Hardfacing Bucket Teeth and Edges: Buildup, Pattern Selection, and Cost Analysis

Hardfacing deposits a wear-resistant alloy onto the surface of a softer base metal to extend the part’s working life in abrasive, erosive, or impact conditions. On heavy equipment, that means bucket cutting edges, teeth, ripper tips, auger flights, conveyor screws, and crusher components. The standard procedure is a buildup layer of E7018 to restore dimension (if the part is worn), followed by one or two layers of chromium carbide hardfacing rod in a pattern that matches the wear condition. Done correctly, hardfacing extends wear life by 2-5x compared to bare steel.

The math is straightforward: if a new cutting edge costs $400 and lasts 500 hours, a hardfaced edge that costs $150 in rod and labor and lasts 400 additional hours saves money. That’s the entire justification for hardfacing.

When to Hardface

Good Candidates

• Bucket cutting edges (excavator, loader, skid steer)
• Bucket teeth (between replacements to extend life)
• Ripper tips and shanks
• Auger flights and cutting edges
• Conveyor screw flights
• Crusher liners and jaw plates
• Plow shares and cultivator shovels
• Mixer paddles and blades
• Ground-engaging tools (GET) on any equipment

Poor Candidates

• Parts that need precision dimensions (shafts, bearing surfaces)
• Parts subject to pure impact without abrasion (hammers, forging dies)
• Parts that run against seals (hardfacing is too rough for seal surfaces)
• Very thin parts that can’t tolerate the welding heat
• Parts cheaper to replace than to hardface

Hardfacing Alloys

Chromium carbide is the default hardfacing alloy for ground-engaging equipment. It’s the best balance of abrasion resistance, availability, and cost. The chrome carbide particles embedded in the iron matrix resist abrasive wear from soil, sand, and gravel.

Tungsten carbide is the premium option for the most severe abrasion. The tungsten carbide particles are harder than any soil or rock mineral. Used on dredge cutter teeth, rock drilling tools, and mining equipment where maximum wear life justifies the high cost.

Manganese hardfacing is for impact, not abrasion. Manganese steel work-hardens under impact, getting harder the more it’s hit. Used on rock crushers, rail crossings, and parts that see heavy impact loading.

Base Layer Buildup

If the part is worn below its original dimension, build it back up with E7018 or ER70S-6 before applying hardfacing. Hardfacing rod is expensive, and using it for dimensional buildup wastes material and money.

Buildup Procedure

1. Clean the wear surface. Remove dirt, rust, old hardfacing residue, and any contamination. A grinder with a flap disc works for field cleaning.
2. Preheat if required. AR400/AR450 base metal needs 300-400F (149-204C) preheat. Mild steel base metal under 1 inch thick usually doesn’t need preheat.
3. Deposit E7018 buildup. Run stringer beads to fill the worn profile back to within 1/8 to 3/16 inch of the original surface. This leaves room for the hardfacing layer on top.
4. Settings: E7018 1/8-inch at 120-140A, or 5/32-inch at 150-180A, DCEP. Stringer beads only, no weave patterns wider than 3x rod diameter.
5. Interpass temperature: Keep below 500F (260C) for AR base metal, 600F (316C) for mild steel.

Why Not Skip the Buildup?

Hardfacing rods produce brittle deposits that are crack-prone in thick layers. More than two layers of chromium carbide hardfacing is wasteful. The third layer cracks off the second layer under service stress. Build up with ductile E7018, then apply one or two layers of hardfacing as a wear surface.

Hardfacing Application

Pattern Selection

The deposition pattern determines how the hardfacing wears and how it interacts with the material being handled.

Crosshatch pattern: Two layers of stringer beads at 45 degrees to each other. The ridges wear slower than the grooves, creating a self-sharpening edge on cutting edges. Best for bucket edges, plow shares, and cutting tools.

Dot pattern: Individual weld deposits (about 1/2-inch diameter) spaced in a grid, 1/2 to 3/4 inch apart. The dots wear slower than the base metal between them, creating a waffle-like surface that grips loose material. Best for chute liners, conveyor beds, and surfaces where material slides.

Stringer bead pattern: Parallel beads running perpendicular to the direction of material flow. The leading edge of each bead creates a step that slows material movement. Best for wear plates in hoppers and chutes.

Herringbone pattern: V-shaped beads pointed in the direction of material flow. Provides moderate abrasion protection with a self-cleaning effect as material moves between the V-arms.

