Гурова Г.Г., Николаева Н.С. - Обучение разговорной речи и чтению литературы на английском языке по специальности Сварка, страница 6

The plate edges must be tightly butted (1/32-in.maximum gap) ... with the square butt jointd) in ... of ...5. V preparation gives the desired penetration ...excessive current and the volume of the V is considerably less than that required by other weldingmethodse) for6. When the welding composition is retained ... asupport below the joint, slightly greater root gapsare permissiblef) with7.

The single-V groove without root face is commonly used ... nearly all thicknesses when usingsubmerged arc backing fluxg) by8. It is not commonly used below 3/8-in. thickness... adequate penetration can be obtained for thesethicknesses without bevellingh) over319. Copper backing is not recommended ... the tendency of the weld metal to fuse to the backingpiecei) because of2.20. Right or wrong?1. Single-V Groove without Root Face is used with non-fusiblebacking for single-pass butt welds of 5/16-in. or greater thickness.2. When using Single-V Groove with Root Face the maximum thicknessof the plate is in the neighbourhood of 1–1/4 to 1–1/2-in.

3. The single-Vgroove butt joint with root face and without external backing is usedfor two pass welds where plate thickness exceeds 5/8-in. 4. With fusiblebacking, the root face dimension is 1/8 to 3/16-in. 5. With non-fusiblebacking, the root face dimension is 1/8 to 3/16-sm. 6. The finishingweld penetrates down into and refuses a portion of the backing weld toensure complete penetration. 7.

The plate edges must be tightly butted(1/16-in. maximum gap) as with the square butt joint. 8. The single-Vgroove without root face is commonly used for nearly all thicknesseswhen using submerged arc backing flux. 9. The single-V groove without root face is commonly used below 3/8-in. thickness since adequatepenetration can be obtained for these thicknesses without bevelling.10. Titanium backing is not recommended because of the tendency ofthe weld metal to fuse to the backing piece.2.21.

Read the text paying attention to the active vocabulary tocheck if your predictions were correct.Groove Butt Joint WeldsDouble-V Groove Butt Joint is the basic joint design for two-passsubmerged arc welds. It is commonly used for thickness up to 2-in., andeven greater thicknesses have been welded successfully. For thicknesses above 2-in., however, thejoint for multipass welding is recommended. Thedouble-V groove joint is normally designed witha large root face to provide adequate support forthe initial weld which serves as backing for the weld from the oppositeside.

The maximum possible misalignment in fit-up is 25 per cent ofthe root face. The root faces must be closely butted along their entire32length. The maximum permissible root gap is 1/32-in. If the root gapis larger the flow of material through the gap, when making the initialweld, must be prevented. Several methods are used. A small stringerbead can be laid manually in the bottom of the v in which the finishingweld is to be made. A length of wire may be tacked into the finishingweld.

Submerged arc backing flux may be tamped into the gap ahead ofthe weld. The stringer bead, wire, or backing flux should be removedbefore making the finishing joint if a high-quality joint is required. Toensure 100-per cent penetration and the removal of any slag or porosityin the bottom of the backing weld, the finishing weld should penetrateinto and refuse the backing weld to a depth of 3/16 to 5/16-in. Sincethis joint is widely used in pressure vessel fabrication, one limitationshould be noted. When making circumferential welds, the ratio of jointthickness to cylinder diameter must be at least 1/25.

Otherwise, the largepool of molten metal will tend to run, causing unstable welding actionand undesirable weld shape. Manual weld backing is sometimes usedwith the double-V groove butt joint when the joint has a small (1/8-in.maximum) root face and a root gap of about 1/8-in. If conditions requirethat the manual weld be thicker than 3/8-in., however, the single-V andU groove butt joint is preferred.The Single-U Groove Butt Joint is often used for multipass submerged arc welds. Any thickness of material can be welded using thisjoint design.

A small manual backing weld is often made from the reverse side of the joint. If themanual weld is not made, the root faces must beclosely butted (1/32-in. maximum root gap). Forextremely thick material, double-U groove buttjoints may be used. These are essentially two single-U groove butt jointswith a common root. If a manual weld is used to back the first submerged arc weld pass, it may be desirable to remove it later if maximumquality is required. The use of gas metal-arc manual welds eliminatesthe need for removal prior to submerged arc welding.

