Precious Metal PSr70-HD (Hard-drawn wire)
Supply condition
GOST PSr70 (ПСр70)
Choose when stiff straight lengths or automatic ring-feeding requires spring-back and dimensional stiffness.
Values for the HD condition
Other PSr70 tempers and conditions
PSr70 is listed in 3 conditions; see the grade overview at PSr70.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As cast | Melting-shop feedstock for re-drawing, atomizing or remelt; not used directly at the joint. | 130 | 280 | 15 | 75 HB | 37 % IACS |
As built (as printed) | Property set describing the solidified joint after brazing — used for joint-strength design checks. | 150 | 300 | 18 | 80 HB | 38 % IACS |
HDThis page Hard-drawn wire | Choose when stiff straight lengths or automatic ring-feeding requires spring-back and dimensional stiffness. | 430 | 520 | 5 | 142 HB | 38 % IACS |
What is PSr70-HD?
PSr70-HD is PSr70 supplied in the HD condition — choose when stiff straight lengths or automatic ring-feeding requires spring-back and dimensional stiffness. PSr70-HD has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 97% of precious metal grades. Elongation at break is 5% and the elastic modulus is 85 GPa (12.3 Msi). PSr70-HD has a density of 9.85 g/cm³ (0.356 lb/in³), lighter than 73% of precious metal grades. It melts at 730°C (1,346 °F).
Advantages
- High strength — 430 MPa (62.4 ksi), better than 97% of precious metal grades
- Easy to machine — 60/100, better than 97% of precious metal grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 100% of precious metal grades
- Limited ductility — 5%, worse than 93% of precious metal grades
- Limited formability — 45/100, worse than 91% of precious metal grades
- Difficult to weld — 25/100, worse than 78% of precious metal grades
PSr70-HD properties
Typical room-temperature values for PSr70-HD; 20 are specific to this condition. Other listed values are PSr70 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
PSr70-HD has a density of 9.85 g/cm³ (0.356 lb/in³), lighter than 73% of precious metal grades. It melts at 730°C (1,346 °F).
Mechanical10
PSr70-HD has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 97% of precious metal grades. Elongation at break is 5% and the elastic modulus is 85 GPa (12.3 Msi).
Thermal6
PSr70-HD is rated for continuous service to 150°C (302 °F). It conducts heat at 155 W/m·K (89.6 BTU/hr·ft·°F), better than 66% of precious metal grades. Thermal expansion is 19 µm/m·K (10.6 µin/in·°F).
Electrical3
PSr70-HD conducts electricity at 38 % IACS, better than 68% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), worse than 61% of precious metal grades.
Sustainability4
Producing a kilogram of PSr70-HD takes about 1,100 MJ of energy and emits 95 kg of CO₂ — less than 71% of precious metal grades. Typical recycled content is 50%.
Manufacturability6
PSr70-HD's machinability is good (60/100, better than 97% of precious metal grades); weldability poor (25/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PSr70-HD
Is PSr70 easy to machine?
Rarely machined; the soft, gummy Ag-Cu matrix smears — use sharp, high-rake tools and light cuts if trimming preforms.
Can PSr70 be welded?
Not a weldable structural alloy; it is the filler itself — torch, induction, furnace or resistance brazing at about 760–830 °C with silver-braze flux or in dry hydrogen/vacuum (mind Zn volatilization in vacuum).
Can PSr70 be formed, bent or molded?
Excellent cold formability in the annealed state — draws to fine wire, rolls to foil and stamps into rings/shims; interanneal after ~50 % reduction.
What surface finishes work on PSr70?
Joint fillets clean up readily by pickling off flux residues and light polishing; the silver-rich surface tarnishes in sulfide atmospheres and can be lacquered or plated if appearance matters.
PSr70 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 |
|---|---|---|
| Agsilver content defining the grade | 69.5 – 70.5 | 70 |
| Znmelting-range depressant, improves flow | 3.5 – 4.5 | 4 |
| Pbimpurity limit | ≤ 0.01 | — |
| Feimpurity limit | ≤ 0.05 | — |
| Biimpurity limit | ≤ 0.01 | — |
| Total impuritiesper GOST 19738 purity requirement | ≤ 0.15 | — |
| Cubalance, ~26 % | balance | — |
PSr70-HD — frequently asked
What is PSr70-HD used for?
PSr70-HD is typically used for stainless steel brazing, instrument and electrical brazing and precision assembly brazing. In short: highest-silver GOST braze; narrow melting range; AWS BAg-10 equivalent.
What is the yield strength of PSr70-HD?
PSr70-HD has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 97% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is PSr70-HD easy to machine?
Reasonably — machinability is rated good (60/100, better than 97% of precious metal grades). Rarely machined; the soft, gummy Ag-Cu matrix smears — use sharp, high-rake tools and light cuts if trimming preforms.
Can PSr70-HD be welded?
Not readily — weldability is rated poor (25/100). Not a weldable structural alloy; it is the filler itself — torch, induction, furnace or resistance brazing at about 760–830 °C with silver-braze flux or in dry hydrogen/vacuum (mind Zn volatilization in vacuum).
What surface finishes work on PSr70-HD?
Joint fillets clean up readily by pickling off flux residues and light polishing; the silver-rich surface tarnishes in sulfide atmospheres and can be lacquered or plated if appearance matters.
Can PSr70-HD be formed, bent or molded?
Excellent cold formability in the annealed state — draws to fine wire, rolls to foil and stamps into rings/shims; interanneal after ~50 % reduction.
What is the maximum service temperature of PSr70-HD?
PSr70-HD 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.
Sources
- GOST 19738-74 Припои серебряные. Марки — Gosstandart / Rosstandart (1974)
- AWS A5.8/A5.8M Specification for Filler Metals for Brazing and Braze Welding (BAg-10 comparison) — AWS (2019)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (silver brazing filler metals) — ASM International (1993)
- AWS Brazing Handbook, 5th ed. — AWS (2007)
- Ag-Cu-Zn phase and property data compilations — ASM Alloy Phase Diagram Database (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.