{"id":6096,"date":"2026-09-06T12:51:32","date_gmt":"2026-09-06T09:51:32","guid":{"rendered":"https:\/\/aesinn.com\/test-ve-olcum-hizmetleri\/astm-a123-a153-sicak-daldirma-galvaniz-kaplama-muayenesi-ve-kalinlik-kontrolu\/"},"modified":"2026-09-06T12:54:40","modified_gmt":"2026-09-06T09:54:40","slug":"astm-a123-a153-sicak-daldirma-galvaniz-kaplama-muayenesi-ve-kalinlik-kontrolu","status":"publish","type":"page","link":"https:\/\/aesinn.com\/en\/test-ve-olcum-hizmetleri\/astm-a123-a153-sicak-daldirma-galvaniz-kaplama-muayenesi-ve-kalinlik-kontrolu\/","title":{"rendered":"ASTM A123 \/ A153 Hot-Dip Galvanizing Coating Inspection and Thickness Control"},"content":{"rendered":"<h2 class=\"wp-block-heading\">The Purpose of Hot-Dip Galvanizing and Inspection<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Hot-dip galvanizing is a process where steel or iron products are immersed in a bath of molten zinc to form a metallurgically bonded zinc coating on the surface. This zinc layer protects the steel from corrosion both through a physical barrier and a galvanic (sacrificing anode) effect. The lifespan of the coating&#039;s protection largely depends on the thickness and continuity of the zinc layer.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The purpose of galvanizing inspection is to objectively assess whether the coating thickness meets the minimum values specified in the relevant standard, whether there are any unacceptable defects on the surface, and whether the coating has sufficient adhesion. Inadequate or defective coatings can lead to premature corrosion in the field and loss of structural lifespan.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n\n<li>Verifying the adequacy of corrosion protection<\/li>\n\n\n<li>To confirm that the coating thickness meets the minimum grade values.<\/li>\n\n\n<li>Detecting visual defects such as bare spots, bubbles, and slag.<\/li>\n\n\n<li>To evaluate the adhesion of the coating to the substrate steel.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Relevant ASTM Standards and Scopes<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The American Society for Testing and Materials (ASTM) standards, most frequently cited in international projects and export specifications for hot-dip galvanizing, are summarized below. Each standard addresses a different product group or function; therefore, which standard is applied during inspection depends on the type of product.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n\n<li>ASTM A123\/A123M: Hot-dip galvanizing applied to structural steel products. Includes categories such as plates, profiles (structural shapes), strips and bars, pipes and tubes, wire, and reinforcement.<\/li>\n\n\n<li>ASTM A153\/A153M: Zinc coating applied to iron and steel hardware and fasteners (cast parts, bolts, nuts, washers, rolled\/pressed\/forged parts and other small parts). These parts are usually centrifuged to remove excess zinc.<\/li>\n\n\n<li>ASTM A385\/A385M: This is a standard of practice that defines good engineering practice in design and application to achieve a quality zinc plating (considering issues such as ventilation\/drainage holes and material compatibility).<\/li>\n\n\n<li>ASTM E376 is a standard for the non-destructive measurement of coating thickness on a substrate metal using magnetic field or eddy-current methods.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Regulatory Status: Is ASTM Mandatory in T\u00fcrkiye?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">ASTM standards are voluntary technical standards originating from the United States and do not constitute automatically binding legal regulations in T\u00fcrkiye. In T\u00fcrkiye, products requiring galvanizing are subject to relevant national or harmonized European standards (e.g., TS EN ISO 1461) or applicable technical regulations.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">ASTM A123 and A153 are more commonly required in practice for export projects or international engineering projects, as mandated by contracts and specifications. Therefore, the validity of ASTM in a project stems from the specifications or the contract between the parties. For this reason, it is important to clarify in the specifications which standard and which edition (revision year) will be used before the inspection.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Coating Thickness: Grading System and Minimum Values<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In ASTM A123, coating thickness is expressed using a grade system. A grade number also corresponds to the minimum average thickness of that coating in microns; for example, Grade 100 means a minimum average thickness of 100 microns (approximately 3.9 mils). All thickness values in the standard are minimums; there is no upper limit (maximum thickness) requirement.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The required grade is determined from the standard tables according to the material category (plate, profile, pipe\/tube, etc.) and steel thickness. For example, in the structural shapes category, the minimum average coating values vary from approximately 45 microns to 100 microns with increasing steel thickness; the typical minimum value for medium-thickness structural shapes is around 65 microns. In the pipe and tube category, the typical minimum value in the medium-thickness range is around 45 microns.