AWS A5.7 / A5.7M: The Complete Classification Guide for Copper and Copper-Alloy Bare Welding Rods and Electrodes
What Is AWS A5.7 / A5.7M and What Does It Cover?
AWS A5.7/A5.7M is the American Welding Society specification titled "Specification for Copper and Copper-Alloy Bare Welding Rods and Electrodes."
It prescribes the requirements for classification of copper and copper-alloy bare electrodes and rods used with gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and plasma arc welding (PAW).
Classification is based on the chemical composition of the filler metal, with additional requirements for manufacture, sizes, lengths, and packaging.
The specification is also adopted as ASME SFA-5.7 and appears in Section II, Part C of the ASME Boiler and Pressure Vessel Code.
The current edition is AWS A5.7/A5.7M:2026, which revises AWS A5.7/A5.7M:2007 (R2017).[reference:0]
The specification covers compositions in which the copper content exceeds that of any other element.
Always verify specific classification requirements with the latest edition of A5.7/A5.7M.
What is the scope of AWS A5.7/A5.7M?
AWS A5.7/A5.7M covers bare copper and copper-alloy welding rods and electrodes for gas shielded arc welding processes.
The specification applies to filler metals used for welding copper to copper, copper to steel, copper to cast iron, and for surfacing and buildup applications.
The bare product form distinguishes A5.7 from AWS A5.6, which covers covered (flux coated) electrodes for the shielded metal arc welding process.[reference:1]
The specification makes use of both U.S. Customary Units and the International System of Units, with each system to be used independently of the other.[reference:2]
How does AWS A5.7 differ from AWS A5.6?
AWS A5.7 and AWS A5.6 are complementary standards covering different product forms of copper and copper-alloy filler metals.
AWS A5.7 covers bare solid wires and rods for gas metal arc, gas tungsten arc, and plasma arc welding, where an externally supplied shielding gas protects the weld pool.
AWS A5.6 covers covered (flux coated) electrodes for shielded metal arc welding, where the flux coating provides shielding and slag formation.
Many alloy compositions appear in both specifications but with different product forms and welding process applicability, such as ECuNi in A5.6 and ERCuNi in A5.7.[reference:3]
AWS A5.7 copper and copper-alloy bare welding rods and electrodes are classified using an alphanumeric system that begins with the prefix "ER" for electrode or rod.
The prefix is followed by "Cu" for copper, and then a suffix letter or letter combination that identifies the principal alloying element or elements.
For example, "ERCuSi-A" indicates a copper-silicon alloy (silicon bronze), "ERCuSn-A" indicates a copper-tin alloy (phosphor bronze), and "ERCuNi" indicates a copper-nickel alloy.
Additional letters or numbers further distinguish specific composition variants, such as ERCuSn-A and ERCuSn-C, or ERCuAl-A1, ERCuAl-A2, and ERCuAl-A3 within the aluminum bronze family.
The classification system is designed to allow users to quickly identify the general alloy family and select a filler metal appropriate for the base metal and service conditions.
What does the "ER" prefix mean?
The "ER" prefix stands for electrode or rod, indicating that the filler metal can be used as either a spooled wire electrode for GMAW or a straight rod for GTAW, depending on the product form and diameter.
This dual-purpose designation is common for bare solid wires that can serve in semi-automatic and automatic welding processes as well as manual TIG welding.
The "ER" prefix distinguishes A5.7 classifications from the covered electrode classifications in AWS A5.6, which use the "E" prefix alone.
What do the alloy suffixes mean?
The alloy suffixes in AWS A5.7 classifications identify the principal alloying elements beyond copper.
ERCu is unalloyed copper with a minimum copper content of 98.0%.
ERCuSi-A contains silicon as the principal alloying addition, producing a silicon bronze deposit.
ERCuSn-A and ERCuSn-C contain tin as the principal alloying addition, producing phosphor bronze deposits with different tin levels.
ERCuNi contains nickel as the principal alloying addition, producing a copper-nickel deposit.
ERCuAl-A1, ERCuAl-A2, and ERCuAl-A3 contain aluminum as the principal alloying addition, producing aluminum bronze deposits with different aluminum levels.
ERCuNiAl contains nickel and aluminum, producing a nickel-aluminum bronze deposit.
ERCuMnNiAl contains manganese, nickel, and aluminum, producing a manganese-nickel-aluminum bronze deposit with very high strength.
What Is the Complete List of AWS A5.7 / A5.7M Types?
The AWS A5.7/A5.7M classification list comprises bare copper and copper-alloy welding wires and rods organized by alloy family.
