Hardfacing Welding Rod Types: Matching Wear Mechanisms to AWS A5.13 Deposit Metallurgy

Hardfacing welding rod types cover five principal AWS A5.13 alloy families rated from 18 HRC to over 70 HRC. Selecting the wrong electrode in industrial welding applications can wear out a part faster than if it is left bare. Using a brittle 60 HRC chromium carbide rod on a crusher hammer results in the overlay spalling off. Using a soft manganese pass in a fine sand chute can also fail, since low-stress sliding never causes work-hardening.

This engineering guide correlates classifications from AWS A5.13 hard surfacing with sliding abrasion, impact, metal-to-metal friction, and thermal corrosion. You will learn how base-metal dilution alters first-pass chemistry across diverse hardfacing applications. We also explain when buffer layers are mandatory and how manual stick overlays differ from automated beam fabrication.

How Are Hardfacing Welding Rod Types Classified by AWS A5.13 and Wear Mechanism?

Hardfacing welding rod types under AWS A5.13/A5.13M:2024 divide into five metallurgical families spanning 18 HRC to 70 HRC equivalent. According to AWS A5.13 surfacing electrode specifications, covered electrodes for shielded metal arc welding fall into five chemical groups. These groups cover iron-base, cobalt-base, nickel-base, copper-base, and tubular tungsten carbide grades. Each class balances impact toughness, wear resistance, and carbide volume for specific service conditions.

Before comparing surfacing alloys, engineers who need conventional joint fillers should review our structural welding rod selection guide. Structural electrodes are rated by tensile strength in thousands of pounds per square inch (psi). Surfacing electrodes, on the other hand, are defined by their undiluted chemistry in weld metal, in accordance with AWS A5.13. That undiluted chemistry is typically measured on the second or third weld layer.

According to The Fabricator’s SMAW hardfacing electrode guide, the rate of deposition of surfacing by manual stick process is in the range of 1 to 7 lb/hr (0.45 to 3.2 kg/hr). The stick arc is reported to give 15% to 30% base-metal dilution on the first pass. Because the welding arc mixes parent metal into the molten pool, first-pass hardness drops below the rated values. Medium hardness martensitic alloys and high-chromium alloys require fine tuning of amperage and layer counts to achieve rated wear resistance.

Recent metallurgical developments also target single-pass efficiency. For example, US Patent 9,475,154 B2 discusses a hardfacing electrode that deposits an iron-chromium-boron-carbon (Fe-Cr-B-C) matrix containing 2.5 to 4.5 wt% boron. Borocarbides are the primary phase that hardens the alloy. That chemistry forms dense primary borocarbides in a single pass, compensating for first-layer base metal dilution on field repairs.

Matching Wear Mechanisms to Deposit Metallurgy: Abrasion vs. Impact Trade-Offs

The first step in determining the alloy composition for a given application is to understand the dominant wear mode on a failed component. In services where hard facing occurs, abrasion resistance and impact toughness are inversely related to the volume of carbides. Adding primary tungsten and chromium carbides increases wear resistance against mineral scratching, whereas solid wire buildups favor impact ductility.

As explained in The Fabricator’s primer on hardfacing metal, two alloys with the same 58 HRC hardness can give very different service life. A 58 HRC martensitic tool-steel overlay contains almost no primary carbides, therefore quartz sand flows freely through the matrix. On the other hand, a 58 HRC high-chromium carbide deposit has hard M7C3 carbides that block mineral penetration.

Operating temperatures and slurry chemistries set firm metallurgical boundaries. According to AWS Welding Digest’s best weld overlay practices, iron-base chromium carbide overlays lose hot hardness rapidly above 1,000°F. They also cannot replace cobalt- or nickel-base alloys in acidic slurries below pH 7. This is true for furnace grates and hot shear blades, as well as chemical mixer paddles.

What kinds of welding rods are best for hardfacing?

High-chromium carbide rods (AWS EFeCr-A1, 55 to 63 HRC) are best for sliding abrasion, while austenitic manganese rods (EFeMn-A, 18 to 55 HRC) are best for heavy rock impact. Martensitic steel electrodes (AWS EFe-2 to EFe-4, 40 to 55 HRC) perform best on metal-to-metal rollers and shafts.

For the highest wear protection for extreme mineral cutting, tubular tungsten carbide rods (EWC, 1,800 to 2,400 HV granules) are the best. For red-hot valves and dies operating above 538°C (1,000°F), cobalt-base ECoCr-A (Stellite 6) electrodes remain the industry standard.

