Precious Metal BAg-4: Properties, Machinability & Uses

BAg-4 tempers and conditions

BAg-4 is supplied in one standard condition, ANN.

ANN

Supply forms, finishes and certifications

Ways BAg-4 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.

Option	What it is	Type
FLUX-COATED	Flux-Coated Rod	Supply form
PREFORM	Preform	Supply form
WIREDefault	Bare Wire / Rod	Supply form
PASTE	Braze Paste	Printing process
POWDER	Atomized Powder	Printing process

What is BAg-4?

BAg-4 is a cadmium-free 40% silver Ag-Cu-Zn-Ni brazing filler (UNS P07400, BAg40CuZnNi) in which the nickel addition improves wetting of stainless steel and cemented carbide. Its melting range is wider than that of the eutectic grades, so it fills stepped or loose-fitting joints, and it is supplied as wire, annealed and flux-coated rod, stamped preforms, powder and paste. As-brazed values are about 450 MPa tensile, 20% elongation and 100 HB. It is applied at 780-900 °C by torch, induction, furnace or resistance brazing; the zinc content rules out vacuum brazing, where BAg-8a or BVAg-0 apply. BAg-4 has a density of 9.1 g/cm³ (0.329 lb/in³), lighter than 89% of precious metal grades. It melts at 671°C (1,240 °F). BAg-4 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 81% of precious metal grades. Elongation at break is 22% and the elastic modulus is 90 GPa (13.1 Msi).

What is BAg-4 used for?

stainless steel fabrication
carbide tooling
food-service equipment
general gap-filling joints

Advantages

Low embodied carbon — 48 kg CO₂/kg, better than 92% of precious metal grades
Lightweight — 9.1 g/cm³ (0.329 lb/in³), better than 89% of precious metal grades
High strength — 250 MPa (36.3 ksi), better than 81% of precious metal grades

Limitations

Difficult to weld — 20/100, worse than 86% of precious metal grades
Needs corrosion protection — 62/100, worse than 83% of precious metal grades
Limited formability — 70/100, worse than 78% of precious metal grades
Poor heat conductor — 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 76% of precious metal grades
Hard to polish — 70/100, worse than 76% of precious metal grades

BAg-4 properties

Typical room-temperature values; bars are the position among precious metal grades.

Physical3

BAg-4 has a density of 9.1 g/cm³ (0.329 lb/in³), lighter than 89% of precious metal grades. It melts at 671°C (1,240 °F).

Density9.1 g/cm³0.33 lb/in³

Melting Point (Solidus)671°C1,240 °F

Liquidus Temperature779°C1,434 °F

Mechanical9

BAg-4 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 81% of precious metal grades. Elongation at break is 22% and the elastic modulus is 90 GPa (13.1 Msi).

Elastic (Young's) Modulus90 GPa13.1 Msi

Shear Modulus34 GPa4.9 Msi

Poisson's Ratio0.35

Tensile Strength (Ultimate)420 MPa60.9 ksi

Yield Strength (0.2% offset)250 MPa36.3 ksi

Elongation at Break22%

Shear Strength220 MPa31.9 ksi

Hardness, Brinell95 HB

Hardness, Vickers100 HV

Thermal5

BAg-4 is rated for continuous service to 350°C (662 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 76% of precious metal grades. Thermal expansion is 18.5 µm/m·K (10.3 µin/in·°F).

Thermal Conductivity55 W/m·K31.8 BTU/hr·ft·°F

Specific Heat Capacity300 J/kg·K0.07 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)18.5 µm/m·K10.3 µin/in·°F

Max Service Temperature (continuous)350°C662 °F

Min Service Temperature-196°C-321 °F

Electrical3

BAg-4 conducts electricity at 15 % IACS, worse than 65% of precious metal grades.

Electrical Conductivity15 % IACS

Electrical Resistivity1.15×10⁻⁷ Ω·m4.53 µΩ·in

Magnetic Responsenon-magnetic

Chemical & Environmental2

Corrosion resistance is good (62/100), worse than 83% of precious metal grades.