The classifications identified in available reference materials include ERCu, ERCuSi-A, ERCuSn-A, ERCuSn-C, ERCuNi, ERCuAl-A1, ERCuAl-A2, ERCuAl-A3, ERCuNiAl, and ERCuMnNiAl.[reference:4][reference:5]
The ERCuAl-A1 and ERCuAl-A3 classifications are represented in AWS A5.7 and have corresponding covered electrode designations in AWS A5.6 (ECuAl-A2 and ECuAl-B respectively).
Additional classifications may be present in the 2026 edition of the standard.
For the complete and authoritative list of classifications in the current edition, always verify with the latest edition of A5.7/A5.7M, as classifications may be added or revised with each edition.
Which classifications are included in AWS A5.7?
The classifications included in AWS A5.7, as referenced in available technical literature and product datasheets, are ERCu, ERCuSi-A, ERCuSn-A, ERCuSn-C, ERCuNi, ERCuAl-A1, ERCuAl-A2, ERCuAl-A3, ERCuNiAl, and ERCuMnNiAl.
ERCu is unalloyed copper with a minimum of 98.0% copper, used for welding pure copper and for electrical conductivity applications.
ERCuSi-A is a silicon bronze with approximately 2.8% to 4.0% silicon, used for welding copper-silicon alloys and for MIG brazing of zinc-coated steel sheets.[reference:6]
ERCuSn-A is a phosphor bronze with 4.0% to 6.0% tin, used for welding copper-tin alloys and for bearing surfaces.[reference:7]
ERCuSn-C is a phosphor bronze with 7.0% to 9.0% tin, used for higher-tin bronze welding and wear-resistant overlays.[reference:8]
ERCuNi is a copper-nickel alloy with 29.0% to 33.0% nickel, used for welding copper-nickel alloys in seawater applications.[reference:9]
ERCuAl-A1 is an aluminum bronze with 6.0% to 8.5% aluminum, used for overlays on wear-resistant surfaces.
ERCuAl-A2 is an aluminum bronze with 8.0% to 11.0% aluminum and iron additions, used for welding aluminum bronze and for corrosion-resistant overlays.[reference:10]
ERCuAl-A3 is a higher-aluminum aluminum bronze for higher-strength applications.
ERCuNiAl is a nickel-aluminum bronze with 8.5% to 9.5% aluminum and 4.0% to 6.0% nickel, used for welding nickel-aluminum bronze castings and seawater components.[reference:11]
ERCuMnNiAl is a manganese-nickel-aluminum bronze with 11.0% to 14.0% manganese, 1.5% to 3.0% nickel, and 6.0% to 8.5% aluminum, used for the most demanding copper-alloy welding and surfacing applications.[reference:12]
The AWS A5.7 specification may include general (G) classifications for filler metals that do not conform to the specific chemistry of numbered classifications, with composition agreed between supplier and purchaser.
The "G" suffix would indicate that the filler metal meets the mechanical property and usability requirements but the exact alloy content is controlled by the manufacturer's specification.
For the availability and exact composition of any G-classified filler metals in the current edition, verify with the latest edition of A5.7/A5.7M and the manufacturer's datasheet.
What Is ERCu and What Are Its Key Properties?
ERCu is an unalloyed copper bare welding wire and rod designed for welding pure copper, deoxidized copper, and oxygen-free copper base metals.
Its typical chemistry includes copper at a minimum of 98.0%, with silicon at a maximum of 0.50%, manganese at a maximum of 0.50%, phosphorus at a maximum of 0.15%, and other elements at a maximum of 0.50% total.[reference:13]
The filler metal provides a weld deposit with high electrical and thermal conductivity, excellent ductility, and good corrosion resistance in non-oxidizing environments.
Typical mechanical properties include tensile strength of approximately 220 MPa (32 ksi) and elongation of 30% to 40%.
ERCu is welded with DC electrode positive (DCEP) or AC and is suitable for all positions.
Typical applications include welding copper bus bars, electrical conductors, chemical processing equipment, and repairing electrical conductivity parts such as electrode holders and flanges.
Preheating thicker sections to 400°C to 600°C is recommended to ensure proper fusion.
Common trade names include Nihonweld N-Cu, Selectrode 1281, and Hyundai SM-Cu.
What are the typical applications for ERCu?
ERCu is used for welding pure copper components such as bus bars, electrical conductors, and chemical processing equipment.
It is also used for repairing electrical conductivity parts such as electrode holders and flanges, and for overlaying steel and joining heavier sections of copper to steel.
The high electrical conductivity of the deposit makes ERCu particularly suitable for applications where current-carrying capability must be maintained across the weld.
What shielding gas is used with ERCu?
