Solder & Low-Melting Alloy Sn95Cu4Ag1
Sn95Cu4Ag1 is a lead-free tin solder from the Sn-Cu-Ag family in which copper is raised to 4% and silver to 1% to lift joint strength and liquidus above eutectic Sn-Cu and standard SAC compositions, giving about 48 MPa tensile, 32 MPa yield and 22% elongation at 18 HB.
Reference datasheet — Sn95Cu4Ag1 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 Sn95Cu4Ag1?
Sn95Cu4Ag1 is a lead-free tin solder from the Sn-Cu-Ag family in which copper is raised to 4% and silver to 1% to lift joint strength and liquidus above eutectic Sn-Cu and standard SAC compositions, giving about 48 MPa tensile, 32 MPa yield and 22% elongation at 18 HB. It is selected for elevated-temperature or higher-strength lead-free joints and is stocked as bar, solid and flux-cored wire, preforms and atomised powder. The trade-off is a wide pasty/liquidus range that makes thin-section filling and rapid freezing difficult, and service temperature is capped near 150 °C. Where a sharp melting point is required, eutectic Sn96.5Ag3.5 or SAC305 is the usual alternative. Sn95Cu4Ag1 has a density of 7.35 g/cm³ (0.266 lb/in³), lighter than 84% of solder & low-melting alloy grades. It melts at 217°C (423 °F). Sn95Cu4Ag1 has a yield strength of 32 MPa (4.64 ksi) and a tensile strength of 48 MPa (6.96 ksi) — stronger than 73% of solder & low-melting alloy grades. Elongation at break is 25% and the elastic modulus is 48 GPa (6.96 Msi).
What is Sn95Cu4Ag1 used for?
- High-strength industrial soldered joints
- Specialty lead-free joints requiring higher liquidus
- Flame- or induction-heated copper tube and fitting joints
- Step soldering above standard SAC reflow temperature
- Stamped and extruded solder preforms
- Flux-cored wire for manual and automated feeding
- Atomised powder for paste and dispensing blends
Advantages
- High service temperature — 150°C (302 °F), better than 92% of solder & low-melting alloy grades
- Conducts heat well — 60 W/m·K (34.7 BTU/hr·ft·°F), better than 89% of solder & low-melting alloy grades
- Lightweight — 7.35 g/cm³ (0.266 lb/in³), better than 84% of solder & low-melting alloy grades
- Stiff — 48 GPa (6.96 Msi), better than 81% of solder & low-melting alloy grades
Limitations
- Limited ductility — 25%, worse than 76% of solder & low-melting alloy grades
Sn95Cu4Ag1 properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Sn95Cu4Ag1 has a density of 7.35 g/cm³ (0.266 lb/in³), lighter than 84% of solder & low-melting alloy grades. It melts at 217°C (423 °F).
Mechanical11
Sn95Cu4Ag1 has a yield strength of 32 MPa (4.64 ksi) and a tensile strength of 48 MPa (6.96 ksi) — stronger than 73% of solder & low-melting alloy grades. Elongation at break is 25% and the elastic modulus is 48 GPa (6.96 Msi).
Thermal6
Sn95Cu4Ag1 is rated for continuous service to 150°C (302 °F). It conducts heat at 60 W/m·K (34.7 BTU/hr·ft·°F), better than 89% of solder & low-melting alloy grades. Thermal expansion is 22.5 µm/m·K (12.5 µin/in·°F).
Electrical3
Sn95Cu4Ag1 conducts electricity at 11.5 % IACS, better than 71% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 52% of solder & low-melting alloy grades.
Sustainability4
Producing a kilogram of Sn95Cu4Ag1 takes about 330 MJ of energy and emits 17 kg of CO₂ — more than 86% of solder & low-melting alloy grades. Typical recycled content is 30%.
Manufacturability7
Sn95Cu4Ag1's machinability is poor (30/100, worse than 60% of solder & low-melting alloy grades); weldability poor (20/100); formability excellent (90/100).
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 solder & low-melting alloy family
Yield strength against density for every solder & low-melting alloy grade FabDigit runs. Sn95Cu4Ag1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Sn95Cu4Ag1
Is Sn95Cu4Ag1 easy to machine?
