The following is the Vulcan Systems, LLC Roll Press & Finish Grind Rolls Repair Procedure:
- Removal of hardfacing layer: Air arc down to a depth that cleans cracked material, probably all the way down to the base metal. Any Hardfacing area not removed could result in fatigue cracking.
- Clean area after arcing: Use grinder to remove slag area left over from air-arcing. Stress-relieve roll press roll with a needle hammer or a jack hammer.
- Pre-heat: Pre-heat roll press roll with soaking heat for approximately six hours. Do not rush the pre-heat process as heat needs to be distributed throughout the roll. Use a 300 degree F temp stick for uniform heat distribution.
- Welding of roll press: Roll speed: 13-14 inches per min; needle gun each pass; stress relieve each layer.
- Stress relieve each layer as soon as possible: Hot stress peening as soon as possible after the weld beat is put down is very important. Needle gun each pass. Stress relieve each layer all the way across from one side to the other. Use jack hammer for this procedure.
- Maintain 300 degrees on roll: Maintaining a constant heat is important as well. Too much build-up and not enough heat causes loss of tensile strength to base metal. Too much heat can result in undercutting and a draw to cracking in weld arc.
- Build-up layers: Build-up layers using 7/64” Vulcan OMC-414. Set your voltage between 30 and 34 volts and your amperage between 500 and 600 amps. Weld at a rate of 140 to 155 inches per minute. No gas is required for this wire.
- Transition layer: Use one pass of Vulcan 7/64” OMC-900-HF. This wire prevents stress and/or J-cracking problems. Set your voltage between 29 and 30 volts and your amperage between 320 and 370 amps. Weld at a rate of 140 to 150 inches per minute (surface space). Maintain 300 degrees F roll heat. No gas is required for this wire.
- Hardfacing cap layers: Use one pass of Vulcan 7/64” OMC-700-HF. Set your voltage between 27 and 28 volts and your amperage between 250 and 300 amps. Weld at a rate of 120 to 130 inches per minute. No gas is required for this wire.
- Profiling : Use one pass of Vulcan 7/64” OMC-900-HF. Be sure to use a waving pattern of build-up as follows:
Procedure images and diagrams:
*This page last edited 02/13/2019
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