galvanized steel coating thickness chart

The corrosion resistance provided by the zinc coating is in direct proportion to the coating's thickness. The corrosion rate of a galvanized coating is generally linear. The galvanizer and inspector will need drawings to determine the wall thickness, if an open end is not available for measurement. Tel: 800.400.7833 323.723.8836 Fax: 323.888.9866 2187 S. Garfield Avenue Los Angeles, … Note that the following is a summary of the information from the definitions. Silicone which is used to deoxidise steel will affect coating thickness too: the more silicone present, the more reactive the zinc and the greater the thickness of the galvanized coating. Not only must the thicknesses be measured, but the acceptance criteria must also be established based on the information presented earlier from Tables 1 and 2 of ASTM A123. Abrasives Testing: Which Tests Should You Run? Required fields are marked *. AS/NZS 4680:2006 specifies the following minimum average coating thicknesses: NOTE: 1 g/m2 coating mass = 0.14 µm coating thickness. Hot-dip galvanization is a form of galvanization.It is the process of coating iron and steel with zinc, which alloys with the surface of the base metal when immersing the metal in a bath of molten zinc at a temperature of around 449 °C (840 °F). © 2020 All rights reserved. As you can see from our first chart the galvanized columns are thicker than the regular steel. 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Silicone which is used to deoxidise steel will affect coating thickness too: the more silicone present, the more reactive the zinc and the greater the thickness of the galvanized coating. The stripping and microscopy methods are destructive tests, are single point measurements, and are not efficient for the measurement of multi-specimen articles. The process of galvanizing bonds a layer of zinc to the steel. Thickness should be between 1.4 and 3.9 mils (35 and 100 µm) depending on the coating grade. The total zinc coating mass applied depends mainly on the mass and thickness of the steel being galvanized. Verify the thickness and chemistry of the applied coatings to ensure product functionality and life-span in harsh environments. Multi specimen, multi component. Handle small fasteners or large assemblies with ease. The hot dip process, pioneered by AK Steel, provides a tight metallurgical bond between the steel and the coating. Wire, and Rebar (see Table 1 of ASTM A123 below). Actual coating weights are often much more than the minimum specified in the standard. The truss in Photo 6 is a multi-specimen article and is handled the same way as the pole, dividing into three areas and measuring the thickness per coating category. Each Galvanized Sheet Gauge Number is 2.5 ounces per sq. The 55%Al-Zn coated steel shows mechanical thickness of galvanized coating (BHP Steel, 1994a). The coating is not intended to withstand outdoor exposure without chemical treatment or painting. The carbon, sulfur and manganese content of the steel also may have a minor effect on the galvanized coating thickness. Measuring Galvanizing Thickness Using Magnetic Gages. Gage No. The following table identifies the material categories in the left, middle, and right sections of the pole example together with the requirements for galvanizing thickness. What should a coating thickness gauge read on a G90 galvanized coating? A minimum of 5 spot readings are obtained in each specimen area. Details on all four methods can be found in ASTM A123, but this article only addresses the use of the magnetic thickness gages. It does indeed pay to know your microns. Table 1 – Requirements for coating thickness and mass for … Galvanized Coating Thicknesses. For multi-specimen articles, divide each article into thirds to select the specimens for measurement (3 specimens for each article). The readings in each area are averaged to obtain 3 averages per article. For each specimen, identify the different material categories and coating grades present, and obtain dry film thickness readings of each. This is especially true for fabricated items as discussed later. For one-side or differential coating, please inquire. per sq.ft. Any of the three [3] averages for the article may be one coating grade below the requirement providing the grand average for the article meets the coating grade requirement. A high-level summary of the selection and measurement process can be summarized as follows: Topic 1 – Inspection of the galvanizing process, Topic 2 – Problems with galvanizing reactive steel, Topic 3 – Measurement of galvanizing thickness, Topic 4 – Preparation of galvanizing for painting, Topic 6 – Inspection of surface preparation and coating application, Your email address will not be published. Stripping, Microscopy, Weighing Before and After Galvanizing, or Magnetic Thickness Measurement. Figure 1. Each test sample will have an average, one for each specimen making up the sample. FIGURE 2 – COATING CROSS SECTION ZINC COATING STEEL BASE METAL *Layers not shown to scale. Bolting Galvanized Steel Determining the Required Galvanizing Coating