Which operation is generally discouraged for hard drawn copper tubing?

Which operation is generally discouraged for hard drawn copper tubing?

• A. Bent
• B. Soldered
• C. Crimped
• D. Welded

Answer: (A)

Hard drawn copper tubing is much stronger and less ductile than annealed copper. Bending it tends to work-harden the metal and thin the wall on the inside curve, which can create micro-cracks and eventual leaks in a pressurized line. For that reason, bending hard drawn copper tubing is generally discouraged. If bending is necessary, use a long radius or pre-formed elbows, or anneal the tube first to restore ductility before bending. Soldered, crimped, and welded joints are methods for connecting tubing, not bending the tube itself, and are not limited by this temper issue when performed correctly.

Hard drawn copper tubing is much stronger and less ductile than annealed copper. Bending it tends to work-harden the metal and thin the wall on the inside curve, which can create micro-cracks and eventual leaks in a pressurized line. For that reason, bending hard drawn copper tubing is generally discouraged. If bending is necessary, use a long radius or pre-formed elbows, or anneal the tube first to restore ductility before bending. Soldered, crimped, and welded joints are methods for connecting tubing, not bending the tube itself, and are not limited by this temper issue when performed correctly.