Fab Times | The Advent of Gas Welding Advanced Welding’s Importance

The advent of gas welding advanced welding’s importance

Contradictory Nature of War

Philadelphia shipyards during World War 1

Gas Welding

Welding overtook riveting during the shipbuilding process because of improved speed and quality. Of the three welding techniques previously mentioned, gas welding jumped to the front of the line because of the limited technology available for arc and resistance welding. In addition to available technology, gas welding provided several advantages over other methods such as:

  • It can weld all types of metal
  • Needs less maintenance
  • It’s portable

Weakened Welds

Early in its history, somebody discovered issues during the gas welding process. Oxygen and nitrogen kept permeating the welds, which lead to excessive and way too much corrosion and excessive brittleness. These issues resulted directly in the welds’ degradation and significant damage to ships, aircraft, and bridges.

Noble Gases

Shielding Gas

Shielding gas is a gas blown down on top of the weld pool, creating an artificial atmosphere surrounding it. Its main job is protecting the weld pool from contamination from atmospheric gases such as oxygen, nitrogen, and hydrogen.

Welding Gases

Inert Gases

These gases are odorless, non-chemically, reactive, and colorless.

Argon (Ar)

Argon is the third most common gas on Earth, making it inexpensive to use. Except at extremely high temperatures, argon doesn’t react with most substances. As a shielding gas, it’s typically used with aluminum and stainless-steel welding applications. However, argon helps constant metal transfer from the electrode to the weld pool, improving arc stability.

Helium (He)

Helium is comparatively more expensive than other noble gases because it’s hard to produce, and there is limited availability on Earth. It improves heat input and provides deeper metal penetration, but arc consistency is difficult to maintain. However, when combined with argon, helium’s starting inconsistencies improves considerably.

Semi-Inert Gases

These gases are used as a blend or pure. If the correct percentages are applied, they improve a weld’s quality.

Carbon Dioxide (CO2)

Carbon dioxide is cheaper than argon, but you get what you pay for; reduced quality and increased spatter. Because of these deficiencies, carbon dioxide is usually mixed with other gases.

Oxygen (O2)

Oxygen is usually used in a mixture with other gases changing the fluidity of molten metal and improving welding speed. Mixing it with acetylene increases the heat in a flame high enough to weld steel.

Nitrogen (N)

Nitrogen is the most common gas found in Earth’s atmosphere. Mixing it with other noble gases creates the opportunity for some specialized welding practices. Nitrogen works well with nitrogen-rich metals, but not carbon steel.

Hydrogen

Hydrogen is a very reactive gas-think Hindenburg. If used in small amounts, it’s safe to use and increases the blend’s heat.

Compressed Air

Compressed air is the cheapest noble gas. When mixed with other gases, it produces a stronger flame during lower temperatures compared to oxy-fueled flames. This allows welders greater control over the carbon coating’s thickness applied to their welds.

Acetylene

Acetylene is easy to produce and cheap to use. When combined with oxygen and used as a fuel source for certain welding types, it creates a flame hot enough to cut or weld most metals.

Propane

Propane is also known as Liquid Petroleum Gas (LPG), used as a fuel source, but it’s dangerous because it burns exposed skin. Propane doesn’t produce a reducing zone, so it’s unable to be used in gas welding. Instead, it’s used for brazing.

Propylene

Propylene is a blend of oxygen and burns much hotter than propane and oxygen. This attribute allows for non-structural fusion welding, heating, brazing, and more. Because it’s supplied in disposable, small canisters, propylene isn’t feasible for welding large items.

Shielding Gas Effects

In addition to creating an artificial atmosphere over a weld pool, shielding gases also affect the welding process in several ways. This includes:

In Sum

The Chinese sage, Laozi, wrote, “ The flame that burns twice as bright burns half as long.

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