrawn, rinsed immediately in clean running water, and any black deposit removed with a fibre brush, care being taken to clean out all holes and pockets.

The samples shall then be wiped dry with ;I clean, soft cloth and, except after the final dip, returned immediately to the solution. If the copper has been removed and zinc appears underneath, the sample does not fail the test. This condition, sometimes known as white rust, can occur on freshly galvanized ;irticles which are transported or stored under damp, badly ventilated conditions. Galvanized artides should never be stored on clinkers or ashes.