Giáo trình Anh văn chuyên ngành công nghệ hàn Trường CĐ nghề Lilama 2

Giáo trình Anh văn chun ngành cơng nghệ hàn

1

LỜI NĨI ĐẦU
T X
T

T

ứ

ứ

T

Q T

d

ự ỉ
LAMA 2,

d

Q

ự
d

ỹ

ủ T S

V
–
ở T
S Lê Quang Trung,
S
“Anh văn chuyên ngành công nghệ Hàn”.
T

ủ

ẩ
ự

dù

&G
S E
P ú ỹ

d S d
S
WS

d–
P…
T

ứ
ắ

ý

ủ T
Q
d

Q

…

ễ T

ủ

ứ

dự
ứ

ủ d
ỏ

ữ

Chúng tôi xin chân thành cảm ơn!
NHÓM BIÊN SOẠN

R

ỉ


Giáo trình Anh văn chun ngành cơng nghệ hàn

2

UNIT 1: TERMINOLOGY AND STANDARD
I.

II.

VOCABULARY
- Arc :
- Edge :
- Metal:
- Joint :
- Electrode :
- Welding :
- Welded joint:
- Welding process:
- Weld:
- Welding structure:
- Melt (n):
- Melt (iv / tv)
- Melted (pp)
- Molten (adj)
- Mass:

- Cool (iv / tv):
- Clamp:
- Base metal:
- Circuit:
- Stream:
- Temperature:
- Bright:
- Welding machine:
- Amperage :
- Voltage :
- Generator :
- Transformer :
- Rectifier :

Liê

ự

Hàn
Q

hàn

Sự nung
C

ẹ

ữ

ị
Sáng, sáng chói
Máy hàn
dị

ỉ

GRAMMAR:
Passive voice:
Form:
Subject (S) + Verb ( V) + Object ( O)
S

1.

+

‘to be’

+

The passive tense
present, past, past perfect ...v.v

V_ed (past participle) + (by….)
„

‟

„

‟

„

‟

ỉ

ứ

)


Giáo trình Anh văn chun ngành cơng nghệ hàn

3

of an active tense voice is formed by putting the verb „ be‟ at the same tense as the
active verb in front of the past participle of the active verb. The subject of the active
„agent’ f
T „agent’ is very often not
mentioned. When it is mentioned it is preceded by „by’ and placed at the end of the
clause:
Ex: This plate of metal was welded by my father.
2.

Passive voice at present and past tenses:
S

+

V

S

+

is / are +

Active:
Passive:
S
S

+

O
V_ ed

We build this bridge.
This bridge is built.
V ( past simple)

+

O

+ was / were + V_ ed

Active:
Passive:
3.

+

They broke the window.
The window was broken.

Passive voice at continuous tense requires the present continuous form of to be:
S + is / am / are + V_ing

+ O

S + is / are + being + V_ed ( past participle)
Active:
Passive:
4.

They are repairing the bridge.
The bridge is being repaired.

Auxiliary + infinitive combinations are made passive by using a passive infinitive:
S + should / can

+V

+ O

S + should / can

+ be

+

Active:
Passive:
Active:

V_ed ( past participle)

You should shut these doors
These doors should be shut
You can use the process to deposit metal to form a surface with
alternative properties.


Giáo trình Anh văn chun ngành cơng nghệ hàn

Passive:

4

The process can also be used to deposit metal to form a surface with
alternative properties.

III. PRACTICE
This lesson Arc welding is a method of joining two pieces of metal into one solid
piece. To do this, the heat of an electric arc is concentrated on the edges of two
pieces of metal to be joined. The metal melts and, while these edges are still molten,

addition melted metal is added. This molten mass cools and solidifies into one solid
piece.

Figure 1
The electric arc is made between the work and the tip and of a small metal wire, the
electrode, which is clamped in a holder and held in the hand. A gap is made in the
welding circuit by holding th
f
d
6‟‟- ‟‟ w f
the parent or
base metal being welded. The electric current jumps this gap and makes an arc, which is
held maintained and moved along the joint to be welded, melting the metal as it is moved.
Arc welding is a manual skill requiring a steady hand, good general physical conditions,
and good eyesight. The operator controls the welding arc and, therefore, the quality of the
weld made.