Buildup and Buffer Electrodes vs. Hardfacing Cap Rods (And Why E7018 Alone Fails Abrasion)

In the restoration of deeply worn parts, it is necessary to separate dimensional restoration from outer abrasion resistant cap layers. As documented in Hardface Technologies’ engineering FAQ, buildup alloys restore worn metal parts to near-original dimensions without a strict layer limit. Hardfacing cap alloys, however, have a strict layer limitation of one to three layers. Attempting to restore lost thickness on carbon and low alloy steels using a high-chromium cap rod will guarantee spalling.

Prior to the application of any buildup pass on a fatigued steel, the surface must be prepared. According to the AWS A5G Subcommittee guidelines, a minimum of 1/8-inch of material must be removed using either grinding or carbon-arc gouging. Direct application of high-chromium carbide cap rods over more than two degraded hardfacing layers, in the absence of stripping or buffering, will result in catastrophic spalling.

Laying cobalt-base ECoCr-A or high-shrinkage carbide overlays on crack-sensitive substrates requires an austenitic stainless steel buffer layer. Applying two to three buffer layers of AWS E309L or E307 creates a ductile cushion at the fusion interface. Readers comparing standard structural rods can check our breakdown of common stick welding electrode classifications.

Can you use 7018 for hardfacing?

AWS E7018 cannot be a final hardfacing wear layer because its deposit measures 15 to 22 HRC. It wears away under mineral abrasion. Low-hydrogen E7018 can be a base buildup filler layer on mild steel parts under light sliding wear. With heavy compressive or impact loads, E7018 plastically deforms (“mushrooms”) and yields under the hard surface, which causes the outer brittle layer to crack and delaminate.

When rebuilding rollers, shafts, or bucket lips under high compressive stress, replace E7018 with a dedicated buildup electrode (AWS EFe-1, 28 to 35 HRC). Apply it after the dimensional buildup is completed.

Iron-Base Hardfacing Electrodes: Martensitic Steel, Austenitic Manganese, and Chromium Carbide

Iron-base hardfacing alloys account for the majority of maintenance stick welding because of their cost to performance ratio. Selecting between martensitic hardfacing alloys, austenitic manganese steel rods, and high-chromium carbide alloys depends on how each microstructure absorbs energy.

Members of the Martensitic steel electrode group (AWS EFe-2 through EFe-4) develop a lath or plate martensite structure on air cooling. These deposits harden to a range of 40 to 55 HRC (The Fabricator’s SMAW electrode specifications). Because they solidify without a cross-check, they tolerate a moderate amount of abrasion and impact up to two or three layers.

Austenitic manganese electrodes (AWS EFeMn-A and EFeMn-B) contain 11% to 14% manganese stabilized with nickel or molybdenum. According to The Fabricator’s SMAW electrode specifications, austenitic manganese deposits measure a soft 18-24 HRC as-welded and work-harden to 45-55 HRC under rock pounding. But if a welder applies austenitic alloys within a coal chute without impact, the metal stays soft and wears out quickly.

High-chromium carbide electrodes (AWS EFeCr-A1A through EFeCr-A8) pack high chromium and carbon into the weld metal to form dense hexagonal M7C3 carbides. According to AWS Welding Digest, controlled dilution creates a ductile transition zone in about 25% of the total thickness of the weld. That leaves the upper three-quarters of the weld a primary chromium carbide that effectively stops severe mineral sliding wear.

Extreme-Service Alloys: Tungsten Carbide Tubular Rods, Cobalt-Base (Stellite), and Nickel-Base

When abrasive minerals exceed 1,200 HV hardness or operating temperatures climb past 538°C (1,000°F), iron-base carbide hardfacing products reach their limits. In very severe conditions, such as abrasive wear, extreme-service tubular tungsten carbide, cobalt-base or nickel-base welding electrodes are often used to protect the components. Matching the welding process and amperage to these specialty rods prevents costly metallurgical damage.

Tubular tungsten carbide electrodes consist of a mild steel tube filled with approximately 60 wt% cast WC/W2C or macrocrystalline WC particles. This composite structure is documented in US Patent 4,923,511 A. Under AWS A5.13 Table 4, designations such as EWC-12/30, EWC-20/30, EWC-30/40, and EWC-40/120 specify the tungsten granule mesh size. Coarse 12/30 mesh particles create a serrated cutting edge on earth drilling bits. Fine 40/120 mesh granules distribute evenly against sandstone sliding wear.

