Question

Choose the word that best completes this sentence. Welding in confined spaces and on stainless steel generates _____________ a very toxic chemical.

Answer 1

Welding in confined spaces and on stainless steel generates hexavalent chromium. Hexavalent chromium is a compound that is generally used in textile dyes and wood preservation. 

Answer 2

Hexavalent chromium

Step-by-step explanation:

Tungsten Inert Gas (TIG) is the most widely used welding technique for stainless steel of small thicknesses, since, although it has lower performance than MIG, it does not produce such high temperatures of the material and, thus, prevents deformations.

The tungsten electrode, usually pure, may contain small amounts of zirconium or thorium in percentages below 2%. If the contribution of metal to the welding is necessary, it is done externally by means of a rod.

The most commonly used gases for arc protection are helium or argon, or a mixture of both, supplied through a nozzle in the torch or welding gun.

The chemical agents that may be present in the welding tasks described are:

From the base material

1. Chromium compounds (III)

2. Chromium compounds (VI)

3. Insoluble inorganic nickel compounds

4. Iron oxide (III): Fe2O3

5. Manganese oxide (IV): MnO2

The consequences that can be generated by chromium VI compounds (or hexavalent) are:

-Lung and paranasal sinus cancer

-Respiratory irritation

-Sensitization