Improving the Quality of the Coating at Hot-Dip Galvanizing of Machine Steels in the Zinc Melt with Microadditives of Nickel

Бондарева, О. С.; Melnikov, A. A.

doi:10.4028/www.scientific.net/kem.685.380

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…Nickel and Tin-Antimony are conventional chemical composition of the coating which is generally used for brass alloys. Previous studies demonstrated that the quality of the coating, especially in the hot-dipping technique, is directly related to the process parameters [11,14,15]. An appropriate coating should guarantee the free from defect, excellent adhesion and uniformity of thickness.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive study of the effect of hot-dipping process parameters on Sn-Sb coating properties for α-brass substrate

Barak

Tamizifar

2021

Metall Mater Eng

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This study's main purpose is to achieve an optimal hot-dip coating condition of Sn-Sb for an α-brass alloy. Therefore, the hot-dipping parameters, including pre-flux lubricants, immersion temperature, time, and withdrawal speed were investigated. ZnCl2 and SnCl2 were used as pre-flux bath additives. The temperature of the immersion bath was selected to be in the range of 250-300 °C. Also, the exposing time and withdrawal speed of the specimens during the hot-dipping process were in the range of 10-60 sec and 254-1524 mm/min, respectively. Visual inspection of the coating revealed that by using SnCl2 as a pre-flux additive, high-quality smooth coating is achieved. According to the AFM result, the initial roughness value of the substrate was 450 nm. The coating's roughness value with SnCl2 and SnCl2+ZnCl2 pre-fluxes were in the range of 300-500 and 700-900 nm, respectively. Therefore, ZnCl2 pre-flux is associated with a rougher surface. Corrosion test analysis revealed that both coating condition with different pre-fluxes leads to increasing corrosion resistance however better improvement in corrosion behavior is accomplished by smooth coating surface. The quantitative analysis of the polarization curve revealed that the corrosion rate of the smooth coating is decreased 7-12.5 times in comparison with the substrate. According to the SEM analysis, the predominant phases which were appeared at the interface of the coating and substrate were Cu3Sn and Cu6Sn5. SEM analysis revealed that the Cu3Sn intermetallic compound was this first phase, which was promoted near to the substrate vicinity during the hot-dipping process.

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Section: Introductionmentioning

confidence: 99%

Comprehensive study of the effect of hot-dipping process parameters on Sn-Sb coating properties for α-brass substrate

Barak

Tamizifar

2021

Metall Mater Eng

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“…However, at a nickel concentration of 0.06-0.09%, the floating dross formation is observed; it settles on the product and leads to defects in the coating surface [9]. Dross formation is due to the fact that the solubility limit of nickel in zinc with iron impurity at 450°C is 0.06% [10][11][12]. Chinese researchers note that a nickel concentration of 0.05% is effective and provides a reduction in coating thickness on Q235 steel (Si = 0.15%) [13].…”

Section: Introductionmentioning

confidence: 99%

Application of Nickel Tablets in Hot-Dip Galvanizing for Silicon and Phosphorus Steel Reactivity Control

Бондарева

Turovsky²,

Turovsky³

2020

MSF

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Alloying zinc melt with nickel is used to control the thickness of the zinc coating on steels with different contents of silicon and phosphorus. Nickel is involved in the formation of iron-zinc phases in the coating and inhibits their growth. The use of zinc-nickel master alloys is well studied and has a significant disadvantage - the significant wastage of nickel in the bottom dross. The application of nickel tablets avoids wastage, because it allows us to distribute nickel evenly throughout the bath volume. The aim of this work was to determine the working concentration of nickel introduced into the melt from nickel tablets for a wide range of silicon-containing steels and for a galvanizing time of 2-5 minutes. It was found that the nickel concentration of 0.04% leads to the coating thickness decrease and normalization of the variation in coating thickness on steels with a silicon equivalent SiEV 0.12-0.28% at the galvanizing time of 2-5 minutes, and on high-silicon steel (SiEV 0.75%) at the holding time of 3 minutes. A nickel concentration of 0.03% is effective for SiEV steels 0.12-0.18% with a galvanizing time of 2-3 minutes. "Sandeline Peak" is completely smoothed out with a holding time of 3-5 minutes in the melt with a Ni content of 0.05%. The nickel presence in the zinc melt modifies the ζ-phase structure in the coating, making it more dense and uniform in thickness.

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“…Very little research on high-temperature galvanizing has been done. It was mainly performed abroad [7][8][9]. The main aim of this work is to study the influence of elevated temperatures of hot-dip galvanizing on the thickness and microstructure of zinc coatings on fixing products and elaborate recommendations for optimal technological parameters of hot-dip galvanizing.…”

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confidence: 99%

Study of the Temperature Effect on the Structure and Thickness of Hot-Dip Zinc Coatings on Fixing Products

Бондарева

2014

AMM

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Hot-dip galvanizing of steels is usually performed by immersing the metal in a bath with molten zinc in the temperature range from 450 to 460 °C. In some cases it is necessary to obtain a minimal coating thickness. For example, high-strength bolts and other fixing products require a minimal thickness of the coating because a too thick zinc coating requires additional work on re-threading, which leads to spalling of coatings, a loss of corrosion resistance and, consequently, failure of the entire product. The main aim of this work was to study the influence of elevated temperatures of hot-dip galvanizing on the thickness and microstructure of zinc coatings on bolts and nut preform. The microstructure and elemental composition of the coating were studied by scanning electron microscopy and energy dispersion X-ray microanalysis. It was found that the coating thickness obtained in the range between 475 and 535°C decreases with temperature and reaches a minimum at 535°C. The structure of the coating after high-temperature hot-dip galvanizing was fundamentally different from the structure of the coating made at standard temperatures 450-460°C. This coating formed at 535°C was dense, homogeneous, non-porous and composed of a mixture of the δ and ζ-phases without distinct phase boundaries. That’s why it was recommended to maintain the bath temperature in the range between 533°C and 537°C. It allows us to obtain a hot-dip galvanized coating of a minimal thickness and a good quality on fixing products.

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Improving the Quality of the Coating at Hot-Dip Galvanizing of Machine Steels in the Zinc Melt with Microadditives of Nickel

Cited by 4 publications

References 5 publications

Comprehensive study of the effect of hot-dipping process parameters on Sn-Sb coating properties for α-brass substrate

Comprehensive study of the effect of hot-dipping process parameters on Sn-Sb coating properties for α-brass substrate

Application of Nickel Tablets in Hot-Dip Galvanizing for Silicon and Phosphorus Steel Reactivity Control

Study of the Temperature Effect on the Structure and Thickness of Hot-Dip Zinc Coatings on Fixing Products

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