| 摘要 |
<p>Apparatus is provided for continuously forming and galvanizing tubing that includes washing and acid pickling assemblies, a zinc manifold through which the heated tube moves for application of the zinc coating, and an air wipe and water quench assembly for treatment of the zinc coating. The washing and acid pickling assemblies include two concentric pipe sections joined and sealed adjacent their ends with the tubing being axially drawn through the assembly, the pipe section of smaller diameter having annularly and longitudinally spaced holes therein through which water or acid under pressure is counterconcurrently directed against the tube from the larger pipe section or header, thereby to prepare the entire outer surface of the tubing for galvanization. The zinc manifold has a central coating chamber in fluid communication with a heated zinc reservoir, and the molten zinc contained therein is pumped to such central chamber of the manifold at a rate substantially to fill same, with drains being provided in the manifold to recycle excess zinc to the reservoir and to establish zinc flow through such central chamber. The air wipe, positioned downstream of the zinc manifold, is operative to direct a helical countercurrent air stream against the periphery of the coated tubing to remove and redistribute excess molten zinc, such air wipe being positioned immediately upstream of a water quench trough operative countercurrently to cycle water at preselected temperature ranges and flow rates along the coated tubing. The process of the invention includes the steps of continuously advancing the tubing, heating such tubing, coating the surface of the tubing, wiping the coated tubing, and immediately water quenching the coated tubing, such steps being performed at interrelated and preselected temperatures and rates for controlling iron-zinc alloy thickness and coating thickness and appearance.</p> |
