I. Reading skills

1. Pre-reading tasks

a) You will read a text about non-ferrous metals and their alloys.

• What non-ferrous metals are of primary commercial importance from your point of view?

• What metal is considered to be the most widely used metallic material?

b) Read and remember the following words and word-combinations used in their specialized meanings.

aluminum [ə’ljuminəm] n алюміній

bronze [brƆnz] n бронза

conductivity [‚kƆndʌdk’tiviti] n провідність

copper [’kƆpə] n мідь

household plumbing [’plʌmbiŋ] n слюсарно-водопровідно справа

lead [led] n свинець

leaded brass [bra:s] n свинцева латунь

low-grade ore n руда низької якості

magnesium [mæg’ni:zjəm] n магній

manganese [‚mæŋgə’ni:z] n марганець

nickel [’nikl] n нікель

nickel silver n нейзильбер

non-ferrous [’nƆn ’ferəs] adj кольоровий (метал), той, що не містить заліза

red brass n червона латунь (з низьким вмістом цинку)

tin n олово

yield [ji:ld] strength n міцність та текучість

zinc [ziŋk] n цинк

2. Read and translate the following text into Ukrainian.

Non-ferrous metals and their alloys. Aluminum

Seven non-ferrous metals are of primary commercial importance: copper, zinc, lead, tin, aluminum, nickel, and magnesium. Some 40 other elements are frequently alloyed with these to make the commercially important alloys.

Metals are generally tested according to standardized methods to determine their mechanical properties. For normal use at room temperature the most important properties are the yield strength, the ultimate tensile strength, the elongation, and the reduction in area.

Copper. Historically, copper became one of the first engineering metals because it, unlike other metals, can occur in nature in the metallic form as well as an ore. Mass copper can be obtained by simply crushing rocks and physically removing chunks of solid copper. There is relatively little of this form of copper left today, and most of today’s supply of copper is obtained from copper ores that at best may contain only 5% by weight copper. There is no need to mention the cost of copper today. Anyone who has done any household plumbing lately can attest to the fact that copper has become more expensive and scarce each year. It is at least five times the cost of low-carbon steel. The high cost undoubtedly reflects the complexity of cost of low-carbon steel. The high cost undoubtedly reflects the complexity of obtaining copper from low-grade ores.

Copper and copper alloys are indispensable engineering materials. They have unique corrosion characteristics, strengths that can be greater than steels, and they have electrical and thermal conductivity exceeding most other engineering materials.

Since copper is such an old engineering material, over the years a very confusing vocabulary has developed to name alloys. What is the difference between a brass and a bronze? What is cupronickel, red brass, or a nickel silver?

A brass, by age-old definition, is a copper alloy containing zinc as the principal alloying element. The term leaded brass is used to describe copper-zinc-lead alloys, and the term tin brass is used to describe copper-zinc-tin alloys.

The term bronze usually means a copper alloy with tin as the major alloying element. However, this family of copper alloys has evolved into a group that may have elements other than tin as the major alloying element. Some bronzes do not even contain tin; aluminum bronze has aluminum as the major alloying element; manganese bronze has zinc. The alloys of copper and nickel, formerly called cupronickels, are now called copper-nickel alloys.

The nickel silver are copper alloys with nickel and zinc as principal alloying elements. The new terminology for nickel silver is copper-nickel-zinc alloys.

Aluminum. Aluminum was first produced in the laboratory in about 1825. However, wide acceptance of aluminum as an engineering material did not occur until World War II. Aluminum is the most abundant metal in nature. Some 8%, by weight of the earth’s crust is aluminum. Many rocks and minerals contain a significant amount of aluminum. Unfortunately, aluminum does not occur in nature in the metallic form. In rocks, aluminum is present in the form of silicates and other complex compounds.

In 1850 the cost of aluminum was about $500/lb. Improvements in processing techniques in 1850 to 1860 lowered the price to around $25/lb, but these prices still made aluminum almost a precious metal.

There are several properties that set aluminum apart from other metals. First, it is lighter than all other engineering metals except magnesium and beryllium.

A second important property of aluminum is its thermal and electrical conductivity. Because of its lower density, aluminum has a higher conductivity than copper per unit mass.

The third property that is responsible for wide use of aluminum alloys is its corrosion resistance. For applications involving atmospheric corrosion resistance it is probably the most widely used metallic material.

The most important alloying elements in aluminum alloy systems are copper, manganese, silicon, magnesium, and zinc.