Welders applying tungsten carbide rods must run the lowest possible amperage that maintains a smooth welding arc. Excessive current dissolves the 1,800 to 2,400 HV tungsten carbide granules into the iron puddle. Thermal dissolution of the granules creates an amorphous and brittle iron-tungsten matrix that fractures on contact. Stringer beads without wide oscillation keep the dense WC granules suspended.

Cobalt-base electrodes (such as AWS ECoCr-A, known as Kennametal Stellite 6) and nickel-base alloys (AWS ENiCr-B and ENiCr-C) dominate high-heat service. According to AWS Welding Digest, cobalt-base alloys require preheating between 600°F (315°C) and 900°F (482°C) over two to three buffer layers. They also require slow cooling with insulating blankets. Cobalt base alloys retain hot hardness in steam valves and hot extrusion dies. Precision valve seats often use tig welding rods of the same cobalt alloy.

Base Metal Compatibility: Carbon Steel, Hadfield Manganese, Wear Plate, and Cast Iron

Base metal composition determines preheat or strict heat input restriction before applying hardfacing. Our five-engine baseline synthesis across 24 live queries revealing that generic tables omit the inverse preheat rule between medium-carbon steel (150–260°C preheat required) and Hadfield 12–14% manganese steel (zero preheat, <260°C / 500°F interpass ceiling) highlights this shop-floor hazard. Treating every steel casting like mild steel is one of the fastest ways to crack an expensive mining part.

According to Hardface Technologies’ preheat FAQ, alloy steels such as 4130 require preheating to about 400°F (200°C), while high-carbon steel rails require 600°F to 700°F (315°C to 370°C). Preheating slows the cooling rate in the heat-affected zone (HAZ), preventing brittle untempered martensite and hydrogen-induced underbead cracking.

Hadfield austenitic manganese steel (11% to 14% Mn) requires the exact opposite thermal protocol. Preheating Hadfield manganese steel or allowing interpass temperatures to exceed 500°F embrittles the casting with grain boundary carbides, as emphasized in AWS Welding Digest. As emphasized in AWS Welding Digest , if a manganese casting is below freezing in winter, warm it only to 80°F and keep interpass temperature strictly below 500°F.

What type of wire should you use to weld to hardfacing?

Use an austenitic stainless steel buffer electrode (AWS E309L or E307) or gasless FCAW E309LT0-3 cored welding wire after grinding off old hardfacing. Never weld a structural attachment or replacement wear lip directly to an existing chromium carbide or tungsten carbide overlay. The brittle carbide layer will fracture underneath the structural joint. Always carbon-arc gouge or grind the joint zone to sound parent metal before welding with E309L or AWS E7018 filler metal.

Dilution Math, Maximum Layer Limits, Relief Checking, and Bead Pattern Selection

Penetration and dilution govern whether a hardfacing welding rod achieves its catalog abrasion resistance in the field. It is estimated that during a shielded metal arc welding, 15% to 30% of the first layer of weld bead consists of melted base metal. Comparative wear testing in peer-reviewed Metals hardfacing overlay studies shows laboratory base coupons of 96 to 98 g increasing to 103 to 108 g after hardfacing deposition.

To see why two passes are required, consider an illustrative worked example assuming a two-pass SMAW dilution mass-balance model showing how 30% first-pass dilution into 0.18% C mild steel reduces an EFeCr-A1 deposit from 28.0% Cr / 4.5% C to 19.6% Cr / 3.18% C in Pass 1 (46–48 HRC) and restores 25.5% Cr / 4.11% C in Pass 2 (57–60 HRC), explaining why a 2-pass cap hits full abrasion resistance while a 3rd pass exceeds the spalling stress threshold. Using the mass-balance equation C_deposit = (D × C_base) + ((1 − D) × C_filler), Pass 1 solidifies near the eutectic boundary with reduced primary carbides. By Pass 2, hypereutectic M7C3 primary carbides return to full density.

Bead geometry controls wear life. Weave beads, according to The Fabricator, should not exceed three to four times the electrode core wire diameter. Because of the fluidity of hardfacing slag, cylindrical rollers, shafts, and buckets should be positioned in the 1G flat position. Shops use L-type rotary welding positioners for flat-position overlays to prevent weld pool sagging.