Figure 2


Giáo trình Anh văn chun ngành cơng nghệ hàn

5

Figure 3 Illustrates the action that takes place in the electric arc. It closely resembles
what is actually seen during welding
T “
” is seen in the middle of the picture. This is the electric arc created by
the electric current flowing through the space between the end of the electrode and the
work. The temperature of this arc is about 60000C, which is more than enough to melt

metal. The arc is very bright, as well as very hot, and cannot be looked at with the naked
eye without risking painful, though usually temporary, injury.

Figure 3
The arc melts the parent, or base, metal and actually digs into it, much as the water
through a nozzle on a garden hose digs into the earth. The molten metal forms a molten
pool or crater and tends to flow away from the arc. As it moves away from the arc, it
cools and solidifies. A slag forms on top of the weld to protect it during cooling.
There are several types of welding machines include motor-generators, engine-driven
generators, transformers, rectifiers, and combination transformer and rectifiers. Each type
has its place and purpose. The basic function of each is the same-providing a source of
controlled electric power for welding. This controlled electric power has the
characteristic of high amperage at low voltage. The high amperage is required to provide
sufficient heat at the arc. The voltage must be low enough to be safe for handling and yet
high enough to maintain the arc. The welding machine permits the welder (welding
operator) to control the amount of current he uses. This, in turn, controls the amount of
heat of the arc. Some welding machine also permits the operator to select either a forceful
or soft arc and to control its characteristics to suit the job.
These are some standard that is used for welding
1. ASME (American Society of Mechnical Engineers), includes:
- ASME Boiler& Pressure Vessel Code
- ASME Code For Pressure Piping


Giáo trình Anh văn chun ngành cơng nghệ hàn

2. AWS (American Welding Society)
- AWS D1.1- Structural Welding Code - Steel
3. API (American Petroleum Institute) :
- API 650 – Welded Steel Tanks For Oil Storage

- API 1104 – Welding Of Pipelines And Related Facilities
4. ISO (Internaytional Standardization Organization)
5. EN (European Standard/Normal)
6. JIS – Japanese Industrial Standards
IV. EXERCISE
1. Give main ideas of paragraph?
2. What is arc welding?
3. What happens in the arc?
4. What do the electrodes affect to the arc?
5. List and explain the uses of the standards?

6


Giáo trình Anh văn chun ngành cơng nghệ hàn

7

UNIT 2: WELDED JOINT AND WELD
Object: to show the types and position of welded joints
I.

VOCABULARY:
- Welding position
- Flat
- Vertical
- Overhead
- Horizontal
- Butt joint
- Corner joint

- Lap joint
- Tee joint
- Edge joint
- Butt weld
- Fillet weld
- Groove angle
- Groove weld
- Spot weld
- Spot
- Geometry
- Configuration
- Preparation
- Surface
- Weld reinforcement
- Weld concavity
- Weld width
- Leg of a fillet weld
- Sealing run

V trí hàn
Hàn
Hàn ứ
Hàn ử
Hàn ngang
Liên
Liên
Liên
Liên
ữT
Liên

hàn giáp
Góc vát
hàn

có vát mép

hàn
d

Sự

ẩ

õ
hàn lót

II. GRAMMAR:
THE COMPARISON OF ADJECTIVES
Shorter adjectives: form of regular comparison.
Most common adjectives are short words. They form their comparatives and superlatives
as shown:
Adjecctive
Comparative
Superlative
Clean
Cleaner
Cleanest
Big
Bigger
Biggest

Strong
Stronger
Strongest
Long
Longer
Longest


Giáo trình Anh văn chun ngành cơng nghệ hàn

8

Notes on the comparison of shorter adjectives
Spelling of comparative and superlative forms:
- Most one-syllable adjectives form their comparatives and superlatives like clean: -er
and -est are added to their basic form.
- Many one-syllable adjectives end with a single consonant after a single vowel-letter.
This consonant doubles in the comparative and superlative, as in the case of big:
bigger, biggest.
- Many one-syllable adjectives end in -e, like nice or safe. These add -r and -st to the
basic form: safer, safest.
- Some adjectives, like dry, end in -y with a cosonant letter before it. These adjectives
are usually two-syllable. In the comparative and superlative -y is replaced by i:
drier, driest.
Longer adjectives:
Most longer adjectives combine with quantifiers „more‟ / „less‟ to form their
comparatives and „ most‟ / „ least‟ to form their superlatives
Ex: This joint is more beautiful than that one.
This position is the most difficult job when welding a fabrication.
Compound noun:

