Answer the following questions
1.What technologies used to fabricate metal products can you name?
2.When did the mankind start to use metalworking?
3.What method became available with the advent of copper smelting?
4.What is strain hardening?
5.What process can bring about strain hardening?
6.Why was the Iron Age so delayed?
7.How did the tilt hammer get its name?
8.What famous inventor contributed much to the art in metalworking processes?
9.What is the principle of work of the high-speed steam hammer?
10.What new types of equipment were developed in the 20 century?
Match the events with the correct dates.
1.The earliest records of metalworking a) the13th century
in the Middle East
2.The advent of copper smelting b) 1480
3.The beginning of the Bronze Age c) around 4000 B.C.
4.The development of the tilt hammer d) the 17th century
5.The designing of a machine for the e) around 8000 B.C.
rolling of lead
6.The appearance of large mills f) until the middle of the
18th century
7.The use of water wheels in the mills g) the 20th century
8.The industrial revolution h) the 19th century
9.Rapid development of rolling i) the end of the 18th century
10.The development of new materials j) around 2500 B.C.
with special properties
3. Find in the text the English equivalents of the following words / expressions.
A: загрязнения, ковка, штамповка, выплавка меди, деформационное упрочнение, сплав, олово, очищение железной руды.
B: рычажный молот, ковка полос и листов, плечо рычага, кузнец.
C: прокатный стан, с целью производства монет, материалы на основе железа.
D: удовлетворение требований, большая мощность, огнестрельное оружие, побуждали к совершенствованию, в существенном количестве.
E: свойства, применение, винтовой пресс, имели преимущество, диапазон, широко распространенные малоуглеродистые стали, повышение эффективности.
Write a summary of the text.
Drawing
Drawing consists of pulling metal through a die. One type is wire drawing. The diameter reduction that can be achieved in one die is limited, but several dies in series can be used to get the desired reduction.
Sheet metal forming
Sheet metal forming (штамповка листового металла) is widely used when parts of certain shape and size are needed. It includes forging, bending and shearing. One characteristic of sheet metal forming is that the thickness of the sheet changes little in processing. The metal is stretched just beyond its yield point (2 to 4 percent strain) in order to retain the new shape. Bending can be done by pressing between two dies. Shearing is a cutting operation similar to that used for cloth.
Each of these processes may be used alone, but often all three are used on one part. For example, to make the roof of an automobile from a flat sheet, the edges are gripped and the piece pulled in tension over a lower die. Next an upper die is pressed over the top, finishing the forming operation (штамповку), and finally the edges are sheared off to give the final dimensions.
Forging
Forging is the shaping of a piece of metal by pushing with open or closed dies. It is usually done hot in order to reduce the required force and increase the metal's plasticity.
Open-die forging is usually done by hammering a part between two flat faces. It is used to make parts that are too big to be formed in a closed die or in cases where only a few parts are to be made. The earliest forging machines lifted a large hammer that was then dropped on the workpiece, but now air or steam hammers are used, since they allow greater control over the force and the rate of forming. The part is shaped by moving or turning it between blows.
Closed-die forging is the shaping of hot metal within the walls of two dies that come together to enclose the workpiece on all sides. The process starts with a rod or bar cut to the length needed to fill the die. Since large, complex shapes and large strains are involved, several dies may be used to go from the initial bar to the final shape. With closed dies, parts can be made to close tolerances so that little finish machining is required.
Two closed-die forging operations are given special names. They are upsetting and coining. Coining takes its name from the final stage of forming metal coins, where the desired imprint is formed on a metal disk that is pressed in a closed die. Coining involves small strains and is done cold. Upsetting involves a flow of the metal back upon itself. An example of this process is the pushing of a short length of a rod through a hole, clamping the rod, and then hitting the exposed length with a die to form the head of a nail or bolt.
Exercises