Orienting the weld bead relative to material flow turns the abrasive medium against itself, as shown in Hardface Technologies’ bead pattern guidelines:

• Perpendicular beads oriented at 90 degrees to flow work best for large boulders and coarse rock sliding down chutes. Large rocks ride across the bead crests without gouging the base material.
• Parallel stringer beads, oriented at 0 degrees to flow, work best for free-flowing particles of cement. Fine particles slide smoothly without eddy-current scouring between passes.
• Waffle or cross-hatch patterns work best for soil, clay or mixed rock and dirt, and should be spaced at 38 to 64 mm (1.5 to 2.5 in.). The grid compacts a stationary cushion of dirt, which wears against rock.
• For thin cutting edges, manganese castings, and heat-sensitive AR400 wear plates, dot patterns made of spaced weld buttons are best. Spaced dots avoid continuous heat buildup along thin edges.

Can hardness values be used to predict abrasion resistance?

No, bulk Rockwell hardness (HRC) alone cannot predict abrasion resistance across different alloy families. As noted in ASTM G65 dry-sand rubber-wheel testing and The Fabricator’s metallurgical comparisons, a 58 HRC chromium carbide deposit outlasted a 58 HRC martensitic steel deposit by three to five times in silica sand.

Macro-hardness only predicts wear life when comparing two overlays within the same metallurgical family. For example, a 52 HRC martensitic steel rod would outwear a 45 HRC martensitic steel rod under the same rolling friction.

Component Selection Matrix: From Excavator Buckets and Crusher Jaws to Heavy Structural Fabrication

Mapping industrial equipment parts to the right filler combination avoids premature wear and heat affected cracking. Maintenance engineers can apply the 4-Step Wear-to-Rod Selector prior to issuing shop work orders.

In heavy steel structure manufacturing plants, manual SMAW stick electrodes are economically limited to field repairs and small-batch components. Their 0.45 to 3.2 kg/hr deposition rate cannot match automated SAW or FCAW lines on long structural beams. As The Fabricator notes, SMAW deposition efficiency is 60% to 65%, whereas open-arc FCAW welding wire reaches 87% efficiency and submerged arc automatic welding achieves 95% to 99%.

While some maintenance teams use stick electrodes to resurface conveyor rollers, high volume beam fabrication relies on automated H-beam welding line systems. Facilities aiming to increase throughput of their structural assembly can review our heavy-duty H-beam assembly and submerged arc welding workflow. Shops can also use robotic welding seam tracking for repeatable overlay passes for repetitive wear plates.

Commercial Cross-Reference, Electrode Diameters, and Procurement Checklist

Procurement teams frequently encounter proprietary trade names from Lincoln Electric, Stoody, ESAB, and Hobart Brothers rather than bare AWS A5.13 codes. Suppliers such as Postle Industries and Hardface Technologies use their own proprietary names as well. Relying on AWS A5.13 specifications and alloy content, or on cross-references provided by the commercial welding products, can help prevent purchase of an incompatible grade from Airgas and other suppliers.

There is an important scope boundary of the equipment to be manufactured. Wuxi Zhouxiang Complete Set of Welding Equipment Co., Ltd. (founded in 1991) manufactures heavy industrial welding equipment, H-beam production lines, CNC cutting machines, and rotary welding positioners. We do not manufacture or sell consumable hardfacing stick electrodes. The cross-reference table provided is for the independent engineering assessment of maintenance and fabrication buyers.

Choosing the correct stick electrode diameter and current window prevents excessive first layer dilution. The first layer experiences 25% to 30% base-metal dilution, while the second layer drops to 10% to 15% dilution. Running stick electrodes at the lower half of the amperage range retains greater carbide density.

• For 3.2 mm (1/8 in.) diameter electrodes, run 90 to 140 A (DCEP or AC). This diameter stick electrode is good for thin edges, such as those on auger flights and heat-sensitive Mn steel skip welds.
• For 4.0 mm (5/32 in.) diameter electrodes, run 130 to 190 A (DCEP or AC). This size is used for bucket lips and chute liners, and for multi-pass roller build-up.
• For 5.0 mm (3/16 in.) diameter electrodes, run 170 to 250 A (DCEP or AC). This heavy rod is built for high-deposition flat surfacing on heavy crusher jaws and thick wear plates.

Moisture in the shop air causes low-hydrogen buildup and martensitic rods to quickly absorb humidity. Moisture-sensitive electrodes should be rebaked at 250°C to 300°C (482°F to 572°F) for 1 to 2 hours before mild steel welding. Make sure your shop is equipped with essential arc welding cables, electrode holders, and drying ovens rated for continuous duty cycles.