Hot-dip galvanizing
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Presentation of the hot-dip galvanising process and of the different parameters that are important when choosing one product over another. There are two suggestions for different types of treatment lines: a fully acid line with enhanced protection for rough environments needing passivation and another line with alkaline degreasing for extremely greasy parts.
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Hot-dip galvanizing
- 1. SOCOVRAI® Ptg. de la Masìa, 13 bxos LD6 08349 Cabrera de Mar – Barcelona (España) Tel: +34 93 754 17 47– Fax: +34 93 754 16 52 admin@angem.com
- 2. Protect steel & iron against corrosion Hot-dip galvanizing • A Zn layer is chemically attached to the steel surface. • Zn corrodes slower than iron and, thus, protects iron from corroding. • Very strong protection against corrosion. Electroplating • Different metals (Ni, Cr…) are attached to the base metal surface. • Used for high-gloss applications.
- 3. HDG is used in heavy-duty industries Building & Construction Street Furniture & Road Safety Wire frame Utilities & Piping Agricultural-used steel Transportation & Automotive Fasteners
- 4. Hot-dip galvanising stages Degreasing Etching Flux Galvanising • Acid (cold, pre-etching) • Alkaly (warmed, needs rinsing off) Rinsing • Mechanic • Water-based dilution: acid or alkaly • ZnCl2 and NH4Cl double and triple salts • ZnCl2 Rinsing • Protection against corrosion Drying Passivation • Protection against white corrosion
- 5. Our products
- 6. ANGEM proposes the full range of products DEGREASING ETCHING FLUX GALVANISING PS series PASSIVATION IC series Additives Salts Additives Additives Passivants
- 8. How to choose a degreaser Shape and quanity of parts Dirt type Process cost Alloy type Degre aser Form of application
- 9. Advantages of acid degreaser Acie Alkaly
- 11. A corrosion inhibitor improves etching Reduce Fe concentration Avoid overetching
- 12. Optimum etching requires a balance between HCl y Fe Difficult to control the acid attack on the metal • Higher temperature • Higher HCl concentration Etching speed • Higher Fe concentration Reduce bath activity
- 13. A CI enlarges the margin of etching Decapado óptimo en HCl a 20ºC Conc. de Hierro / (g/L) 300 250 Exhausted bath 200 Renovate bath 150 HCl attacks base A corrosion inhibitor enlarges margins metal 100 50 0 0 50 100 150 200 Conc. HCl / (g/L) Tiempos mayores Óptima Saturación 250
- 14. SOCOVRAI ® IC120: environmentally friendly No VOCs Low toxicity No APEs No ADR SOCOVRAI® IC 120 Environmentallyfriendly Has alcoxylated alcohol and phosphonated derivatives
- 15. SOCOVRAI® AH131N reduces process vapor Socovrai AH131N Etching with HCl + AH131N
- 19. Our suggestions
- 20. High-protection acid line DEGREASING ETCHING FLUX GALVANIZING PASSIVATION SOCOVRAI® PSAG 80 – 130 g/l 25ºC Yearly cleaning SOCOVRAI® IC120 (0,3%) + AH131N (2 l/m3) HCl] >100 g/L, [Fe3+]<140 g/L T: 25 ºC DE-ZINC SOCOVRAI® IC 33 Sel double + SOCOVRAI® AF132 (5 g/l) + ATH3 (0,5%) D: 1,2 – 1,26 g/l 65 -70ºC SOCOVRAI® AR32 ADL 3P 450ºC 50-70ºC
- 21. Line with alkaly degreaser DEGREASING RINSING ETCHING FLUX GALVANIZING SOCOVRAI® PSB 7 -20 % 55 - 60ºC Cleaning every 6 moths SOCOVRAI® IC120 (0,3%) + AH131N (2 l/m3) HCl] >100 g/L, [Fe3+]<140 g/L T: 25 ºC DE-ZINC SOCOVRAI® IC 33 Sel double + SOCOVRAI® AF132 (5 g/l) + ATH3 (0,5%) D: 1,2 – 1,26 g/l 65 -70ºC SOCOVRAI® AR32 450ºC
- 22. ANGEM Specialities is: Technology Product Proximity Technical support Specialized in metal Speed Bath analysis R+D Customized products Competitive prices Agility ISO 9001 Ley de envases –R.D.782/1998