Certified Welding Inspector Practice Exam

Which gas is used in laser beam cutting to blow molten metal away?

1. Inert gas

2. Assist gas

3. Shielding gas

4. Combustion gas

The correct answer is: Assist gas

In laser beam cutting, the use of an “assist gas” is crucial for effectively removing molten metal from the cutting area. When laser cutting occurs, the intense heat generated by the laser melts the material being cut. The assist gas is then introduced through the cutting nozzle to blow away the molten metal, aiding in the clearing process and promoting a clean cut. This process not only helps in maintaining the quality of the cut but also prevents the re-deposition of the molten material back onto the workpiece, which could lead to imperfections. The type of assist gas can vary depending on the material being processed; for example, oxygen may be used for cutting steel, while nitrogen might be chosen for cutting aluminum or other materials to minimize oxidation. Understanding the role of the assist gas is vital, as it is specifically intended to enhance the cutting performance by managing the molten material, ensuring the operation remains efficient and the resulting edges are smooth and clean.