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Hot-Dip Galvanizing HOT-DIP GALVANIZING TABLE OF CONTENT The company 3 Affiliations 4 Mission & values 5 Services 7 Specialties 7 Research & Development 7 Seminar 8 Hot-dip galvanizing 10 Sustainable development 17 Technical information 19 Design 21 Prevent distortion 26 Post-galvanizing treatments 27 THE COMPANY With over 40-years experience in hot-dip galvanizing and a solid commitment towards its customers, Corbec inc. has become the leading galvanizer in central and eastern Canada. Our two installations, conveniently located in the east-end of Montreal and in Quebec City, are equipped with kettle sizes allowing for the galvanizing of a wide range of steel products, such as: • Engineered structures such as bridges, wind mills, electrical towers, etc. • Exposed architectural steel structures • Fences and farming equipment • Original Manufactured Equipment (OEM) • A variety of metal pieces and hardware For many years, Corbec participates and is involved with galvanizing associations as well as technical and engineering societies throughout the world. Operations staff and management are up to date on developing technologies and general improvements in our industry. 3 Our coatings are in conformity with international standards and our turn-around time will respect your tightest schedules. 4 AGA – American Galvanizers Association. www.galvanizeit.org ICCA – Canadian Institute of Steel Construction. www.icca.ca OIQ – Ordre des Ingénieurs du Québec. www.oiq.qc.ca ACRGTQ – Association des constructeurs de routes et grands travaux du Québec. www.acrgtq.ca MISSION AND VALUES Corbec Galvanizing the standard… As a leading hot dip galvanizer, we are committed to offering consistently superior quality, at a competitive price with reliable service. Our excellence is built on employee expertise and our ability to surpass industry expectations. 5 Corbec builds on its skills… With a view to becoming the leader in the Canadian market, Corbec will expand to meet emerging needs. To facilitate the implementation of its management model, Corbec will promote participative management and knowledge transfer. In the interest of remaining a leading-edge and innovative company, Corbec is committed to maintaining its involvement in research and development and enabling its employees to develop new capabilities. AFFILIATIONS Corbec Our values... Corbec has built a reputation for reliability founded on its fundamental values, which the company has imparted to its employees, suppliers and other business partners. 6 AFFILIATIONS FAIRNESS OPEN-MINDEDNESS RELIABILITY COOPERATION EFFICIENCY SERVICES SPECIALTIES R&D SERVICES OFFERED 7 • Packing according to specifications • Timelines and deadlines according to your needs (advanced production scheduling) • Fast delivery (upon request) • Technical support OUR SPECIALTIES • Galvanizing process for bent rebar • Galvanizing large parts • Trailer galvanizing RESEARCH AND DEVELOPMENT Our research and development department works in conjunction with our client projects to develop new procedures and methodology adapted to their needs. We also work with specifier’s such as Ministère des Transports du Québec and Hydro Québec to improve contracts and specifications. SEMINARS 8 Corbec is pleased to offer training seminars, tailored to the needs of your production and design teams. At your offices or ours this activity will be customized for the size and goals of your group. Also, you can address your own set of questions prior to the seminar and we will prepare a presentation where your concerns will be at the forefront. Seminars are typically one to four hours and include an overview of the hot-dip galvanizing process. Seminars can, at your request, include a tour of one of our plants. Your team will be able to see, up-close, the production process and better understand the details surrounding hot-dip galvanizing. This activity sounds interesting? Please contact our coordinator of sales & marketing at 514-364-4000 or send a written request to [email protected]. HISTORY OF GALVANIZING Hot-dip galvanized steel has been effectively used for more than 150 years. The value of hot-dip galvanizing stems from the relative corrosion resistance of zinc, which, under most service conditions, is considerably better than iron and steel. In addition to forming a physical barrier against corrosion, 9 zinc, applied as a hot-dip galvanized coating, cathodically protects exposed steel. Furthermore, galvanizing for protection of iron and steel is favoured because of its low cost, the ease of application, and the extended maintenance- free service it provides. HOT-DIP GALVANIZING Galvanic Series of Metals CORRODED END (Anodic or less noble) Magnesium Zinc Aluminium Cadmium Steel Lead Tin HISTORY