[{"data":1,"prerenderedAt":182},["ShallowReactive",2],{"content:processes:galvanising-plating:en":3},{"slug":4,"category":5,"locale":6,"title":7,"subtitle":8,"metaDescription":9,"intro":10,"sections":13,"designTips":105,"applications":113,"pricingLeadTime":146,"faq":148,"cta":164,"keywords":165,"image":173,"related":177},"galvanising-plating","processes","en","Galvanising and Zinc Plating","Hot-dip galvanising, electro zinc plating and zinc flake for steel parts in Egypt, the UAE and Saudi Arabia","Galvanising and zinc plating for laser-cut and welded steel parts: hot-dip 55-85 µm, electroplating 5-25 µm, coating tables, design rules and lead times in Egypt, UAE, KSA.",[11,12],"Galvanising and zinc plating protect steel by covering it with zinc, which corrodes sacrificially before the steel does. Hot-dip galvanising gives a thick 55 to 85 µm layer for outdoor structures; electro zinc plating gives a thin 5 to 25 µm layer for indoor parts and fasteners; zinc flake coatings sit in between for high-strength bolts. CutLinq quotes the coating together with cutting, bending and welding, so you upload one DXF or STEP file and receive a binding price within 12 hours.","Below you will find the coating thickness each process delivers, expected life in dry desert, urban and Gulf coastal exposure, the design rules that prevent rejects in the zinc bath, and what to specify on the drawing.",[14,57,85,96,101],{"heading":15,"paragraphs":16,"table":19,"bullets":56},"Hot-dip galvanising versus zinc electroplating",[17,18],"Hot-dip galvanising (ISO 1461) dips the finished part in molten zinc at about 450 °C. The zinc alloys with the steel, so the coating cannot peel and covers cut edges, welds and the inside of tubes. Thickness depends on steel thickness: 45 µm minimum below 1.5 mm, 55 µm for 3 to 6 mm and 70 to 85 µm above 6 mm. The surface is matt grey with some spangle and drips; threads need re-tapping.","Electro zinc plating (ISO 2081, often called electro-galvanising) deposits 5 to 25 µm from a bath at room temperature, followed by a passivation: blue\u002Fclear, yellow (iridescent), black or trivalent thick-film. The finish is bright and dimensionally exact, suitable for brackets, fasteners and parts that will be assembled or painted, but it lasts only a few years outdoors and much less in salt air.",{"headers":20,"rows":26},[21,22,23,24,25],"Process","Coating thickness","Life to first rust, dry inland (C2)","Life, Gulf coastal (C4-C5)","Effect on dimensions",[27,33,39,45,51],[28,29,30,31,32],"Hot-dip galvanising","55 to 85 µm","40+ years","10 to 20 years","+0.1 to +0.2 mm per face, threads re-cut",[34,35,36,37,38],"Electro zinc, blue passivated","5 to 12 µm","3 to 8 years","under 1 year","+0.01 mm, exact",[40,41,42,43,44],"Electro zinc, thick-film passivated","12 to 25 µm","8 to 15 years","1 to 3 years","+0.02 mm",[46,47,48,49,50],"Zinc flake (Geomet type)","8 to 15 µm","15+ years","5 to 10 years","+0.02 mm, no hydrogen embrittlement",[52,53,31,54,55],"Pre-galvanised sheet DX51D+Z275","20 µm per face","2 to 5 years (cut edges bare)","None, already on the sheet",null,{"heading":58,"paragraphs":59,"table":61,"bullets":56},"Coating thickness by steel thickness (ISO 1461)",[60],"The standard sets minimum local and mean thickness by section thickness. Silicon and phosphorus content of the steel changes reactivity: S235JR and S355J2 with silicon between 0.04 and 0.14% (the Sandelin range) can grow a dull, thick, brittle coating. Where appearance matters, ask for aluminium-killed steel or accept a grey matt finish.",{"headers":62,"rows":67},[63,64,65,66],"Steel thickness","Local minimum","Mean minimum","Typical actual",[68,73,77,81],[69,70,71,72],"under 1.5 mm","35 µm","45 µm","50 to 60 µm",[74,71,75,76],"1.5 to 3 mm","55 µm","60 to 70 µm",[78,75,79,80],"3 to 6 mm","70 µm","70 to 90 µm",[82,79,83,84],"over 6 mm","85 µm","85 to 120 µm",{"heading":86,"paragraphs":87,"table":56,"bullets":90},"Design rules for the zinc bath",[88,89],"Closed sections must have vent and drain holes so that molten zinc flows in and air and moisture escape; a sealed tube can burst. A hole of 10 mm minimum, or 25% of the tube diagonal, at each end and at each internal cross-member is the usual rule. Overlapping plates should be seal-welded or left with a gap above 1 mm, otherwise trapped acid bleeds out as rust stains weeks later.","Parts distort: long thin plates and asymmetric welded frames bow in the 450 °C bath. Keep length-to-thickness ratios moderate, weld symmetrically and expect ±3 mm straightness over 2 m on light frames. Threaded holes should be tapped oversize or re-tapped afterwards; typical practice is M10 tapped after galvanising, or nuts galvanised with 0.4 mm oversize threads to ISO 10684.",[91,92,93,94,95],"Vent and drain holes: 10 mm minimum, at both ends of every closed section","Lifting holes or lugs: 12 mm minimum, so the part can hang in the bath","Avoid pockets that hold zinc; add a 5 mm drain hole in the low corner","Maximum bath sizes in the region are usually about 12 m by 1.5 m by 2.5 m; larger parts are double-dipped","Mask threads and machined fits with plugs or machine them afterwards",{"heading":97,"paragraphs":98,"table":56,"bullets":56},"Which coating for which exposure in MENA",[99,100],"Inland Riyadh or 10th of Ramadan is dry with