Piston rods will be reconditioned according to hard surface treatment. While others used the method of metal spray or welding the piston rod with harder material, we weld the piston rod with original material and do a hard surface treatment afterwards. This will minor the chance to get small haircracks like you can have when you weld with a harder material. Hardness of an piston rod is around 280 brinell while our method will result in a hardness of 300 brinell.

 

Process will be as follows; 

 

  • Pre-machining till clean material
  • Pre-heating of entire rod to 200 degrees
  • Automatic SAW welding of running surface
  • Stress relieving in over at 650 degrees for 4 hours
  • Machining running surface to 0.2mm above original diameter
  • MPI check
  • Surface hardening of running surface
  • Final grinding of running surface to original diameter
  • MPI check
  • Skimming upper/lower flange in line with running surface
  • Hardness after repair: 300 Brinell