Noun + Noun:
Ex: Butt joint, lap joint, class room
III. PRACTICE
There are numerous types of welded joints and various positions in which they are
welded. Figure below shows a variety of these joints as they may appear on welding jobs
There are four basic welding positions: FLAT (F), VERTICAL (V), OVERHEAD (OH);
HORIZONATAL (H). It is possible to weld any type of joint in any of the four positions,
but whenever possible joints are placed in the flat position. Welding in the flat position is
much faster and easier than any of other positions.
A summary of the basic types of joints and basic types of welds is shown in figure below
In a joint, the adjoining members may contact each other in several ways, as illustrated
by the butt, T, corner, lap and edge joints. These general descriptions of the joint
geometry, however, do not define the weld joint configuration, since it can be made in
various ways. Thus, a weld butt joint can be made square, double-square, single-bevel,
double-bevel, single-V, double-V, or by four other joint configurations. A T-connection
can be made with a double fillet, as shown: or it may be made with a single or doublebevel or single or double J. V and U weld joints are feasible only for butt and corner
welds because of the need for the preparation of both surfaces.


Giáo trình Anh văn chun ngành cơng nghệ hàn

1.

Types of joints
1.1. Butt Joint

1.2. Tee Joint

1.3. Corner Joint

1.4. Lap Joint

1.5. Edge Joint

2.

Types of welds
2.1. Fillet Weld

9


Giáo trình Anh văn chun ngành cơng nghệ hàn

Single
2.2. Square Weld

Single

10

Double

Double

2.3. Bevel Groove Weld .

Single

Double

2.4. Vee Groove Weld

Single

Double

2.5. J Groove Weld

Single

2.6. U Groove Weld

Double


Giáo trình Anh văn chun ngành cơng nghệ hàn

11

Single
Double
UNIT 3: WELDING CONSUMABLES
Object: to deliver the uses and characteristics of the metal electrode
I.
-

VOCABULARY
Characteristic:
Core:

Lõi
Cover:
Vỏ ỏ
Shielded Metal Arc Welding (SMAW): Hàn
Desired weld:
M
Consist of:
Bao
Cellulose:
X
Rutile:
Rutin
Dioxidizing:
Ôxy hóa
Binders:
Extrusion:
ù ra, é
i
Tensile Strength :
ự kéo
Physical properties:
í
í
Stabilize:
Làm
Essential:
ủ
DC: Dirrect current:
Dịng
AC: Alternating current: Dòng

Slag removal:
Gỡ Lo ỏ ỉ
Consistently:
Liên
ỉ
Depend on:
Tùy
Filler wire:
Q
Electrode wire:
Dây hàn
Self-shielding Wire:
Dây
ự
Flux cored electrode:
Dây
õ
Arc welding electrode:
cự
Covered electrode:
Que
Electrode covering:
T
Welding flux:
T
hàn
Shielding gas:
Khí
Position:
V trí

Relationship:
liên quan
Designation:
Sự
Characteristic:
tính
Operation:
Sự
Compound:
Ghép,
Medium:
Trung bình

à

ành


Giáo trình Anh văn chun ngành cơng nghệ hàn

12

II. GRAMMAR
RELATIVE CLAUSES
a. Defining relative clauses
These describe the preceding noun in such a way as to distinguish it from other nouns of
the same class. A clause of this kind is essential to the clear understanding of the noun.
Normally relative clauses should be placed directly after their noun or pronoun:
Example: The noise that the welders made woke everybody up.
Relative pronouns used in defining relative clauses

The format is as follows:
Subject
Object
Possessive
For things which
which
whose / of which
That
that
Defining relative clauses: things
b. Subject
Either which or that, which is more formal:
- This is the construction that / which was finished yesterday.
- This is the fabrication that shows the job of my students.
c. Object of a verb
Which or that, or no relative at all:
- The tool that / which you welded is becoming dangerous.
d. Object of a preposition
The formal construction is preposition + which, but is more usually to move the
preposition to the end of the clause, using which or that or omitting the elative altogether:
- The ladder on which the welders usually stand to join a construction.
- The ladder which / that the welders usually stand on to join a construction.
e. Relative adverb: where
Where can replace „in/ at which‟
„w
‟
- That is the shop where (= in/ at which) students usually practise their tasks after
studying theory.
III. PRACTICE
The first specification for mild-steel covered electrodes, AWS A5.1 was writen in