OF GALVANIZING Nickel Brass Bronzes Copper Nickel-Copper Alloys Stainless Steels (passive) Silver Gold Platinum 10 Protected End (CathodicProcessus or more noble)de galvanization Galvanization process Cooling and Finition Drying Zinc Flux bath Rinsing Solution Pickling Caustic Rinsing Cleaning What is hot-dip galvanizing Hot-dip galvanizing is a metallurgical bond between steel and molten zinc, produced in specific installations and under controlled conditions. The process, of molecular adhesion between two metals is unique and simple, yet provides excellent molecular adherence and cathodic protection. THE ADVANTAGES Galvanizing provides great resistance Once the freshly cleaned material is submerged in the molten zinc bath @ 450C (840 degrees F), a metallurgical bond is created composed of inter-metallic layers and a pure zinc layer. The first inter-metallic layer is actually harder than the base steel. This quality is what gives galvanized steel its great impact and abrasion resistance. The soft, pure zinc layer helps absorb some of the shock and the inter-metallics protect the base material. 11 Microphotography of metallic coating Coat ETA 100% Zn Index of hardness 70 DPN Coat Zeta 94% Zn 6% Fe Index of hardness 179 DPN Coat Delta 90% Zn 10% Fe Index of hardness 244 DPN Coat ETA 100% Zn Index of hardness 70 DPN Coat Gamma 75% Zn 25% Fe Base steel Index of hardness159 DPN Hot-Dip GalvanizedHot-Dip Galvanized Steel’s Steel’s Estimated Estimated Service Service Life inLife Soil in Soil High Chlorides (>20 PPM) Low Moisture (<17.5%) High Chlorides (>20 PPM) High Moisture (<17.5%) 300 300 pH=9.4 H 2 O=5.0% 250 pH pH=7.9 H 2 O=10.5% 250 H 2 O 200 pH 200 H 2 O 150 pH=6.6 H 2 O=17.5% 150 pH=8.6 H 2 O=17.6% Service life (years) life Service 100 (years) life Service 100 pH pH=7.4 H 2 O=26.8% H 2 O pH H O 50 50 2 12 pH=6.0 H 2 O=40.0% 0 0 1.0 2.0 3.0 4.0 5.0 6.0 1.0 2.0 3.0 4.0 5.0 6.0 Zinc Coating Thickness (mils) Zinc Coating Thickness (mils) Low Chlorides (<20 PPM) High Moisture (>7.0) Low Chlorides (<20 PPM) Low Moisture (<7.0) 300 300 pH=7.0H 2 O=5.0% pH=9.0 H 2 O=5.0% 250 250 pH 200 H 2 O 200 pH=7.8 H 2 O=19.3% pH H 2 O 150 pH 150 H 2 O pH=6.0 H 2 O=19.4% Service life (years) life Service (years) life Service 100 100 pH=7.0 H 2 O=40.0% pH H 2 O 50 50 pH=5.0 H 2 O=40.0% 0 0 1.0 2.0 3.0 4.0 5.0 6.0 1.0 2.0 3.0 4.0 5.0 6.0 Zinc Coating Thickness (mils) Zinc Coating Thickness (mils) Service life is defined as the time to necessary part replacement 1 mil=25.4 pm=056 oz/ft3 or underground maintenance. HDG coatings have a foreseeable service-life Coating service-life is foreseeable as long as climate conditions - in which the coatings are exposed - are known. The ASTM has published the results of a research conducted in different environments where zinc coatings could be exposed to a variety of climate conditions. 100 ) 90 80 Key 70 Rural 60 Suburban Temperate Marine 50 Tropical Marine 40 Industrial 30 20 10 13 Time to First Maintenance* (years 0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Average Thickness of Zinc (mils) 1 mil = 25.4μm = 0.56oz/ft2 *Time to first maintenance is defined as the time to 5% rusting of the steel surface. Rust takes its toll on painted surfaces Here is what happens to painted steel when scratched…The exposed steel corrodes and forms a rust « bubble ». This “bubble”, larger than the surface occupied by the steel will expand and lift the paint off the surface, creating a blister. In the meantime, the cavity of corrosion and the blister continue to progress. Zinc coating Steel discovered is protected Base steel 14 Galvanizing offers sacrificial protection Here is what happens in the case of galvanized steel when scratched…Thanks to its galvanic protection, the zinc coating sacrifices itself to protect the steel to which it is bonded. This sacrificial protection will prevail as long as zinc is within proximity. Should the hot-dip galvanized coating Conventional Current be damaged or scratched, the steel will find protection against corrosion thanks to the surrounding zinc that has higher Electrons External Circuit Electrons electrochemical properties than those of steel. Since corrosion is an electrochemical process, it will attack the surrounding zinc rather than the exposed steel. Thus said, contrary to other types of processes claiming to corrosion protection, it is not required to touch-up Cathode Anode noticeable cracks, flaws or gaps on galvanized coatings. Electrolyte Figure 1 : Bi-metallic couple Galvanizing is a cost-efficient process 15 Studies have shown that HDG is highly competitive when it comes to cost-comparison as a whole: each type of coating product has its set of characteristics to battle corrosion (and ultimately protect steel).
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