Question

What should the outer diameter of a thick-welled lance be, for having good results?

(a) 13 mm to 15 mm

(b) 15 mm to 17 mm

(c) 17 mm to 19 mm

(d) 19 mm to 21 mm

The question was posed to me in exam.

This intriguing question comes from Oxygen Cutting in chapter Welding and Related Processes of Casting-Forming-Welding II

Answer 1

Correct choice is (c) 17 mm to 19 mm

To elaborate: In oxygen lance cutting, when the lance is made up of a thick wall, with its outer diameter of 17 mm to 19 mm, and possessing an inner diameter of 8 mm to 6 mm, respectively, then good results can be obtained.