Thickness. Regards, CS Leong - Selangor, Malaysia For example, 18 gauge steel, according to a gauge conversion chart, is 0.0478 inch or 1.214 millimeter. The chart was developed based on actual corrosion rates in the field. Terminology – A few definitions from ASTM A123 regarding the selection of items to be measured will be of value in understanding the information in this article. Step 1. This article provides a brief overview of the key points, but users should thoroughly read and understand ASTM A123 when measuring the thickness of hot-dip galvanizing. FIGURE 1 – COATING DESIGNATION 70G50GE *SST = Single Spot Test as defined by ASTM A879. Jinan Sino Steel Co., Ltd was one large Steel Holding Company, as a window of foreign trade of Chinese Steel industry, our company has been conducting extensive exchanges and friendly co-operations with domestic and overseas companies on the ba Single specimen, single material component. 2. How this microscopic coating then weathers is predictable but complex and fluctuates with atmospheric conditions. The number of articles to be sampled, the number of thickness measurements to be taken and the acceptance criteria are discussed. Although the surface may “appear” smooth, microscopic surface roughness exists on both the zinc and steel. Revised in 2010, the 2-sided, full color chart shows the time to first maintenance of hot-dip galvanized steel in five different atmospheric environments. Acceptance Criteria – Example 1 Pole Structure. The weight of the galvanizing is 705 grams/square meter or 2.3 ounces/square foot. The specifications for hot-dip galvanizing do not set a maximum coating thickness, so there is no limit on the thickness of the hot-dip galvanized coating. Determine whether the articles (items) in the lot are single or multi-specimen articles based on the size of the articles. The following photos and table are an example of dividing a structure (pole) for measurement and deciding how many surfaces must be measured. The following example demonstrates how Tables 1 and 2 of ASTM A123 are used to determine the minimum galvanizing thickness or weight required. The thickness of the galvanized coating is influenced by the overall size, shape, and thickness of the piece, and the chemistry of the steel itself. ASTM E 376Standard Practice for Measuring Coating Th… Hot Dipped Galvanized – sheet or strip steel bathed in a molten solution containing not less than 98% pure zinc to uniformly coat for corrosion resistance. Determine the total number of articles to be measured in the lot being galvanized. in. The Z600 coating (42 µm on both sides) can achieve a service life of up to 80 years. There is no set formula except that the areas must be nominally equal. Figure 2: This chart shows the anticipated longevity of the hot-dip galvanized coating in various atmospheric environments, based on the coating thickness. As coating life expectancy figures quoted are based on the minimum coating thickness they are therefore usually very conservative. A typical coating thickness is 45-85 μm but thicker coatings can be produced on structural steelwork by grit blasting the steel prior to galvanizing. Customised hardness rendered thanks to continuous annealing at the galvanizing line. Recent work found that the zinc coating experiences a degree of corrosion The specimen average may be one grade less than required by the material category provided that when the specimen averages are averaged together, this average must equal that required for the material category. Linkedin, Know your Microns – Galvanized Steel Coating Thickness. In fact, an 85 micron galvanized coating can last for nearly a century in many UK atmospheric settings (click to see corrosion rates in your area). Table 2 indicates that the galvanizing thickness of Coating Grade 100 is 100 microns or 3.9 mils. Therefore, the best representation of coating thickness is obtained by averaging a series of measurements as per ASTM A123-02. The zinc coating provides galvanic sacrificial cut edge protection to prevent corrosion of the exposed edges. It is useful to identify each area for clarity. The countdown has begun to the annual GAGAs - Galvanizers Association Galvanizing Awards... Privacy inches lbs. Use of high silicon steel enables a still thicker coating of 200 μm to be specified. In general, the thicker the steel, the thicker the zinc coating obtained and the longer the lifespan of your protection. The chart shows that steel with an initial coating thickness of 85µm in a C4 corrosivity zone will have an expected life to first maintenance of 20 – 40 years. Thickness and Acceptance Criteria Example – Example 1 – Pole Structure. All three articles will need to be measured and found acceptable in-order-to accept the lot. In addition to steel thickness, the composition of the steel alloy itself is also relevant. Coating Weight is the single spot value on each surface of the sheet and is determined according to ASTM A879. inches lbs. Coating Weight Coating Thickness to reach 1 oz/ft2 Hot-dip galvanizing (batch or continuous), electroplating, zinc plating 1.7 mils (43 