Гурова Г.Г., Николаева Н.С. - Обучение разговорной речи и чтению литературы на английском языке по специальности Сварка (1058938), страница 4
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The efficiency is dependenton the welding process usedg) is the intermittent weldобеспечивалось равномерное и полное проваривание до корня шва.Оптимальная комбинация заданных параметров определяется большим числом факторов. Слишком малый зазор и малый угол могутне обеспечить полный провар. Неправильное сочетание шириныи глубины шва приводит к образованию трещин в шве.(656)1.27. Answer the following questions.1.
What are the five basic types of weld joints? 2. Can you define abutt joint? an edge joint? a lap joint? corner and tee joints? 3. Where arethey mainly used? 4. What does the type of joint selected for any welding job affect? 5. What is a multipass weld? 6. What factors influencethe selection of the proper joint type? 7. What configuration can a roothave? 8. How can the bevel angle and the groove angle be compared?9. What is a groove radius? 10. How is the root penetration measured?11. What zone is interesting for the welder? 12. Why does a welder haveto control the heat input? 13. Why can the effects of welding on the material surrounding the weld be detrimental? 14.
How does the thermal20diffusivity of the base material influence the HAZ? 15. Can you classifythe welding processes according to the size of the HAZ?1.28. Make up and practice short situations using the followingwords and word combinations:1) can be geometrically prepared, basic types of weld joints, alignedin the same plane, at right angles to each other, for maximum jointefficiency, of two or more members lying in the same plane;2) are most frequently performed, any type of joint, to make multipass welds, may materially affect, the quality and strength of the weld;3) the parts of the joint, closest to each other, viewed in cross section, an opening or space;4) the HAZ, has not been melted, the structural or mechanical properties, the intermittent weld, the blue area;5) can be detrimental, varying size and strength, the thermal diffusivity of the base material, the amount of heat injected.1.29.
Make up dialogues using the word expressions of Ex. 1.28.Writing.1.30. Read the text and translate it in written form.Welding PositionsThe importance of welding in the flat position whenever possiblecannot be stressed too strongly. The quality of the weld is better, theoperation easier and faster. However, occasions will arise when it is necessary to work on parts fixed in position under which condition weldsmust be deposited horizontally, vertically and overhead. It must be realized at the very beginning that welding in these positions is difficultand will require constant practice to develop skill.As in the case of welding in the flat position, it is best to startpracticing by first running bead welds in the various positions.
Then asfacility is gained on these operations practice may be continued on buttand fillet welds (tee and lap joints) in these positions.One of the first facts noted when welding in these positions is thatthe force of gravity tends to cause the molten metal to drip (fall) down.The technique used, therefore must be designed to overcome this and21since it is difficult it is best to approach this by steps. To accomplishthis, start by making horizontal bead welds on plates inclined at 45 degrees.
When this has been mastered so that uniform beads can be madeconsistently, practice on welding vertically may be started. Again beginwith an easy operation such as running beads vertically on plates set at45 degrees.To progress with this practice it is necessary now to move the platesinto vertical position.
Welding vertically may be performed either bycarrying the weld upward or starting from the top and welding down.It is generally conceded that working upward is easier and therefore,bead welds in this manner should be practiced. Since bead welds are oflimited practical value, this experience must be extended by practicingon butt welds in the vertical and horizontal patterns.In use, the beveled plate edges should be spaced on the backing stripand the strip tack welded to the plates on the reverse side.(1938)From http://www.key-to-steel.com/default.aspx?ID=CheckArticle&LN=RU&NM=192Unit 2Butt Joint WeldsPreview.
In this unit you will get more detailed informationabout butt joints.Warming-up.2.1. Before reading the texts of the Unit “Butt Joint Welds” try toanswer the following questions.1. What types of butt joints can you name? 2. Is the choice of thetype dependant on the material thicknesses? 3. What are the applicationsof each type?2.2.
Match the words in column A with their definitions in column B.AB1) groovea) the separation between the parts to be joinedat the root of the joint2) root faceb) the portion of the prepared edge of a part tobe joined by a groove weld that has not beengrooved3) reinforcementc) an opening or space provided between theedges of the metal parts to be welded4) stringer beadd) a term used to describe weld metal in excessof the metal necessary to fill a joint.5) root openinge) the portion of the joint where the metals areclosest to each other6) tackf) a weld bead made without much weavingmotion237) rootg) to hold parts of an assembly in proper alignment temporarily until the final welds aremade.2.3.
