English for Welders. Иностранный язык

62 Pages·00.435 MB·Russian

by  Коллектив авторов

Министерство образования и науки Российской Федерации
Сибирский федеральный университет

ENGLISH for WELDERS
(ИНОСТРАННЫЙ ЯЗЫК)

Учебно-методическое пособие

Электронное издание

Красноярск
СФУ
2014
УДК 811.111 (07) 
ББК 81.432.1я73 
И683

Составители: Ступина Татьяна Владимировна,
Тихонова Евгения Владимировна

И683 English for Welders. Иностранный язык: учебно-методическое пособие
[Электронный ресурс] / сост.: Т. В. Ступина, Е. В. Тихонова. – Электрон.
дан. – Красноярск: Сиб. федер. ун-т, 2014. – Систем. требования: PC не
ниже класса Pentium I; 128 Mb RAM; Windows 98/XP/7; Adobe Reader
V8.0 и выше. – Загл. с экрана.

Учебно-методическое пособие составлено для аудиторной и
самостоятельной работы студентов Механико-технологического факультета
ПИ СФУ. Издание является основным учебным материалом для работы на втором
курсе. Пособие включает 25 текстов, построенных с учетом особенностей
программы подготовки специалистов в области сварочного производства,
технический словарь, глоссарий.
Предназначено для студентов-бакалавров специальности «Оборудование и
технология сварочного производства».

УДК 811.111 (07) 
ББК 81.432.1я73 

© Сибирский
федеральный
университет, 2014

Электронное учебное издание

Подготовлено к публикации ИЦ БИК СФУ

Подписано в свет 21.08.2014 г. Заказ 1792
Тиражируется на машиночитаемых носителях

Издательский центр
Библиотечно-издательского комплекса
Сибирского федерального университета
660041, г. Красноярск, пр. Свободный, 79
Тел. [phone]. E-mail: [email protected]
http://rio.sfu-kras.ru

2
CONTENTS

1. WELDING TECHNOLOGY. TYPES OF WELDING ................................................................... 4
2. AUTOMATIC PLASMA ARC WELDING.................................................................................... 5
3. THE ADVANTAGES OF AUTOMATIC PLASMA ARC WELDING ........................................ 6
4. PERCUSSIVE ARC WELDING ..................................................................................................... 7
5. GAS-TUNGSTEN ARC WELDING .............................................................................................. 8
6. MAKING A GAS TUNGSTEN ARC WELD ................................................................................ 9
7. GAS-METAL ARC WELDING .................................................................................................... 11
8. ALUMINIUM WELDING ............................................................................................................ 12
9. ELECTRIC ARC WELDING ........................................................................................................ 13
10. ELECTRIC WELDING ............................................................................................................... 14
11. TIG WELDING ........................................................................................................................... 15
12. PROJECTION WELDING .......................................................................................................... 16
13. DIFFUSION WELDING ............................................................................................................. 16
14. GAS WELDING .......................................................................................................................... 17
15. ULTRASONIC COLD WELDING ............................................................................................. 18
16 .LASER WELDING ..................................................................................................................... 19
17. RESISTANCE WELDING (PART 1) ......................................................................................... 20
18. RESISTANCE WELDING (PART 2) ......................................................................................... 21
19. FRICTION WELDING................................................................................................................ 22
20. EXAMPLES OF USE OF FRICTION WELDING ..................................................................... 24
21. EQUIPMENT .............................................................................................................................. 26
22. PLASMA WELDING EQUIPMENT .......................................................................................... 28
23. SOLDERING ............................................................................................................................... 29
24. FILLER METAL SELECTION................................................................................................... 30
25. ALUMINIUM FILLER METAL ................................................................................................. 31
VOCABULARY BANK.................................................................................................................... 32
TYPES OF WELDING ...................................................................................................................... 36
WELDING GLOSSARY ................................................................................................................... 37
WELDING SYMBOLS ..................................................................................................................... 62

3
1
WELDING TECHNOLOGY. TYPES OF WELDING

► While reading pay attention to the description of welding types. Make up
your own list of new words and expressions to the text.

