An old-fashioned kerosene blowtorch

A blowtorch is a special type of gas welder. It has an additional lever on the handle that, when squeezed, supplies an extra flow of oxygen out of a center hole in the mouthpiece. When the steel is heated to its melting point, the extra flow of oxygen will burn (oxidise) the molten iron and blow it away, effectively cutting the steel. The word "blowtorch" is often used loosely to mean any sort of oxy-gas torch.

After reading activity

Match each term with its meaning

1. acetylene	A. A flammable fuel gas composed of carbon and hydrogen having the chemical formula C2H2.When burned with oxygen, it produces a hot flame, having a temperature between 5700°F and 6300°F. It is a colorless gas, having a disagree-able odor that is readily detected even when the gas is highly diluted with air. When a portable welding outfit, it is obtained directly from the cylinder. In the case of stationary equipment, it can be piped to a number of individual cutting stations.
2. oxygen	B. A chemical element with the chemical symbol O and atomic number 8. It is the second most common element on Earth, composing around 49% of the mass of Earth's crust and 28% of the mass of Earth as a whole, and is the third most common element in the universe. On Earth, it is usually covalently or ionically bonded to other elements.
3. hydrogen	C. A chemical element in the periodic table that has the symbol H and atomic number 1. At standard temperature and pressure it is a colorless, odorless, nonmetallic, univalent, tasteless, highly flammable diatomic gas (H2). With an atomic mass of 1.00794 g/mol, it is the lightest element. It is also the most abundant, constituting roughly 75% of the universe's elemental matter

 

4. acetone	D. In chemistry, (also known as propanone, dimethyl ketone, 2-propanone, propan-2-one and β-ketopropane) it is the simplest representative of the ketones. It is a colorless mobile flammable liquid with melting point at −95.4 °C and boiling point at 56.53 °C. It has a relative density of 0.819 (at 0 °C). It is readily soluble in water, ethanol, ether, etc., and itself serves as an important solvent. The most familiar household use of it is as the active ingredient in nail polish remover. It is also used to make plastic, fibers, drugs, and other chemicals.
5. aluminum	E. A silvery and ductile member of the poor metal group of chemical elements. In the periodic table it has the symbol Al and atomic number 13. It is found primarily in the bauxite ore and is remarkable for its resistance to corrosion (due to the phenomenon of passivation) and its light weight. It is used in many industries to manufacture a large variety of products and is very important to the world economy. Structural components made from this metal and its alloys are vital to the aerospace industry and very important in other areas of transportation and building.
6. carbon	F. A chemical element in the periodic table that has the symbol C and atomic number 6. An abundant nonmetallic, tetravalent element, it has several allotropic forms. It occurs in all organic life and is the basis of organic chemistry. This nonmetal also has the interesting chemical property of being able to bond with itself and a wide variety of other elements, forming nearly ten million known compounds. When united with oxygen it forms carbon dioxide, which is vital to plant growth. When united with hydrogen, it forms various compounds called hydrocarbons which are essential to industry in the form of fossil fuels.
7. oxy-gas torch	G. A blowtorch has several meanings, which deal with tools that consume fuel. It may mean a cutting torch, a handheld torch used for cutting metal.
8. natural gas	H. Commonly referred to as gas, is a gaseous fossil fuel consisting primarily of methane. It is found in oil fields and natural gas fields, and in coal beds. When methane-rich gases are produced by the anaerobic decay of non-fossil organic material, these are referred to as biogas. Sources of biogas include swamps, marshes, and landfills (see landfill gas), as well as sewage sludge and manure by way of anaerobic digesters, in addition to enteric fermentation particularly in
	cattle.

 

Speaking

 

True or false?

 

1. The only used fuel gas in oxy-fuel welding is acetylene.

2. 'Oxidation' and 'combustion' are two terms which mean one and the same process.

3. Oxygen is the best fuel in oxy-fuel welding.

4. The blowtorch has two valves and one connection.

5. The welder wears goggles to protect his hands from burns.

6. The procedures and equipment used for gas welding and gas brazing are different. 

7. When setting up the equipment, the valve cap is removed before the oxygen tank is fastened.

8. Both pliers and a wrench are used to tighten the nut of the regulator.

9. Sunglasses can be used instead of goggles to protect eyes from sparks and splatter. 

10. The size of the flame depends on the size of the orifice in the tip and can be adjusted by the valves on the torch and by the regulator settings.