ERCu is typically welded with 100% argon shielding gas for both GMAW and GTAW processes.
Argon provides good arc stability and protects the weld pool from oxidation.
For thicker sections, helium additions may be used to increase heat input and improve fusion.
Always verify the recommended shielding gas with the manufacturer's datasheet for the specific product.
What Is ERCuSi-A and What Are Its Key Properties?
ERCuSi-A is a silicon bronze bare welding wire and rod designed for welding copper-silicon alloys and for surfacing applications requiring corrosion resistance.
Its typical chemistry includes silicon at 2.8% to 4.0%, manganese at approximately 1.5%, iron at a maximum of 0.50%, and copper as the balance.[reference:14]
The filler metal produces a weld deposit with good corrosion resistance and moderate strength, suitable for welding copper-silicon alloys such as Everdur.
Typical mechanical properties include tensile strength of approximately 330 to 370 MPa and elongation of approximately 40%.[reference:15]
ERCuSi-A is also widely used for MIG brazing of zinc-coated steel sheets in the automotive industry, where its low melting temperature and good wetting characteristics provide advantages over conventional welding.
Typical applications include welding silicon bronze castings and wrought components, surfacing for corrosion resistance in marine and chemical environments, and MIG brazing of coated steels.
Common trade names include Hyundai SM-CuSi, ESAB OK Autrod 19.30, and Certilas SiBz.
What are the typical applications for ERCuSi-A?
ERCuSi-A is used for welding silicon bronze castings and wrought components, such as Everdur pumps and valves, and for surfacing applications requiring corrosion resistance in marine and chemical environments.
It is also widely used for MIG brazing of zinc-coated steel sheets in automotive body assembly, where the lower heat input minimizes zinc coating damage compared with conventional steel welding.
Typical applications include pump components, valve bodies, marine hardware, and automotive sheet metal joining.
What shielding gas is used with ERCuSi-A?
ERCuSi-A is typically welded with 100% argon shielding gas for GMAW and GTAW processes.[reference:16]
For MIG brazing applications, argon or argon-helium mixtures may be used depending on the thickness of the material and the desired heat input.
The choice of shielding gas affects arc stability, bead appearance, and the degree of zinc coating damage in brazing applications.
What Is ERCuSn-A and What Are Its Key Properties?
ERCuSn-A is a phosphor bronze bare welding wire and rod with a moderate tin content, designed for welding copper-tin alloys and for bearing and wear-resistant applications.
Its typical chemistry includes tin at 4.0% to 6.0%, phosphorus at 0.10% to 0.35%, and copper as the balance.[reference:17]
The filler metal produces a weld deposit with good wear resistance, bearing properties, and corrosion resistance in marine and industrial environments.
Typical mechanical properties include tensile strength of approximately 320 to 360 MPa and elongation of approximately 20% to 25%.[reference:18]
ERCuSn-A is used for welding and surfacing copper-tin alloys, bronzes, and brasses, and for bearing surfaces and pump components.
Typical applications include pump impellers, valve seats, bearing bushes, and worm gears.
Common trade names include Hyundai SM-CuSn A, Nihonweld N-CuSn-A, and Tensileweld ERCuSn-A.
What are the typical applications for ERCuSn-A?
ERCuSn-A is used for welding and surfacing copper-tin alloys, bronzes, and brasses, and for bearing surfaces and pump components.
It is also used for joining copper to Cu-Sn alloys and for the butt joining of brass to steel, particularly where preheating is applied for large components.
Typical applications include pump impellers, valve seats, bearing bushes, and worm gears requiring resistance to wear and corrosion.
What is the difference between ERCuSn-A and ERCuSn-C?
ERCuSn-A and ERCuSn-C differ primarily in their tin content and resulting hardness and wear resistance.
ERCuSn-A contains 4.0% to 6.0% tin, producing a deposit with moderate hardness and good machinability.
ERCuSn-C contains 7.0% to 9.0% tin, producing a harder and more wear-resistant deposit.
ERCuSn-C is preferred for applications requiring higher wear resistance, such as worm gears and heavily loaded bearing surfaces, while ERCuSn-A is more suitable for general-purpose bearing and corrosion-resistant applications.
What Is ERCuSn-C and What Are Its Key Properties?
ERCuSn-C is a phosphor bronze bare welding wire and rod with a higher tin content than ERCuSn-A, designed for welding higher-tin bronzes and for wear-resistant overlays.
Its typical chemistry includes tin at 7.0% to 9.0%, phosphorus at 0.10% to 0.35%, and copper as the balance.[reference:19]
The filler metal produces a harder deposit than ERCuSn-A, with better resistance to wear and galling.
