the sheets to be united are passed steadily between an upper co
roll with an edge of the width of seam weld desired, and a condi:
mandrel, plate, or similar copper roll forming the under electrode
The weld so formed is a line or strip of a width determined by tin
width of the contact surface of the welding roll. Thin steel tube;
with lap welds are made by this method, and it has also found ap-
plication in the construction of thin metal containers such as stee
thermos bottles, the parts of which are united without solder.

Snap Welding. This term is now commonly applied in connex
ion with the Thomson resistance process to welds made by i
contact of the pieces during heating, followed by quick applicatior






WELDING



965



of heavy pressure to force the heated surfaces together. With iron
and steel the method secures a very strong weld and the heating is
confined closely to the weld itself. Moreover, there is a saving of
time and often of energy.

Percussion Welding. If an electric condenser of large capacity be
discharged by wire terminals of relatively small section made to
approach each other in line, the discharge occurs with a flash of light
at or before actual contact, depending on their potential difference.
With sufficient capacity of condenser the restricted areas of the op-
posed ends of the discharge wires are brought superficially for an
instant to a high temperature, and if immediately pressed into firm
contact will weld or unite. In percussive or percussion welding the
condenser (or, better, a polarization battery of limited capacity) is
charged from any suitable source of electric energy and its terminals
attached to the work pieces, which are then brought into percussive
contact, as by arranging to have one of them fall toward the other
from an appropriate height determined by experiment. The per-
cussion may be assisted by a weight or spring suitably adjusted.
The discharge occurs as above described, and the heated opposed
surfaces are brought instantly together by the forcible impact. A
weld may thus be obtained between the pieces. The rise of tem-
perature is confined almost entirely to the thin layer of metal forming
the joint. The heating effect is thus more local than in any other form
of welding. It is applicable to small work and it extends to a con-
siderable degree the practical possibilities of electric welding. The
stored energy of an electro-magnetic circuit may also be employed
for the instantaneous discharge demanded by percussion welding.

Electric Arc Welding. Stimulated in large measure by the need
of rapid ship construction in the World War, and the modern exten-
sion of electric supply, that form of fusion welding in which the
electric arc is employed has in the past few years grown rapidly in
importance and extent of application. Many forms of arc-welded
joint in steel structures have already been to a degree standardized.
The arc terminal applied to the work (usually the negative electrode
when direct current is used) is a wire or rod of mild steel, mounted in
a suitable holder manipulated by the operator, upon whose skill the
perfection of the work largely depends. These electrode wires
ordinarily vary in diameter according to the scale of the work or
current strength used, and range from ^ in. to & in. or more. As
the welding wire is rapidly consumed in the operation of fusing a
joint, it is constantly fed forward. Automatic arc welders have
been devised and in these the arc separation is controlled automat-
ically and the wire also fed automatically from a reel. In operation
the arc voltage may be from 10 to 20 volts and the current traversing
the arc may be from 80 to 200 amperes or more. The welding is
attended by much sputtering and projection of fused and super-
heated globules of iron from the end of the wire electrode toward the
cooler and heavier masses of the work pieces. In fact, the deposition
of metal on the work is possibly due to a jet of iron vapour from the
electrode wire, carrying fused iron globules as a result of explosive
boiling of the iron. This action would be a natural consequence of
the central area of the end of the electrode wire being at the highest
temperature, as it loses heat by radiation less readily than the outer
surface of the wire at the arc. This central area reaches a temp-
erature of about the boiling point of iron. The temperature of
the arc is so high that the surface of the work pieces, however mas-
sive such pieces may be, is penetrated and fused so that incorporation
of the metal of the work and that from the welding electrode wire takes
place. The welding may be regarded as a progressive filling or plaster-
ing action by condensed iron vapour and fused iron. The operation is
facilitated by coating the electrode wire lightly with mineral films,
such as lime, which probably act by furnishing volatile material
which adds to the stability of the arc. Depending on the strength of
current in the arc and the skill of the operator, from I Ib. to 2 Ib. of
metal per hour may be deposited in effecting the welds, and about
80 % of the metal of the wire used enters the welds, the remaining
20% being vapourized, burned into oxide, or scattered in small
globules. When plates of over -fg in. in thickness are to be butt-
welded they should be bevelled before abutting them, so that a
groove of not less than 60 flare shall be provided, to be filled with the
fused metal (see fig. 3.). Where the plates meet at an angle, as
in fig 4, the fused metal is deposited either at a or b, or both.