Because of theinternal and external slag-free nature of gas metal arc deposits, subsequent submerged arc welds of excellent quality can be produced overthem.(2843)From http://www.esabna.com/EUWeb/SA_handbook/585sa2_28.htm332.22. Vocabulary to the text “Groove Butt Joint Welds”. Try to memorize the following words and word combinations.1) Single-V Groove (butt) — V-образная разделка (стыкового соединения) со скосом двух кромок;2) Single-U Groove (butt) — V-образная разделка (стыкового соединения) с одним криволинейным скосом двух кромок;3) Double-V Groove (butt) — Х-образная разделка (стыкового соединения) с двумя (симметричными) скосами двух кромок;4) Double-U Groove (butt) — Х-образная разделка (стыкового соединения) с двумя криволинейными скосами двух кромок;5) stringer bead — валик, наплавленный без поперечных колебаний электрода, горелки;6) to tack — сваривать прихваточным швом;7) initial [ı nıS(@)l], adj — начальный, исходный;8) backing weld — подварочный шов;9) circumferential [s@ kmf(@) ren(t)S(@)l] weld — кольцевой (круговой) шов;10) pressure vessel — сосуд высокого давления, автоклав.Word Study2.23.

Read the words correctly. Consult the dictionary if necessary.Reinforcement, approximately, misalignment, bevelling, relatively,subsequent, successfully, neighbourhood.2.24. Pick out in the text all the expressions with the followingwords and give their Russian equivalents. Make up sentences of yourown with these expressions.Root; joint; backing; groove; thickness.2.25. Translate the following word combinations into Russian.Single-pass butt welds; relatively small quantities; desired penetration without excessive current; square groove butt joint without rootopening; the basic joint design; excessive reinforcement; for most industrial applications; the internal and external slag-free nature of gasmetal arc deposits; subsequent submerged arc welds of excellent quality; maximum permissible root gap.342.26.

Make up and practise short situations using the followingwords and word combinations:1) weld reinforcement, flowing through the root opening, weld backing, reverse side of the joint;2) root face, non-fusible backing, minimum damage to the backing;3) adequate penetration, without bevelling, reasonable misalignment;4) multipass welding, large root face, initial weld, several methodsare used;5) manual backing weld, from the reverse side of the joint, need forremoval.2.27.

Make up dialogues using the word expressions of Ex. 2.26.2.28. Put the verbs in brackets into the necessary form (Active orPassive). Translate the following sentences into Russian paying attentionto the underlined words.1. Any thickness of material can ... (to weld) using this joint design.2. The root faces must ... closely (to butt) along their entire length.3.

The single-V groove butt joint without root face must always... (tohave) weld backing. 4. The stringer bead, wire, or backing flux should... (to remove) before making the finishing joint if a high-quality joint isrequired. 5. A small stringer bead can ... (to lay) manually in the bottomof the v in which the finishing weld is ... (to make). 6.

Root gap shouldnot ... (to exceed) 1/16-in. 7. For extremely thick material, double-Ugroove butt joints may ... (to use). 8. Weld reinforcement, which tendsto become excessive for thicker welds, can ... (to control) by adjustingthe root opening. 9. When the root opening exceeds 1/16-in., however,the opening should ... closely (to fill) with submerged arc welding fluxahead of the weld. 10.

For instance, the 1G position weld refers to agroove weld that is ... (to make) in the flat position. 11. It is importantthat you have a good understanding and can ... (to apply) the techniquesfor welding in each of the test positions.2.29. Scan the text and find the correct answers.1. In which cases is square butt welding used? 2. Why are relativelysmall quantities of wire used in Single-V Groove welding with RootFace? 3. What kind of backing is recommended for Single-V Groove35welding without Root Face? Prove your answer.

4. What kind of jointis used for two-pass submerged arc welds? 5. How can the flow ofmaterial through the gap be prevented when making a double-V buttjoint? 6. Why should the finishing weld penetrate into and refuse thebacking weld to a depth of 3/16 to 5/16-in when making a double-Vbutt joint? 7.

In which cases is double-U groove butt joint used?2.30. Compare the types of butt joints.Typesof weldsPossiblethicknessesNumberof passesDimensionsof root openingsAdvantages2.31. Find in the texts the English equivalents for the followingphrases:1) поддерживается постоянным по всей длине шва; 2) обратная сторона соединения; 3) стремится стать чрезмерным для болеетолстых швов; 4) сравнительно небольшое количество проволоки;5) так как это соединение часто используется; 6) не позволяет части подварочного шва осуществить полное проплавление; 7) таккак нужное проплавление может быть достигнуто без разделки кромок; 8) зазор между свариваемыми кромками может быть допустим;9) отношение толщины соединения к диаметру цилиндра; 10) чтобыобеспечить 100-процентное проплавление.2.32. Group work.

Describe main features of the types of weldsshown in the pictures. You may simulate this process on your computerand demonstrate the results to your group-mates.2.33. Make up a summary in English of the text “Groove Butt JointWelds”.Writing.2.34. Read the text and translate it in written form.Overhead-Position WeldingOverhead welding is the most difficult position in welding. Not onlydo you have to contend with the force of gravity but the majority of thetime you also have to assume an awkward stance. Nevertheless, with36practice it is possible to make welds equal to those made in the otherpositions.To retain complete control of the molten puddle, use a very short arcand reduce the amperage as recommended.