{"id":364,"date":"2026-07-09T07:25:37","date_gmt":"2026-07-09T07:25:37","guid":{"rendered":"https:\/\/sudhaind.com\/blog\/?p=364"},"modified":"2026-07-29T07:35:08","modified_gmt":"2026-07-29T07:35:08","slug":"passivation-of-galvanised-and-galvalume-steel-strip-preventing-white-rust","status":"publish","type":"post","link":"https:\/\/sudhaind.com\/blog\/passivation-of-galvanised-and-galvalume-steel-strip-preventing-white-rust\/","title":{"rendered":"Passivation of Galvanised and Galvalume Steel Strip: Preventing White Rust"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"364\" class=\"elementor elementor-364\">\n\t\t\t\t<div class=\"elementor-element elementor-element-822df69 e-con-full e-flex e-con e-parent\" data-id=\"822df69\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"42df014\" \n\t\tclass=\"e-42df014-56a57bd e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>Passivation of Galvanised and Galvalume Steel Strip: Preventing White Rust<\/strong>\n\t\t<\/h2>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-83c6867 e-flex e-con-boxed e-con e-parent\" data-id=\"83c6867\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t\t\t\t\t<p class=\"e-paragraph-base\" data-interaction-id=\"a555da2\"  >\n\t\t\t\t\t\t\t\tPassivation is a surface treatment process that applies a clear chromium layer onto freshly galvanised and Galvalume coated steel strips. Utilizing high-performance <strong>metal passivation chemicals<\/strong>, this protective chemical film prevents white rust, storage stains, and bronzing effects that downgrade surface quality during transit. For continuous coil coating lines, a reliable <strong>passivation chemical<\/strong> is essential to protect the finish and reduce customer rejections.<br>\n\t\t\t\t\t<\/p>\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"453193c\" \n\t\tclass=\"e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>What is SUPASS Passivation Chemical?<\/strong>\n\t\t<\/h2>\n\t\t\t\t<div class=\"elementor-element elementor-element-b988694 elementor-widget elementor-widget-text-editor\" data-id=\"b988694\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">SUPASS is a proprietary, highly acidic, reddish-green liquid <\/span><b>anti-corrosion passivation chemical<\/b><span style=\"font-weight: 400;\"> manufactured by Sudha Speciality Chemicals. It uses both hexavalent and trivalent chromium chemistry to deposit a self-healing protective film over zinc alloys, serving as a comprehensive <\/span><b>passivation solution for metal surface treatment<\/b><span style=\"font-weight: 400;\">.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">While operations handling different metal substrates might require a dedicated <\/span><b>stainless steel passivation chemical<\/b><span style=\"font-weight: 400;\">, SUPASS is designed specifically for continuous galvanised strips and works seamlessly with conventional dip squeeze, spray squeeze, Roll Coater, and Chem Coater applications.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"393c549\" \n\t\tclass=\"e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>What are the Benefits of SUPASS for Coil Operations?<\/strong>\n\t\t<\/h2>\n\t\t\t\t<div class=\"elementor-element elementor-element-358f6ed elementor-widget elementor-widget-text-editor\" data-id=\"358f6ed\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">When moisture reaches unprotected zinc, white rust forms rapidly. SUPASS resists this corrosive attack while keeping operational overhead low.<\/span><\/p><ul><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf Superior Corrosion Resistance:<\/b><span style=\"font-weight: 400;\"> Delivers 96 hours of salt spray resistance and self-healing hexavalent chrome protection against white rust and bronzing.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf Energy Efficient Processing:<\/b><span style=\"font-weight: 400;\"> Operates effectively at room temperature (20 to 45 degrees Celsius), eliminating the need to heat or cool the bath solution.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf Water and Space Conservation:<\/b><span style=\"font-weight: 400;\"> Requires no post-rinse system, freeing up factory floor space and reducing water consumption.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf Simplified Waste Management:<\/b><span style=\"font-weight: 400;\"> Contains no chelating agents, making effluent treatment straightforward and compliant.<\/span><\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"c1a819f\" \n\t\tclass=\"e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>Technical Specifications and Operating Parameters<\/strong>\n\t\t<\/h2>\n\t\t\t\t<div class=\"elementor-element elementor-element-194bbc4 elementor-widget elementor-widget-text-editor\" data-id=\"194bbc4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">To achieve optimal coating weights and superior salt spray resistance, plant engineers must maintain the following operational parameters.