FIG. 3.




FIG. 4.



Arc welding can be carried on even upon the under side of the
work (such as a boiler or tank in situ). In this case the electric arc
is at the upper end of the welding wire, and the disadvantageous
position results in the rate of forming the welds being about 60 /
of that in ordinary work. The actual rate at which seams can be



made in arc welding naturally depends upon the thickness 1 of the
plates to be united, the kind of joint to be made and other condi-
tions. With automatic machines on small work it may rise to about
2 ft. per minute, while in heavy work by hand operation it may not
exceed 2 in. per minute. Ordinary arc welds on steel may possess a
tensile strength of as high as 50,000 Ib. per sq. in., but there is almost
negligible elongation. Cast iron is amenable to arc welding when
proper precautions are taken. Likewise bronze and copper may be
arc-welded, a favourable condition for which is preheating of the
work pieces. Arc welding has usually been done by the use of direct
current, and special dynamo generators are constructed for supplying
the current, such generators having been designed with regulating
characteristics suitable to welding. The alternating-current arc
is, however, adaptable to welding, provided the frequency is not
too low. Arc welding covers a large field of application, constantly
extending. It is employed in the construction of tanks, and is espe-
cially useful in caulking the seams of tanks which must retain
oil or thin liquids without leak. It is revolutionizing the fabrication
of many structures of iron and steel, and is much used for repair
work. It is readily applicable to joining broken pieces and to re-
placing metal worn away in use, of which the restoration of rail
surfaces of tramways in situ is now a familiar instance. It is generally
found to be less costly in application than the other forms of fusion
welding, such as that by the use of oxygen blowpipe or thermit
welding. (E. T.)

(2) GAS-TORCH WELDING. Gas-torch welding is variously
known as " autogenous " welding, " oxy-acetylene blowpipe "
welding, " hot gas flame " welding, " fusion " welding, and
other terms which are more or less inaccurate, general, and con-
fusing. The gas combinations more commonly used for torch or
blowpipe welding are either oxygen-acetylene or oxygen-hydro-
gen. Of these two, oxy-acetylene is in more general use for
welding, while oxy-hydrogen, on account of its longer flame, is
generally used to supply heat for steel-cutting torches. The
oxy-acetylene flame has a maximum heat under ideal conditions
of about 3,400 C., and oxy-hydrogen about 2,000 C.




FIG. i. Principle of the low pressure or
injector type of gas torch.



The use of a blowpipe or torch in some form was known to the
ancients, but the high-temperature gas flame is a development
of the last quarter of a century, and especially the past ten years.
The application of the oxy-acetylene torch to metallic welding
dates experimentally from 1901 and commercially from 1903;
Edmond Fouche, Paris, who did considerable experimenting in
conjunction with Ficard, is generally credited with making the
first really practical torch. The early torches used both oxygen
and acetylene under high pressure, but this proved too danger-
ous, and a low-pressure or injector type was next used. Follow-
ing this was the Gauthier-Ely positive or medium pressure
torch, which used both gases under moderate and independent
pressure. The injector and the positive-pressure types are the
ones now in commercial use. The development of the latter is
largely due to Augustine Davis and Eugene Bournonville.




FIG. 2. Principle of the medium
or positive-pressure type of gas torch.



The fundamental principle of the low-pressure or injector type of
torch is shown in fig. I. The acetylene enters at A and the oxygen



966



WELFARE WORK IN INDUSTRY



at B. The acetylene, at less than i-lb. pressure, goes to chamber C,
from which it is sucked by the oxygen, under 5 to 3O-lb. pressure,
pouring out of nozzle D, and is carried along with the oxygen into
the mixing chamber E. The thoroughly mixed gases issue from the
nozzle of the torch, where they are burned.