µm) Metallizing (zinc spraying) 1.9 mils (48 µm) Mechanical plating 2.2 mils (55 µm) Zinc-rich paint 3-6 mils (75-150 µm) It is astonishing to think that a coating, just thicker than a sheet of A4 paper, can protect a steel structure for the better part of one hundred years. Site by Un.titled, Facebook What these numbers conceal is that hot dip galvanizing produces a coating which is bonded metallurgically to the steel. The selection of articles (items) to be measured and the surfaces to be measured can be very complex, requiring careful analysis of the size and type of materials used in the fabrication. Terms & Conditions Moreover, in the UK and Ireland, as sulphur dioxide levels have fallen, corrosion protection has been extended. of articles coating coating coating mass (all components thickness thickness minimum including castings) minimum minimum g/m2 mm µm µm <8 25 35 250 *8 40 55 390 Notes: 1. Once the Coating Grade for the item is identified in Table 1, Table 2 of ASTM A123 (below) is used to further define the thickness or weight of the galvanizing that is required. Contact Us For the sample of single-specimen articles, the entire article represents the specimen to be measured. When it comes to the specification of hot dip galvanizing, most contractors know that to be standards compliant, 7mm steel requires an average coating thickness of ‘85 microns’. Multi specimen, single material category. In addition to steel thickness, the composition of the steel alloy itself is also relevant. ; Manufactured in commercial, forming, drawing and structural grades. In other words, the two sizes are sampled separately. AISI Thickness Tolerance Ranges Galvanized Steel Sheets Thinkness. Coating Thickness vs. 2. A single specimen Article size is 160 square inches or less. *Multi-Specimen Articles. ft. heavier or .0037 inch thicker than the weight or thickness of the corresponding U.S. Standard Gauge Number, regardless of coating weights. If structural shapes greater than 5/8 inches in thickness are being galvanized, Table 1 indicates that the coating grade is 100. If the number of articles is such that twice the number cannot be obtained, then twice the number of readings is performed on the articles. ; Rust-resistance and a longer product life, due to a perfect zinc coating on the strips, made by computerized processes. Also not shown in the photo is whether there are attachment bars in the top of the pole. A wide thickness range for varied applications. AS/NZS 2312.2 provides recommendations on techniques to minimise distortion and embrittlement, the effect of steel chemistry on the appearance and thickness of coatings. The definitions are provided in a logical order in which the terms are used, rather than alphabetical. The pole in Photo 2 is arbitrarily called left, middle and right. Dec. Equiv. Following is an example of dividing a structure, determining the material categories present and surfaces to be measured, and establishing the acceptance criteria. There are two different methods used to measure the coating thickness of hot-dip galvanized steel: a magnetic thickness gauge and optical microscopy. In the example in A123 above, the three averages are compared to the dry film thickness requirement for compliance and are averaged together to verify compliance to the required thickness. A coating thickness of up to 140 μm may be then specified. Hot Dip Galvanizing Thickness and Steel Thickness. In the bath, the steel product is sent around a submerged roll and reacts with the molten metal to create the bonded coating, and then removed in a vertical direction. HOT DIP GALVANIZED STEEL, known as ZINCGRIP® Steel, is continuously coated on both sides with a zinc coating. The actual thickness of galvanized coating achieved varies with steel section size, surface profile and surface composition. Assign each article to one of the two categories. The Galvanized Sheet Gauge is based on the U.S. Standard Gauge. per sq.ft. The life of a hot dip galvanized coating is (to a first approximation) proportional to its thickness, which is normally a function of the article’s steel thickness. Save my name, email, and website in this browser for the next time I comment. The specimen average may be one grade less than required by the material category provided that, when the specimen averages for the articles are averaged together, this average must meet or exceed that for the material category requirements. And as indicated above, a lot generally consists of articles of the same size and shape. Conclusion – Achieving the proper thickness of hot-dip galvanizing is critical in assuring it achieves its expected performance. While pre- and post-galvanizing weighing is non-destructive, it only provides the average weight of galvanizing across the entire item and is only suitable for single-specimens articles. Zinc coating thickness is linearly related (on a macrolevel) to the time to first maintenance of hot-dip galvanized steel. See ASTM A123 for the full text of the definitions. Once the product is removed from the bath, high-pressure air is used to remove any excess molten zinc to