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Preview. In this unit you will study different types of weld joints, ways of edge preparation and standard terms for the description of parts of a joint.



Preview. In this unit you will study different types of weld joints, ways of edge preparation and standard terms for the description of parts of a joint.

Warming – up.

Match the words in A with the definitions in B.

A B
1. A lap joint a. A joinery technique in which two members are joined by simply butting them together.
2. A butt joint b. A joinery technique in which two members are located at right angles to each other.
3. An edge joint c. A joinery technique used to join the edges of two or more members lying in the same plane.
4. Corner and tee joints d. A joinery technique used to produce a joint by overlapping two ends or edges.

1.2 Before you start reading the text try to answer the following questions:

1. What parameters are welds classified by? 2. What types of welds do you know? 3. How can joints be subdivided within these types? 4. What does the choice of weld depend on?

 

Word study.

Read the words correctly. Consult the dictionary if necessary.

Geometrically, frequently, to characterize, various, structure, however, quality, to arrange, physical, strength, applicable, accessibility, to affect, angle, virtually, regulatory, jigging, particular, height.

 

Read the text again and find the correct endings for the phrases below.

1. Double-V preparation joints are characterized

a) by the two pieces of material each tapering to a single centre point at one-half their width;

b) by the two pieces of material each tapering to a single centre point at one-third their height;

c) by the two pieces of material not tapering to a single centre point at one-half their height;

d) by the two pieces of material each tapering to a single centre point at one-half their height.

2. A butt joint is used

a) to join two members located at right angles to each other;

b) to join two members aligned in the same plane;

c) to join two members by lapping one piece of metal over another;

d) to join the edges of two or more members lying in the same plane.

3. When making up a lap joint, for maximum joint efficiency

a) you should overlap the metals a minimum of three times the thickness of the thickest member you are joining;

b) you should overlap the metals a minimum of four times the thickness of the thinnest member you are joining;

c) you should overlap the metals a minimum of three times the thickness of the thinnest member you are joining;

d) you should overlap the metals not more than three times the thickness of the thinnest member you are joining.

4. An edge joint should only be used

a) for joining metals one forth inch or less in thickness that are not subjected to heavy loads;

b) for joining metals one forth inch or more in thickness that are not subjected to heavy loads;

c) for joining metals one forth inch or less in thickness that are subjected to heavy loads;

d) for joining metals one fifth inch or less in thickness that are not subjected to heavy loads.

5.Resistance spot welding

a) is most frequently performed on edge joints;

b) is most frequently performed on lap joints;

c) is less frequently performed on lap joints;

d) is most rarely performed on lap joints.

6.Shielded metal arc welding

a) can weld only joints that are not subjected to heavy loads;

b) is not versatile and can weld virtually only one type of joint ;

c) is most frequently performed on lap joints;

d) is extremely versatile and can weld virtually any type of joint.

7.In cross section, the corner joint forms

a)an L-shape; b) a T-shape; c) a U-shape; d) a V-shape.

8.What is one of the strongest types of joints available?

a) a butt joint; b) a lap joint; c) an edge joint; d) a corner joint.

9 .The selection of the proper joint type doesn’t depend on

a) the joint thickness and material; b)the number of pieces to be welded;

c) the accessibility of the joint; d)the type of testing.

10. Some processesare most frequently performed on lap joints. Choose the odd one out.

a) resistance spot welding; b) electron beam welding document.write("Artisan Welding Projects: 25 Decorative Projects for Hobby Welders')\" onMouseOut=\"hideuarxtip()\">welding"); ;

c) the electrogas welding; d) laser beam welding.

Find in the text the English equivalents for the following phrases.

другие варианты также существуют; вместо прямолинейных кромок; в зависимости от используемого процесса; как гласит название; применяются в обоих видах металлических конструкций; в 3 раза превышая толщину самого тонкого элемента; один из элементов делается с отбортовкой; под прямым углом друг к другу; которые не подвержены большим нагрузкам; даётся возможность охладиться; это позволяет производить сварку; больших сечений; и других столь же важных факторов; количество деталей, которые необходимо сварить.

 

Fill in the gaps with the necessary prepositions.