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">ASTM A153 classifies hardware and fasteners into A, B, C, and D classes, with coating amounts given as both zinc weight and thickness. For example, for Class B, which includes rolled, pressed, and forged parts, the average zinc coating value is approximately 2.0 ounces\/ft\u00b2 (approximately 75 microns). Areas with threads are not subject to thickness requirements.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Note: The values above are examples for informational purposes only. The applicable grade and minimum thickness for each project should be determined according to the product category, steel thickness, and the tables in the current edition of the standard referenced in the specifications.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n\n<li>Grade number = minimum average coating thickness in microns (e.g., Grade 100 = 100 microns)<\/li>\n\n\n<li>The values are minimums; there is no upper thickness limit in A123.<\/li>\n\n\n<li>The required value depends on the material category and steel thickness.<\/li>\n\n\n<li>In A153, screw thread areas are exempt from thickness requirements.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Examination Methods<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Galvanized coating inspection is generally carried out using non-destructive methods and consists of several complementary steps. It is essential that the equipment used for measurements and the number of samples comply with the requirements of the referenced standard.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n\n<li>Magnetic\/eddy-current thickness measurement: According to ASTM E376, coating thickness is measured using non-destructive thickness gauges that operate on the principle of a magnetic field or eddy current. Measurements are taken from a specific number of test sites and an average is calculated.<\/li>\n\n\n<li>Visual inspection: Examining the surface for defects such as bare spots, bubbles, roughness, slag residue, flow, and dripping.<\/li>\n\n\n<li>Adhesion assessment: Checking whether the coating adheres adequately to the substrate (using methods defined in the standard).<\/li>\n\n\n<li>Mass\/thickness relationship: The known relationship between the mass of zinc per unit area and the coating thickness can be utilized.<\/li>\n\n\n<li>Sample count: In A123, inspection is carried out on a lot basis, with parts grouped accordingly; multiple test areas are measured on each sample part and compared with the grade value.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Typical Application Areas<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Hot-dip galvanizing is commonly used on steel products where a long service life is expected in outdoor or corrosive environments. Coating inspection of these products is crucial for verifying both manufacturing quality and field service life.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n\n<li>Steel structures and structural steel elements.<\/li>\n\n\n<li>Lighting and power poles, lighting fixture carriers<\/li>\n\n\n<li>Guardrail, barrier and platform elements<\/li>\n\n\n<li>Industrial structural steel, platform gratings and ladders.<\/li>\n\n\n<li>Fasteners and hardware such as bolts, nuts, and washers.<\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">The Relationship Between Galvanizing and Cathodic Protection<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Galvanizing is one of the methods that protects steel against corrosion, and it provides a kind of local protection thanks to the sacrificial (galvanic) behavior of zinc. In this respect, it is based on the same electrochemical principle as cathodic protection: the more active metal (zinc) corrodes first, compared to the steel it protects.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, galvanizing and design cathodic protection systems (e.g., galvanic anode or external current source systems for buried pipelines or marine structures) have different application areas and often complement each other. While the coating provides the first line of defense against atmospheric and general surface corrosion, cathodic protection is designed to provide continuous protection in structures underground or underwater. Which corrosion protection method or combination is suitable should be evaluated according to the environment and design requirements of the structure.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Information Note<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This page is for informational purposes only; it provides general technical information and does not substitute for accredited inspection, testing, or certification services. Each application under ASTM A123\/A153 must be evaluated by an authorized engineer\/mechanical engineer based on the project-specific specification and the current edition of the standard. AES&#039;s T\u00dcRKAK accreditation is limited to the scope of 6.1 Electrical Installations; galvanizing work is handled within the framework of an authorized engineer&#039;s technical evaluation based on ASTM references.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Related Services<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n\n<li><a href=\"https:\/\/aesinn.com\/en\/trafo-ve-guc-sistemleri\/katodik-koruma\/\">Cathodic Protection<\/a><\/li>\n\n\n<li><a href=\"https:\/\/aesinn.com\/en\/test-ve-olcum-hizmetleri\/tahribatsiz-muayene-ndt\/\">Non-Destructive Testing (NDT) Services<\/a><\/li>\n\n\n<li><a href=\"https:\/\/aesinn.com\/en\/muayene-periyodik-kontrol\/mekanik-ekipman-muayeneleri\/atmosferik-depolama-tanklari-muayenesi\/\">Atmospheric Storage Tank Inspection<\/a><\/li>\n\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Frequently Asked Questions<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">How is galvanizing thickness measured?