108 Metallurgy-High

Metallurgy FOCUS Question How do people change metals to create useful objects?

冶金学焦点问题人们如何将金属制成有用的物品?

Medieval Metallurgy For thousands of years, people have made useful objects out of metal. One type of metal is called bronze. During the Bronze Age, people made many useful and beautiful things with bronze. People used it to make cooking tools and spears. Bronze is a mixture of two other metals. It is made of copper and tin. Mixing metals together or adding other ingredients can create a stronger metal. This kind of metal is called an alloy. The Iron Age came later. Iron is common and is found in Earth's crust. It weighs less than bronze and is slightly stronger.

中世纪冶金学几千年来，人们一直在用金属制造有用的物品。 有一种金属叫做青铜。 在青铜时代，人们用青铜制作了许多实用而美丽的东西。 人们用它来制作烹饪工具和长矛。 青铜是其他两种金属的混合物。 它是由铜和锡制成的。 将金属混合在一起或添加其他成分可以产生更强的金属。 这种金属叫做合金。 铁器时代随后到来。铁很常见，存在于地壳中。 它的重量比青铜轻，而且稍强一些。

Strength from the Ground Today, people use steel to make bridges, buildings, and cars. Steel is an alloy made of iron and carbon. Steel is much stronger than either bronze or iron. People dig, or mine, to find iron on Earth's surface or underground. Enormous machines mine iron and other metals. The iron is found in special rock called iron ore. The ore must be crushed into smaller bits after it is hauled away. But that's not all that has to happen in order to get steel.

今天，人们用钢来建造桥梁、建筑物和汽车。 钢是铁和碳的合金。 钢比青铜和铁都要坚固得多。 人们挖掘或采矿，在地球表面或地下寻找铁。 巨大的机器开采铁和其他金属。 铁存在于一种叫做铁矿石的特殊岩石中。 矿石被运走后必须粉碎成更小的碎片。 但这还不是获得钢铁的全部条件。

The Smelting Process The iron ore must be melted to pull out the iron. First, coal is heated to 1,315 degrees Celsius (2,400°F). The heat removes gases from the coal. It turns the coal into something called coke. Burning coke helps remove the carbon found naturally in iron ore. Machines lift the iron ore and coke to the top of a blast furnace. Limestone is added to help remove other materials from the iron. Hot blasts of rising air melt the ore. The metal falls down through the furnace. Iron collects in a container at the bottom. Anything that is not iron rises to the top of the container and is removed. Next, the melted iron is placed in an oxygen furnace.

冶炼过程必须将铁矿石熔炼出来。 首先，煤被加热到1315摄氏度(2400华氏度)。 热量从煤中除去气体。 它把煤变成一种叫做焦炭的东西。 燃烧焦炭有助于去除铁矿石中天然存在的碳。 机器将铁矿石和焦炭提升到高炉顶部。 加入石灰石是为了帮助去除铁中的其他物质。 上升空气的热风融化了矿石。 金属从炉子里掉下来。 铁在容器底部聚集。 任何非铁的东西都会上升到容器的顶部并被移除。 接下来，将熔化的铁放入氧气炉中。

Oxygen is blown onto the iron to remove extra carbon. This process changes the iron into steel. The amount of carbon left in the iron determines which type of steel is made. The liquid steel is poured into a container called a ladle. The giant ladle lifts the hot, drippy steel to the top of another machine. The steel is poured into a mold, called a cast. The steel is sprayed with water until it cools and becomes solid. The steel is reheated and flattened into sheets. People can make useful items from these sheets.

氧气被吹到铁上以除去多余的碳。 这个过程把铁变成钢。 铁中碳的含量决定了钢的种类。 钢水被倒入一个叫做长柄勺的容器中。 巨大的钢勺将滚烫的、滴落的钢铁提升到另一台机器的顶部。 钢被倒入一个叫做铸件的模子里。 向钢喷水，直到它冷却并变成固体。 钢被再次加热并压扁成片状。 人们可以用这些床单制作有用的物品。

Types of Steel The kind of steel you end up with depends on what you add to or remove from the iron during the smelting process. Mild steel is iron with 0.25 carbon. It is strong and flexible. Building supports, parts of ships, and car bodies are made of mild steel. Carbon steel is iron with 1.5 carbon. Nails made of carbon steel can puncture brick or concrete. The steel used in spacecraft is a mixture of iron and titanium. Iron mixed with manganese makes steel used in machinery and helmets. Both of these alloys are light and strong. Word Wise Stainless steel is a special blend of iron, nickel, and chromium. It does not easily stain or rust in water as regular steel does. Many tools for cooking and eating are made of stainless steel.

你最终得到的钢的种类取决于你在冶炼过程中从铁中添加或去除什么。 低碳钢是含0.25个碳的铁。 它结实而灵活。 建筑支架、船舶部件和汽车车身都是用低碳钢制成的。 碳钢是含1.5个碳的铁。 碳钢做的钉子可以刺穿砖或混凝土。 宇宙飞船用的钢是铁和钛的混合物。 铁和锰混合制成用于机械和头盔的钢。 这两种合金都很轻很结实。 不锈钢是铁、镍和铬的特殊混合物。 它不像普通钢那样容易在水中染色或生锈。 许多做饭和吃饭的工具都是用不锈钢做的。