1. The weld joint is where two or more metal parts are joined … welding. a) in
2. An edge joint should only be used … joining metals 1/4 inch or less in thickness. b) of
3. Lap joints are commonly used … torch brazing and spot welding applications. c) on
4. A joint of this type may be … square or grooved. d) by
5. Welds can be geometrically prepared … many different ways. e) over
6. A lap joint is made by lapping one piece of metal … another f) for
7. Corner joints are used to join two members located … right angles to each other. g) either
8. Instead … having straight edges single-U and double-U preparation joints are curved, forming the shape of a U. h) to
9. Many pieces can be welded together in a lap joint geometry depending … the process used and the thickness of the material. i) with
10. Double-V preparation joints are characterized by the two pieces of material each tapering … a single centre point j) at

Translate the following word combinations into Russian.

Two or more metal parts; the five basic types of weld; double-V preparation joints; the two pieces of material each tapering to a single centre point; two members located at right angles to each other; the edges of two or more members lying in the same plane; one piece of metal; sheet metal work; metals ¼ inch or less in thickness; thick sections arranged in a single-V preparation joint; the type of joint selected for any welding job; the pieces being welded; fit-up obtainable; available edge preparation equipment; available edge preparation equipment; a number of pieces to be welded.

Make up a summary in English to the text “Weld joints”.

Scan the text “Weld joints” and fill in the table using the information from the text.

Types of welds Characteristics Applications
     

Read the text paying attention to the active terminological vocabulary.

PARTS OF JOINTS (2830 п. Зн.)

While there are many variations of joints, the parts of the joint are described by

standard terms. The root of a joint is that portion of the joint where the metals are closest to each other. The root may be a point, a line, or an area, when viewed in a cross section. A groove is an opening or space provided between the edges of the metal parts to be welded. The groove face is that surface of a metal part included in the groove. A given joint may have a root face or a root edge. The root face is the portion of the prepared edge of a part to be joined by a groove weld that has not been grooved. As you can see, the root face has relatively small dimensions. The root edge is basically a root face of zero width. The groove face and the root face are the same metal surfaces in some joints. The specified requirements for a particular joint are expressed in such terms as bevel angle, groove angle,groove radius, androot opening.The bevel angle is the angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member. The groove angle is the total angle of the groove between the parts to be joined. For example, if the edge of each of two plates were bevelled to an angle of 30 degrees, the groove angle would be 60 degrees. This is often referred to as the “included angle” between the parts to be joined by a groove weld.

Word Study

Scan the text and fill in the left part of the table using the information from the text. Find the information in the Internet and your textbooks to fill in the right part.

Term Definition in English Translation Definition in Russian
       

Heat-affected zone

 

The zone of interest for the welder is the heat-affected zone. This zone includes that portion of the base metal that has not been melted; however, the structural or mechanical properties of the metal have been altered by the welding heat. Because the mechanical properties of the base metal are affected by the welding heat, it is important that you learn techniques to control the heat input. One technique often used to minimize heat input is the intermittent weld. In the picture you can see the HAZ of a pipe weld, with the blue area being the metal most affected by the heat.

Zones in a weld.

The effects of welding on the material surrounding the weld can be detrimental—depending on the materials used and the heat input of the welding process used, the HAZ can be of varying size and strength. The thermal diffusivity of the base material plays a large role—if the diffusivity is high, the material cooling rate is high and the HAZ is relatively small. Conversely, a low diffusivity

leads to slower cooling and a larger HAZ. The amount of heat injected by the welding process plays an important role as well, as processes like oxyacetylene welding have an unconcentrated heat input and increase the size of the HAZ. Processes like laser beam welding give a highly concentrated, limited amount of heat, resulting in a small HAZ. Arc welding falls between these two extremes, with the individual processes varying somewhat in heat input. To calculate the heat input for arc welding procedures, the following formula can be used: , where Q = heat input (kJ/mm), V = voltage

(V), I = current (A), and S = welding speed (mm/min). The efficiency is dependent on the welding process used, with shielded metal arc welding having a value of 0.75, gas metal arc welding and submerged arc welding, 0.9, and gas tungsten arc welding, 0.8.

From (http://en.wikipedia.org/wiki/Welding#_note-27#_note-27)

Word Study

Writing

Warming-up

2.1 Before reading the texts of the Unit “Butt Joint Welds” try to answer the following questions:

1. What types of butt joints can you name?

2. Is the choice of the type dependant on the material thicknesses?

3. What are the applications of each type?

 

2.2 Match the words in column A with their definitions in column B:

A B

1. groove a) the separation between the parts to be joined at the root of the joint  
2.root face b) the portion of the prepared edge of a part to be joined by a groove weld that has not been grooved  
3. reinforcement c) an opening or space provided between the edges of the metal parts to be welded
4. stringer bead d) a term used to describe weld metal in excess of the metal necessary to fill a joint.
5. root opening e) the portion of the joint where the metals are closest to each other
6. tack f) a weld bead made without much weaving motion
7. root   g) to hold parts of an assembly in proper alignment temporarily until the final welds are made.