Welding is one of the leading engineering processes in modern machine-
building. Practically there is no branch of industry where different methods of
welding, thermit cutting, soldering and glueing are not used.
Welding may be briefly defined as a localized consolidation of metals by
means of heat. The practice of joining two pieces of metal together by some form of
welding process is among the most ancient of the metallurgical arts. Welding
methods may be broadly classed as plastic or fusion processes. In the plastic
processes, the application of external pressure is necessary to force the material
together and effect the welding, but no added material (weld metal) is necessary.
Welds accompanied by fusion are by far the most common, and these
ordinarily do not require the application of pressure. If the edges of two adjacent
pieces of metal are heated to a temperature of fusion, and then allowed to cool, the
process is known as fusion or autogenous welding.
Fusion welding processes find the greatest application in industry. They
employ different heat sources such as electric arc, plasma jet, electric beam, gas
flame, light beam, chemical reaction energy. Among the types of arc welding there
are coated electrode arc welding, shielded arc welding (using argon, helium,
hydrogen, carbonic gas, nitrogen), flux cored electrode welding, plasma arc welding
and microplasma welding. At present nonproductive and labour-consuming methods
of manual electric arc welding and gas welding are mainly used on the construction-
sites and in repair operations.
Different processes of resistance welding are also widely employed. They are
as follows: contact spot welding, ultrasonic welding, explosion welding, induction
welding, seam welding, butt welding, projection welding, pressure thermit welding,
high frequency welding. These processes are used for joining various metals, alloys
and plastics. Even biological tissues can be joined with some of these methods.
The application of progressive welding and cutting operation in machine-
building is possible only on the basis of complex mechanization, automation and
robotization of a number of labour-consuming assembly and welding processes.

CHECK 1
1 Make up a plan of the text you have read.
2 Explain the meaning of the words:
soldering, glueing, fusion, spot, adjacent, labour-consuming.
3 Give examples of different heat sources, types of arc welding.
4
2
AUTOMATIC PLASMA ARC WELDING

► Read the article and complete the following phrases:
a) a non-consumable… ;
b) high flow rate… ;
c) constriction and… ;
d) restrictions for carbon… .

Plasma is an ionized high temperature gas consisting of electrons and positive
ions. It has no resultant charge and forms the major part of the arc column through
which electric current passes.
This description has changed with time and applies specifically to the high
density energy state brought about by physical constriction of an electric arc.
Many applications based on this use the high temperature of the plasma stream
and its high energy density. First was plasma cutting, followed by hard surfacing,
metal spraying and welding.
Thermal energy for welding comes from an electric arc, passing through inert
gas shielding, struck between a non-consumable tungsten electrode (pure or
thoriated) and the workpiece. Supply of filler wire takes place outside the torch.
This arc is constricted by a small orifice through which it is forced to pass.
A second gas which may be the same as or different from the first,
thermodynamically confines the plasma, and also shields the weld.
TYPES OF ARCS:
NON-TRANSFERRED OR FORCED ARC
This is established between the negative polarity electrode and a positive
orifice. This type of arc can become attached to different points of the orifice, but the
high flow rate of the plasma gas forces it outside.
Main applications of this type of arc are:
• low energy welding (microplasma) of small workpieces, whether or not they
conduct electricity;
• for striking the main arc.
TRANSFERRED ARC
This is established between electrode and workpiece, and the plasma producing
stream carries all the welding current. The anode spot roots on the workpiece and,
because of this, transmits more heat to the joint. Confinement of this arc leads to
constriction and concentration of energy.
For single pass welding or a bevel root pass, pure argon is used, or mixtures
based on argon and hydrogen (with certain restrictions for carbon steels and some
stainless steels) or argon and helium.
The shielding gas, in addition to protecting molten metal, penetrates into the
stream of plasma and, depending on its physical properties, affects arc characteristics.
Choice and combination of gases affects results, particularly, welding speed,
bead width, melted zone shape.

5
CHECK 2
1 Define the main idea of the text.
2 Find the information about:
a) plasma cutting;
b) filler wire;
c) single pass welding;
d) shielding gas.
3 Answer the question:
Does plasma have a resultant charge?

3
THE ADVANTAGES OF AUTOMATIC PLASMA ARC WELDING

► Translate the following text using your active vocabulary, glossary and
technical dictionary.

The plasma process has these advantages:
• Surface conditions of the weld bead is such that an additional pass is
immediately possible using any other arc welding process;
• Good appearance and compactness of weld beads;
• With all grades of metal, good mechanical properties;
• Limited deformation of sheet metal and a small area affected by heat because
of high energy density;
• High reliability regarding quality of results.
Furthermore, the process is well-suited to manufacture and butt welding of
tubes from stainless and carbon steel for thicknesses greater than 3 mm.
These advantages in quality and reliability, and reduction in preparation and
fabrication time, make plasma a leading welding process.
Developments in electronics and data processing in the field of welding
contributed greatly to many aspects of plasma welding.
All these improvements should lead to progress in this process in future and
permit its full development.
Manufacture of stainless steel tube from strip was one of the first applications
of plasma welding. Plasma welding quickly became essential for tube manufacture
because there is usually no access for welding from inside a tube and only plasma
welding can reliably make high quality joints with complete penetration.