 

Answer the following questions:

 

1. What are the other two names of the oxy-fuel welding process?

2. What does the high temperature needed to melt the metal obtained by?

3. Is acetylene always shipped to the welding site in containers?

4. Why is hydrogen useful for underwater welding?

5. How can hydrogen be produced for small torches?

6. How is oxygen delivered to the welding site?

7. What does the apparatus used in gas welding consist of?

8. What colour are the oxygen and fuel hoses?

9. What is a neutral flame?

10. How many parts does an acetylene flame have?

 

Use the plan to make a report about gas welding:

 

1. Difference between Oxy-fuel welding and oxy-fuel cutting.

2. Fuel gases used for gas welding.

3. Parts of the apparatus used in gas welding.

4. Rules of setting up the equipment

5. Regulating the flame.

Writing

Translate the following sentences from Russian into English:

1. Контактная сварка осуществляется нагревом или расплавлением металлов при прохождении электрического тока в месте контакта сдавливаемых изделий. Выполняется сжатием листовых заготовок между стержневыми электродами (точечная контактная сварка) или вращающимися роликами (шовная контактная сварка) либо прижатием торцов изделий (стыковая контактная сварка).

2. Дуговая сварка (электродуговая сварка) - вид сварки, при которой кромки свариваемых металлических частей расплавляют дуговым разрядом между электродом и металлом в месте соединения.

3. Электронно-лучевая сварка - сварка расплавлением материалов в месте их соединения пучком электронов с энергией до 100 кэВ. Выполняется в вакууме. Применяется для прецизионной сварки, сварки изделий из особо чистых, разнородных или тугоплавких металлов (например, в микроэлектронике).

4. Газовая сварка - способ сварки металлических изделий с помощью газового пламени, образованного при сгорании смеси горючего газа (ацетилена, водорода, паров бензина и др.) с кислородом. Применяют для сварки тонкостенных изделий из стали, цветных металлов и сплавов, для наплавки твёрдых сплавов при ремонтных работах.

5. Электрошлаковая сварка - сварка плавлением металлов в месте соединения. Источником нагрева металла служит теплота, которая выделяется при прохождении электрического тока через расплавленный шлак, находящийся в зазоре между соединяемыми деталями.

6. Печная сварка (кузнечная, горновая) - соединение пластическим деформированием (например, с помощью молота) металлических изделий, нагретых в печах или горнах.

7. Диффузионная сварка - производится сдавливанием предварительно нагретых (без расплавления материалов) соединяемых деталей в вакууме, в результате чего происходит диффузия атомов материалов контактирующих деталей. Используют для сварки изделий из трудносвариваемых металлов, неметаллов, пластмасс.

8. Термитная сварка - технологический процесс, при котором зазор между соединяемыми деталями, предварительно нагретыми до 400 — 700°C, заполняется металлическим расплавом, полученным при сгорании термита. Используется для сварки проводов, труб, рельсовых стыков.

9. Газопрессовая сварка, соединение встык стержней, труб, фасонных профилей и т. д. нагревом мест сварки газовым пламенем до оплавления или пластического состояния металла и последующим сжиманием (осаживанием) соединяемых частей.

10. Высокочастотная сварка, сварка, при которой кромки свариваемых деталей нагревают токами ВЧ до их размягчения или оплавления и сжимают. Ток в изделии наводится индукционным или контактным способом. Используют, например, для сварки труб из ленты.

 

PART 5. MODERN DEVELOPMENTS

Lead-in

Prior to reading text, say if the method described below is a conventional one. What makes it conventional/unconventional? 

Why does this welding process best fit for aluminium and its alloys?

What should be changed in the parameters when shifting from welding aluminium to steel?

 

Vocabulary

 

ductile   гибкий, ковкий, поддающийся обработке threadedс резьбой, нарезной

pin                           цапфа 

shoulder буртик; поясок   debris      осколки, обломки; обрезки; лом   shrinkage   усадочная деформация  

solute                      растворенное вещество, раствор  

 

Find the English equivalent sin the text for the following Russian words and word combinations:

 

Традиционные технологии сварки, нагрев при трении, выработка теплоты (тепловыделение), инструментальная оснастка, в деформированном состоянии, нержавеющая сталь, шестивалентный хром, зона термического влияния, накаленный докрасна, механическая обработка, элемент конструкции.

 

Reading