<\/span><\/p><table><tbody><tr><td><p><b>Parameter<\/b><\/p><\/td><td><p><b>Recommended Range<\/b><\/p><\/td><\/tr><tr><td><p><b>Application Temperature<\/b><\/p><\/td><td><p><span style=\"font-weight: 400;\">20 to 45 degrees Celsius (Room Temp)<\/span><\/p><\/td><\/tr><tr><td><p><b>Total Chrome Content<\/b><\/p><\/td><td><p><span style=\"font-weight: 400;\">Approximately 60.0 g\/L<\/span><\/p><\/td><\/tr><tr><td><p><b>Contact Time<\/b><\/p><\/td><td><p><span style=\"font-weight: 400;\">1 to 2 seconds<\/span><\/p><\/td><\/tr><tr><td><p><b>Peak Metal Temperature (PMT)<\/b><\/p><\/td><td><p><span style=\"font-weight: 400;\">55 to 75 degrees Celsius<\/span><\/p><\/td><\/tr><tr><td><p><b>Squeeze Roll Pressure<\/b><\/p><\/td><td><p><span style=\"font-weight: 400;\">3 to 6 kg\/cm2<\/span><\/p><\/td><\/tr><tr><td><p><b>Coating Weight<\/b><\/p><\/td><td><p><span style=\"font-weight: 400;\">15 to 25 mg\/m2 per side<\/span><\/p><\/td><\/tr><\/tbody><\/table>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"74af713\" \n\t\tclass=\"e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>How to Maintain a Passivation Bath for Maximum Yield<\/strong>\n\t\t<\/h2>\n\t\t\t\t<div class=\"elementor-element elementor-element-5dada07 elementor-widget elementor-widget-text-editor\" data-id=\"5dada07\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">For line managers focused on cost control, SUPASS delivers highly predictable yield and maintenance cycles. Follow these standard guidelines for optimal bath life:<\/span><\/p><ul><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf\u00a0 Control Chemical Consumption:<\/b><span style=\"font-weight: 400;\"> When properly calibrated, chemical consumption is approximately 75 ml (+\/- 2 ml) per 100 square meters of steel strip.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf\u00a0 Use Correct Equipment:<\/b><span style=\"font-weight: 400;\"> Squeeze rolls must be constructed of chromic acid-resistant rubber like Hypalon. Holding tanks should utilize Type 316 stainless steel or PVC linings.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf\u00a0 Ensure Rapid Drying:<\/b><span style=\"font-weight: 400;\"> The treated strip must be dried rapidly at a PMT of 55 to 75 degrees Celsius. Air movement must remove water without physically disturbing the wet film.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>\u25cf\u00a0 Prevent Zinc Contamination:<\/b><span style=\"font-weight: 400;\"> Maintain a short reaction distance to the squeeze rolls (maximum 1.0 meter) and keep bath temperatures below 40 degrees Celsius. Zinc contamination must stay below 2000 ppm and never exceed 3000 ppm to avoid turbidity.<\/span><\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"8d95545\" \n\t\tclass=\"e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>Safe Handling and Effluent Disposal Guidelines<\/strong>\n\t\t<\/h2>\n\t\t\t\t<div class=\"elementor-element elementor-element-299fab9 elementor-widget elementor-widget-text-editor\" data-id=\"299fab9\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">Because SUPASS contains hexavalent chromium, strict safety and disposal protocols are required. Hexavalent chromium waste is managed through chemical reduction using Sodium Bisulphite. The supernatant liquid can then be discharged once it meets local regulatory standards for trivalent and hexavalent content. Workers must wear standard personal protective equipment, including rubber gloves, aprons, boots, and face shields, to prevent skin and eye contact.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<h2 \n\t\tdata-interaction-id=\"0cf5b31\" \n\t\tclass=\"e-heading-base\" \n\t\t \n\t\t\n\t>\n\t\n\t\t\t<strong>Why Collaborate with Sudha Speciality Chemicals<\/strong>\n\t\t<\/h2>\n\t\t\t\t<div class=\"elementor-element elementor-element-648d232 elementor-widget elementor-widget-text-editor\" data-id=\"648d232\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">Sudha Speciality Chemicals Private Limited, a <\/span><b>passivation chemical manufacturer,<\/b><span style=\"font-weight: 400;\"> is a Kolkata-based company established in 2002. Our technical team provides end-to-end support for bath make-up, routine maintenance, and analytical control to ensure your galvanising line runs smoothly.<\/span><\/p><p><b>Contact us today to discuss passivation solutions for your continuous coil line:<\/b><\/p><ul><li style=\"font-weight: 400;\" aria-level=\"1\"><b>Visit:<\/b><a href=\"https:\/\/www.google.com\/search?q=https%3A%2F%2Fwww.sudhaind.com\"> <span style=\"font-weight: 400;\">www.sudhaind.com<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>Email:<\/b><a href=\"mailto:info@sudhaind.com\"><span style=\"font-weight: 400;\"> info@sudhaind.com<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><b>Call:<\/b><a href=\"tel:+919874050345\"><span style=\"font-weight: 400;\"> +91 9874050345<\/span><\/a><\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Passivation of Galvanised and Galvalume Steel Strip: Preventing White Rust Passivation is a surface treatment process that applies a clear [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":366,"comment_status":"open","ping_status":"open","sticky":false,"template":"elementor_header_footer","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"full-width-container","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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