Сборник технических текстов с заданиями для профессии 15. 01. 05 «Сварщик» (ручной и частично механизированной сварки (наплавки)
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Control of welding fumeExposure to fumeFor many gas and arc welding processes, the fume concentration in the immediate vicinity of the weld is well above its exposure limit. The amount of fume generated is determined primarily by welding process, consumable and welding procedure. However, the following aspects are likely to influence the degree to which the welder is exposed to fume: 
Thus, welders using the same process may be exposed to different levels of fume. The risks for each job should, therefore, be assessed individually. Welding positionThe welding position (flat, vertical, horizontal or overhead) and proximity of the welder to the fume plume affect exposure. As the welder naturally bends over the workpiece, the flat position induces the highest level of fume in the breathing zone. The welder should adopt a working position which ensures that his head is away from the plume. Location and type of workplaceWelding in a large workshop, or outdoors, prevents build-up of fume and gases. However, in a small workshop, fume will not be readily dispersed and the welder may be subjected to a higher than average exposure. Working in confined spaces, in particular, requires an efficient, monitored, ventilation system so exposure is controlled and there is no depletion of oxygen in the working atmosphere. Control of welding fume If welding fume cannot be eliminated, control measures should be adopted as follows:
RPE should not be considered until the effectiveness of all other techniques has been explored. Choice or modification of the welding processProcess choice is usually made on the basis of weld quality, economics and equipment availability. Nevertheless, if other processes can be used, it should be borne in mind that some processes, such as submerged-arc and TIG, generates significantly less particulate fume than MMA, MIG and FCAW. Consumable manufacturers also supply information on fume composition which can be used in selecting welding rods for a particular job.Improvement in working practicesA substantial improvement can often be made by placing the workpiece so the welder can avoid the plume which rises above the weld. In large scale fabrications, the welding sequence should be organised to minimise the work carried out in enclosed or confined spaces. Safe practice and accident avoidance
 Safe practice and accident avoidance
3. Напишите правила основные правила техники безопасности. 4. Запишите и выучите новые слова. bare spot оголенный участок wire feeder механизм подачи (электродной или присадочной) проволоки ground connection 1) заземление, замыкание на землю 2) соединение на корпус power switch переключатель мощности rupture а) пробой (изоляции) б) излом, разрушение, разрыв confined space замкнутый объём, замкнутое пространство exhaust hood вытяжной шкаф; вытяжной колпак 5. Прочитайте текст. Safety and Scheduled Maintenance Protect Your Welding Assets Q: What can I do to avoid electrical shocks? A: Wet working conditions must be avoided, because water is an excellent conductor and electricity will always follow the path of least resistance. Even a person's perspiration can lower the body's resistance to electrical shock. Poor connections and bare spots on cables further increase the possibility of electrical shock, and therefore, daily inspection of these items is recommended. Equipment operators should also routinely inspect for proper ground connections. Q: How can I inspect and maintain my wire feeder? A: Periodically inspect the electrode wire drive rolls. If dirty, remove the drive rolls and clean with a wire brush. Deformed drive rolls should be replaced. Drive rolls should be changed, adjusted or cleaned only when the wire feeder is shut off. In addition, check the inlet and outlet guides and replace if they are deformed from wire wear. Remember that when power is applied to a wire feeder, fingers should be kept away from the drive roll area. Q: What are some important electrode safety considerations? A: Welding power sources for use with MIG and TIG welding normally are equipped with devices that permit on/off control of the welding power output. If so, the electrode becomes electrically hot when the power source switch is ON and the welding gun switch is closed. Never touch the electrode wire or any conducting object in contact with the electrode circuit, unless the welding power source is off. Welding power sources used for shielded metal arc welding (SMAW or Stick welding) may not be equipped with welding power output on/off control devices. With such equipment, the electrode is electrically hot when the power switch is turned ON. Q: How should I store my gas cylinders? A: Cylinders should be securely fastened at all times. Chains are usually used to secure a cylinder to a wall or cylinder cart. When moving or storing a cylinder, a threaded protector cap must be fastened to the top of the cylinder. This protects the valve system should it be bumped or dropped. Cylinders should not be stored or used in a horizontal position. This is because some cylinders contain a liquid which would leak out or be forced out if the cylinder was laid in a flat position. Also, welding guns and other cables should not be hung on or near cylinders. A gun could cause an arc against the cylinder wall or valve assembly, possibly resulting in a weakened cylinder or even a rupture. Q: How can I tell if my regulator is faulty? A: The following symptoms indicate a faulty regulator: Leaks - if gas leaks externally. Excessive сreep - if delivery pressure continues to rise with the downstream valve closed. Faulty gauge - if gauge pointer does not move off the stop pin when pressurized, nor returns to the stop pin after pressure release. Do not attempt to repair a faulty regulator. It should be sent to your designated repair center, where special techniques and tools are used by trained