Rebuild It Instead of Replacing It

Worn bucket lips, crusher cones, plowshares, shovel teeth and pump housings are expensive to replace
and cheap to rebuild. Hardfacing and overlay welding restores dimensions and adds
wear-resistant surface to worn steel, often extending component life to 3–10× its original
service interval. An engine driven welder is the ideal tool for hardfacing in the
field, where the part cannot travel to a shop.

What Hardfacing Does

  • Restores dimensions: Builds up worn steel to original profile.
  • Adds wear resistance: Surface resists abrasion, impact, metal-to-metal wear and
    gouging.
  • Cost savings: Hardfaced parts last many times longer, reducing replacement and
    downtime costs.
  • Field application: The engine driven welder welds the part
    in place—no disassembly, transport or re-machining.

Wear Mechanisms and Alloy Selection

  • Abrasion (low-stress sliding): Gravel, sand, ore. Use chromium-carbide alloys
    (e.g., AWS A5.13 RCo-Cr) or chrome-molybdenum martensitic (e.g., RFe-1).
  • Gouging and high-impact: Impact loading with moderate abrasion. Use martensitic
    alloys (RFe-5 to RFe-12) for toughness and hardness.
  • Metal-to-metal wear: Bearing surfaces and cam followers. Use nickel-base or
    cobalt-base alloys for low-friction, tough surfaces.
  • High-temperature wear: Hot environments like coke drums. Use cobalt or
    nickel-chromium alloys that retain hardness at temperature.

Hardfacing Electrode and Process Selection

  • Open-arc (self-shielded FCAW): Common for field hardfacing; single pass, good
    deposition. Use RFe-5 (carbide type) or RFe-8.
  • Stick (SMAW): Manual, versatile; good for complex shapes and vertical/overhead
    positions. Rods like Build-up (FC-1 type) first, then wear layer.
  • Arc length: Keep short; carbide dissolution reduces wear resistance.
  • Layer thickness: One to three layers; too thick risks cracking. Two layers is
    typical for most field applications.

Preparation and Technique

  • Clean the part: Remove all paint, oil, grease and loose scale before welding.
  • Preheat: 150–300 °C depending on steel type and section thickness;
    reduces cracking risk in the hardfacing layer.
  • Work-harden zones: For austenitic manganese steel parts (e.g., jaw crusher
    liners), weld with austenitic stainless (309L) only—never hardface directly on manganese.
  • Interpass cleaning: Remove slag between passes; inspect for cracks before the next
    layer.
  • Cool slowly: Insulate the part after welding; rapid quench causes cracking.

Where Hardfacing Pays Off Most

  • Mining and quarry: Bucket lips, loader teeth, dozer blades, crusher cones.
  • Agriculture: Plowshares, cultivator points, header parts.
  • Construction: Excavator teeth, compactor drums, dragline components.
  • Rail: Frogs, crossings and rail ends.
  • Oil and gas: Pump plungers, sucker rods, valve seats.

Conclusion

Hardfacing and overlay welding with an engine driven welder rebuilds worn parts
and multiplies component life, saving thousands in replacement cost. Match the alloy to the wear
mechanism, prepare properly, preheat and cool slowly. Explore our hardfacing
consumables and equipment to get started with field overlay welding.

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