• Weld parameters are those inputs used to control the welding process and weld quality.
  
• Weld parameters were modified to improve weld toughness.
  
• Table shows weld parameters by group, noting the changes from traditional to modified

OPERATION

TRADITIONAL PARAMTERS Smooth, flat joint prep. Light initial load at discharge. High upset load to forge softened material Intense heat generated at interface by carefully controlled contact resistance. Melting or near melting temperatures at interface following discharge. Heating and softening of adjacent material by axial diffusion. Sensitive to uniformity of contact.

MODIFIED PARAMETERS Shaped end and high constant load. Primary heat generated through high current density in shaped end. Heating rates and stress in shaped end is function of cross-sectional area. Spatial temperature profile developed according to specific joint preparation. Softened material displaces radically as it reaches its forging temperature. Increasing the cross-sectional area slows the heating rate by reducing the local current density. Peak temperature limited by on-demand forging action. Continuous deformation during heating produces fine weld line microstructure.

Additional Pages on Homopolar Welding:

Program Description

The Program

Basics of Homopolar Welding

Homopolar Generators

Homopolar Welding Parameters

Weld Parameters and Results Using Modified HPW Method

Joining 12 Inch Pipe in 3 Seconds

X-65 Impact Toughness

Real World Welding Conditions

Commercial Hompolar Welding Systems

For further information please Contact:

Dr. Robert Hebner

(512) 232-1628