Carbureting device which positively and
r intimately mixes the two gases in proper proportion
^- /OXYGEN




Oxygen needle
Valvej



Acetylene needle
Valve



\ACETYLENE
The two gases strike
together at right angles
creating a vortex which
insures intimate mixture

The diameters of the parts in the carbureting device
are proportioned to each size of lip, to deliver proper
volumes of gas for each size of flame produced

| luminous Cone of Flame

Secondary reaction. Hydrogen and carbon
monoxide burn, taking the necessary oxygen
from the air and produce water vapor and
carbon dioxide.



FIG. 3. A typical positive-pressure gas torch



The positive-pressure torch principle is illustrated in fig. 2. Here
the oxygen, at from I to 14-lb. pressure, enters at A, and the acety-
lene, at from I to 24-lb. pressure, enters at B. The oxygen enters
the small chamber C and thence out through the centre hole. The
acetylene goes to chamber D and also out through the centre hole.
The two gases start to mix at E and are thoroughly mixed in the
channel F in the torch nozzle G. A typical positive-pressure torch
is shown in fig. 3. Torches are made with tips set at various angles
from 90 to straight, the latter being principally used in welding and
cutting machines. Where the work is heavy the tips are water-
cooled. In welding very thin metal the edges are often turned up or
" flanged " and the torch used to fuse them together without using
any additional metal. On heavier work the edges to be welded are
V-eed out at an angle of from 60" to 90", and this channel is filled
in by using a welding rod or wire, care being taken to obtain perfect
fusion between the old metal and new. Welding of this kind is
progressive, as the welder gradually works along the channel, filling



Oxygen Tank Valve



OXYGEN REGULATOR

^. - Tankor High-
Pressure Gage



Tank or High-

Pressure Gage

Connecting Nut - -

Adapter ;

Safety Valve-



Outlet Connection

V- Gutting
Nozzle

-Torch
Head



TORCH
Cutting Valve




Acetylene Hose_. -

FIG. 4. Typical oxy-acetylene cutting unit

as he goes. The torch is given a weaving motion from side to side in
order to fuse the sides of the V and to puddle in the added metal
from the rod. On all torch welding work allowance must be made
for expansion and contraction, and on repair work of complicated
design, like an automobile cylinder, preheating with charcoal, gas-
and-air torches, or other means is usually necessary. Preheating is
also sometimes resorted to in order to save the more expensive gases.
Nearly all of the common medals may be welded with the gas torch,
though some are more difficult than others. Steel ship or boiler plate



is about the easiest, though aluminium, cast iron, copper, and many
alloys present no serious difficulties.

The set-up for a welding outfit is practically the same as that of the
one for cutting shown in fig. 4. A cutting torch, however, differs
from a welding torch in that it has a separate high-pressure oxygen
vent. The cutting of steel and wrought iron is based on the fact that
a jet of oxygen directed on to a previously heated spot of steel
causes it to ignite and burn away rapidly in the form of iron oxide.
The oxide runs or is blown out of the cut or " kerf," in a stream,
provided the torch is fed along properly. The tips used for cutting
may have one or several heating jets preceding or surrounding the
cutting oxygen jet. Only steel or wrought-iron can be successfully
cut on a commercial scale, though channels or slots may be melted in
any metal. A typical job of steel plate cutting is shown in fig. 5,
and a typical cutting torch in fig. 6. Cast iron is cut with difficulty,
and only by using a special tip and highly preheating the oxygen in
a positive-pressure torch or by using an excess of acetylene and an
unusually large tip on the low-pressure types.



FIG. 5. Cutting through a steel plate




CUTTING OXYGEN



CONICAL

GROUND
SEAT



COPPER
TIP



CUTTING .
JET OF ?M
OXYGEN ,',




? ACETYLENE ;

'REHEA'
OXYGEN



y. OXYGEN CUTTING
Si



SET TRIGGER VALVE

OXYGEN CUTTING

PREHEATING PACK ' NG
FLAME

' PACKING
CUTTING VALVE NUT

TRIGGER
(Remains in Open Position)