Extremely soft and prone to sticking to the cutting edge; use sharp tools with large positive rake, high spindle speed, light feed and generous lubrication. In practice shapes are produced by stamping or extrusion rather than by cutting.
Can Sn95Cu4Ag1 be welded?
Not a structural welding alloy — it is itself the filler. Joints are made with an active flux (ZnCl₂ type or halogen-free organic acid) and flame or induction heating to 330–380 °C; watch for dissolution of thin-wall copper at these temperatures.
Can Sn95Cu4Ag1 be formed, bent or molded?
Extrudes and draws to wire, rolls to foil and stamps into preforms without difficulty. In casting the wide pasty zone requires good feeding and risering to avoid shrinkage porosity.
Sn95Cu4Ag1 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 |
|---|---|---|
| Cuforms primary Cu6Sn5; raises liquidus significantly | 3.5 – 4.5 | 4 |
| Agrefines structure, improves wetting and creep resistance | 0.8 – 1.2 | 1 |
| PbRoHS lead-free limit | ≤ 0.07 | |
| Sb | ≤ 0.05 | |
| Bi | ≤ 0.05 | |
| Fe | ≤ 0.02 | |
| Znresidual zinc degrades wetting | ≤ 0 | |
| Al | ≤ 0 | |
| Cd | ≤ 0 | |
| As | ≤ 0.03 | |
| Snbalance, about 95% | balance |
What surface finishes work on Sn95Cu4Ag1?
Flux residue must be removed after soldering by water wash or isopropanol to prevent electrochemical migration. The surface develops a natural tin oxide film; the solder is not plated or anodised.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Sn95Cu4Ag1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- IEC C40A10
How much does Sn95Cu4Ag1 cost?
Sn95Cu4Ag1 is a high-cost solder & low-melting alloy ($$$$), 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.
Sn95Cu4Ag1 — frequently asked
What is Sn95Cu4Ag1 used for?
Sn95Cu4Ag1 is typically used for high-strength industrial soldered joints, specialty lead-free joints requiring higher liquidus, flame- or induction-heated copper tube and fitting joints, step soldering above standard SAC reflow temperature, stamped and extruded solder preforms and flux-cored wire for manual and automated feeding. In short: higher-liquidus lead-free solder; stronger than eutectic Sn-Cu; wide pasty range.
What is the yield strength of Sn95Cu4Ag1?
Sn95Cu4Ag1 has a typical yield strength of 32 MPa (4.64 ksi) and a tensile strength of 48 MPa (6.96 ksi) — stronger than 73% of solder & low-melting alloy grades.
Is Sn95Cu4Ag1 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 60% of solder & low-melting alloy grades). Extremely soft and prone to sticking to the cutting edge; use sharp tools with large positive rake, high spindle speed, light feed and generous lubrication. In practice shapes are produced by stamping or extrusion rather than by cutting.
Can Sn95Cu4Ag1 be welded?
Not readily — weldability is rated poor (20/100). Not a structural welding alloy — it is itself the filler. Joints are made with an active flux (ZnCl₂ type or halogen-free organic acid) and flame or induction heating to 330–380 °C; watch for dissolution of thin-wall copper at these temperatures.
What surface finishes work on Sn95Cu4Ag1?
Flux residue must be removed after soldering by water wash or isopropanol to prevent electrochemical migration. The surface develops a natural tin oxide film; the solder is not plated or anodised.
Can Sn95Cu4Ag1 be formed, bent or molded?
Extrudes and draws to wire, rolls to foil and stamps into preforms without difficulty. In casting the wide pasty zone requires good feeding and risering to avoid shrinkage porosity.
What is the maximum service temperature of Sn95Cu4Ag1?
Sn95Cu4Ag1 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Sn95Cu4Ag1 cost?
Sn95Cu4Ag1 is a high-cost solder & low-melting alloy ($$$$), 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
- ISO 9453 — Soft solder alloys: chemical compositions and forms — ISO (2020)
- IEC 61190-1-3 — Requirements for electronic grade solder alloys — IEC (2017)
- ASM Handbook Vol. 3: Alloy Phase Diagrams (Sn-Cu, Sn-Ag-Cu) — ASM International (1992)
- ASM Handbook Vol. 6: Welding, Brazing and Soldering — Solder Alloy Properties — ASM International (1993)
- GB/T 20422 (2018)
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.