In pairs/groups discuss the following.What type of butt joint weld would you choose to:• weld parts less than 5/16-inch thick;• weld parts more than 5/16-inch thick;• get multipass submerged arc welds;• two-pass submerged arc welds.2.4. Read the text making paying attention to the active vocabularyto check if your predictions were correct.Square Groove Butt Joint WeldsGood quality single pass welds up to 5/16-in. thick can be madeusing the square groove butt joint without root opening and with suitablebacking.Weld reinforcement, which tends to become excessive for thickerwelds, can be controlled by adjusting the root opening. Variations in rootopening, alignment of welding wire with the joint,and the amount of weld metal required generallylimit the thickness of this type of weld to 3/4-in.Two pass welds up to 5/8-in. thick are made without root opening.
It is essential in two-pass weldsthat the edges be closely butted since weld backing is not used. Themaximum permissible root opening is 1/32-in. unless the joint is backedsufficiently to prevent the welding composition from flowing throughthe root opening.
With such support greater root openings can be used.When the root opening exceeds 1/16-in., however, the opening shouldbe closely filled with submerged arc welding flux ahead of the weld.The maximum root opening is approximately 1/8-in. because of the difficulty of refusing the welding flux at the base of the first pass weld.If the root gap is maintained constant for the entire length of the seam,plate up to 3/4-in. can be welded with square butt joints. The first weldis a backing weld made on the reverse side of the joint; the work is thenturned over and the finishing weld is made.
The finishing weld pene24trates down into and refuses a portion of the backing weld to ensure acontinuous weld structure throughout the plate thickness.A satisfactory method of getting the required penetration of the finishing weld without excessive reinforcement is to back gouge a groove1/8 to 5/16-in. deep in the top of the joint after the backing weld hasbeen made. When gouging is used, no additional preparation or cleaning is needed except to remove any adhering slag. The advantage of thesquare groove butt joint is that it requires a minimum of edge preparation yet produces good quality welds with adequate penetration.
(1995)From http://www.esabna.com/EUWeb/SA_handbook/585sa2_28.htm2.5. Vocabulary to the text “Square Groove Butt Joint Welds”. Tryto memorize the following words and word combinations:1) square butt groove — подготовка (разделка) стыкового соединения без скоса кромок;2) weld backing — подкладка под шов;3) to penetrate [ penıtreıt] — проникать, проплавлять;4) root face — поверхность притупления (кромки);5) single pass — однопроходный;6) excessive [ık sesıv], adv — чрезмерный, избыточный;7) alignment [@ laınment], n — расположение по одной линии, выравнивание;8) to adjust [@ Ãst], v — настраивать, регулировать;9) essential [ı sen(t)S(@)l], adj — обязательный, непременный;10) permissible [p@ mıs@bl], adj — допустимый;11) sufficiently [s@ fıS(@)ntlı], adv — достаточно;12) composition, n — структура, состав;13) to maintain [meın teın], v — поддерживать, сохранять;14) to refuse [rı fjUz], v — зд.
переплавлять;15) gouging [ gaUÃı ] — поверхностная резка, строжка;16) adhering [@d hı@rı ] slag — прилипший шлак.Word Study2.6. Read the words correctly. Consult the dictionary if necessary.Sufficiently, adjusting, approximately, amount, permissible, maintain, reverse, gouge, throughout, adhere, adequate, ensure.252.7. Translate the following word combinations into Russian.Good quality single pass welds up to 5/16-in. thick; a square groovebutt joint without root opening; weld reinforcement; alignment of welding wire with the joint; the amount of weld metal required; two passwelds up to 5/8-in.
thick; submerged arc welding flux ahead of the weld;the welding composition; a satisfactory method of getting the requiredpenetration; the finishing weld without excessive reinforcement.2.8. Translate the following sentences into Russian paying attentionto the underlined words.1. The power source may also be a capacitor-discharge type. 2. Weldreinforcement, which tends to become excessive for thicker welds, canbe controlled by adjusting the root opening. 3. Submerged arc weldingcan be used to make horizontal fillet welds. 4. When the root openingexceeds 1/16-in., the opening should be closely filled with submergedarc welding flux ahead of the weld. 5.
Arc stud welding may be doneusing a dc power source similar to those used with the shielded metal arcwelding process. 6. Prior to welding, the studs generally have a small nibor bump which is to help initiate the arc. 7. Current and gas flow ratesmust be carefully regulated to prevent too large a keyhole. 8. The weldershould wear flash goggles, approved clothing, safety shoes, and leathergloves. 9. Single pass welds up to 5/16-in. thick can be made usingthe square groove butt joint without root opening. 10. Friction weldingis a specialized process and has applications only where a sufficientvolume of similar parts is to be welded because of the initial expensefor equipment and tooling.
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