Final answer:
The correct answer to the question about how a rolled groove joint is formed is by pressing a steel ring into the copper tube wall. Option C is correct.
Step-by-step explanation:
Rolled groove joints are a method of connecting pipes and tubes often used in piping systems. These types of joints are particularly common in the installation of fire sprinkler systems and other industrial applications. When constructing a rolled groove joint, a machine is used to press a tool into the outer surface of the pipe.
In the case of the question, a rolled groove joint is formed by pressing a steel tool into the copper tube wall. The correct answer to this question is c) Ring. The process involves the use of a specialized grooving machine, which typically uses a circular, wheel-shaped tool, often called a grooving ring, to create the indentation around the circumference of the pipe. This indentation is then fitted with a coupling that locks into place, creating a secure joint.
This process uses a grooving machine to create an indentation that is then fitted with a coupling for a secure joint.