Question

Give reasons for the following.

Hydrogen is used to weld metals.

Answer 1

Hydrogen:

• Hydrogen is a chemical element having an atomic number equal to one.
• It was discovered by Henry Cavendish.
• It is a gas with no color and odor and has the lowest density of all gases.
• It is a highly inflammable gas.
• It exists in the diatomic form in nature so 2 atoms of hydrogen make one molecule H₂.

Hydrogen welding:

• Atomic hydrogen welding (AHW) is a welding process that uses an arc between two tungsten electrodes in a shielding atmosphere of hydrogen.
• It is named atomic hydrogen welding because the arc disassociates the hydrogen into atomic form.
• During the release of the heat, temperatures in the range of 3400 ºC to 4000 ºC are reached.
• This heat is enough to melt the metals and weld them together.
• Hydrogen provides heat and also acts as shielding gas for molten metal.