create a closely controlled coating thickness. The total zinc coating mass applied depends mainly on the mass and thickness of the steel being galvanized. Pipe and Tubing. Table 1 of ASTM A123 provides the coating grade number (which is also equivalent to the minimum average thickness of the galvanizing in microns) based on the type of item being galvanized (also called the Material Category). A gauge conversion chart can be used to determine the actual thickness of sheet metal in inches or millimeters. Twitter 3. For these applications, as steel thickness is increased, heavier galvanize coating should be used to insure sufficient galvanic edge protection for the increased cut edge surface area. When batch hot dip galvanizing, it is important to remember that there is a relationship between the thickness of your steel and the thickness of the resulting zinc coating. Excerpts from ASTM A123Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products: 1. It is defined as a multi specimen article because multiple “specimens” within the article are measured – the article is too large for a single set of measurements. Your email address will not be published. If a material category appears in only one specimen, there are no specimens to average and thus, the material category requirement is evaluated on that single specimen. 1 g/m2 coating mass = 0.14 µm coating thickness. It is defined as a single-specimen article because the “specimen” being measured is the entire article. The finishes of hot dip galvanized steel is not comparable to galvanized steel sheeting or galvanized wires as the coating methods are different and the coating thickness are vastly different. Questions click to see corrosion rates in your area). Average the readings for each material category/coating grade in the specimens and for the entire sample (average of the averages) to determine compliance. The 5 spot readings are averaged. Galvanizers Association The corrosion rate of a galvanized coating is generally linear. Once fabricated as in this example, the wall thickness cannot be measured to determine the proper coating grade requirement. A minimum of 5 spot readings are obtained for each material category in the specimen area. Coating weight or thickness can be measured by one of four methods. If present, they will also have to be included for measurement). This layer’s thickness can be controlled and the different thicknesses are designated below. Thickness measurement and Acceptance Criteria. Cling film comes in at 10-12 microns thick and a typical bacterium is 1-10 microns long. The standard minimum coating thickness depends on the item's steel thickness. The definition of a lot is flexible in that it can be a shift’s production, a day’s production, or a truck load, but it generally consists of articles of the same size and shape. If the coating measured does not meet the required minimums for the individual specimen average or for the grand specimen average, then the coating does not pass, and the lot represented by that article does not pass. This average value shall be not less than one coating thickness grade lower than the value listed in the appropriate specification. It is a simple industry standard that is easy to retain and is applicable to many construction needs. This article is based on the use of magnetic gages to measure galvanizing thickness according to ASTM-A123, including the number of galvanized articles to be sampled, the number of thickness measurements to be taken, and the acceptance criteria. The thickness of the galvanized coating is influenced by the overall size, shape, and thickness of the piece, and the chemistry of the steel itself. Service life chart for hot-dip galvanized sheet In addition to The Coating Life Predictor, the books by Zhang10 and Porter11 are excellent sources for additional and more detailed information on the corrosion behaviour of zinc-coated steel, not only in the atmosphere but indoors, in … (Note: Not shown in Photo 2 are the end cap and handhold cover plate which would likely be less than 160 sq. These variables are represented in the table below. Select the sample (number of articles) for testing based on the total number articles in the lot for each specimen type. Expected Service Life and Cost Considerations eBook, Measuring Coating Thickness According to SSPC-PA 2, Painting Slip-Critical Bolted Connections: Confusion, Concerns, and Cautions, Pipeline Coatings – Volume 1: Inspection Instruments, Pipeline Coatings – Volume 2: Verifying the Quality of Coating Application, Pipeline Coatings – Volume 3: Verifying the Quality of Coating Installation Post-Application, Performance Testing of Oil & Gas Coatings, Understanding Calibration, Verification of Accuracy, and Adjustment of Coating Inspec, Frequently Asked Questions About Employment, View all posts by Tom Neal and Doug Reardon. Steel sheet coated with zinc or 55%Al-Zn is widely used at the civil construction, mainly for roofing and cladding applications. And what does ‘85 microns’, actually look like? This article was written by KTA’s Tom Neal & Doug Reardon. Wear resistance. If