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The most common method is using non-destructive thickness gauges operating on the magnetic field or eddy-current principle, as defined by ASTM E376. The device is brought into contact with the steel surface, and the thickness of the zinc coating is read in microns. According to the standard, measurements are taken from multiple test areas, the average thickness is calculated, and compared with the corresponding grade value.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is the difference between ASTM A123 and A153?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">ASTM A123 covers hot-dip galvanizing of structural steel products such as plates, profiles, and pipes. ASTM A153 applies to hardware and fasteners such as bolts, nuts, washers, and cast parts; these smaller parts are usually centrifuged to remove excess zinc. In short, A123 is for large structural products, while A153 is for smaller parts and fasteners.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What is the minimum coating thickness?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">There is no single fixed value; the minimum thickness is determined from the standard tables according to the product category and steel thickness. In ASTM A123, this value is expressed by a grade number, and the grade number directly corresponds to the minimum average thickness in microns (e.g., Grade 100 = 100 microns). For example, in structural designs, the values may vary approximately between 45-100 microns. The exact value should be confirmed from the current table of the applicable standard for each project.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Is the ASTM standard mandatory in T\u00fcrkiye?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">No. ASTM is a voluntary standard originating in the US and is not automatically binding legislation in T\u00fcrkiye. ASTM A123\/A153 is required in practice as a requirement of specifications, contracts, export or international projects. Therefore, its validity stems from the specifications of the work; it must be clarified which standard and its revision will be used before the inspection.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What defects should be looked for in galvanized coatings?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Visual inspection examines bare spots (uncoated areas), bubbles, excessive roughness, slag residue, dripping\/flowing, and sharp protrusions. The adhesion of the coating to the substrate is also assessed. Thickness measurements, along with these visual assessments, reveal whether the coating meets the acceptance criteria.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What kind of service does AES provide in this regard?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">AES handles hot-dip galvanizing according to ASTM A123\/A153 standards through technical evaluation and information provided by authorized engineers; technical reports can be prepared regarding coating thickness and visual defects. This work constitutes a technical evaluation by an authorized\/mechanical engineer. AES&#039;s T\u00dcRKAK accreditation is only within the scope of 6.1 Electrical Installations; therefore, galvanizing inspection is not offered as an accredited inspection\/certification service.<\/p>","protected":false},"excerpt":{"rendered":"<p>S\u0131cak dald\u0131rma galvaniz kaplama, \u00e7elik \u00fcr\u00fcnleri korozyona kar\u015f\u0131 koruyan yayg\u0131n bir y\u00f6ntemdir. Bu sayfada ASTM A123 ve A153 standartlar\u0131n\u0131n kapsam\u0131, kaplama kal\u0131nl\u0131\u011f\u0131 kabul kriterleri ve muayene y\u00f6ntemleri tarafs\u0131z bi\u00e7imde a\u00e7\u0131klanmaktad\u0131r. \u0130\u00e7erik yaln\u0131zca bilgilendirme ama\u00e7l\u0131d\u0131r.<\/p>","protected":false},"author":1,"featured_media":6101,"parent":2518,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","slim_seo":{"title":"ASTM A123\/A153 Galvanizing Coating Inspection","description":"Unbiased technical information on ASTM A123 and A153 hot-dip galvanizing inspection, thickness measurement, acceptance criteria, and grading values."},"_pplb_hide_from_list":false,"footnotes":""},"class_list":["post-6096","page","type-page","status-publish","has-post-thumbnail","hentry"],"acf":[],"taxonomy_info":[],"featured_image_src_large":["https:\/\/aesinn.com\/wp-content\/uploads\/aes-astm-galvaniz-2026-1024x1024.png",1024,1024,true],"author_info":{"display_name":"Emre Metin","author_link":"https:\/\/aesinn.com\/en\/author\/yonetim\/"},"comment_info":"","_hostinger_reach_plugin_has_subscription_block":false,"_hostinger_reach_plugin_is_elementor":false,"_links":{"self":[{"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/pages\/6096","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/comments?post=6096"}],"version-history":[{"count":2,"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/pages\/6096\/revisions"}],"predecessor-version":[{"id":6105,"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/pages\/6096\/revisions\/6105"}],"up":[{"embeddable":true,"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/pages\/2518"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/media\/6101"}],"wp:attachment":[{"href":"https:\/\/aesinn.com\/en\/wp-json\/wp\/v2\/media?parent=6096"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}