STAC a division of GuiDon sa : +32 15 253810 E-S : [email protected] A C Slameuterstraat 1 b Industrial : stacoat.com Coatings B-2580 Putte STA C Belgium Industrial Coatings Bank: CRELAN : 103-2239738-76 VAT : BE 0453.727.693 IBAN : BE91 1032 2397 3876 RPR Mechelen Let STA Ckle those corrosion problems! BIC (SWIFT code) : NICABEBB ref : STAC-U1; Application guide metal Subject : STAC-U1-Systems: Application guide metal STAC-U1-Systems: THE preferred protection of metal constructions STAC-U1-Systems are the protective & marine coatings par excellence, for the conservation of metal con- structions (metals, steel and other ferrous alloys, non-ferrous alloys), which are applied under various conditions, in the shop and in the field. A few important advantages are: ➢ Preparation: limited preparation needed (even with UHP; water blasting without abrasives), cleanliness from Sa 2 and roughness of 25-60 µm (target ≥ 40 µm) is sufficient, moderate flash rust and moisture tolerant ➢ Application: 1-component, no mixing errors, no potlife, independent of the weather (15 to 99 % humidity, –12 to 50°C), tolerates surface moisture (avoid frozen surfaces, ice crystals and condensation), tolerates moder- ate flash rust, low consumption, fast overcoatable (can even be accelerated up to 75 % by adding STAC-U1- ACCELERATOR), good pit flow, high spray productivity, limited equipment cleaning time and rapid delivery time. They can be exposed to rain, fog and condensation (at ± 20°C) after ± 3–4 hours (± 1 hour with accelerator) (however, variations in brightness and/or aspect may appear). The maximum overcoat time without preparation is ± 5 days (on clean surface). ➢ Cured: strong adhesion to the structure, exceptional impact and abrasion resistance, excellent chemical and thermal (–40 to +150°C) resistance, selective galvanisation, excellent flexibility (allow deformation of the structure) and elasticity (± 30 %) and easy maintenance. Metal and alloy types The number of alloys in general and steel grades in particular is vast and difficult to summarize consistently. In appendix an attempt is made to review the most common types (see appendix I). The table below gives a summary. Ferrous alloys Carbon Other alloy elements All Manganese Silicon Chromium Nickel Molybdenum Vanadium Titanium Copper Phosphorus Wolfram Cobalt Steel 0,2 - 2,1 % Carbon steel Low alloy steel < 1,5 % ✓✓ ✓✓ Medium alloy steel 1,5 - 10 % ✓✓ ✓✓ ✓ ✓ ✓ ✓ High alloy steel > 10 % Stainless steel ✓✓ ✓✓ Weathering steel (Corten) ✓ ✓✓ ✓✓ ✓ ✓ Tool steel ✓✓ ✓ ✓ ✓✓ ✓✓ Dual-phase steel ✓✓ ✓✓ Maraging steel ✓✓ ✓✓ TRIP steel Eglin steel Hadfield steel ✓✓ etc… Cast iron 2,1 - 6 % 1 - 3 % ✓✓ ✓✓ Explanation: ✓✓ = major element ✓ = minor element = sporadic element Galvanised steel Hot-dip galvanisation Electrolytic galvanisation Metallisation Cold galvanisation Cold selective galvanisation Other metals and non-ferrous alloys Other metals: aluminium, copper, tin, etc… Non-ferrous alloys: bronze (copper and tin), brass (copper and zinc), etc… Let S TA Ckle those corrosion problems! STAC-U1; Application guide metal.docx Page 1 of 22 Edition: January 2020 (cancels and replaces the preceding ones) S T A C Industrial Coatings Surface preparation STAC advises cleanliness for metal surfaces before the application of coating systems according to the norms ISO 8501-1 (abrasive blasting and tooling) and SSPC-SP 12 (water jetting). In appendix a review is given of the different cleanliness grades according to different standards and the used cleaning methods (see appendix II). STAC advises roughness for metal surfaces before the application of coating systems according to the norm ISO 8503-1. This norm defines the profile type according the abrasive type: grit (angular) and shot (rounded). In appendix a review is given of the roughness types and the different parameters (see appendix III). Cleaning in general Clean the surface always first as necessary, with steam, water (e.g. with sodium triphosphate), solvent and/or neutralisation product, to remove all contaminants (e.g. oil, grease, lubricants, mud, acids). When dry, if neces- sary, clean further and roughen by blasting and/or power tooling. Blast DAB (dry abrasive blast) or WAB (wet abrasive blast), with hard angular grit, or UHP (ultra-high pressure water jet). In the two latter cases, additional degreasing may still be required. Vacuum clean till completely dust-free, assure it is touch-dry (e.g. towels, heath cannons) and start priming immediately. Cleanliness Remark: Steel = standard steel = carbon steel. Steel (ferrous alloys): new DAB or WAB to Sa 2 (for non-immersion and/or atmospheric use) or Sa 2,5 (for immersion or heavy load use) to remove all mill scale (oxidation skin) and rust. Steel (ferrous alloys): old Tooling (HTC and/or PTC BM) up to St 3 and/or blasting (DAB or WAB) to Sa 2,5 (and/or UHP to WJ 2) to remove all visible impurities (mill scale, rust, etc ...). Steel (ferrous alloys): with old paint Overcoat The old paint layer may be suitable to be overcoated with STACPRIMER-U1-ZIMIO, if it meets the following minimum requirements: ➢ Still in good condition and a adhesion strength of ≥ 1,7 MPa (250 psi) (ASTM D4541 Pull-off adhesion test). ➢ Compatibility with STACPRIMER-U1-ZIMIO checked and approved. ➢ Checked on the presence of lead (refer to the local regulations relating to lead-containing paints). Tooling (HTC and/or PTC) up to St 2 to remove all poorly adhering matter (mill scale, rust scale, old paint, etc…). Subsequently, sweep blast the surface to create sufficient profile, to ensure good coating adhesion. Recoat after complete removal If the old paint layer does not meet the above mentioned minimum requirements, it needs to be removed completely. Tooling (HTC and/or PTC BM) up to St 3 and/or blasting (DAB or WAB) to Sa 2,5 (and/or UHP to WJ 2) to remove all visible impurities (mill scale, rust, etc ...). Finally, extra blasting to Sa 2,5 may be required on very corroded areas (e.g. pit corrosion). Steel (ferrous alloys): with old galvanisation First clean chemically, to remove all contaminants (e.g. oil, grease, lubricants, mud). Then, high pressure water cleaning (HP WC) ≥ 50 MPa (x10=bar, x145=psi). Additional tooling up to St 3 might be needed on heavy corroded areas. Let S TA Ckle those corrosion problems! STAC-U1; Application guide metal.docx Page 2 of 22 Edition: January 2020 (cancels and replaces the preceding ones) S T A C Industrial Coatings Steel (ferrous alloys): with new galvanisation Local mechanical damage, due to transport, drilling, cutting, welding, … First local clean chemically, to remove all contaminants (e.g. oil, grease, lubricants, mud). Then local tooling to St 2–3. After thorough vacuum cleaning, retouch with STACPRIMER-U1-ZIMIO. Topcoat needed on the whole surface, for heavy chemical and/or mechanical service. Lightly sweep blast (DAB or WAB) or chemically etch, to remove zinc salts and create minimum weathered profile. Remark: in this case, it's better to use STACPRIMER-U1-HISO or -ALUMIO as primer, before the topcoat, because the cathodic protection (galvanisation effect) already exists. High alloy steel Weathering steel (Cor-Ten) High pressure water cleaning (HP WC), ≥ 50 MPa (x10=bar, x145=psi). Additional tooling to St 2 may be nec- essary for heavy corroded areas. Then chemical cleaning to remove all contaminants (e.g. oil, grease, lubricants, mud). Stainless steel DAB or WAB to Sa 2 (for non-immersion and/or atmospheric use) or Sa 2,5 (for immersion or heavy load use) to remove all mill scale (oxidation skin) and rust. Other ferrous alloys Cast iron, ferrous alloys with 2,1–6 % carbon and 1–3 % silicon and/or manganese, is the best known and is prepared in the same way as carbon steel. Non-ferrous metals and alloys Non-ferrous metals: aluminium, copper, tin, … DAB or WAB to Sa 2 (for non-immersion and/or atmospheric use) or Sa 2,5 (for immersion or heavy load use) to remove all mill scale (oxidation skin). Non-ferrous alloys: bronze, brass, … Bronze and brass are the best known. Bronze, an alloy of copper and tin, is prepared in the same way as carbon steel. Brass, an alloy of copper and zinc, is prepared in the same way as carbon steel. Roughness Roughness profile (conform ISO 8503-1): angular, type “fine (G)”, depth (Rz) 25–60 µm, target ≥ 40 µm. Salt concentration in steel surface (Bresle test, conform ISO 8502 ): off-shore ± 20 mg/m², lining ± 30 mg/m², at- mospheric ± 60 mg/m² (as mixed salts). Salt concentration Salt concentration in steel surface (Bresle test, conform ISO 8502, as mixed salts): ➢ Off-shore ± 20 mg/m² ➢ Lining ± 30 mg/m² ➢ Atmospheric ± 60 mg/m². Good practices STAC-U1-Systems are developed for application on a variety of substrates and have an excellent adhesion to most existing coatings. Apply always a test sample to determine coating adhesion and/or compatibility. Ensure welds, repair areas, joints and surface are properly cleaned, roughened, dust-free and treated (e.g. stripe primer on welds, angular structures, build-up and fixation parts) prior to primer application. Let S TA Ckle those corrosion problems! STAC-U1; Application guide metal.docx Page 3 of 22 Edition: January 2020 (cancels and replaces the preceding ones) S T A C Industrial Coatings Product storage and handling Storage The shelf life of STAC-U1-Systems is 12 months under standard conditions. They should be stored in a covered shelter, dry and well ventilated, away from source of heat or ignition, strong acids, strong bases, oxidising (and/or reducing) agents and direct sunlight. Storage temperature can range from 10 to 25°C and should be kept constant. The canisters must be kept carefully sealed and upright, to avoid moisture intrusion and/or leakage. Handling The product temperature must be brought to ≥ 3°C above the dew point temperature before opening the can and agitating.