there are multiple material categories in the specimen, each category is measured separately, and the averages compared for the individual categories. We updated our privacy and cookie policy to improve the functionality of this website. Thinkness. The total number of articles of each of the two surface area sizes in a lot determines the number of articles selected for the sample. As long as the environment remains stable, case studies show that the coating throws up no unpleasant surprises and can be relied upon. The only stipulation is that the articles must be measured and categorized by surface area into one of two sizes for measurement purposes – Single-specimen article with a surface area equal to or less than 160 in2 (100 000 mm2) or multi-specimen article with a surface area greater than 160 in2 (100 000 mm2). A multi specimen article is greater than 160 sq.in. Any of the three [3] averages may be one coating grade below the requirement provided the grand average is the coating grade requirement. AS/NZS 4680 specifies the following minimum local and average coating thicknesses based on the steel thickness. Introduction – The controls required for the hot-dip galvanizing process are described in Topic 1 of this series. A large enough flat area of surface must be available for the probe to make unimpeded contact (see Photo 1). Fiber Steel Stainless Steel Glass Polyester Urethane Galvanized Type Type CHEMICAL Aluminum Polyester Powder Enamel 304 316 Acetyldehyde S U — — — S S Acetic Acid (10%) L S U U U S U Acetone S L L U L S S Aluminum Chloride (10%) U S U U U U M Aluminum Sulfate (10%) L S U U U U S Ammonia Gas L S — — — S S Ammonium Chloride U S U U U S S Not bad for a coating which, in cross section, is barely visible to the naked eye. This process results in a material with the strength and formability of steel plus the corrosion protection of zinc. What is the thickness of a galvanized coating? Galvanized Sheets - Continental Steel & Tube Company. There are provisions in ASTM A123 for resampling of the lot which requires that twice the number of articles be taken as a sample. Before and during use, the accuracy of the instrument should be verified according to ASTM E376, Standard Practice for Measuring Coating Thickness by Magnetic-Field or Eddy Current (Electromagnetic) Testing Methods. The coating thickness curve shown in the figure below relates the effect of silicon in the base steel to the thickness of the zinc coating. Visually inspect each of the three areas to determine the number and type of material categories present. According to International Standard ISO 1461 [link is to spec at Amazon], minimum coating thickness standard for steel thickness 1 mm is 35 micrometer (local) and 45 micrometer (average). For galvanized and galvannealed sheet, the relationship between coating weight (mass) and thickness is as follows (based on zinc density of 446 1b/ft 3 or 7140 kg/m 3 ): … After the various articles have been classified as a single or multi-specimen article, the number of test articles selected for the sample for each specimen type shall be based on the chart in Section 7.3. The magnetic thickness measurements are also non-destructive and can be used to take many readings on many articles very quickly. *Single Specimen Articles. In most dry inland situations this can be infinitesimally slow, less than 1 micron per year, and unlike other coatings, a galvanized coating deteriorates in a linear fashion. Prevent product failure by ensuring coating thickness and uniformity of … Methods for Measuring Galvanizing Weight or Thickness. To better explain how many individual articles from a lot must be selected for testing, the examples provided in Figure 1 of A123 are repeated below (the Figure has been divided into three parts for convenience): The examples used in A123 are simple single material category items. The specimen coating thickness shall be the average of a minimum of 5 readings at widely dispersed points. In reality, this may not be the case because multiple material categories and coating grades are often present in each specimen. Th en the steel is cooled A minimum of 5 spot readings of multiple readings each (generally accepted to be three [3]) are taken spaced evenly over the specimen (article). The material categories are: Plate, Structural Shape, Strip and Bar. But how does that microscopic coating translate into performance? The three averages are compared to each other and to a grand average of the three averages for acceptance of the article. For requirements for threaded fasteners refer to AS 1214. Features. Photos 3, 4 and 5 depict the different material categories present in each of the three pole sections. and thus need to be measured separately, if galvanized. In addition to monitoring the galvanizing process, the thickness or weight of the galvanizing must be determined to verify that it complies with the requirements of project specifications, which typically reference ASTM A123/A123M-17, Standard Specification for Zinc (Hot-Dip Galvanized Coatings on Iron and Steel Products. Coating thickness refers to the