PREHEATING ,OXYGEN VALVE

OXYGEN
ACETYLENE

ACETYLENE VALVE





VALVE

REMOVABLE PLUS
SPRING



FIG. 6. A typical cutting torch

The same sources of gas supply are used in cutting as in welding.
These are commonly cylinders or drums containing the gases under
pressure up to 225 Ib. per sq. in. and from 100 to 300 cu. ft. capac-
ity for acetylene, and 1,800 Ib. per sq. in. and from loo to 200 cu. ft.
capacity for oxygen or hydrogen. Acetylene, however, may be
generated on the premises, in which case the pressure must not exceed
15 Ib. per square inch. Obviously pressure as great as that mentioned
for cylinders must be reduced for use in the torch and for this pur-
pose regulators are used which automatically keep the gases supplied
to the torch close to the pressure for which they are set. Gas-torch
welding machines that are practically automatic are in use in many
large plants for straight or circular seam welding of drums, cylinders,
tubes, kettles and the like. Cutting machines are much more
commonly used than welding machines. The cutting machines
range from the simple, hand-fed, straight-line cutters to complicated
motor-driven automatic machines that will cut rounds, squares, ovals
or other patterns. One type of cutting machine is made on the panto-
graph principle, and by following a template or pattern the operator
can use two torches and cut two separate steel plates at once. A
cutting machine will, as a rule, cut a narrower and more even kerf
than can be done by hand. Under favourable conditions a machine
can be made to cut a kerf not over -fa in. wide, while a careless or
inexperienced operator with a hand torch may cut a kerf J in. or
more in width. (E. Vi.)

WELFARE WORK IN INDUSTRY. Human beings possess
intelligence, and their well-being depends on psychological as
well as on physiological make-up. Mental and physical activity
are necessary to health. From the industrial point of view both
require to be maintained in order to ensure the efficiency which
represents for the employer a contented personnel, and for the
employed not merely physical health, but a "worth while" life.



WELFARE WORK IN INDUSTRY



967



The development of industrial processes brought about dur-
ing the last century and a half by the application of mechanical
power has introduced greater variations into the conditions of
life and of work than formerly existed. During the period while
control was being established over the efficiency of mechanical
devices, the relation of the worker to these devices, and study of
the efficiency of human beings in relation to altered conditions
of work, were largely neglected. Nevertheless, industrial develop-
ment in England, as elsewhere, has been followed step by step
by "occupational" legislation, controlling employment in fac-
tories, mines, workshops and other places, aimed at protect-
ing physical health. But knowledge of how to protect health
lagged for many years behind the rapid alterations which were
taking place; and the hurry onward to develop wealth-produc-
ing industries left no time for taking full advantage of what
knowledge did exist. Certainly no organized effort was made
during the igth century to acquire new knowledge, and little
or no recognition was given to the new psychological influences
brought into existence even though their effect upon the workers
was manifested in riots and strikes.

The commencement of the 2oth century saw a few far-seeing
employers coming to appreciate that their workers were individ-
uals with whom personal contact must be established and main-
tained, and that modern industrial concerns were far too large
to permit of this contact being established by a busy works
manager. These employers delegated this side of their duties
to definite persons, entrusted with supervision of the welfare of
their workers. The result of this action was in every case
markedly successful, and 30 British factories in 1913 sent rep-
resentatives to a conference held at York. Nevertheless, pre-
vious to the World War the possibilities of welfare work were
undeveloped. One of its results has been to attract more and
more attention to its importance.

Welfare work, as such, may for convenience be considered
alone. In practice it cannot be separated from supervision
of health. The difference between health supervision and wel-
fare is the difference between supervising the health of domestic
animals such as prize cattle and of human beings. Mere pro-
vision of healthy surroundings and of means for personal hygiene
does not meet the needs; there must be appeal to and cooperation
with those concerned. The true spirit of industrial welfare work
cannot be fostered merely by enforcing compliance with legal
requirements. Welfare work means something different; it
means educating and training each individual worker to take
an intelligent interest not only in his own health and efficiency
but also in that of his fellow workers, and in that of the industrial
establishment of which he forms a part. Legal requirements
can but seldom go further than fixing a minimum standard of
accommodation needed; they cannot deal with the personal
idiosyncrasy of workers, or establish a code of healthy etiquette,
or ensure personal cooperation.

