Module 4
Постоянный/переменный ток, электрическая дуга, присадочный материал, источник питания, положительно заряженный анод, остатки флюса, светофильтры, волна типа "синусоида", гармоническая волна/ прямоугольная волна, плавящийся электрод, свариваемые металлы, пересечение нулевого уровня, пленка ПВХ, горючие материалы, наплавка 2
Arc Welding Arc welding refers to a group of welding processes that use a welding power supply to create an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi- inert gas, known as a shielding gas, and filler material is sometimes used as well. Gas Welding Uses Flame from burning gas to create welding heat. Propane torch: (Soldering, heating) Good for sweating pipes, starting fires, and spending hours trying to heat frozen bolts, while the surrounding metal gets just as hot. Oxyacetylene torch: (Cutting, welding, brazing, soldering, leading) Most universal and useful welding tool. (Uses Acetylene gas and Oxygen for hot flame) With the right bits, rod, and technique, you can weld almost anything. Good for cutting anything from sheet metal to the turret off a tank, lead filling, brazing (a sort of hard soldering process) welding plate, welding sheet metal, welding aluminium, heating frozen bolts, or alternately cutting them off, drilling holes in plate, welding cast iron, shrinking and forming steel, and can double as a flame thrower in a pinch. Drawbacks are: Overheating of some types of work, harder to control quality of some processes. Oxy-propane: (Soldering, brazing, heating) A cheap compromise between low cost and portable propane, and Oxy-Acetylene. Better than the former, not as good as the latter. 4
1. There is always a welding pool in solid-phase welding processes. 2. Total energy input in all welding processes is greater than needed to produce a weld. 3. Reactions of metals with the atmosphere or other nearby metals are favorable to the properties of a welded joint. 4. Fluxes and inert atmospheres play a protective role and prevent oxidation. 5. The heat-affected zone is a region with unaltered properties. 6. Residual stress is present in all welded structures. 5
1. What is arc welding? 2. What kind of current and electrodes are used in arc welding? 3. What is the welded region protected by? 4. Why is constant current power supply most often used for manual welding processes ? 5. How does the type of the electrode charge (positive/negative) influence the speed of welding and weld penetration? 6. What problem is related to the use of alternating current in gas tungsten welding ? 7. What is the function of flux in shielded metal arc welding? 8. What are the main advantages and disadvantages of manual metal arc welding ? 9. Which type of metal arc welding uses a separate filler material? 10. What do the welding protection clothes include? 6
1. Взаимопроникновение атомов металлических изделий под действием высокой температуры и давления приводит к образованию сварного соединения. 2. Сварка находит широкое применение во всех отраслях промышленности и в строительстве. 3. При сварке давлением лучше свариваются металлы с большей теплопроводностью, а необходимым условием получения высококачественного соединения является предварительная очистка свариваемых поверхностей. 4. При сварке плавлением используется присадочный металл, подача которого может осуществляться автоматически. 5. Чем ниже температура нагрева металла, тем выше необходимое для получения соединения давление. 6. Изготовление и монтаж стальных конструкций невозможны без применения сварки. 7. Сварка широко применяется в строительстве для создания каркаса зданий. 8. По типу подачи присадочного материала сварочные процессы делятся на ручные и механизированные. 9. Концентрация высоких температур на малых участках (неравномерность нагрева) приводит к появлению внутреннего напряжения в металлах. 10. Свариваемые детали должны находиться в непосредственной близости друг от друга. 7
Types (SMAW, MMA, GMAW, MIG, FCAW, SAW, GTAW, TIG, electroslag welding, stud arc welding, EGW, TCAW); Types of filler material used (consumable/none-consumable, covered/bare electrode/wire ); Type of current used (direct/alternating); Type of shielding gas used (helium, argon, CO2 ). 9
1. Electrogas welding is less hazardous than electroslag welding. 2. Electroslag welding is more frequently used to weld in a horizontal orientation. 3. Carbon Arc Welding is broadly used in industry in the present time. 4. Filler metal is always necessary in Atomic Hydrogen Welding. 5. Quenched and tempered steels are not welded using Electrogas welding. 6. Carbon Arc Welding is the newest arc welding process. 11
1. What kind of electrodes are used in Electrogas and Atomic Hydrogen Welding processes? 2. What structures can be welded by Electrogas welding? 3. Can thick workpieces be easily welded by Electroslag welding? 4. Why is Electrogas welding relatively unsafe and hazardous? 5. What is the difference between Electrogas and Electroslag welding? 6. Why does the operator have to wear protective clothes? 12
1. To ensure safety while using arc welding processed operators have to wear…. 2. Electroslag welding is no more used to weld…. 3. In Electrogas welding the weld area is protected from atmospheric contamination …. 4. In Atomic Hydrogen Welding the work itself becomes…. 5. Since Electrogas welding is performed at great heigh …. 13
