N

Welding Glossary

inhalation, ingestion, skin and/or eye contact. Symptoms of toxic exposure include sensitization dermatitis, allergic asthma, pneumonitis; [potential occupational carcinogen(lung and nasal cancer)]
 * Nickel** - Welders who weld on alloys that contain Nickel are at risk for toxic exposure. Exposure routes may include
 * NITROGEN OXIDES - ** The ultraviolet light of the arc can produce nitrogen oxides (NO, NO2), from the nitrogen (N) and oxygen (O2) in the air. Nitrogen oxides are produced by gas metal arc welding (GMAW or short-arc), gas tungsten arc welding (GTAW or heli-arc), and plasma arc cutting. Even greater quantities are formed if the shielding gas contains nitrogen. Nitrogen dioxide (NO2), one of the oxides formed, has the greatest health effect. This gas is irritating to the eyes, nose and throat but dangerous concentrations can be inhaled without any immediate discomfort. High concentrations can cause shortness of breath, chest pain, and fluid in the lungs (pulmonary edema).

This Group was originally named the "inert gases", as it was thought they formed no compounds. However, compounds of these gases are now well documented. Helium, neon and argon form no known compounds. Welders use helium and Argon, as shielding gases, which protect the molten weld pool from atmospheric contamination.
 * Nobel Gases ** - The six noble gases are found in the group 18 of the periodic table. These gases were given this name because it was though that they would not mix with other gases. For this reason these elements were considered to be inert gases until the 1960's. The Nobel gases have an oxidation number of 0 prevents, this the noble gases from forming compounds readily. All Noble gases have the maximum number of electrons possible in their outer shell (2 for Helium, 8 for all others), making them stable. The Nobel gases are:
 * Helium
 * Neon
 * Argon
 * Krypton
 * Xenon
 * Radon
 * Krypton forms KrF2, a colourless solid, on reaction with fluorine.
 * Xenon forms a wide range of compounds with oxygen and fluorine.


 * Noise **


 * Non-Ferrous Metal ** – Metal which does not contain Iron i.e. Copper, Zinc, Gold, Tin, Aluminum, Brass, Bronze, Chromium, Nickel


 * Nozzle ** - In term used when used by welder refers to device, which directs shielding gasses.

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