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Hardfacing Electrodes and Wires

Hardfacing adds a wear-resistant layer to parts that face abrasion, impact, heat or metal-to-metal wear. This sheet sorts the main surfacing alloy families, what each resists and how build-up and hardfacing layers are used together.

Ref WG-0110AWS A5.13AWS A5.21

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

Hardfacing (surfacing) deposits an alloy on the surface of a part to restore it or to make it last longer. It is used on bucket teeth, crusher parts, augers, tillage tools, dredge pumps, rolls and shafts. Products come as stick electrodes, flux-cored and metal-cored wires, solid wires and bare rods. AWS A5.13 covers surfacing electrodes for shielded metal arc welding. AWS A5.21 covers bare electrodes and rods for surfacing. Many hardfacing products are sold by trade name with a typical hardness and wear claim rather than an AWS class, so read the data sheet.

How to identify

Start with the wear. Abrasion is grinding by sand, soil, rock or slurry. Impact is pounding or gouging. Metal-to-metal wear is sliding or rolling contact. Heat and corrosion often come with one of the others. Most parts see a mix, so choose the alloy for the main wear type. Then check the base metal: carbon steel, low-alloy steel, cast iron or austenitic manganese steel.

Surfacing alloy families

Family	Resists	Typical parts	Notes
Build-up (low-alloy steel)	Restores dimension	Rollers, idlers, worn parts before hardfacing	Tough, machinable; not wear resistant by itself
Martensitic	Metal-to-metal wear, moderate impact	Shafts, rolls, track parts	Hardness depends on dilution and cooling
Austenitic manganese	Heavy impact; work hardens	Crusher parts, rail frogs, manganese buckets	Keep heat input low on manganese steel base metal
Chromium carbide	Severe abrasion, low to moderate impact	Ag tools, buckets, chutes	Fine check cracks across the bead are normal
Complex carbide	Abrasion with heat	Sinter plants, high-temperature chutes	Specialty
Tungsten carbide	Extreme abrasion	Drill bits, auger flights, mixer paddles	Carbides in a matrix; often applied by oxyfuel or special wire
Cobalt-based (for example ECoCr-A)	Heat, corrosion, galling	Valve seats, hot shear blades	Expensive; high quality work
Nickel-based	Corrosion and some wear	Pump parts, chemical service	Often with carbides

Key points

Hardfacing alloys are often limited to one, two or a few layers. The data sheet sets the limit.
Use a build-up alloy first when a part is badly worn, then cap it with hardfacing.
Chromium carbide check cracking relieves stress. Do not use it where cracks would cause a leak or be a problem.
Preheat and interpass temperatures depend on base metal and part size. Get them from the filler maker or the procedure.
Manganese steel is damaged by high heat. Keep it cool between passes.
Bead patterns such as stringers, dots or waffles change how material wears. Ask the filler maker.

Common mistakes

Putting chromium carbide on a part that takes heavy impact.
Stacking too many layers of a hard alloy and causing spalling.
Hardfacing over cracked or dirty base metal.
Using a carbon steel build-up rod on manganese steel.

Governing standards: AWS A5.13 (surfacing electrodes for SMAW); AWS A5.21 (bare electrodes and rods for surfacing). Filler maker data sheets for layer limits and procedures.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

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