Corrosion ResistanceGood62/100

Chemical Resistance SummaryGood in fresh water, mild atmospheres and most organics; Zn/Cu content makes it vulnerable to ammonia and amine stress cracking, sulfur-bearing media and strong oxidizing acids; not for saline dezincifying service without protection.

Sustainability3

Producing a kilogram of BAg-4 takes about 720 MJ of energy and emits 48 kg of CO₂ — less than 87% of precious metal grades. Typical recycled content is 45%.

Embodied Energy (primary production)720 MJ/kg309,545 BTU/lb

Embodied Carbon (primary production)48 kg CO₂/kg

Typical Recycled Content45%

Manufacturability6

BAg-4's machinability is fair (45/100, better than 59% of precious metal grades); weldability poor (20/100); formability very good (70/100).

MachinabilityFair45/100

WeldabilityPoor20/100

Formability (cold)Very good70/100

CastabilityVery good75/100

Brazeability / SolderabilityExcellent88/100

PolishabilityVery good70/100

Common Calculations5

Specific Strength (UTS / density)calculated46 kN·m/kg

Specific Stiffness (E / density)calculated9.9 MN·m/kg

Modulus of Resiliencecalculated347 kJ/m³

Thermal Diffusivitycalculated20.1 mm²/s

Thermal Shock Resistance Indexcalculated14

Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.

Strength versus weight in the precious metal family

Yield strength against density for every precious metal grade FabDigit runs. BAg-4 is highlighted; hover a dot for its name, or open the interactive family chart.

Working with BAg-4

Is BAg-4 easy to machine?

Rarely machined; the alloy is gummy and smears — use sharp HSS tooling, and dress solidified fillets with abrasives instead of cutting.

Can BAg-4 be welded?

Not a fusion-weld filler — arc heat volatilizes zinc; joints are made by torch, induction, furnace (air/inert with flux) or resistance brazing at 780–900 °C.

Can BAg-4 be formed, bent or molded?

Readily cold-drawn to fine wire and rolled to strip/preforms; interanneal to avoid cracking in tight bends.

BAg-4 chemical composition (wt %)

Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.

Element	Spec limit (wt %)	Nominal
Ag	39 – 41	40
Cu	29 – 31	30
Niimproves wetting of stainless steel and cemented carbide	1.5 – 2.5	2
Cdcadmium-free grade, impurity limit	≤ 0.01
Other (total)total of other elements per AWS A5.8	≤ 0.15
Znbalance, nominally 26–30%	balance

What surface finishes work on BAg-4?

Fillets polish to a bright silver colour, accept nickel/chrome plating after thorough flux-residue removal in hot water or 5–10% citric/sulfuric pickle.

Equivalent designations

Standards and trade names that resolve to Precious Metal BAg-4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.

UNS: P07400
GB (China): BAg40CuZnNi

Other Silver alloys grades

Closest precious metal grades by properties

Compare BAg-4 with…

Benchmark BAg-4 against the top 3 neighbours

How much does BAg-4 cost?

BAg-4 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.

BAg-4 — frequently asked

What is BAg-4 used for?

BAg-4 is typically used for stainless steel fabrication, carbide tooling, food-service equipment and general gap-filling joints. In short: nickel-bearing, wets carbide; wide melting range for gaps; cadmium-free 40% silver.

What is the yield strength of BAg-4?

BAg-4 has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 81% of precious metal grades.

Is BAg-4 easy to machine?

Reasonably — machinability is rated fair (45/100, better than 59% of precious metal grades). Rarely machined; the alloy is gummy and smears — use sharp HSS tooling, and dress solidified fillets with abrasives instead of cutting.

Can BAg-4 be welded?

Not readily — weldability is rated poor (20/100). Not a fusion-weld filler — arc heat volatilizes zinc; joints are made by torch, induction, furnace (air/inert with flux) or resistance brazing at 780–900 °C.