1940. As the welding industry expanded and the number of types of electrodes for
welding steel increased, it became necessary to devise a system of electrode
classification to avoid confusion. The system used applies to both the mild-steel A5.1
and the low-alloy steel A5.5 specification. (Figure 4 – Covered electrode)


Giáo trình Anh văn chun ngành cơng nghệ hàn

13

Figure 4
Table 1 AWS numbering system
a. The prefix “E” designates arc welding electrode
b. The first two digits of 4-digit numbers and the first three digits of 5-digit numbers
indicate minimum tensile strength
E60XX
60,000 psi Tensile Strength
E70XX
70,000 psi Tensile Strength
E110XX
110,000 psi Tensile Strength
c. The next –to- last digit indicates position
EXX1X
All positions
EXX2X
Flat position and horizontal fillets
d. The last two digits together indicate the type of covering and the current to be use
e. The suffix (example : EXXXX-A1) indicates the approximate alloy in the deposit
-A1
½% Mo

-B1
½% Cr, ½% Mo
-B2
1-1/4%Cr, ½% Mo
-B3
2-1/4%Cr, 1% Mo
-C1
2-1/2%Ni
-C2
3-1/4%Ni
-C3
1%Ni, .35%Mo, .15%Cr
-D1&D2 .25-.15%Mo, 1.25-2.00%Mn
-G
50 min Ni, .30 min Cr, .20 min Mo, .10min V
(only one of the listed elements is required)


Giáo trình Anh văn chun ngành cơng nghệ hàn

14

Classifications of mild and low-alloy steel electrodes are based on an “E” prefix and a
four or five-digit number. The fisrt two digits (or three, in a five-digit number)
indicate the minimum required tensile strength in thousands of pounds per spuare
inch. For example, 60=60.000 psi, 70=70.000psi, and 100=100.000psi. the next to the
last digit indicates the welding position in which the electrode is capable of making
satisfactory welds: 1= all position – flat, horizontal, vertical, and overhead; 2= flat and
horizontal fillet welding. The last two digits indicate the type of current to be used and
the type of covering on the electrode (see table 2)

Originally a color identification system was developed by the National Electrical
Manufacturers Association (NEMA) in conjunction with the American Welding
Society to identify the electrode’s classification. This was a system of color markings
applied in a specific relationship on the electrode.
Table 2 – AWS A5.1-69 electrode designations for covered arc-welding electrodes
Designation
EXX10
EXX11
EXX12
EXX13
EXX14
EXX15
EXX16
EXX18
EXX20
EXX24
EXX27
EXX28

Current
DC(+) only
AC or DC(+)
AC or DC(-)
AC or DC(+ , -)
AC or DC(+ , -)
DC (+) only
AC or DC(+)
AC or DC(+)
AC or DC(+ , -)
AC or DC(+ , -)

AC or DC(+ , -)
AC or DC(+)

Covering type
Organic
Organic
Rutile
Rutile
Rutile, iron-powder (approx 30%)
Low – hydrogen
Low – hydrogen
Low – hydrogen, iron-powder (approx 25%)
High iron-oxide
Rutile, iron-powder (approx 50%)
Mineral, iron-powder (approx 50%)
Low – hydrogen, iron-powder (approx 50%)

In addition to the classifications specified by the American Welding Society,
electrodes can be classsified by the characteristics of the molten metal and molten
flux during the welding operation. These broad classifications are fast-freeze, fast-fill,
and fill-freeze, the terms being descriptive of the operation of the electrode.
Fast-freeze electrodes
Fast-freeze electrodes are compounded to deposit weld metal that solidifies rapidly
after being melted by arc, and are thus intended specifically for welding in the vertical
and overhead positions.


