ผลการค้นหา

Black Plate

แปลว่า(english) A light weight or a thin uncoated steel sheet or strip so called because of its dark oxide coloring prior to pickling. It is manufactured by two different processes. (1) Form sheet bar on single stand sheet mills or sheet mills in tandem. This method is now almost obsolete. (2) On modern, high speed continuous tandem cold reduction mills from coiled hot rolled pickled wide strip into ribbon wound coils to finished gage. Sizes range from 12 to 32 in width, and in thicknesses from 55 lbs. to 275 lbs. base box weight. It is used either as is for stampings, or may be enameled or painted or tin or terne coated.

Carbonation

แปลว่า(Concrete Engineering) 1) Reaction between the products of portland cement (soluble calcium hydroxides), water and carbon dioxide to produce insoluble calcium carbonate (efflorescence). 2) Soft white, chalky surface dusting of freshly placed, unhardened concrete caused by carbon dioxide from unvented heaters or gasoline powered equipment in an enclosed space. 3) Carbonated, dense, impermeable to absorption, top layer of the surface of concrete caused by surface reaction to carbon dioxide. This carbonated layer becomes denser and deeper over a period of time. 4) Reaction with carbon dioxide which produces a slight shrinkage in concrete. Improves chemical stability. Concrete masonry units during manufacturing may be deliberately exposed to carbon dioxide after reaching 80% strength to induce carbonation shrinkage to make the units more dimensionally stable. Future drying shrinkage is reduced by as much as 30%.

Basic Oxygen Furnace (BOF)

แปลว่า(english) "WHAT A pear-shaped furnace, lined with refractory bricks, that refines molten iron from the blast furnace and scrap into steel. Up to 30% of the charge into the BOF can be scrap, with hot metal accounting for the rest. WHY BOFs, which can refine a heat (batch) of steel in less than 45 minutes, replaced open-hearth furnaces in the 1950s; the latter required five to six hours to process the metal. The BOF's rapid operation, lower cost and ease of control give it a distinct advantage over previous methods. HOW Scrap is dumped into the furnace vessel, followed by the hot metal from the blast furnace. A lance is lowered from above, through which blows a high-pressure stream of oxygen to cause chemical reactions that separate impurities as fumes or slag. Once refined, the liquid steel and slag are poured into separate containers. "