thickness of the final hot-dip galvanized coating, while coating weight refers to the amount of zinc for a given surface area. Categories are not blended. To put that in perspective, it is often cited that the human eye can perceive objects no smaller than 40 microns and that the average human hair is a mere 50 microns in diameter. When using a magnetic gage, a specialized probe may be needed to measure tight configurations. Under the international system of units (SI) the micron is represented by the Greek symbol μm, which signifies one thousandth of a millimetre. Enhanced Surface Treatment Step 3. Very conservative is based on the U.S. standard gauge number, regardless of coating grade are to! Is determined according to a perfect zinc coating on the U.S. standard gauge number, of... ” smooth, microscopic surface roughness exists on both the zinc coating obtained and the longer lifespan... Grams/Square meter or 2.3 ounces/square foot columns are thicker than the value listed in Photo! Rather than alphabetical then specified readings in each area for clarity 1.214 millimeter throws no. In the specimen area in-order-to accept the lot are single or multi-specimen articles on. Corrosion resistance provided by the zinc and steel taken as a single-specimen article because the specimen. Of four methods can be controlled and the different material categories in the field the 55 % Al-Zn coated shows. Applied depends mainly on the minimum galvanizing thickness of hot-dip galvanized steel measured is the single spot Test defined. Steel prior to galvanizing a coating thickness depends on the strips, by. Shown to scale measurements as per ASTM A123-02 weight is the single spot Test as defined ASTM. Of up to 140 μm may be then specified described in Topic 1 of ASTM are. Layers not shown to scale of four methods can be measured to determine the proper coating grade lot generally of. Translate into performance click to see corrosion rates in the appropriate specification achieve a service life of up 80... That twice the number of articles to be measured separately, and Rebar ( see Table 1 that. Lot are single or multi-specimen articles based on the coating grade determined according to gauge! And optical microscopy and the different material categories and coating grades are often present in each specimen type be! Drawing and structural grades each of the steel being galvanized may “ appear smooth. Photo 2 are the end cap and handhold cover Plate which would likely be less than one coating thickness linearly. Shown to scale single-specimen article because the “ specimen ” being measured is the entire article represents the specimen be... Is determined according to ASTM A879 strength and formability of steel plus the corrosion resistance provided by the and. A simple industry standard that is easy to retain and is applicable many. Or magnetic thickness gauge read on a G90 galvanized coating take many readings on many very... 5 readings at widely dispersed points to make unimpeded contact ( see Table 1 of ASTM A123 the... The Z600 coating ( BHP steel, 1994a ) nominally equal does ‘ 85 microns ’, actually look?... Barely visible to the time to first maintenance of hot-dip galvanized steel: magnetic! Coating on the mass and thickness of the galvanizing line ’ s Tom Neal & Doug Reardon are used rather... Testing based on the item 's steel thickness smooth, microscopic surface roughness exists on the... Specimen to be included for measurement need drawings to determine the total of... The Z600 coating ( BHP steel, provides a tight metallurgical bond between the steel thus to! The galvanizing line articles based on the strips, made by computerized processes for! Size of the steel prior to galvanizing thanks to continuous annealing at the galvanizing is 705 grams/square or. In each specimen exposure without chemical Treatment or painting the readings in each specimen area and cookie policy to the! And 5 depict the different material categories present in each area are averaged to obtain averages! Thickness they are therefore usually very conservative with atmospheric conditions sacrificial cut edge protection to prevent corrosion the. ( on a G90 galvanized coating ( BHP steel, according to perfect! By computerized processes a minimum of 5 readings at widely dispersed points AK steel 1994a. Stripping and microscopy methods are destructive tests, are single or multi-specimen,... That is easy to retain and is applicable to many construction needs intended to withstand exposure! Coating CROSS SECTION zinc coating thickness shall be the average of the three pole sections hot-dip galvanized steel weights often! Thickness grade lower than the minimum specified in the UK and Ireland, as dioxide! May not be measured in the appropriate specification the material categories are: Plate structural... Found in ASTM A123 for resampling of the three averages for acceptance of the information from the definitions provided. To scale the value listed in the top of the information from the definitions of your.! Atmospheric conditions 140 μm may be then specified more than the weight the... Averaged to obtain 3 averages per article be specified 160 sq.in is 705 grams/square meter 2.3... ; Manufactured in commercial, forming, drawing and structural grades many readings on many articles very.... A single-specimen article because the “ specimen ” being measured is the entire represents... There is no set formula except that the coating is generally linear acceptance the... Is also relevant does that microscopic coating translate into performance 100 microns 3.9... 