Typical mechanical properties include tensile strength of approximately 350 to 400 MPa and elongation of approximately 15% to 20%.
ERCuSn-C is recommended for welding copper with Cu-Sn alloys and for the butt joining of brass with steel.
Typical applications include welding and surfacing of phosphor bronze and leaded bronze components, bearing surfaces, worm gears, and pump parts requiring higher wear resistance.
Common trade names include Magmaweld ERCuSn7, Hyundai SM-CuSn C, and CEWELD E ZIBRO.
What are the typical applications for ERCuSn-C?
ERCuSn-C is used for welding and surfacing of phosphor bronze and leaded bronze components, bearing surfaces, worm gears, and pump parts requiring higher wear resistance.
It is also used for the butt joining of brass with steel, where the higher tin content provides improved strength and wear resistance compared with ERCuSn-A.
Typical applications include worm gears, heavily loaded bearing bushes, pump sleeves, and wear rings.
What shielding gas is used with ERCuSn-A and ERCuSn-C?
ERCuSn-A and ERCuSn-C are typically welded with 100% argon shielding gas for GMAW and GTAW processes.[reference:20]
For thicker sections and multi-layer hardfacing on steel, pulsed argon arc welding is recommended to control heat input and minimize dilution.
Preheating is suggested for large components to ensure proper fusion and to reduce cracking risk.
What Is ERCuNi and What Are Its Key Properties?
ERCuNi is a copper-nickel bare welding wire and rod designed for welding copper-nickel alloys and for applications requiring resistance to seawater corrosion and cavitation.
Its typical chemistry includes nickel at 29.0% to 33.0%, manganese at approximately 0.75%, iron at 0.40% to 0.75%, titanium at approximately 0.30%, and copper as the balance.[reference:21]
The filler metal produces a 70% Cu-30% Ni deposit with excellent resistance to seawater corrosion, erosion, and cavitation.
Typical mechanical properties include tensile strength of approximately 345 MPa and elongation of approximately 25% to 30%.[reference:22]
ERCuNi is welded with 100% argon shielding gas and is suitable for all positions.
Typical applications include welding 70/30 and 90/10 copper-nickel alloys, cladding copper-nickel clad steels, and fabricating seawater piping, heat exchangers, and marine components.
Common trade names include Lincoln Techalloy 413, Hyundai SM-CuNi, and UTP A 387.
What are the typical applications for ERCuNi?
ERCuNi is used for welding 70/30 and 90/10 copper-nickel alloys in seawater piping, heat exchangers, condensers, and marine components.
It is also used for cladding copper-nickel clad steels and for joining copper-nickel to steel and other alloys.
Typical applications include seawater desalination plants, shipbuilding, offshore platforms, and chemical processing equipment where resistance to seawater corrosion and cavitation is essential.[reference:23]
What is the difference between ERCuNi and ECuNi?
ERCuNi and ECuNi are the bare wire/rod and covered electrode versions, respectively, of the same 70/30 copper-nickel alloy system.
ERCuNi is used with gas shielded processes such as GMAW and GTAW, while ECuNi is used with the shielded metal arc welding process.
The weld deposit chemistry and corrosion resistance are essentially the same for both product forms, but the welding process, equipment, and operating characteristics differ.
ERCuNi is generally preferred for automatic and semi-automatic welding, while ECuNi is used for manual stick welding in field applications.
What Is ERCuAl-A1 and What Are Its Key Properties?
ERCuAl-A1 is an aluminum bronze bare welding wire and rod designed for overlays on wear-resistant surfaces and for applications requiring corrosion resistance in seawater and acidic environments.
Its typical chemistry includes aluminum at 6.0% to 8.5%, manganese at a maximum of 0.50%, silicon at a maximum of 0.10%, and copper as the balance.[reference:24]
The filler metal is iron-free, producing a deposit with good corrosion resistance and moderate hardness of approximately 125 HB.[reference:25]
Typical mechanical properties include tensile strength of approximately 68,000 psi (470 MPa), yield strength of approximately 28,000 psi (190 MPa), and elongation of approximately 47%.[reference:26]
ERCuAl-A1 is typically welded with 100% argon or a 75% argon/25% helium mixture and is suitable for all positions.
Typical applications include overlays on shafts, propellers, housings, couplings, bushings, valve seats, and pumps.
ERCuAl-A1 is not recommended for joining applications; it is designed primarily for surfacing and overlay work.
Common trade names include Harris Aluminum Bronze A1, Selectrode 7084, and SIFALBRONZE No 32.
What are the typical applications for ERCuAl-A1?