sand abrasion and extreme UV; zinc lasts long but abrasion on the windward side removes 1 to 2 µm per year. Coastal Jeddah, Dammam, Alexandria and the entire UAE coast fall into ISO 12944 categories C4 to C5 with salt and 80 to 90% humidity in summer, where electroplated parts fail within a year and hot-dip galvanising should be combined with powder coating (a duplex system) for a life beyond 20 years.","For an indoor control panel or machine bracket, electro zinc with thick-film passivation is enough and keeps the part dimensionally exact. For anything outdoors or in a wash-down area, choose hot-dip or use stainless 1.4301 (304) instead.",{"heading":102,"paragraphs":103,"table":56,"bullets":56},"What to write on the drawing",[104],"State the standard and any finish class: for example 'Hot-dip galvanised to ISO 1461, tZn 70' or 'Zinc electroplated Fe\u002FZn 12\u002FC, trivalent thick-film passivation, ISO 2081'. Add which faces may show drips, which threads are to be re-tapped, and whether you require a coating-thickness report (magnetic gauge, 5 readings per part). If the part is later powder coated, say so: the galvaniser will then skip the water quench and the coater will sweep-blast and outgas before coating.",[106,107,108,109,110,111,112],"Put vent and drain holes of at least 10 mm at both ends of every closed tube before sending the file.","Keep flat plate at or below 1200:1 length-to-thickness to limit bowing in the hot-dip bath.","Add 0.2 mm clearance on each face of galvanised mating parts; a 10 mm slot becomes about 9.7 mm after galvanising.","Specify tapping after galvanising for threads M12 and smaller, or oversize nuts to ISO 10684.","Choose electro zinc 12 to 25 µm with thick-film passivation for indoor parts that must stay bright and exact.","For coastal sites specify duplex: hot-dip galvanising plus 80 µm polyester powder coating.","Leave a 1.5 mm gap or seal-weld all overlapping plates to avoid acid bleed-out.",{"headers":114,"rows":118},[115,116,117],"Industry","Example parts","Typical material",[119,123,127,131,135,139,143],[120,121,122],"Solar","Mounting posts, purlins, clamps","S355J2 hot-dip galvanised, 3 to 6 mm",[124,125,126],"Construction","Handrails, balustrades, ladders","S235JR tube, hot-dip",[128,129,130],"HVAC","Duct supports, unit stands","S235JR angle, hot-dip or DX51D+Z",[132,133,134],"Electrical","Cable trays, ladders, brackets","DX51D+Z275 1.5 to 2 mm, or hot-dip after fabrication",[136,137,138],"Machinery OEM","Guards, brackets, fasteners","S235JR electro zinc 12 µm",[140,141,142],"Oil and gas","Grating, pipe supports, platforms","S355J2 hot-dip 85 µm",[144,145,126],"Agriculture","Greenhouse frames, feeders",[147],"Hot-dip galvanising is priced by weight, so the three drivers are part mass, the surface preparation needed (blasting to remove paint or heavy scale costs extra) and any rework such as re-tapping, straightening or fettling drips. Electroplating is priced by surface area and batch, with small racked parts costing more per piece than barrel-plated hardware. Galvanising adds roughly 15 to 30% to the price of a simple welded steel bracket. Lead time is 3 to 5 working days for electroplating and 5 to 8 working days for hot-dip, on top of fabrication, giving 8 to 15 working days for a complete galvanised assembly.",[149,152,155,158,161],{"q":150,"a":151},"Which one should I use for a solar structure in Jeddah?","Hot-dip galvanising to ISO 1461 with at least 70 µm mean thickness. Near the coast, add a powder coat or specify 85 µm. Electroplating will show red rust within a year in that air.",{"q":153,"a":154},"Will galvanising change my hole sizes and threads?","Yes. Each face grows by 0.1 to 0.2 mm, so a 10.5 mm hole becomes about 10.2 mm and M10 threads will not accept a standard nut. Ask for re-tapping or design with 0.4 mm extra clearance.",{"q":156,"a":157},"Can you galvanise parts cut from pre-galvanised DX51D sheet?","Re-galvanising is possible but rarely worth it. Cut edges of DX51D+Z275 are protected by the surrounding zinc for sheet up to about 2 mm. For thicker or welded parts, fabricate in black steel and hot-dip afterwards.",{"q":159,"a":160},"My welded frame came back bent after galvanising. Why?","The 450 °C bath relieves welding stresses and thin, asymmetric frames move. Straightening is possible but it is better to weld symmetrically and keep plate below 1200:1 length to thickness. Tell us at quoting stage if straightness matters.",{"q":162,"a":163},"Do you provide a coating thickness certificate?","Yes on request. Suppliers in the CutLinq network measure with a magnetic gauge per ISO 2178 and issue a report with mean and minimum values for the batch. State this need with your upload.","Upload your DXF or STEP file, choose hot-dip or zinc plating in the options, and receive a binding quote within 12 hours.",[166,167,168,169,170,171,172],"hot dip galvanising Egypt","zinc plating UAE","galvanizing services Saudi Arabia","electro galvanised steel parts","ISO 1461 galvanizing","galvanised steel fabrication","zinc coating thickness",{"src":174,"alt":7,"width":175,"height":176},"processes\u002Fgalvanising-plating.jpg",900,505,[178],{"category":179,"slug":180,"title":181},"guides","corrosion-protection-options","Corrosion Protection Options for Steel Parts",1790794197628]