Giáo trình Anh văn chun ngành cơng nghệ hàn

15

Fast- freeze electrodes provide deep penetration and maximum admixture. The weld
bead is flat with distinct ripples. Slag formation is light, and the arc is easy to control.
Applications for fast-freeze electrodes are:
1. General-purpose fabrication and maintenance welding
2. Vertical-up and overhead plate welds requiring X-ray quality
3. Pipe welding
4. Welds to be made on galvanized, plated, painted, or unclean surfaces
5. Joints requiring deep penetration, such as square-edge butt welds
6. Sheet- metal welds, including edge, conner, and butt welds
Fast-fill electrodes
Fast-fill electrodes are compounded to deposit metal rapidly in the heat of the arc and
are, thus, well suited to high-speed welding on horizontal surfaces. The weld metal
solidifies some what slowly; therefore this type of electrode is not well suited for outof-position welds.
Arc-penetration is shallow with minimum admixture. The bead is smooth, free of
ripples, flat or slightly convex. Spatter is negligible. Slag formation is heavy, and the
slag peels off rapidly.
Applications for fast-fill electrodes are:
1. Production weld on plate having a thickness of 3/16 or more.
2. Flat horizontal fillets, laps, and deep groove butt welds.
3. Welds on medium-carbon crack-sensitive steel when low-hydrogen
electrodes are not available. (Preheat may be required)
Fill-freeze electrodes
Fill-freeze electrodes are compounded to provide a compromise between fast-free
and fast-fill characteristics, and thus provide medium deposition rates and medium
penetration.
Applications for fill-free electrodes include:
1. Downhill fillet and lap welds
2. Irregular or short welds that change direction or position.
3. Sheet-metal lap or fillet welds

4. Fast-fill joints having poor fitup.
5. General-purpose welding in all position.


Giáo trình Anh văn chun ngành cơng nghệ hàn

16

Table 3 Welding parameter
Approximate Electrode Amperage Settings

Diameter of
Electrode
Inches(Millimeters)
3/32 in
1/8 in
5/32 in
3/16 in
7/32 in
1/4 in

(2.4 mm)
(3.2 mm)
(4.0 mm)
(4.8 mm)
(5.6 mm)
(6.4 mm)

Fast Freeze
E6010 - E6011

Fill Freeze
E6013 - E7014

Fast Fill
E7024 - E7028

Low Hydrogen
E7018

Current Setting

Current Setting

Current Setting

Current Setting

Amperes

Amperes

Amperes

Amperes

40 - 90
75 - 130
80 - 160
110 - 225

200 - 260
220 - 325

75 - 105
100 - 165
135 - 225
185 - 280
235 - 340
260 - 425

85 - 155
100 - 175
160 - 270
220 - 330
270 - 410
315 - 520

70 - 140
90 - 185
140 - 230
210 - 300
230 - 380
290 - 440


Giáo trình Anh văn chun ngành cơng nghệ hàn

17

UNIT 4: WELDING TECHNOLOGY

Object: To introduce general about welding technology
I.

VOCABULARY
- Manual welding:
Hàn tay
- Mechanized welding :
Hàn
- Automated welding :
Hàn ự
- Fusion welding:
Hàn
- Arc welding:
Hàn
- Surfacing:
Hàn ắ
- Arc welding using a consumable electrode: Hàn
dù
ch
- Arc welding using non-consumable electrode: Hàn
qua dù
khơng nóng ch
- Submerged arc welding:
Hàn d
(Hàn h
- Gas shielded arc welding:
Hàn
g trong mơi tr
í
- TIG (Tungsten inert gas welding): Hàn

ự w f
ự
trong mơi
í
- MIG – Metal inert gas welding: Hàn
ự
-

MAG – Metal active gas welding: Hàn
ự
í
í
Self-shielded welding:
Hàn
ự
Pulsed arc welding:
Hàn
Manual arc welding:
Hàn
Automatic arc welding:
Hàn
ự
Robotic welding:
Hàn robot
Double arc welding:
Hàn
Multi-arc welding:
Hàn
Twin electrode welding:
Hàn 2

ự
Semi-automatic arc welding: Hàn
ự
Plasma welding:
Hàn plasma
Electroslag welding:
Hàn
ỉ
Laser welding:
Hàn laze
Gas welding:
Hàn khí
Resistance welding:
Hàn
ở
Spot welding:
Hàn
Resistance seam welding:
Hàn
Step-by-step welding:
Hàn
Constant:
Liên
Heat source:
Gap:
, khe
Withdraw:
Rút ủ ỏ
Spark gap:
Protect:

ử

ự
ự

í
í


Giáo trình Anh văn chun ngành cơng nghệ hàn

-

Adjust:
Maintain:
Stainless steel:
Concentrate:
Equal (to):

18

ỉ

Duy trì
Thép
T trung
T

ỉ

ân

II. GRAMMAR:
The passive voice with may, can, should and must
S + can / may / should / must + V + O

S + can / may / should / must + be + V_ed (Past participle)
Active:
Passive:
Active:
Passive:

You should shut these doors
These doors should be shut
You can use the process to deposit metal to form a surface with alternative
properties.
The process can be used to deposit metal to form a surface with alternative
properties.