ERCuAl-A1 is designed for surfacing and overlay applications, not for joining.
Typical applications include overlays on shafts, propellers, housings, couplings, bushings, valve seats, and pumps that require a wear-resistant bronze surface.[reference:27]
It is frequently used on marine hardware exposed to salt water and certain acid conditions, where its iron-free composition provides excellent corrosion resistance.[reference:28]
The deposit work-hardens under compressive loads, making it suitable for bearing surfaces and wear applications.
What shielding gas is used with ERCuAl-A1?
ERCuAl-A1 is typically welded with 100% argon or a 75% argon/25% helium mixture for GMAW applications.
For GTAW, 100% argon is commonly used with DC electrode negative (DCEN) polarity or high-frequency AC.
The choice of shielding gas affects arc stability, heat input, and bead appearance, with helium additions increasing heat input for thicker sections.
What Is ERCuAl-A2 and What Are Its Key Properties?
ERCuAl-A2 is an iron-bearing aluminum bronze bare welding wire and rod designed for joining aluminum bronze, silicon bronze, and manganese bronze, as well as for overlays requiring corrosion and wear resistance.
Its typical chemistry includes aluminum at 8.0% to 11.0%, iron at approximately 1.5%, silicon at a maximum of 0.10%, and copper as the balance.[reference:29]
The iron addition provides higher strength and hardness than ERCuAl-A1, with a typical as-welded Brinell hardness of 130 to 150 HB.[reference:30]
Typical mechanical properties include tensile strength of approximately 60,000 to 70,000 psi (410–480 MPa), yield strength of approximately 35,000 psi (240 MPa), and elongation of approximately 28%.[reference:31]
ERCuAl-A2 is welded with 100% argon or a 75% argon/25% helium mixture for GMAW, and with DCEN or high-frequency AC for GTAW.
Typical applications include maintenance and repair of ship propellers, hydraulic pistons, impellers, valve seats, bushings, and mixer arms.
ERCuAl-A2 is often described as the "all-purpose workhorse alloy" of copper-based filler metals.
Common trade names include Inweld Aluminum Bronze A-2, Selectrode 7084, and CEWELD CuAl9Fe.
What are the typical applications for ERCuAl-A2?
ERCuAl-A2 is used for joining dissimilar metal combinations such as aluminum bronze to steel or copper to steel, and for overlays exposed to frictional wear or corrosive media such as salt water, alkalis, and some acids.[reference:32]
Typical applications include maintenance and repair of ship propellers, hydraulic pistons, impellers, tractor gear housings, brake drums, paper mill rolls, pickling hooks, valve seats, bushings, and mixer arms.[reference:33]
The deposit work-hardens under compressive loads, making it suitable for bearing and wear applications.
What is the difference between ERCuAl-A1, ERCuAl-A2, and ERCuAl-A3?
ERCuAl-A1, ERCuAl-A2, and ERCuAl-A3 differ primarily in their aluminum content and whether they contain iron.
ERCuAl-A1 contains 6.0% to 8.5% aluminum and is iron-free, producing a softer, more ductile deposit primarily used for surfacing.
ERCuAl-A2 contains 8.0% to 11.0% aluminum with iron additions of approximately 1.5%, producing a harder, stronger deposit suitable for both joining and surfacing.[reference:34]
ERCuAl-A3 contains higher aluminum content (typically 10% to 11%) with iron and other additions, producing the highest hardness and wear resistance among the aluminum bronze filler metals.
The selection among these three depends on the required balance of hardness, strength, ductility, and corrosion resistance.
What Is ERCuNiAl and What Are Its Key Properties?
ERCuNiAl is a nickel-aluminum bronze bare welding wire and rod designed for welding nickel-aluminum bronze castings and for applications requiring high resistance to corrosion, erosion, and cavitation.
Its typical chemistry includes aluminum at 8.5% to 9.5%, nickel at 4.0% to 6.0%, iron at 3.0% to 6.0%, manganese at 0.50% to 3.5%, and copper as the balance.[reference:35]
The filler metal produces a deposit with excellent mechanical properties, good toughness, and crack resistance.
Typical mechanical properties include tensile strength of approximately 600 to 650 MPa, yield strength of approximately 400 MPa, elongation of approximately 15%, and Brinell hardness of 160 to 200 HB.
ERCuNiAl is particularly suitable for welding cast ship propellers conforming to MIL-B-21230 Alloy 2, marine components, and for joining dissimilar metals.
Common trade names include AMPCO-TRODE 46, UTP A 3444, and Nihonweld N-CuNiAl.
What are the typical applications for ERCuNiAl?