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.

 

Word Study

Project Work. Choose several plate thicknesses within the proper range and speak about joining these plates using the information from the text and the Internet. You may simulate this process on your computer (make up a presentation) and demonstrate the results to your group-mates.

Word Study

Right or wrong?

1. Single-V Groove without Root Faceis used with non-fusible backing for single-pass butt welds of 5/16-in. or greater thickness. 2. When using Single-V Groove with Root Facethe maximum thickness of the plate is in the neighbourhood of 1-1/4 to 1-1/2-in. 3. The single-V groove butt joint with root face and without external backing is used for two pass welds where plate thickness exceeds 5/8-in. 4. With fusible backing, the root face dimension is 1/8 to 3/16-in. 5. With non-fusible backing, the root face dimension is 1/8 to 3/16-sm. 6. The finishing weld penetrates down into and refuses a portion of the backing weld to ensure complete penetration. 7. The plate edges must be tightly butted (1/16-in. maximum gap) as with the square butt joint. 8. The single-v groove without root face is commonly used for nearly all thicknesses when using submerged arc backing flux. 9. The single-v groove without root face is commonly used below 3/8-in. thickness since adequate penetration can be obtained for these thicknesses without bevelling. 10. Titanium backing is not recommended because of the tendency of the weld metal to fuse to the backing piece.

Word Study

Writing

Warm up

3.1 Before reading the text try to answer the following questions:

1. Try to give the definition to comer joints as its name implies.

2. What are the angles between the plates to be welded?

 

Corner Joints (2850)

One of the major types of welding connection is the corner joint. As its name implies, this joint is used to connect two parts together to form a comer. This weld type is extremely useful and can be preformed with either a high or low energy density welder. There are a total of four common sub types of corner joint, each, as usual, having its own benefits and disadvantages.

The first common corner joint sub type is made by beveling both parts, usually at 45 degrees for a 90 degree joint, then placing the two faces together, and melting the outside edge. This is usually done with a low energy density welder but a high-energy density welder can be used. A weld bead may also be added to the inside of the comer to reinforce the weld. This weld is fairly fast and easy to create, but can have problems with strength due to the relatively low area of the weld, as well as aesthetic appearance.

The second type of comer joint is essentially a butt weld between two pieces that are perpendicular. This weld can be done with a low energy density welder if the parts are small enough, but is usually done with a high energy density beam. This allows deep penetration and can form a weld that is as strong as the base material. This advantage of strength is countered by the increased proneness of joints to deformation, as well as the increased difficulty and equipment cost of the weld. As in the case with normal butt joints, the edges may be machined prior to welding to improve fit, alignment or welding properties.

The third type of corner welds is the melt through weld. In this weld, the corner is assembled and the beam is used to melt through the top component and into the lower component. This type of weld works best when the top piece is relatively thin compared to the bottom piece, allowing it to be melted through with a minimal energy input. This type of welds is preformed exclusively with high energy density sources. This weld can be made easily without the need to precisely follow a joint, but it can be weak due to the very low cross sectional area of the weld. If necessary, multiple passes can be made if the bottom piece is sufficiently thick, improving the weld strength.

The final major type of comer joints is truly a flange joint. This is used for making corners in plates or foils that are too thin for the other types of welds. To make this type of joints a 90-degree flange is made in one of the components. This flange is then aligned to the other piece to be welded, and the welder is run over the edges of the two parts. This melts the edges together and forms the weld bead. This method can be used with either a high or low energy density source and is fast and reliable, but tends to make extremely weak joints due to the leverage and odd stress angles that the flange causes.

from: Joining Technologies | Newgate International Business Center (slightly

abridged)

Edge Joints

Edge joints are often used when the members to be welded will not be subjected to great stresses. Edge joints are not recommended where impact or great stress may occur to one or both of the welded members. An edge joint occurs when the edges of parallel or nearly parallel members meet and are joined by a weld. If required, the joints can be altered by grinding, cutting or machining the edges into a groove. The groove can be a square, beveled, V, J, or U. The main purpose of the groove is to allow proper penetration or depth of fusion. Complete joint penetration refers to weld metal that extends completely through the groove and has complete fusion into the base metal.