Application Procedure

1. Preheat the base metal per material requirements (see table below).
2. Apply the first layer. Run stringer beads (no weave) in the chosen pattern. Leave 1/4-inch gaps between beads. These gaps allow for contraction without lifting the deposit off the base.
3. Let it cool slightly between beads, but don’t let it get below the minimum interpass temperature.
4. Apply the second layer (if specified) at 45 or 90 degrees to the first layer.
5. Don’t apply more than two layers. Additional layers spall off and waste material.
6. Allow check cracks. Hardfacing is supposed to develop relief cracks (check cracks) as it cools. These cracks relieve internal stress and prevent the deposit from popping off the base in large chunks. They’re normal, not defects.

Preheat Requirements

Manganese steel is the exception: Do NOT preheat manganese. Manganese steel embrittles if heated above 500F (260C). Keep it cool during hardfacing. Weld short beads and let them cool. Some operators cool the part with compressed air between passes.

Settings

Edge Buildup vs. Replacement

When to Hardface the Existing Edge

• Edge is worn but still has at least 50% of its original thickness
• The edge material is sound (no cracks, no delamination)
• Replacement edge isn’t readily available
• Equipment downtime for edge replacement exceeds hardfacing time
• You’re extending the edge life until a scheduled maintenance window

When to Replace the Edge

• Edge is worn below 50% of original thickness
• Edge is cracked or damaged from impact
• Replacement edge is in stock and installation is quick
• The bucket or implement has other damage that requires shop time anyway
• Cost of replacement is close to cost of buildup + hardfacing

Cost Comparison

Best practice: Install a new edge and hardface it before it goes into service. This gives you maximum wear life from day one and avoids the cost of the buildup layer.

Cost-Per-Hour Analysis

The real measure of hardfacing value is cost per operating hour.

Example: A loader bucket edge costs $400 new and lasts 600 hours in a sand and gravel operation.

• Cost per hour (bare): $400 / 600 = $0.67/hr

Hardfacing the new edge costs $150 in rod and labor and extends the life to 1,200 hours.

• Cost per hour (hardfaced): ($400 + $150) / 1,200 = $0.46/hr

That’s a 31% reduction in edge cost per operating hour. Over 5,000 hours of annual operation, the savings are significant.

Track your wear rates. Record hours when you install a new edge and hours when you replace it. Do the same for hardfaced edges. After a few cycles, you’ll know exactly how much hardfacing extends your wear life in your specific material and conditions.

Specific Equipment Applications

Excavator Bucket Edges

Hardface the bottom edge and the heel (the horizontal surface that scrapes the ground). Crosshatch pattern on the bottom edge, stringer beads on the heel running perpendicular to the digging direction.

Loader Bucket

Hardface the cutting edge, the bottom plate in the first 12 inches from the edge, and the wing edges (side plates). Loader buckets scoop, so the bottom plate behind the edge takes significant wear.

Auger Flights

Hardface the outer edge of each flight (the part that contacts soil or rock). Apply stringer beads running along the flight edge. The flights spin, so the leading edge wears fastest. Concentrate hardfacing there.

Ripper Tips

Ripper tips are typically replaceable, but the shank behind the tip wears too. Hardface the shank wear face to prevent dimensional loss that causes the tip to fit loosely.

Common Hardfacing Mistakes

Applying more than two layers. The third layer of chromium carbide hardfacing spalls off the second. It’s wasted material. Two layers maximum.

Hardfacing impact zones. Chromium carbide is brittle and cracks under impact. Don’t hardface the tip of a bucket tooth that slams into rock. The hardfacing chips off and leaves a rougher surface than bare steel. Use manganese hardfacing for impact areas.

Not preheating AR steel. AR400 and AR450 base metal cracks in the HAZ without preheat. The cracks undermine the hardfacing deposit and can propagate through the base metal.

Grinding hardfacing smooth. The rough surface of hardfacing beads is part of the wear protection. Grinding it smooth removes the hardest outer layer and reduces the effective wear life. Leave it as-deposited.

Hardfacing over old, cracked hardfacing. The new deposit doesn’t bond well to the old, cracked surface. Grind off the old hardfacing down to sound base metal (or the E7018 buildup layer) before reapplying.

Skipping the buildup layer on severely worn parts. Thick hardfacing deposits applied directly to a thin, worn base crack and spall. Build the profile back up with ductile E7018, then apply hardfacing as a surface treatment.

Hardfacing is a maintenance discipline, not a repair. The best time to hardface is before the part wears, not after. Integrate hardfacing into your maintenance schedule and track your cost-per-hour numbers. The data tells you exactly when hardfacing pays and when replacement is the better value.

For more repair topics, see the repair & maintenance overview and our guide to field welding repair procedures.