Precious Metal BAg-20
UNS P07301
BAg-20 (UNS P07301) is the cadmium-free counterpart to BAg-2a, an Ag-Cu-Zn brazing filler with a higher melting range that keeps silver content — and cost — moderate.
Reference datasheet — BAg-20 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
What is BAg-20?
BAg-20 (UNS P07301) is the cadmium-free counterpart to BAg-2a, an Ag-Cu-Zn brazing filler with a higher melting range that keeps silver content — and cost — moderate. It is used for economical general brazing of steel and brass where cadmium-bearing alloys are restricted, and is supplied as wire, rod, flux-coated rod, strip, preforms, powder and paste. The deposit reaches about 430 MPa tensile with 26 % elongation and 105 HB, with service limited to 200 °C. The zinc content rules out high-vacuum furnace brazing and the 766–871 °C range is higher than Cd-bearing fillers; BAg-18 flows at lower temperature if that matters. BAg-20 has a density of 8.7 g/cm³ (0.314 lb/in³), lighter than 96% of precious metal grades. It melts at 677°C (1,251 °F). BAg-20 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 430 MPa (62.4 ksi) — stronger than 73% of precious metal grades. Elongation at break is 26% and the elastic modulus is 88 GPa (12.8 Msi).
What is BAg-20 used for?
- General steel brazing
- Brass and bronze assemblies
- Appliance fabrication
- Hardware and fitting joints
- Steel tube-to-fitting joints
- Sheet metal enclosure joints
- Repair and maintenance brazing
Advantages
- Lightweight — 8.7 g/cm³ (0.314 lb/in³), better than 96% of precious metal grades
- Low embodied carbon — 46 kg CO₂/kg, better than 93% of precious metal grades
Limitations
- Needs corrosion protection — 55/100, worse than 94% of precious metal grades
- Limited service temperature — 200°C (392 °F), worse than 89% of precious metal grades
- Hard to polish — 70/100, worse than 76% of precious metal grades
BAg-20 properties
Typical room-temperature values; bars are the position among precious metal grades.
Physical3
BAg-20 has a density of 8.7 g/cm³ (0.314 lb/in³), lighter than 96% of precious metal grades. It melts at 677°C (1,251 °F).
Mechanical9
BAg-20 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 430 MPa (62.4 ksi) — stronger than 73% of precious metal grades. Elongation at break is 26% and the elastic modulus is 88 GPa (12.8 Msi).
Thermal6
BAg-20 is rated for continuous service to 200°C (392 °F). It conducts heat at 95 W/m·K (54.9 BTU/hr·ft·°F), better than 51% of precious metal grades. Thermal expansion is 19 µm/m·K (10.6 µin/in·°F).
Electrical3
BAg-20 conducts electricity at 20 % IACS, better than 53% of precious metal grades.
Chemical & Environmental2
Corrosion resistance is good (55/100), worse than 94% of precious metal grades.
Sustainability4
Producing a kilogram of BAg-20 takes about 510 MJ of energy and emits 46 kg of CO₂ — less than 95% of precious metal grades. Typical recycled content is 40%.
Manufacturability5
BAg-20's machinability is fair (45/100, better than 59% of precious metal grades); formability very good (75/100).
Common Calculations5
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-20 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BAg-20
Is BAg-20 easy to machine?
The filler itself is rarely machined; it is tough and sticks to the tool, so use sharp edges, high rake and ample lubrication if cutting is needed. Shearing or blanking is the normal way to cut stock.
Can BAg-20 be welded?
Used as a filler, not as a base metal: braze at 766–871 °C with a silver brazing flux (AWS FB3-A or equivalent) and a recommended joint clearance of 0.05–0.13 mm. The zinc content makes it unsuitable for high-vacuum furnace brazing.
Can BAg-20 be formed, bent or molded?
Cold draws to wire, rolls to strip and stamps into preforms readily; interanneal at about 550–600 °C with rapid cooling once work hardened.
BAg-20 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 |
|---|---|---|
| AgAWS A5.8 BAg-20 / UNS P07301 | 29 – 31 | 30 |
| Cu | 37 – 39 | 38 |
| CdCd-free grade; Cd only as unintentional impurity | ≤ 0.01 | |
| Pbimpurity limit | ≤ 0.03 | |
| Other (each)sum of other elements 0.15% max | ≤ 0.15 | |
| Znbalance (approx. 30-34%) | balance |
What surface finishes work on BAg-20?
Remove borax-type flux residue completely with hot water or an acid pickle, or the remaining flux will corrode the joint. The fillet is yellow-white and polishes, but the colour difference is visible, so consider plating on cosmetic parts.
Equivalent designations
Standards and trade names that resolve to Precious Metal BAg-20 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P07301
- Also called
- AWS BAg-20
How much does BAg-20 cost?
BAg-20 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-20 — frequently asked
What is BAg-20 used for?
BAg-20 is typically used for general steel brazing, brass and bronze assemblies, appliance fabrication, hardware and fitting joints, steel tube-to-fitting joints and sheet metal enclosure joints. In short: economical cadmium-free filler; BAg-2a replacement grade; general-purpose steel and brass.
What is the yield strength of BAg-20?
BAg-20 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 430 MPa (62.4 ksi) — stronger than 73% of precious metal grades.
Is BAg-20 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 59% of precious metal grades). The filler itself is rarely machined; it is tough and sticks to the tool, so use sharp edges, high rake and ample lubrication if cutting is needed. Shearing or blanking is the normal way to cut stock.
Can BAg-20 be welded?
Used as a filler, not as a base metal: braze at 766–871 °C with a silver brazing flux (AWS FB3-A or equivalent) and a recommended joint clearance of 0.05–0.13 mm. The zinc content makes it unsuitable for high-vacuum furnace brazing.
What surface finishes work on BAg-20?
Remove borax-type flux residue completely with hot water or an acid pickle, or the remaining flux will corrode the joint. The fillet is yellow-white and polishes, but the colour difference is visible, so consider plating on cosmetic parts.
Can BAg-20 be formed, bent or molded?
Cold draws to wire, rolls to strip and stamps into preforms readily; interanneal at about 550–600 °C with rapid cooling once work hardened.
What is the maximum service temperature of BAg-20?
BAg-20 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BAg-20 cost?
BAg-20 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.
Sources
- AWS A5.8M/A5.8 Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- GB/T 10046 (2018)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- AWS Brazing Handbook, 5th ed. — American Welding Society (2007)
- Silver brazing alloy technical data (30 % Ag cadmium-free) (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.