III. PRACTICE:
MANUAL METAL ARC WELDING
Manual metal arc (MMA) welding, also known as shielded metal arc welding (SMAW),
stick welding, or electric arc welding is a constant current drooping arc process (Figure
5).
In manual metal arc welding the heat source is an electric arc, which is formed between a
consumable electrode and the parent plate. The arc is formed by momentarily touching
the tip of the electrode onto the plate and then lifting the electrode to give a gap of 3 mm
– 6 mm between the tip and the plate. When the electrode touches the plate, current
commences to flow and as it is withdrawn the current continues to flow in the form of a
small spark across the gap, which will cause the air in the gap to become ionised, or made

conductive. As a result of this the current continues to flow even when the gap is quite
large. The heat generated is sufficient to melt the parent plate and also melt the end of the
electrode – the molten metal so formed is transferred as small globules across the arc into
the molten pool.


Giáo trình Anh văn chun ngành cơng nghệ hàn

19

Figure 5
Type of operation.
Manual.
Mode of Operation.
Arc melts parent plate and electrode to form a weld pool that is protected by the flux
cover. Operator adjusts the electrode feed rate, i.e. hand movement, to keep the arc length
constant. Slag must be removed after depositing each bead. Normally the SMAW
provides a small degree of penetration, requiring plate edge preparation. Butt welds in
thick plate; or large fillets are deposited in a number of passes. The process can also be
used to deposit metal to form a surface with alternative properties.

TUNGSTEN INERT GAS WELDING
Tungsten inert gas welding is a constant current drooping arc process. It is also known as
TIG, gas tungsten arc welding – GTAW, wolfram inert gas – WIG, and under the trade
names of argon arc and helium arc (Figure 6).

Figure 6


Giáo trình Anh văn chun ngành cơng nghệ hàn

20

Type of Operation.
Usually manual, but can be mechanised.
Mode of Operation.
An arc is maintained between the end of a tungsten electrode and the work. The electrode
is not consumed and the current is controlled by the power source setting. The operator
must control the arc length and also add filler metal if needed to obtain the correct weld;
consequently, a high degree of skill is needed for the best results. The arc is unstable at
low currents. Special provision is made for starting (high frequency or surge injection)
and for welding thin materials (pulse TIG).

METAL INERT GAS WELDING
With a 'flat' volts/amps characteristic an attempted alteration in arc length (volts) will
have little effect, hence arc length (volts) remains constant but a significant change in
current will result. This is often referred to as the 'self-adjusting arc'. Metal Inert Gas
(MIG) welding is a 'flat' arc process (constant voltage process). Also known as Metal
Active Gas (MAG); CO2; Metal-arc Gas Shielded, flux core and GMAW (US). MIG can
be used on all materials, in all positions, with high productivity and low heat input. There
is no CO2 MIG welding with stainless steel. Normally DC positive though some flux
cored processes uses DC negative (Figure 7).

Figure 7
Type of Operation.
Manual, mechanised, semi-automatic and automated (robotics).
Mode of Operation.


Giáo trình Anh văn chun ngành cơng nghệ hàn

21

An arc is maintained between the end of the bare wire electrode and the work piece. The
wire is fed at a constant speed, selected to give the required current, and the arc length is
controlled by the power source. The operator is not therefore concerned with controlling
the arc length and can concentrate on depositing the weld metal in the correct manner.
Hence the name 'semi-automatic' for manual operation, in which wire, gas and power are
fed to a hand held gun via a flexible conduit.
The process can be operated at high currents (250 - 500 A) when metal transfer is in the
form of a 'spray', but, except for aluminium, this technique is confined to welding in the
flat and horizontal positions. For vertical and overhead welding special low current
techniques must be used, i.e. 'dip' transfer or pulsed arc. The arc and weld pool are
shielded by a stream of gas. The electrode can be solid or flux cored.