CHECK 3
1 Compress the text to no more than 4 – 6 sentences.
2 Complete the sentences:
a) The plasma process has 5… .
b) Reduction in preparation and fabrication… .
c) These improvements should… .
3 Make up 4 questions. Ask your partner these questions.
6
4
PERCUSSIVE ARC WELDING

► While reading define if the following statements are true or false:
a) Power is supplied by a bank of capacitors.
b) The weld head moves forward very slowly.
c) Stud welding is the most common application for percussive arc welding.
d) Moisture doesn’t tend to destroy the process.

Percussive arc welding, in principle, utilizes some aspects of the resistance
welding process.
In percussive arc welding, power is supplied by a capacitor bank that is directly
short circuited across the parts being welded as they come into contact with each
other. This process is most reliable when the part in the moving electrode can be
provided with an energy detector or nib. When the nib or energy detector contacts the
mating part, the full charge of the capacitor bank is concentrated at this point. The nib
vaporizes to establish an ionized area and provides a localized arc. The remaining
capacitor charge is used to puddle both the moving part and stationary part. The weld
head moves forward very quickly before the materials solidify, forcing an alloying of
the interface to produce a low penetration, low heat-affected zone weld. When
optimized, the welds will have excellent character and grain structure.
The most common application for percussive arc welding is in stud welding,
such as in the building industry for welding construction fasteners. This process also
finds many automotive, electronic and even medical applications, and is suitable for
applications in high quality electrical joints where weld area for current carrying
capacities is a concern. Percussive arc welding provides an excellent bond of many
materials such as welding aluminum to tungsten and to molybdenum in capacitor and
battery manufacturing.
On the negative side, the process is sensitive to changes in environment and
mechanical configurations. Moisture will tend to destroy the process consistency and
will create inclusions in the welds. Mechanical characteristics of the components
being welded should be held to very exact dimensions.
The biggest drawback in automation is speed. Adequate time must be provided
to recharge the capacitor bank, limiting the system repetition rate to less than 100
welds per min. in most cases.

CHECK 4
1 Find topical sentences in each paragraph of the text.
2 Describe:
a) a nib;
b) a weld head;
c) electrical joints;
d) disadvantages of percussive arc welding.
3 Comment on the phrase:
The biggest drawback in automation is speed.
7
5
GAS-TUNGSTEN ARC WELDING

► While reading and translating the text pay attention to three different types
of current which can be used to maintain an arc.

GTAW: an arc welding process wherein coalescence is produced by heating
with an arc between a single tungsten electrode and the work. Shielding is obtained
from a gas or gas mixture. Pressure may or may not be used and filler metal may or
may not be used. This process has sometimes been called TIG welding.
GTA welding is an excellent process for welding aluminium. Most of the
welding is done with alternating current using argon shielding gas but for some,
particularly those which can be automatically machine welded direct current straight
polarity welding with helium shielding can be used advantageously. An outstanding
feature of the process is the process is the complete absence of fluxes. This is
possible because the arc under proper conditions, removes the oxide film and the gas
shield prevents it from removing. GTA welds have a good appearance. GTA welding
can produce X-ray quality welds in all the weldable alloys. Under some conditions
these welds may have a better structure than welds made by other processes.
Excellent penetration is easily obtained on butt joints that have been suitably
prepared. Since the filler metal is added separately, the welder may control the
amount added to a weld. The characteristics of a welding process are inseparably
associated with the characteristics of the electric arc used to make the weld. Basically
there are three different types of current which can be used to maintain an arc. They
are:
1) Direct current, reverse polarity (DCRP): Electrode is positive, work is
negative.
2) Direct current, straight polarity (DCSP): Electrode is negative, work is
positive.
3) Alternating current (AC): A rapidly changing combination of the first two.
The welding arc
Since alternating current combines the cleaning action of a DCRP arc with the
deeper penetrating ability of the DCSP arc it is the most widely used power system
for welding aluminium. When using alternating current, the arc is extinguished 120
times a second as the current passes through zero and the arc must be reignited as the
current begins the flow in the other direction. The open circuit voltage of the machine
is not usually high enough to assure arc re-ignition, so a high frequency, high voltage
current is superimposed on the welding voltage to initiate and stabilize the arc.
In an inert atmosphere the current flow moves more readily in one direction
than in the other across the arc between a tungsten electrode and another metal and
the difference is particularly pronounced in the case of aluminium.
8
A significant effect of the difference in the resistance to the flow of current in
the two directions results in an unbalanced current wave form. Since the resistance is
higher in the reverse polarity half of the cycle the current flow is less and the cleaning
ability of the arc is reduced. To counteract this tendency toward rectification the
electrical circuit is biased or blocked to achieve a balanced flow of current in both
directions. This is usually done with blocking condensers or solid state devices built
into the circuitry of the source, although storage batteries have been used in bias
circuits for some welding machines.
Torch
Various types of torches are available to suit different applications and current
requirements. Torches may be air or water cooled. All torches provide means for
readily charging the tungsten electrode and the gas nozzles.