ERCuNiAl is used for welding nickel-aluminum bronze castings, particularly cast ship propellers conforming to MIL-B-21230 Alloy 2, marine components, and for joining dissimilar metals.
Typical applications include propellers, pumps, valves, and other components exposed to seawater and requiring resistance to corrosion, erosion, and cavitation.
The filler metal is also suitable for overlays on steel and cast iron where a corrosion-resistant, wear-resistant surface is required.
What shielding gas is used with ERCuNiAl?
ERCuNiAl is typically welded with 100% argon shielding gas for GMAW and GTAW processes.
For MIG welding, pulsed arc transfer is often recommended to control heat input and minimize dilution.
Preheating of large weldments to approximately 150°C may be required, and the interpass temperature should not exceed 150°C to avoid metallurgical degradation.
The heat input should be kept low to maintain the desired microstructure and properties.
What Is ERCuMnNiAl and What Are Its Key Properties?
ERCuMnNiAl is a manganese-nickel-aluminum bronze bare welding wire and rod designed for the most demanding copper-alloy welding and surfacing applications.
Its typical chemistry includes manganese at 11.0% to 14.0%, aluminum at 6.0% to 8.5%, nickel at 1.5% to 3.0%, iron at 2.0% to 4.0%, and copper as the balance.[reference:36]
The filler metal provides the highest strength and hardness among the AWS A5.7 classifications, along with excellent resistance to seawater corrosion, erosion, and cavitation.
Typical mechanical properties include tensile strength of approximately 600 to 650 MPa, yield strength of approximately 400 MPa, elongation of approximately 15%, and Brinell hardness of approximately 220 HB.[reference:37]
ERCuMnNiAl is suitable for joining and surfacing complex aluminum bronzes, particularly those with high manganese content, as well as for cladding on steels and cast irons.
Typical applications include ship propellers, pumps, valves, and components subjected to chemical attack combined with erosion.
Common trade names include UTP A 34 N, AMPCO-TRODE 40, and Certilas CuMn13Al7.
What are the typical applications for ERCuMnNiAl?
ERCuMnNiAl is used for joining and surfacing complex aluminum bronzes, particularly those with high manganese content, as well as for cladding on steels and cast irons and for dissimilar joints.[reference:38]
Typical applications include ship propellers, pumps, and valves in the shipbuilding industry, and chemical industry applications such as valves, slides, and pumps subjected to chemical attack combined with erosion.
The filler metal is also suited for surfacing on waves, gliding surfaces, bearings, and matrices where a low friction coefficient and high wear resistance are required.[reference:39]
What shielding gas and welding parameters are used with ERCuMnNiAl?
ERCuMnNiAl is typically welded with 100% argon shielding gas for GMAW and GTAW processes.
The MIG pulsing method is recommended for optimal weldability and deposit quality.
Preheating of large weldments to approximately 150°C is recommended, and the interpass temperature should not exceed 150°C.
The heat input should be kept low to maintain the desired mechanical properties and crack resistance.
The weld deposit has excellent chip removal machining characteristics and is non-magnetic.[reference:40]
AWS A5.7 specifies chemical composition requirements for each classification of bare copper and copper-alloy welding rods and electrodes.
The composition requirements control copper, tin, manganese, iron, silicon, nickel, phosphorus, aluminum, titanium, and other elements within specified maximum or range limits.
These requirements ensure that the weld deposit achieves the intended mechanical properties, corrosion resistance, and microstructural characteristics.
The exact composition limits for each classification are provided in the standard and should be verified with the latest edition of A5.7/A5.7M.
What are the typical composition ranges for the major alloying elements?
The major alloying element ranges vary by classification.
ERCu requires a minimum copper content of 98.0%.
ERCuSi-A contains 2.8% to 4.0% silicon and approximately 1.5% manganese.
ERCuSn-A contains 4.0% to 6.0% tin and 0.10% to 0.35% phosphorus.
ERCuSn-C contains 7.0% to 9.0% tin and 0.10% to 0.35% phosphorus.
ERCuNi contains 29.0% to 33.0% nickel, 0.40% to 0.75% iron, approximately 0.75% manganese, and approximately 0.30% titanium.
ERCuAl-A2 contains 8.0% to 11.0% aluminum and approximately 1.5% iron.
ERCuNiAl contains 8.5% to 9.5% aluminum, 4.0% to 6.0% nickel, and 3.0% to 6.0% iron.
ERCuMnNiAl contains 11.0% to 14.0% manganese, 6.0% to 8.5% aluminum, 1.5% to 3.0% nickel, and 2.0% to 4.0% iron.