personnel. Q: What are some tips for a safe welding environment? A: The area surrounding the welder will be subjected to light, heat, smoke, sparks and fumes. Permanent booths or portable partitions can be used to contain light rays in one area. The heat and sparks given off are capable of setting flammable materials on fire. Therefore, welding should not be done in areas containing flammable gases, vapors, liquids or dusty locations where explosions are a possibility. Metals with plating, coatings or paint that come near the region of the arc may give off smoke and fumes during welding. These fumes may pose a health hazard to the lungs, therefore an exhaust hood or booth should be used to remove fumes from the area. When welding in confined spaces, such as inside tanks, large containers or even compartments of a ship, toxic fumes may gather. Also, in an enclosed room, breathable oxygen can be replaced by shielding gases used for welding or purging. Care must be taken to ensure enough clean air for breathing. In many companies, it is routine to provide welders with air masks or selfcontained breathing equipment. Q: How should an operator dress for optimum safety? A: Gloves and clothing should be flame-resistant. Clothing made from a dark-colored, tightly woven material is best suited for welding. Gauntlet-type leather gloves should be worn to protect the hands and wrists. Shirt collars and shirt cuffs should be buttoned, and open front pockets are not advisable as they may catch sparks. Also, operators should never store matches or lighters in their pockets. Pants cuffs are not recommended, as they will also catch sparks. Tennis shoes do not qualify as adequate foot protection. Hightop leather shoes or boots are absolutely necessary. Q: Is there a daily maintenance schedule I should follow? A: Below is a general engine drive routine daily maintenance schedule, but it should be modified according to a company's specific conditions. By following a regimen of appropriate and thorough maintenance and safety, a welder from Miller Electric can run dependably for decades. Designed to withstand rough use, these machines use high quality components and are tested for durability. 7.Выпишите из текста главные мысли. 8.Запишите новые слова. Отработайте их чтение. safety engineering - техника безопасности accident - несчастный случай safety rules - правила техники lack - нехватка, отсутствие безопасности training workshop - учебный цех (мастерская) to ensure – обеспечивать 9.Замените русское слово на английское. Используйте новые слова. This was несчастный случай. All people should keep технику безопасности. Do you know правила техники? We work in мастерской. I обеспечиваю safety engineering. 10.Прочтите текст. SAFETY ENGINEERING Accidents to people in industrial enterprises are called industrial traumatism (injury). They occur when workers have not acquired the requisite for skill and lack the necessary experience in handling tools and equipment. Accidents are also caused through neglect of safety rules and regulations in the factories and training workshops. The purpose of safety engineering is to prevent acci dents and to create such conditions of work in industry which will ensure maximum productivity of labour. When taking up new duties or when first going to work at any industrial enterprise each worker is obliged to acquaint him thoroughly with, and to master the safety instructions. 11.Ответьте письменно на вопросы
Unit 17 The History of Welding 1. Прочитайте и переведите текст. With all the power and precision machinery involved in production welding, you might think of welding as a relatively new process. In reality, welding has been around for thousands of years. Early examples of welding have been found in locations ranging from Ireland to India, with some dating back to the Bronze Age. Naturally, these civilizations lacked the vast array of tools and machinery that welders have access to now. How did they manage to weld? The process they used is known as forge welding. To start the process, blacksmiths would heat the metal until it was bright red in color (but still not at its melting point). The blacksmiths would then place the two pieces, slightly overlapping, on an anvil and pound them together. Forge welding has multiple limitations. Only relatively s oft metals can be forge welded, and the process is very labor intensive. In places without electricity, however, the process is still used. Forge welding was the only game in town until the 19th century. With the onset of the industrial revolution, however, numerous discoveries pushed welding forward fast. Research on electricity yielded electrodes and electric arcs. Rudimentary torches were developed by mid-century as well. Both discoveries would play heavily into the welding methods of the next century. By the late 1800s, many of the pieces were in place to make welding a driving force in manufacturing. Still, the methods of this era weren't perfect. Oxidation (the process of metals bonding to the oxygen particles in the atmosphere) occurred during the welding process and made welds porous and brittle. Such welds posed a grave risk to workers. During the period from 1895 to 1905, for instance, poorly made boilers exploded daily, causing thousands of deaths in the process. Clearly there was an urgent need for better welding methods. Over the next few sections, we'll learn more about those new and improved methods, starting with a closer look at the tools of the trade. WELDING AT SEA AND IN SPACEDiver welders routinely repair ships and oil rigs, typically using arc welding (negating the use of a flame). Space welding sits at the other end of the spectrum. The vacuum of space creates an ideal environme nt for welding, since there are no gases to interact with the welding site. Space welding makes massive undertakings like the International Space Station possible. 2. Выпишите все незнакомые вам слова из текста и выучите их. 3. Прочитайте и переведите текст. |
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