Lap joints

Another joint design used a great deal in the welding industry is the lap joint. In order to weld two overlapping pieces of metal, the lap joint is used by means of connecting fillet, plug, slot, spot, projection, or seam welds. A single lap joint is welded from one side; however a single lap joint welded from two sides has a greater strength. The lap joint is the most common joint used in welding, since they are most applicable in welding thin materials.

A lap joint has good mechanical properties, especially when welded on both sides. The type of weld used on a lap joint is generally a fillet weld. If a groove weld is called for, it can be applied with a single or double bevel. The groove weld may or may not be followed with a fillet weld. The degree of overlap of the members is generally determined by the thickness of plate. In other words, the thicker the plate, the more overlap is required.

Fillet Welds

Fillet welds are approximately triangular in cross sectional shape and are made on

members whose surfaces or edges are approximately 90° to each other. Fillet welds

can be as strong, or stronger than the base metal if the weld is the correct size and

the proper welding techniques are used. When discussing the size of fillet welds,

weld contour must first be determined. Contour is the shape of the face of the weld.

There are three types of fillet weld contours: flat, convex, and concave depending

upon a cross section profile.

T-Joints

A T-joint occurs when the surfaces of two members come together at

approximately right angles, or 90°, and take the shape of a "T". On this particular

type of joint, a fillet weld is used. T-joints possess good mechanical strength,

especially when welded from both sides. They generally require little or no joint

preparation and are easily welded when the correct parameters are used. The edges

of the T-joint may be left square if only a fillet weld is required. For groove welding they may be altered by thermal cutting, machining or grinding.

from: Joining Technologies | Newgate International Business Center | (slightly abridged)

 

Writing

Terminological vocabulary

 

acceptable, adj – приемлемый;

accessibility, n – доступность, удобство осмотра и обслуживания;

accommodate, v – приспосабливать(ся);

adhering slag – прилипший шлак.

adjust, v – настраивать, регулировать;

alter, v – меняться;

alignment, n – расположение по одной линии, выравнивание;

angle, n – угол;

bevel angle – угол скоса кромки;

odd stress angle - необычный угол напряжения

included angle – угол разделки( раскрытия) кромок;

applicable, adj – применимый, пригодный;

assembly, n – сборка;

bevelling – скашивание кромки, разделка кромок;

call for, v - требовать

cause, v – вызывать, быть причиной;

composition, n – структура, состав;

concave, adj - вогнутый

conversely, adv – обратно, противоположно, наоборот;

convex, adj - выпуклый

cross section – поперечное сечение;

current, n – электрический ток;

curve, v – изгибаться;

detrimental, adj – вредный, пагубный;

excessive, adv – чрезмерный, избыточный;

in excess of – больше, свыше, сверх нормы.

in the neighbourhood of – приблизительно;

essential, adj – обязательный, непременный;

extend, v – расширяться, удлиняться;

fillet, n - кромка, желобок, углубление

finished joint – чистовой шов;

fit-up, n – сборка соединения под сварку;

flat, adj - плоский

grinding, n. - шлифование

gouging – поверхностная резка, строжка;

govern, v – управлять, обуславливать;

groove, n – подготовка( разделка) кромок под сварку;

groove angle – угол разделки кромок;

groove face – свариваемая кромка, поверхность разделки;

groove radius – радиус закругления кромки;

groove weld – шов с разделкой кромок;

Single-V Groove( butt) - V-образная разделка( стыкового соединения) со скосом двух кромок;

Single-U Groove( butt) - V-образная разделка( стыкового соединения) с одним криволинейным скосом двух кромок;

Double-V Groove( butt) - Х-образная разделка( стыкового соединения) с двумя( симметричными) скосами двух кромок;

Double-U Groove( butt) – Х-образная разделка( стыкового соединения) с двумя криволинейными скосами двух кромок;

heat-affected zone – зона термического влияния;

heat input – ввод тепла;

initial, adj – начальный, исходный;

input, n - подводимая мощность

joint, - соединение;

joint penetration – проплавление (провар) соединения;

