GALVANIZING

Falcon zinc metal industries provides 1- Design, manufacturing, delivery and installation of structural steel elements of a capacity of 15,000 ton per year with ability to increase to 25,000 based on the demand 2- Hot dipped galvanizing of steel with capacity of 50,000 ton per year 3- Hand rails 4- Scaffolding 5- Floor steel Gratings 6- Iron Pipes 7- Providing clients with turnkey solutions to all steel requirements 2 | P a g e Hot Dipped Galvanization four steps: 1. MATERIAL RECIEPT & VISUAL INSPECTION 2. SURFACE PREPARATION 3. GALVANIZING 4. INSPECTION 1. MATERIAL RECIEPT & VISUAL INSPECTION Material is first inspected to check quantities, description, grade or specification and condition of goods (light, medium or heavy rusty). Job order should be issued for identification & traceability. 2. SURFACE PREPARATION The Surface preparation for Galvanizing consists of 5 Stages Chemical Treatment Degreasing, Pickling, Rinsing, Fluxing & Preheating. * I. Degreasing In case of the article surface is with oil and grease the article shall be chemically treated with Acidic Degreasing Agent, the immersion time is depend to oil, grease, dirt…etc. visibility the minimum immersion time is 3 minutes the maximum is 7 minutes and it shall be checked visually after immersion. *II. Pickling, After Acid Degreasing (if done) to ensure that articles are immersed in Hydrochloric Acid solution , The immersion time is depend to the item condition generally heavy rusted items will take 25 to 40 minutes in solution with limits 5% to 16% a visual check shall be well done after pickling to avoid any oxides to run to next stage. 3 | P a g e *III. Rinsing The article surface shall be rinsed with fresh water in the Rinsing Tanks to remove the Hydrochloric Acid residuals & iron salts left over from Stage 2. Double water rinsing baths are available to rinse the items before processing the flux. *IV. Flux pretreatment Bath Temperature is 40°C to 65°C, Time 1min to 3min Fluxing is the final surface preparation step in the galvanizing process. Fluxing removes oxides and prevents further oxides from forming the surface of the metal prior to galvanizing. The article surface shall be treated by Flux solution containing of (Zinc Ammon Chloride of 21 To 28 Degree be) in Fluxing Tank to ensure full chemical bonding between Steel & Zinc. *V. Preheating Temperature 75°C to 85°C, Time 5min The article shall be kept in the Pre-heater to increase the surface temperature of the steel before galvanizing for energy conservation. Also to dry enough & activate the flux layer. 3. GALVANIZING In this stage, the material is completely immersed in a bath consisting less than 99.995% of pure molten zinc for 3 minutes at controlled temperature between 440-455°C. Fabricated items are immersed in the bath until they reach bath temperature. The Zinc metal then reacts with the iron on the steel surface to form a zinc/iron inter-metallic alloy. The articles are withdrawn slowly from the galvanizing bath and the excess zinc is removed by draining, vibrating and/ or centrifuging. Prior to dipping the surface of the Zinc bath is skimmed to ensure no residuals are submersed with the steel to be galvanized. The standard specification of coated Zinc layer shall be as per the following standard like BS EN ISO 1461: 1999, BS 729, AASHTO M 18, ASTM A90, ASTM 123, ASTM 153, ASTM A 143, ASTM A 153, ASTM A 384, ASTM A 385, ASTM A 780, ASTM B6 Etc... 4 | P a g e 4. Cooling / Quenching Finally the article is left to air cool or quenched in water prior to bundling & stored in the galvanized material storage area for inspection Advantages of Hot Dip Galvanizing 1-Lowest first coast Galvanizing is lower in first coast than many other commonly specified protective coating of steel (the application cost of labor intensive coating such as painting has risen far more than the cost of factory operations such galvanizing –the labor component of finished paint coating average about 80% compared to only 30% for galvanizing 2-less maintenance /lowest long term coast Even in cases where the initial cost of galvanizing is higher than alternative coating galvanizing is almost invariably cheapest in the long term (because it lasts longer and needs less maintenance ).and maintenance causes problems and add to costs when structure are located in remote areas and when plant shut-down or disruption to production is involved. 3-long life The life expectancy of galvanized coating on typical structural members is far in excess of 50 years in most rural environments and 20 to 25 years plus, even in sever urban and coastal exposure 4-Reliability Galvanizing is carried out to A.S.T.M standards minimum coating thickness are applied .coating life and performance are reliable and predictable 5-Toughest coating A galvanized coating has a unique metallurgical structure which gives outstanding resistance and mechanical damage in transport, erection and service 5 | P a g e 6-Automatic protection for damaged areas Galvanized coating corrodes prudentially to steel, providing cathodic or sacrificial protection to small areas of steel exposed through damage. Unlike organic coatings, small damage areas need to touch up. 7-Complete protection Every part of galvanized article is protected, even recesses sharp corners and invisible areas .No coating applied to a structure or fabrication after completion can provide the same protection 8-Ease of inspection Galvanized coatings are assessed readily by eye, and simple non-destructive thickness testing method can be used .The galvanizing process is such that if coating appears sound and continuous, they are sound and continuous 9-Faster erection time As galvanized steel members are received they are ready for use .No time is lost on site in surface preparation, painting and inspection .when assembly of structure is completed, and it is immediately ready for use. Or for the next construction stage