The unprecedented demand in the United Kingdom for muni-
tions during the World War called for action to meet varying
needs more rapid and elastic than that of ordinary peace re-
quirements. In 1915, on the formation of the Ministry of
Munitions, Mr. Lloyd George appointed the Health of Muni-
tion Workers' Committee who promptly recommended the
adoption of welfare supervision for munition workers, using the
following words of a well-known employer in support: " If
the welfare workers have the confidence of the employees, , and
are always in touch with them, they will naturally be the medium
whereby matters occasioning dissatisfaction or misunderstanding
can be investigated and put right. By suggesting and advising
upon improvements in conditions of work that may be helpful on
the business side, by initiating and supervising recreative and
other clubs, societies and classes, by visiting the sick, by endeav-
ouring to foster the spirit of good fellowship amongst all grades of
employees, and by being ready to give advice and assistance in
matters affecting individual employees personally and privately
by these and other methods welfare workers may find means
of giving practical effect to the desire of employers to realize
their obligations towards their workers." The Committee also



issued a series of valuable memoranda dealing with workers'
food and industrial canteens; employment of women and of
juveniles; hours of work; industrial efficiency and fatigue;
sickness, injury, and special industrial diseases; ventilation and
lighting; washing facilities; and eyesight in industry. These
various memoranda formed the basis of work undertaken by a
special section established in the Ministry of Munitions en-
trusted with the welfare and health of workers.

Officers of the factory department (lent for the purpose by the
Home Office) directed the work, which is historically important
since thereby the foundations of industrial welfare were laid,
and for the first time official propaganda going ahead of legal
requirements and statute law were largely and successfully
employed. The work was essentially advisory rather than puni-
tive; it aimed at pointing out the lines reforms should take, and
assisting and expediting in every way the carrying out of improve-
ments. The following memoranda, issued by the Ministry of
Munitions, indicate the scope of the work which was being
initiated:

I. WELFARE FOR WOMEN AND GIRLS

The experience which has now been obtained in National and
other factories making munitions of war has demonstrated that the
post of welfare supervisor is a valuable asset to factory management
wherever women are employed. Through this channel attention has
been drawn to conditions of work, previously unnoted, which were
inimical to the well-being of those employed. The following notes
have, therefore, been prepared for the information of employers who
have not hitherto engaged such officers, but who desire to know the
position a welfare supervisor should take and the duties and author-
ity which, it is suggested, might be delegated to her.

It has generally been found convenient that the welfare supervisor
should be directly responsible to the general manager, and should
be given a definite position on the managerial staff in connexion with
the Labour Employment Department of the factory. She is thus
able to refer all matters calling for attention direct to the general
manager and may be regarded by him as a liaison between him and
the various departments dealing with the women employees. The
duty of a welfare supervisor is to obtain and to maintain a healthy
staff of workers and to help in maintaining satisfactory conditions
for the work. In order to obtain both a satisfactory staff from the
point of view of health .and technical efficiency, it has been found
to be an advantage to bring the welfare-supervisor into the business
of selecting women and girls for employment.

Her function is to consider the general health, physical capacity
and character of each applicant. As regards those under 16 years of
age, she could obtain useful advice as to health from the certify-
ing surgeon when he grants certificates of fitness. The manage-
ment can, if they think fit, empower her to refer for medical advice to
their panel doctor other applicants concerning whose general fitness
she is in doubt. The selection of employees furnishes the welfare
supervisor with a valuable opportunity for establishing a personal
link with the workers. Her function is thus concerned with selec-
tion on general grounds, while the actual engaging of those selected
may be carried .out by the overlooker or other person responsible
for the technical side of the work. In this way both aspects of
appointment receive full consideration.

The management may find further that it is useful to consult the
welfare supervisor as to promotions of women in the factory, thus
continuing the principle of regarding not only technical efficiency
but also general considerations in the control in the factory.

The welfare supervisor should ascertain what are the particular
needs of the workers. These needs will then be found to group
themselves under two headings :

(a) Needs within the factory Intramural Welfare.

(6) Needs outside the factory Extramural Welfare.

Intramural Welfare.