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Решение: Контрольная работа №3. Вариант 6

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I. Metallic, ex-minister, foresee, rewrite, unlucky, machinery, transmitter, likewise, disappear, seventeenth, something. II.. . 1.Short trip winter drivings especially in the hours of darkness add an excessive load on the battery, & one morning it may be dead. 2.The centimetre is devided into ten equal parts called millimetres. 3.A Diesel engine is a machine which produces power by burning oil in air which has been quickly compressed to a high pressure by a piston moving in a closed cylinder. III. 1.The boy hid among the branches of a big tree. 2.Physics is an important branch of science. 3.There are three branches of state power: legislative, executive and judicial. 4.Such branches of industry as coal-mining, electronic engineering and textile are highly developed in Great Britain. 5.Yesterday at 6 p.m. Mr. Wilson entered the Butcher Street branch of the National Westminster Bank. 6.The road branches here. 1.r.p.m.3. sec.5. at.ut.7.d.c. 2.NBC4. AC6.b.p.8. h.p. V. 1.All moving parts of machines wear. 2.By the first of January he will be working at this plant for ten years. 3.According to the character of work perfomed the design into the following types: bench lathes, chucking lathes & automatic lathes. 4.By the end of the year the production of cars at our plant will have been increased considerably. 20 VI. 1.Drill presses are buit in a variety of types, but the ordinary upright drill press is to be found in nearly every machine shop. 2.The operator wanted to repair his lathe as soon as possible. 3.To be effective the roughing job must be accurate and must remove as much excess stock as possible in on cut. 4.He was glad to have fulfilled his work ahead of time. VII. 1.Working with machines, sharp tools, motors, electricity one must always be careful. 2.The first voyage around the earth, begun at Seville by Magellan in 1510 and completed at Seville by del Cano in 1552, established that the earth is a globe. 3.Having been used for a long time, the instruments partly lost their former efficiency. 4.The equipment used for this work is similar to that used in hot working. VIII. 1.Cooper was used in prehistoric times for making weapons & tools and later was alloyed with tin to form bronze, which was the most important metal of the Greek & Romans. 2.Many turret lathes have systems of stops or gauges for controlling the travel of the turret carriage, and cross-slide. 3.We know of copper having been used as a conductor owing to its suitable characteristics. 4.Student like experimenting. IX. 1.It is know that this device works well. 2.The question is whether he will finish his work in time. 3.The man whom you saw at our shop is a qualified turner. 4.Engines must be lubricated systematically, otherwise they may be damaged.

Titanium and its alloys As an engineering material titanium has been widely applied only in the last years. Titanium is a silvery-white metal which melts at approximately 1668°C and has a specific gravity of 4.505. Commercially pure titanium possesses high strength properties. The tensile strength of most titanium alloys ranges from 100 to 140 kg/mm2, in conjunction with high elongation. The hardness, tensile strength and yield point of titanium are increased with the degree of cold deformation. The elongation value drops rapidly when the degree of cold deformation (reduction) exceeds 50 per cent and becomes equal to 10 per cent. Impurities found in commercial titanium can be divided into two groups: elements which form interstitial solid solutions with titanium (O2, N, C and H2) and elements which form substitution solid solutions (Fe and other metallic elements). The first have a much greater effect on the mechanical properties than those in the second group. Even very small amounts of oxygen and nitrogen in titanium alloys sharply reduce the ductility. A carbon content of more than 0.2 per cent reduces both the ductility and impact strength of a titanium alloy. It is supposed that the brittleness of titanium is a result of strain ageing and is connected with the presence of dissolved hydrogen in the beta-phase. Titanium and its alloys are hardened either by a surface heat treatment followed by ageing at 400°–500° C or by producing a case which contains nitrogen, carbon and boron. Industrial titanium alloys contain vanadium, molybdenum, chromium, manganese, aluminum, tin, iron or other elements, singly or in various combinations. A combination of high mechanical properties with a low specific weight and excellent corrosion resistance enables titanium to be used in building supersonic aircraft.

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