《Study of Aluminum-Zinc-Silicon Hot-Dip Liquid》.docVIP

Research of Al-Zn-Si Hot-Dip Liquid Causticity and The Alloy Coating Microstructure ZHANG Qing-hui1, LV Jia-shun2, LI Feng2, CHEN Leng1, MAO Wei-min1, SHI Shao-guang 1 (1.School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing100083; 2.Ansteel Technology Center, AnShan, 114001, China) Abstract：The relationship of thickness loss of normal low-carbon cold-rolled steel sheet in aluminum-zinc-silicon hot dip galvanizing liquid (55%aluminum,43.4%zinc and 1.6%silicon) at 600℃ and dipping time has been studied in this paper. And SEM, microprobe, and X-ray diffractometer were applied to analyze the microstructure, micro-chemical composition and phases of this alloy coating, as well as to the phases of bottom dross which formed in this process. The results showed that the weight losing of steel sheet in the hot liquid and dip time has a close linear relation and the alloy coating was mainly composed of four parts which were rich-aluminum dendrite, aluminum-zinc eutectic between dendrite, needle-like rich-silicon phase and alloy layer between the coating and the steel subsurface. Due to this peculiar microstructure of aluminum-zinc-silicon alloy coating, the coated steel sheet had excellent corrosion and heat resistance. Key words：hot-dip galvanizing aluminum-zinc-silicon alloy coating bottom dross causticity Introduction With the widely use of light steel construction in our country, the construction material markets need more and more highly corrosion-resistant coated steel sheet. Aluminum-zinc-silicon coated steel sheet that is also called Galvalume steel sheet or aluminum-zinc coated steel sheet, compared with galvanized steel sheet it has super corrosion resistance and excellent heat resistance. In a high temperature environment of 315℃, it doesn’t change of its color or shape as similar to the high temperature oxidation resistance of aluminum coated steel sheet. Foreign experiences show that when it’s used to low-slope ro