These values should be verified with the manufacturer's datasheet and the latest edition of A5.7/A5.7M.
What are the phosphorus and lead limits?
Phosphorus content is controlled in the phosphor bronze classifications, with ERCuSn-A and ERCuSn-C containing 0.10% to 0.35% phosphorus as a deoxidizer and strengthening element.
In other classifications, phosphorus is limited to a maximum of approximately 0.02%.
Lead is limited to a maximum of approximately 0.02% in most classifications, as higher lead levels can impair weldability and mechanical properties.
These limits ensure consistent weld metal quality and performance across production lots.
The mechanical properties of AWS A5.7 filler metals are determined through tensile tests of the all-weld metal.
The tensile strength requirements range from approximately 220 MPa for ERCu to approximately 650 MPa for ERCuMnNiAl, reflecting the different alloy systems and their strengthening mechanisms.
Yield strength requirements are specified as typical or minimum values for most classifications.
Elongation requirements ensure adequate ductility for the intended applications.
The exact mechanical property requirements for each classification should be verified with the latest edition of A5.7/A5.7M.
What tensile strength and elongation are typical for each classification?
ERCu typically exhibits tensile strength of approximately 220 MPa and elongation of 30% to 40%.
ERCuSi-A typically exhibits tensile strength of approximately 330 to 370 MPa and elongation of approximately 40%.[reference:41]
ERCuSn-A typically exhibits tensile strength of approximately 320 to 360 MPa and elongation of approximately 20% to 25%.[reference:42]
ERCuSn-C typically exhibits tensile strength of approximately 350 to 400 MPa and elongation of approximately 15% to 20%.
ERCuNi typically exhibits tensile strength of approximately 345 MPa and elongation of approximately 25% to 30%.[reference:43]
ERCuAl-A1 typically exhibits tensile strength of approximately 470 MPa and elongation of approximately 47%.[reference:44]
ERCuAl-A2 typically exhibits tensile strength of approximately 410 to 480 MPa and elongation of approximately 28%.[reference:45]
ERCuNiAl typically exhibits tensile strength of approximately 600 to 650 MPa and elongation of approximately 15%.
ERCuMnNiAl typically exhibits tensile strength of approximately 600 to 650 MPa and elongation of approximately 15%.[reference:46]
These values are typical and may vary by product and welding parameters.
What hardness is typical for aluminum bronze and nickel-aluminum bronze deposits?
ERCuAl-A1 typically produces a deposit with Brinell hardness of approximately 125 HB.
ERCuAl-A2 typically produces a deposit with Brinell hardness of 130 to 150 HB.
ERCuNiAl typically produces a deposit with Brinell hardness of 160 to 200 HB.
ERCuMnNiAl typically produces a deposit with Brinell hardness of approximately 220 HB.
The aluminum bronze classifications work-harden under compressive loads, which can increase surface hardness in service.
These values should be verified with the manufacturer's datasheet and the latest edition of A5.7/A5.7M.
Selecting the right AWS A5.7 filler metal depends on the base metal composition, the required mechanical properties, the corrosion resistance requirements, and the welding process.
The first step is to identify the base metal alloy and select a matching or near-matching filler metal classification.
For pure copper, ERCu is appropriate; for silicon bronze, ERCuSi-A; for phosphor bronze, ERCuSn-A or ERCuSn-C; for copper-nickel, ERCuNi; for aluminum bronze, ERCuAl-A1, ERCuAl-A2, or ERCuAl-A3; and for nickel-aluminum bronze or manganese-nickel-aluminum bronze, ERCuNiAl or ERCuMnNiAl.
The second step is to consider the required strength and hardness: ERCu provides the lowest strength, while ERCuMnNiAl provides the highest.
The third step is to consider the corrosion environment: ERCuNi, ERCuNiAl, and ERCuMnNiAl offer the best seawater corrosion resistance.
The fourth step is to verify the welding process compatibility and the recommended shielding gas and welding parameters for the specific application.
Always verify the filler metal selection with the applicable code requirements and the manufacturer's recommendations.
The first step is to determine the base metal composition and select the matching filler metal family.
If the base metal is pure copper, ERCu is the appropriate choice.
If the base metal is copper-nickel, ERCuNi is appropriate.
If the base metal is aluminum bronze, ERCuAl-A1, ERCuAl-A2, or ERCuAl-A3 is appropriate, depending on the required strength and hardness.
If the base metal is nickel-aluminum bronze or manganese-nickel-aluminum bronze, ERCuNiAl or ERCuMnNiAl is appropriate.
The second step is to consider the service environment: for seawater applications, the nickel-bearing classifications (ERCuNi, ERCuNiAl, ERCuMnNiAl) are preferred.