CHECK 5
1 Match the English words and word combinations given below with their
Russian equivalents:
1. voltage a) цепь
2. power source b) вольфрам
3. filler metal c) источник энергии
4. butt joint d) свариваемый, поддающийся сварке
5. circuit e) стыковое соединение
6. tungsten f) напряжение
7. weldable g) присадочный металл
2 Make up 10 questions using your own vocabulary list. Ask your partner
these questions.
3 State what places of the text strengthen your former views.

6
MAKING A GAS TUNGSTEN ARC WELD

► Read the headline of the text and the beginning of each paragraph. Define the
subject of the text.
Essential to any successful welding operation are the preparatory steps which
precede actual welding. They start with the design of the weldment. Such things may
be considered as the welding method, the accessibility of the joint, the choice of base
metal and filler metal and often the inspection methods which are to be used.
Grooved opening, tolerances and weld bead size must be specified. It must be also
decided how the parts are to be positioned, clamped, fixtured or tacked to maintain
alignment and control warpage during welding. It is often impossible to prevent
warpage during welding, so allowances must be made in designing and setting up the
joint.
Cleanliness is a way of life in any GTA welding operation because there are no
fluxes available to help remove oxides, dirt, grease and other forms of contaminants.
9
The only cleaning available in GTA welding of aluminium is the cleaning action of
the AC arc, which can only assist in removal of oxide and is not capable of
eliminating other forms of contamination.
Thorough degreasing should always precede welding. In order to obtain the
highest quality of weld it is often necessary to remove the oxides from the surface of
the work adjacent to the weld bead, particularly on the high magnesium alloys and on
heat treated materials. This way is done chemically in deoxidizing solution but it is
more often carried out by wire brushing grinding, milling, planning or scraping.
Extensive testing has shown that methods such as planning, milling or scraping are
most effective, but are more expensive.
Equipment preparation
In selecting a welding torch for any particular weldment it is helpful to select
the lightest equipment which will do the job satisfactorily. After selecting a torch for
the job, the next step is to select a tungsten size and a gas cup size for the job. As
with the torch, the tungsten should be the smallest diameter which will adequately
carry the welding current to be used. The gas cup also should be as small in diameter
as possible and still provide adequate gas coverage for the arc and the surrounding
base metal. Proper selection of gas cup size is important, because a cut that is too
large interferes with the welder's view of the weld and a cup that is too small provides
insufficient shielding and inferior quality. Tungsten electrodes for GTA welding are
available in three types: pure tungsten, thoriated tungsten and zirconated tungsten.
Pure tungsten electrodes are most often used although zirconated tungsten electrodes
are also suitable for AC welding and will carry more current.
In order to produce the desired electrode diameter it is sometimes
advantageous to grind a taper on the end of the tungsten to produce a small diameter
tip on the electrode. Thoriated tungsten electrodes are not generally recommended for
AC welding because they do not maintain a stable arc but some shops use them for
machine welding using DCSP.
For manual AC welding of aluminium, argon is used as the shielding gas
because it provides a more stable arc and improves the clamping action. For DCSP
welding helium is also used, but may be mixed with 25% of argon for slightly better
starting characteristics and a more stable arc.

CHECK 6
1 Explain the meaning of the words:
base metal, weldment, grinding, GTA, accessibility, remove.
2 Find some facts about:
a) the preparatory steps which precede actual welding;
b) cleanliness;
c) degreasing;
d) warpage.
3 Give a summary of the text.

10