Control And Research On Surface Quality Of Galfan Alloy Coating With Single Hot-dipping On Steel Wire

Galfan(Zn-5%Al-RE) alloy galvanizing layer has become the most hopeful new-type material to replace the traditional galvanizing layer. Al in Zn-5%A1-RE alloy (Galfan) coat has protective screen function of separating steel base from environment, and Zn in it has excellent electrochemic protective function. The anticorrosive capacity of the coat in every atmosphere is two to three times as that of the same thickness coat galvanized by dipping, the machine-shaping and coating properties of which are superior to that of the coat galvanized by dipping. The melting point of the alloy is only 382 ℃, which is 37.5 ℃ lower than that of Zn. The temperature of galvanizing by dipping is 420-450 ℃, so the energy consumption of Galfan coating is lower than that of steel wire galvanizing by dipping. The mechanical property of the coat is same as that of galvanized steel wire, so Galfan coated steel wire is an ideal product substituting galvanized steel wire and its products. So developed countries commonly make use of Galfan alloy instead of traditional galvanizing in armor plate, but they can not generalize in steel wire. Because of the addition of aluminum, the interfacial soakage character is lowered. So using general pre-flux methods, we can not get steel wire that is galvanized in Galfan alloy layer and it is very difficult to control the surface quality. Traditional galvanizing mode of revivification of protected gas can not exert entire superiority, because the mode affect the mechanical property of steel wire as its high cost, high galvanizing temperature. This paper is mainly the process theory of Galfan alloy coating with single hot-dipping on steel wire, and composition character of Gafan alloy, settling coating surface quality of Galfan alloy coating with single hot-dipping on steel wire.This paper expounds characteristics of Galfan alloy, difficulties of Single hot-dipping and advantages of our Single hot-dipping product line. A discuss is conducted on the problem of surface quality in single hot-dipping Galfan alloy steel wire process which is the most hardest to be controlled. And a small product line in laboratory which is simulated an actual production runs through adjusting the electricity density, the padding speed, wiping process. Experiments show that when the electricity density being about 6000 A/m2, padding velocity being 30-40 r/min, N2 air knife or N2 + ceramic ball wiping being used, the composition of flux is very stale,the Galfaned steel have no much defects in the case of surface quality and mass of coating, and the anticorrosion and uniformity property is fine.The paper puts up research and discussion on structure and composition character of Single-coating Galfan alloy, and it analyze the fine anti-corrosion of Galfan alloy. The experiment introduces the different pre-galvanizing process. And the rational process of hot-dipping Galfan alloy steel wire is analyzed. The paper analyses the reason on the problem of surface quality in single hot-dipping Galfan alloy steel wire and finds an optimum single hot-dipping process. And it studies the influence on Galfan alloy coating surface quality of different Al content. Property detection results of Galfan alloy coating show that all property of Galfan alloy coating achieve or exceed standard rate. The coating shows the excellent mechanical property, corrosion resisting property and coating integrate property.