The third step is to verify the availability of the filler metal in the required diameter and form (spooled wire or straight rod), and to confirm the recommended welding parameters for the specific application.
The ASME F-Number is a grouping of filler metals based on their welding characteristics and usability, used in welding procedure qualification under ASME Section IX.
Copper and copper-alloy filler metals are grouped under F-Number 31 through F-Number 37 in ASME Section IX, QW-432.
F-Number 31 covers ERCu; F-Number 32 covers ERCuSi-A; F-Number 33 covers ERCuSn-A; F-Number 34 covers ERCuNi; F-Number 36 covers ERCuAl-A1, ERCuAl-A2, and ERCuAl-A3; and F-Number 37 covers ERCuNiAl and ERCuMnNiAl.[reference:47]
The A-Number is a grouping based on the chemical composition of the deposited weld metal, used for procedure qualification of ferrous materials.
For copper and copper-alloy filler metals, the A-Number may not be directly applicable in the same way as for ferrous materials.
The exact F-Number and A-Number assignments should be verified with the latest edition of ASME Section IX.
AWS A5.7 is part of a broader family of AWS filler metal specifications for copper, nickel, aluminum, and other non-ferrous materials.
Understanding these related standards helps ensure that the correct specification is applied for each welding process and base metal.
The main related standards are A5.6, A5.8, A5.10, A5.14, A5.15, and A5.27.
Each covers different product forms, alloy systems, or welding processes.
What is AWS A5.6/A5.6M?
AWS A5.6/A5.6M covers copper and copper-alloy covered electrodes for shielded metal arc welding.
The specification includes classifications such as ECu, ECuSi, ECuSn-A, ECuSn-C, ECuNi, ECuAl-A2, ECuAl-B, ECuNiAl, and ECuMnNiAl, which correspond to many of the bare filler metal classifications in A5.7.
These covered electrodes are used for manual stick welding of copper and copper alloys, while A5.7 bare wires and rods are used for gas shielded processes.
Verify with the latest edition for current classifications.
What is AWS A5.8/A5.8M?
AWS A5.8/A5.8M covers filler metals for brazing and braze welding, including copper-phosphorus, copper-zinc, and silver-based brazing filler metals.
The specification includes classifications such as BCuP-2, BCuP-5, RBCuZn-A, and BAg-1 through BAg-28.
These filler metals are used for joining copper and copper-alloy components at temperatures below the melting point of the base metal.
Verify with the latest edition for current classifications.
What is AWS A5.15?
AWS A5.15 covers welding electrodes and rods for cast iron.
The specification includes classifications such as ENi-CI, ENiFe-CI, and ESt, which are used for welding cast iron components.
Some copper-alloy filler metals, particularly ERCuMnNiAl and ERCuNiAl, are used for welding cast iron as an alternative to nickel-based electrodes.
Verify with the latest edition for current classifications.
What is AWS A5.27?
AWS A5.27 covers copper and copper-alloy bare welding rods for oxyfuel gas welding.
The specification includes classifications such as RCu, RCuSi-A, RCuSn-A, and RBCuZn-A through RBCuZn-D.
These rods are used with the oxyfuel gas welding process, where the heat source is a gas flame and no external shielding gas is used.
Verify with the latest edition for current classifications.
What is ISO 24373 and how does it relate to AWS A5.7?
ISO 24373 is the international standard that specifies requirements for classification of solid wires and rods for fusion welding of copper and copper alloys.
The ISO 24373 classification system uses a "Cu" prefix followed by a four-digit number and chemical symbols, such as "Cu 6180 (CuAl10Fe)" for an aluminum bronze filler metal corresponding approximately to ERCuAl-A2.[reference:48]
Many products carry dual classifications under both ISO 24373 and AWS A5.7, allowing international acceptance.
The correspondence is product-specific and should be verified with the manufacturer's datasheet and the latest editions of both standards.
Where Can I Find the Official Complete List of AWS A5.7 / A5.7M Types?
The authoritative source for the complete list of AWS A5.7/A5.7M classifications is the latest edition of the specification itself, available from the American Welding Society at pubs.aws.org or through authorized standards distributors such as ANSI.[reference:49]
The specification includes detailed tables covering chemical composition requirements, mechanical property requirements, standard sizes, and packaging requirements for every classification.
Manufacturer technical datasheets and welding consumable catalogs also list AWS A5.7 classifications, but these should be cross-referenced against the official specification for accuracy.
Because classifications may be added or revised with each edition, always verify with the latest A5.7/A5.7M edition to ensure your filler metal selection aligns with the current classification list.