SUBMERGED ARC WELDING
A flat arc process - (constant voltage process). It is used in beam, boom, tractor and
multi-head type rigs (figure 8).
Type of Operation.
Mechanised, automatic or semi-automatic.
Mode of Operation.
An arc is maintained between the end of a bare wire electrode and the work. As the
electrode is melted, it is fed into the arc by a set of rolls driven by a governed motor.
Wire feed speed is automatically controlled so that it equal to the rate at which the
electrode is melted, thus arc length is constant (similar to MIG/MAG - constant voltage).
The arc operates under a layer of granular flux; hence
„submerged arc‟. Some
of the flux melts to provide a protective blanket over the weld pool. The remainder of the
flux is unaffected and can be recovered and re-used, provided it is dry and not
contaminated.

A semi-automatic version is available in which the operator has control of a welding gun
that carries a small quantity of flux in a hopper.


Giáo trình Anh văn chun ngành cơng nghệ hàn

22

Figure 8
IV. PRACTICE
1. What is an inert gas? Name two. Name a widely used GMAW gas that is not
inert?
2. W ‟
f
G
W
?
3. What is one advantage of GMAW over semiautomatic submerged-arc? Over fluxcored electrode welding?
4. Explain the principle of SMAW?
5. Explain the principle of MIG/MAG?
6. Explain the principle of TIG?
7. Explain the principle of SAW?


Giáo trình Anh văn chun ngành cơng nghệ hàn

23

UNIT 5: IMPERFECTION WELDING
Object: to study imperfection welding

I.

VOCABULARY:
- Undercut:
- Overlap:
- Fish eye:
- Slag inclusion:
- Pit, surface pore:
- Porosity:
- Tungsten inclusion:
- Burn through:
- Incomplete joint??:
- Incomplete fusion:
- Weld crack:
- Longitudinal crack:
- Transverse crack:
- Underbead crack:
- Toe crack:
- Hot crack:
- Cold crack:
- Reheat crack:
- Root crack:
- Crater crack:
- Lamellar tear:
- Sub-surface:
- Notch:
- Focal point:
- Fatigue life:
- Stray:
- Fuse:

- In service:
- Discontinuity:
- Diffusion:
- Martensitic:
- Union:
- Adjacent:
- Insufficient:
- Elongate:
- Solidification:
- nozzle:
- Molten:

Cháy chân
tràn
ắ cá
ẫ ỉ
R
R
ẫ vonfram
Cháy xuyên
Hàn
K
V ứ
V ứ d
V ứ
V ứ d
V ứ
V ứ
V ứ
V ứ

V ứ
V ứ
V ứ
d
V
í
Tiêu
Sứ
ự
Nóng
Trong
ửd
Gián
Sự
án
Mactensit hóa già
Sự liê
Lân
T
ủ
Giãn
é d
Sự ứ
ự
ở
Nóng

ủ

hàn

T

ỏ
ửd

d

ự

ắ


Giáo trình Anh văn chun ngành cơng nghệ hàn

II.

GRAMMAR:
THE ARTICLE: A / AN AND THE.

1.

The indefinite article (a/an).
Indefinite article is used before a singular noun which is countable when it is
mentioned for the first time and represents no particular person or thing:
Example:
a butt joint
a lap joint
a position
a way

2.

The use of a / an.
The „a‟ is used before a word beginning with a consonant, or a vowel with a
consonant sound:
Example:
a steel
a bar of steel
a joint
The „an‟ is used before words beginning with a vowel ( a, e, i, o, u) or words
beginning with a mute h:
Example:
an iron
an imperfection
an irregular
or individual letters spoken with a vowel sound:
Example:
an L-plate

3.

The definite article (the).
The definite article is used before a noun which has become definite as a result
of being mentioned in second time or afterward:
Example:
There is a student repairing electric in the shop. The student that you asked to
help me yesterday.
Or before a noun made definite by the addition of a phrase or clause:
Example:

The body of the weld
The area of the arc strike
The damage on the parent material
At the end of
The side of the weld

24


Giáo trình Anh văn chun ngành cơng nghệ hàn

25

III. PRACTICE
1. Defects detected by surface inspection
Defects, which can be detected by visual inspection, can be grouped under five
headings.
1.
2.
3.
4.
5.

Cracks.
Surface irregularities.
Contour defects.
Root defects.
Miscellaneous.

1.1. Surface cracks

A crack is a linear discontinuity produced by fracture. Cracks may be longitudinal,
transverse, edge, crater, centreline, fusion zone, underbead, weld metal or parent metal
(Figure 9 -11).

Longitudinal, in weld metal (centreline)

Longitudinal, in parent plate
Figure 9

Transverse

Crater (star cracking)
Figure 10