{"id":1728,"date":"2026-01-05T14:57:19","date_gmt":"2026-01-05T07:57:19","guid":{"rendered":"https:\/\/dk-metalsurfacetreatment.com\/?p=1728"},"modified":"2026-06-19T08:45:22","modified_gmt":"2026-06-19T01:45:22","slug":"pretreatment-for-hdg","status":"publish","type":"post","link":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/pretreatment-for-hdg\/","title":{"rendered":"Pretreatment for HDG Duplex processes"},"content":{"rendered":"<ul>\n<li style=\"text-align: justify;\" data-rm-block-id=\"block-1\"><strong>Chromium-6 free;<\/strong><\/li>\n<li style=\"text-align: justify;\" data-rm-block-id=\"block-2\"><strong>Excellent adhesion, corrosion protection and cost effective processing<\/strong><\/li>\n<li style=\"text-align: justify;\" data-rm-block-id=\"block-3\"><strong>Meets the GSB and Qualisteelcoat standards, Qualicoat certified<\/strong><\/li>\n<li style=\"text-align: justify;\" data-rm-block-id=\"block-4\"><strong>Multi-metal application<\/strong><\/li>\n<\/ul>\n<h4 style=\"text-align: justify;\" data-rm-block-id=\"block-5\"><strong>AD has developed a chromium(VI)-free pretreatment for Duplex hot dip galvanized steel system for prior to the coating process, the so called DUPLEX coating. In specific PreCoat Z31 enables perfect paint adhesion and corrosion protection on galvanized surfaces. It also provides a passivation against white rust (passivation layer) on the bare substrate.<\/strong><\/h4>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-6\">Chromium(VI)- free pretreatment for Duplex hot dip galvanized steel<\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-7\">PreCoat Z31 is developed for the needs of galvanizers that also offer a powdercoating or wet-painting service to their customers. PreCoat Z31 is a complete chromium(VI)-free pretreatment system (including etching, cleaning, conversion coating) .<\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-8\">PreCoat Z31 product characteristics:<\/p>\n<ul style=\"text-align: justify;\">\n<li data-rm-block-id=\"block-9\">Chromium(III) based<\/li>\n<li data-rm-block-id=\"block-10\">Spray, dip or cascade application<\/li>\n<li data-rm-block-id=\"block-11\">Free of substances of very high concern (SVHC<\/li>\n<li data-rm-block-id=\"block-12\">Multi-metal, suitable for all zinc and aluminum based alloys<\/li>\n<li data-rm-block-id=\"block-13\">Meeting the performance requirements of GSB and Qualisteelcoat<\/li>\n<li data-rm-block-id=\"block-14\">Qualicoat approved<\/li>\n<li data-rm-block-id=\"block-15\">Superior corrosion protection (up to 2000 hours salt spray testing)<\/li>\n<li data-rm-block-id=\"block-16\">Excellent paint adhesion<\/li>\n<\/ul>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-17\"><strong>Ask expert advice on HDG pre-treatment<\/strong><\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-18\">Customer case: WeCoat (Netherlands)<\/p>\n<p>AD Chemicals and WeCoat are launching a chromium (VI)-free pretreatment system for powder coating on galvanized steel, with Weert Group as the first European galvanizer to adopt this technology, which meets GSB and Qualicoat standards (Approval No. A-119). After over eight years of joint research and development, the PreCoat Z31 pretreatment serves as a direct replacement for chromium (VI), preserving essential qualities such as corrosion protection and paint adhesion, achieving over 2000 hours of NSS performance. The companies anticipate this system will become the global market standard for chromium (VI)-free pretreatments on galvanized steel.<br \/>\nTest Results<\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-21\">PreCoat Z31 has been thoroughly tested according to the highest test standards. PreCoat meets the following standards:<\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-22\">Paint adhesion<\/p>\n<ul style=\"text-align: justify;\">\n<li data-rm-block-id=\"block-23\">Cross hatch, according EN ISO 2409 \/ ASTM D3359<\/li>\n<li data-rm-block-id=\"block-24\">Boiling water test\/wet adhesion<\/li>\n<li data-rm-block-id=\"block-25\">Impacttest, according EN ISO 6272-1 \/ ASTM D2794 \/ EN 13523-5.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-26\">Corrosion protection<\/p>\n<ul style=\"text-align: justify;\">\n<li data-rm-block-id=\"block-27\">Machu-test<br \/>\nThis is an accelerated corrosion test on test panels and construction parts according to Qualicoat specifications. The test is made in a warm environment. To create this environment the test panels are placed in the plastic container, which is placed in the Machu Test Bath. The test panels need to be scratched crosswise with a 1mm cutting tool before placing them in the warm moisture test chamber. The fluid content, temperature and remain time are specified.