Т- joint, tee joint — тавровое соединение;

corner joint - угловoе соединениe;

flange joint - сварное соединение, выполненное по отбортовке;

edge joint - стыковое соединение;

lap joint - соединение внахлестку;

leverage, n- сила, усилие

machining, n. -обработка (на станке)

maintain, v – поддерживать, сохранять;

objection, n – возражение;

overlap, v. - перекрывать, частично покрывать, заходить один на другой

plug, n - пробка, заглушка, втулка;

penetrate – проникать, проплавлять;

permissible, adj - допустимый;

positioning, n – установка в удобном для сварки положении;

preparation joint – подготовленное соединение под сварку;

pressure vessel – сосуд высокого давления, автоклав.

projection, n - выступ, выступающая часть;

proneness, n - подверженность чему-либо

reasonable, adj – обоснованный;

refuse, v – зд. переплавлять;

relatively, adv – относительно, сравнительно;

result in, v – привести к…;

retain, v – удерживать, сохранять;

right angle – прямой угол;

root, n – корень шва, вершина разделки кромок, пространство между свариваемыми кромками в месте их наибольшего сближения;

root face – поверхность притупления( кромки);

root opening– зазор между свариваемыми кромками;

root penetration – проплавление (провар) корня шва;

shift, v – передвигать(ся);

single pass - однопроходный;

slightly, adv – немного, слегка;

slot, n- щель, прорезь

spot, n - небольшой участок, пятнышко

square butt groove – подготовка(разделка) стыкового соединения без скоса кромок;

stringer bead – валик, наплавленный без поперечных колебаний электрода, горелки;

subjected to heavy loads – подвергающийся большим нагрузкам;

sufficiently, adv - достаточно;

support, n - суппорт; снабжение;

surround, v – окружать;

tack – сваривать прихваточным швом;

taper,v – сходить на конус, сужаться;

thermal diffusivity – теплопроводность, коэффициент теплопроводности;

tolerate, v – допускать;

turn over, v – переворачивать;

value, n – значение

voltage, n – электрическое напряжение;

weld, n - сварной шов;

backing weld – подварочный шов;

circumferential weld – кольцевой (круговой) шов;

fillet weld — сварной шов угловой

intermittent weld – прерывистый шов;

melt through weld — сварной шов со сквозным проплавлением

multipass weld – многопроходный шов;

seam weld - роликовый шов

weld backing – подкладка под шов;

weld bead - наплавленный валик сварного шва

welder, n - сварочный агрегат

weld reinforcement - усиление шва;

 

Keys to the exercises

1.1 1(d), 2(a), 3(c), 4(b).

1.6 1(d), 2(b), 3(c), 4(a), 5(b), 6(d), 7(a), 8(b), 9(d), 10(c).

1.8 1(d), 2(f), 3(i), 4(g), 5(a), 6(e), 7(j), 8(b), 9(c), 10(h).

1.16 1(e), 2(a), 3(f), 4(g), 5(i), 6(j), 7(b), 8(d), 9(k), 10(c), 11(h).

1.17 1(b), 2(c), 3(a), 4(b), 5(b), 6(d), 7(c), 8(a).

1.25 1(c), 2(a), 3(g), 4(e), 5(b), 6(d), 7(f).

2.2 1(c), 2(b), 3(d), 4(f), 5(a), 6(g), 7(e).

2.10 1(d),2(h),3(i),4(e),5(g),6(c),7(b),8(j),9(f),10(a).

2.19 1 (d), 2(f), 3(h), 4(c), 5(a), 6(g), 7(e), 8(b), 9(i).

3.2 l(c), (a), 3(d), 4(b).

3.7 l(e), 2(a), 3(b), 4(d), 5(c).

References

1. Англо-русский словарь по машиностроению и автоматизации производства. Около 100000 терминов. – Москва: РУССО, 2001. – 1008 с.

2. Большой англо-русский политехнический словарь:В 2 т. Около 200000 терминов /С.М. Баринов и др. – Москва: РУССО, 1999. – 720 с.

3. Oxford Advanced Learner’s Dictionary. – Oxford University Press, 2005.–1700p.

4. Andrew D.Aldhouse. Modern Welding. – The goodhear-WillCox Company, INC, 1997. – 780 p.

5. http://www.rodovens.com/welding_articles/weld_machine.htm

6. Перлов Н. И., Истеев А. И., Тюрин В. А. и др. – Англо-русский металлургический словарь. – Москва: Русский язык, 1985. - 841 с.

 

 

Contents

 

page

Unit 1. Weld joints. Parts of a joint. 3

Unit 2. Butt Joint Welds.22

Keys to the exercises 55

References 56

Preview. In this unit you will study different types of weld joints, ways of edge preparation and standard terms for the description of parts of a joint.

Warming – up.






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