INTRODUCTION TO WELDING AND FABRICATION

INTRODUCTION TO WELDING

In the Navy as well as private industry, welding is
widely used by metalworkers in the fabrication, main-
tenance, and repair of parts and structures. While there
are many methods for joining metals, welding is one of
the most convenient and rapid methods available. The
term welding refers to the process of joining metals by
heating them to their melting temperature and causing
the molten metal to flow together. These range from
simple steel brackets to nuclear reactors.
Welding, like any skilled trade, is broad in scope and
you cannot become a welder simply by reading a book.
You need practice and experience as well as patience;
however, much can be gained through study. For in-
stance, by learning the correct method or procedure for
accomplishing a job from a book, you may eliminate
many mistakes that otherwise would occur through trial
and error.

GERALDINE CELESTE ODCHIGUE

HISTORY OF WELDING

The History of Welding

The Bible mentions Tubal Cain, " forged all types of tools from bronze and iron." He may have been one of the first to join metals with the forging process. His flame was an open hearth into which he placed the metals to be heated to the forging temperature.

In 1892 Morehead and Wilson accidentally discovered how to make acetylene. It was found that combining acetylene with oxygen produced the hottest flame temperature--5720 degrees F. Since this is well above the melting point of most metals the oxyacetylene welding process soon developed.

Welding can trace its historic development back to ancient times. The earliest examples come from the Bronze Age. Small gold circular boxes were made by pressure welding lap joints together. It is estimated that these boxes were made more than 2000 years ago. During the Iron Age the Egyptians and people in the eastern Mediterranean area learned to weld pieces of iron together. Many tools were found which were made approximately 1000 B.C.

PACAMALAN, LIZA FE A.

WHO INVENTED THE WELDING ROD?

INVENTOR: Carl Wilhelm Søderberg (1876-1955) praised his colleagues and maintained that without their help the Søderberg electrode would never have been invented.

Geraldine Celeste Odchigue

SAFETY FIRST

Even a good welder also need things...

Welding Helmet

Welding helmets are headgear used when performing certain types of welding to protect the eyes, face and neck from flash burn, ultraviolet light, sparks and heat. Most commonly used with arc welding processes such as shielded metal arc welding, gas tungsten arc welding, and gas metal arc welding. Welding helmets are necessary to prevent arc eye, a painful condition where the cornea is inflamed. Welding helmets can also prevent retina burns, which can lead to a loss of vision. Both conditions are caused by unprotected exposure to the highly-concentrated UV rays emitted by the welding arc (which can also damage uncovered skin, similar to a sunburn.

Welding Gloves

The importance of welding gauntlets is behind the safety they offer a welder. This is because they protect a welder's hands and wrists from heat and sparks while still offering the flexibility in performance to carry out professional welding without restriction.

Welding Blankets

A welders blanket is uses as a form of safety protection for themselves and for those around them to stop sparks causing fires as burning embers land around them.

Welding Curtains

For safety reasons curtains for welding have been created to reduce hazards such as fires by isolating the area a welder is working in. Welding curtains have been specifically designed to reduce the risk of passing workers being injured by sparks and stopping burning embers before they can find a material that is flammable.

Welding Jacket

A welding jacket is a necessity for most welderes. For any welder safety is paramount and never far from their thoughts. This happens because of the heat and potential dangers associated with welding.

Welding Screens

A welders screen is rectangular metal frames with a heat resistant welding screen in the middle of the rectangular frame. The heat resistant screen is usually joined to the metal frame through a metal hook that goes through holes at the top of the metal frame and brass eyelets on the heat resistant screen. At the bottom of the metal frame, at each end, there is a T-section metal frame with two wheels on casters; this gives the welding screen stability and maneuverability.

Welding Tools

Welding tools and metalworking tools is like a kitchen without utensils

by:kirk kervin orpilla

SAFETY ISSUES

Arc welding with a welding helmet, gloves, and other protective clothing.

Welding, without the proper precautions, can be a dangerous and unhealthy practice. However, with the use of new technology and proper protection, risks of injury and death associated with welding can be greatly reduced. Because many common welding procedures involve an open electric arc or flame, the risk of burns and fire is significant; this is why it is classified as a hot work process. To prevent them, welders wear personal protective equipment in the form of heavy leather gloves and protective long sleeve jackets to avoid exposure to extreme heat and flames. Additionally, the brightness of the weld area leads to a condition called arc eye in which ultraviolet light causes inflammation of the cornea and can burn the retinas of the eyes. Goggles and welding helmets with dark face plates are worn to prevent this exposure, and in recent years, new helmet models have been produced that feature a face plate that self-darkens upon exposure to high amounts of UV light. To protect bystanders, translucent welding curtains often surround the welding area. These curtains, made of a polyvinyl chloride plastic film, shield nearby workers from exposure to the UV light from the electric arc, but should not be used to replace the filter glass used in helmets.


GERALDINE CELESTE ODCHIGUE

UNUSUAL CONDITIONS

Underwater welding

While many welding applications are done in controlled environments such as factories and repair shops, some welding processes are commonly used in a wide variety of conditions, such as open air, underwater, and vacuums (such as space). In open-air applications, such as construction and outdoors repair, shielded metal arc welding is the most common process. Processes that employ inert gases to protect the weld cannot be readily used in such situations, because unpredictable atmospheric movements can result in a faulty weld. Shielded metal arc welding is also often used in underwater welding in the construction and repair of ships, offshore platforms, and pipelines, but others, such as flux cored arc welding and gas tungsten arc welding, are also common. Welding in space is also possible—it was first attempted in 1969 by Russian cosmonauts, when they performed experiments to test shielded metal arc welding, plasma arc welding, and electron beam welding in a depressurized environment. Further testing of these methods was done in the following decades, and today researchers continue to develop methods for using other welding processes in space, such as laser beam welding, resistance welding, and friction welding. Advances in these areas may be useful for future Endeavour’s similar to the construction of the International Space Station, which could rely on welding for joining in space the parts that were manufactured on Earth.

GERALDINE CELESTE ODCHIGUE

PIPELINE WEL;DING

PACAMALAN,LIZA FE A.