<\/li>\n<li data-rm-block-id=\"block-28\">Salt spray test<br \/>\nSalt spray according to ISO9227\/ Din50021\/ ASTM B117.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-29\">Below image shows the test resultts after 500 hours of Neutral Salt Spray Test (NSS) in comparison to a chromium(VI) based pretreatment.<\/p>\n<p data-rm-block-id=\"block-30\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-3827 size-full aligncenter\" src=\"https:\/\/dk-metalsurfacetreatment.com\/wp-content\/uploads\/2026\/01\/PreCoat-Z31-blue-EN.png\" alt=\"\" width=\"904\" height=\"774\"><\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-31\">PreCoat Z31 versus Chromate conversion coating<\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-32\">Below table shows an overview comparison between PreCoat Z31 and a chromate conversion coating.<\/p>\n<table width=\"621\">\n<tbody>\n<tr>\n<td data-rm-block-id=\"block-33\"><\/td>\n<td data-rm-block-id=\"block-34\"><strong>Chromate conversion coating<\/strong><\/td>\n<td data-rm-block-id=\"block-35\"><strong>PreCoat Z31<\/strong><\/td>\n<\/tr>\n<tr>\n<td data-rm-block-id=\"block-36\"><\/td>\n<td data-rm-block-id=\"block-37\"><\/td>\n<td data-rm-block-id=\"block-38\"><\/td>\n<\/tr>\n<tr>\n<td data-rm-block-id=\"block-39\">Environmental impact<\/td>\n<td data-rm-block-id=\"block-40\">-\/-<\/td>\n<td data-rm-block-id=\"block-41\">++<\/td>\n<\/tr>\n<tr>\n<td data-rm-block-id=\"block-42\">Corrosion protection and paint adhesion<\/td>\n<td data-rm-block-id=\"block-43\">++<\/td>\n<td data-rm-block-id=\"block-44\">++<\/td>\n<\/tr>\n<tr>\n<td data-rm-block-id=\"block-45\">Multi-Metal<\/td>\n<td data-rm-block-id=\"block-46\">-\/+<\/td>\n<td data-rm-block-id=\"block-47\">++<\/td>\n<\/tr>\n<tr>\n<td data-rm-block-id=\"block-48\">Robust proces<\/td>\n<td data-rm-block-id=\"block-49\">++<\/td>\n<td data-rm-block-id=\"block-50\">++<\/td>\n<\/tr>\n<tr>\n<td data-rm-block-id=\"block-51\">Meets quality standards<\/td>\n<td data-rm-block-id=\"block-52\">Qualisteelcoat, GSB, Qualicoat<\/td>\n<td data-rm-block-id=\"block-53\">Qualisteelcoat, GSB, Qualicoat<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-54\">Exceeding the market standard<\/p>\n<p style=\"text-align: justify;\" data-rm-block-id=\"block-55\">HDG Pre-treatments have a huge range of requirements on a complex combination of zinc based alloys. This drives the need for close working relationships, consultation, testing and pilot line experimentation. With PreCoat Z31 AD Chemicals shows that replacing chromium-6 while maintaining the highest quality is possible.<\/p>\n<p data-rm-block-id=\"block-55\"><strong><em>See some chemicals for the steel industry here:<\/em><\/strong>\u00a0<a href=\"https:\/\/dk-chemicals.vn\/\" target=\"_blank\" rel=\"noopener\">https:\/\/dk-chemicals.vn\/<\/a><br \/>\n<em><strong>See some of our other products here:<\/strong><\/em>\u00a0<a href=\"https:\/\/dk-metalsurfacetreatment.com\/san-pham-cong-ty-tnhh-hoa-chat-d-k\/\" target=\"_blank\" rel=\"noopener\">https:\/\/dk-metalsurfacetreatment.com\/san-pham-cong-ty-tnhh-hoa-chat-d-k\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Chromium-6 free; Excellent adhesion, corrosion protection and cost effective processing Meets the GSB and Qualisteelcoat standards, Qualicoat certified Multi-metal application AD has developed a chromium(VI)-free pretreatment for Duplex hot dip galvanized steel system for prior to the coating process, the so called DUPLEX coating. In specific PreCoat Z31 enables perfect paint adhesion and corrosion protection<\/p>\n","protected":false},"author":3,"featured_media":2288,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38,24],"tags":[],"class_list":["post-1728","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-general-galvanizing-hdg-en","category-products"],"_links":{"self":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts\/1728","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/comments?post=1728"}],"version-history":[{"count":9,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts\/1728\/revisions"}],"predecessor-version":[{"id":3937,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/posts\/1728\/revisions\/3937"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/media\/2288"}],"wp:attachment":[{"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/media?parent=1728"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/categories?post=1728"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dkmetalsurfacetreatmentcom642.mbws.vn\/en\/wp-json\/wp\/v2\/tags?post=1728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}