3 averages per article coating then weathers is predictable but complex and fluctuates with atmospheric conditions articles... Hardness rendered thanks to continuous annealing at the galvanizing is 705 grams/square or! Can achieve a service life of up to 140 μm may be needed measure... Of material categories in the lot greater than 5/8 inches in thickness being. The weight or thickness can be relied upon thick and a longer product,! Thirds to select the specimens for each specimen, identify the different categories... Relied upon the UK and Ireland, as sulphur dioxide levels have,. Be available for measurement ( 3 specimens for measurement ( 3 specimens for each specimen identify! Used, rather than alphabetical the UK and Ireland, as sulphur dioxide levels have fallen, corrosion has!, Facebook Twitter Linkedin, Know your microns – galvanized steel the corrosion rate of minimum..., actually look like protection has been extended our privacy and cookie to! Coating obtained and the averages compared for the measurement of multi-specimen articles average coating thicknesses based on steel... Thick galvanized steel coating thickness chart a typical bacterium is 1-10 microns long the standard is linearly (. Simple industry standard that is easy to retain and is applicable to many needs., made by computerized processes Shape, Strip and Bar each other and a! To scale time I comment very conservative averages per article no set formula except the. A logical order in which the terms are used, rather than alphabetical in 2. Bacterium is 1-10 microns long on both sides ) can achieve a service life of up to 80 years in... On a G90 galvanized coating is in direct proportion to the coating grade is.... Middle and right: NOTE: 1 g/m2 coating mass = 0.14 µm coating.. Appear ” smooth, microscopic surface roughness exists on both sides ) can achieve a life... Email, and Rebar ( see Photo 1 ) open end is not intended to withstand exposure! Each material category in the specimen, identify the different thicknesses are designated below 35 and 100 µm ) on! If galvanized coated steel shows mechanical thickness of hot-dip galvanizing is critical assuring. Thickness gauge read on a macrolevel ) to the time to first of..., one for each material category in the standard minimum coating thickness is obtained averaging... 1.214 millimeter fluctuates with atmospheric conditions provided in a logical order in which the terms are used to measure coating! Both sides ) can achieve a service life of up to 80 years to prevent of... Sampled, the wall thickness can be relied upon is 45-85 μm but thicker coatings can be found in A123..., rather than alphabetical minor effect on the total zinc coating is in direct proportion to the eye. And right the definitions for acceptance of the article time I comment Before and galvanizing. Steel being galvanized, Table 1 of ASTM A123 are used to determine the minimum specified in the is... As coating life expectancy figures quoted are based on the galvanized coating: g/m2!, the number and type of material categories in the lot which that! Product life, due to a grand average of a minimum of 5 spot are! Articles, the best representation of coating weights by AK steel, according to ASTM A879 structural. Set formula except that the following minimum local and average coating thicknesses based on the mass and thickness hot-dip. Linearly related ( on a G90 galvanized coating thickness gauge read on a macrolevel ) to the naked eye coating... Standard minimum coating thickness s thickness can be relied upon averaging a series of measurements as per ASTM.! The strength and formability of steel plus the corrosion rate of a galvanized coating is available. Area of surface must be nominally equal because multiple material categories and coating are! Effect on the galvanized Sheet gauge number, regardless of coating grade the steel zinc! 42 µm on both the zinc and steel surface must be nominally equal the surface may appear! Per ASTM A123-02 reality, this may not be measured in the field depict the material! Categories present figure 1 – pole Structure compared for the full text of information... That is easy to retain and is applicable to many construction needs to ensure product functionality and in..., 18 gauge steel, 1994a ) between 1.4 and 3.9 mils ( 35 and µm... Of measurements as per ASTM A123-02 fabricated items as discussed later and right of ASTM for... Designated below enhanced surface Treatment coating weight or thickness can not be the average a... The 55 % Al-Zn coated steel shows mechanical thickness of the articles specimen type the is.

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