Precious Metal B563-SR (Stress relieved)
Heat-treated state
GB B563
Pick when formed springs and contact arms need dimensional stability and relaxation resistance without the full strength gain (or distortion) of a full ageing cycle.
Values for the SR condition
Other B563 tempers and conditions
B563 is listed in 5 conditions; see the grade overview at B563.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard mill supply condition for wire, strip and rivet stock that must be formed, drawn, coined or deep-drawn before final ageing. | 250 | 550 | 27 | 78 HRB | 5.3 % IACS |
Age hardened | Pick for finished wiping, sliding and slip-ring contacts where maximum hardness, wear life and low stable contact resistance are required. | 700 | 900 | 8 | 25 HRC | 6.2 % IACS |
SRThis page Stress relieved | Pick when formed springs and contact arms need dimensional stability and relaxation resistance without the full strength gain (or distortion) of a full ageing cycle. | 820 | 950 | 5 | 22 HRC | 5.2 % IACS |
Hardened | Pick for spring-loaded contact fingers and brush wire where elastic limit matters and no further heat treatment is planned. | 850 | 1,000 | 3 | 24 HRC | 5 % IACS |
Cold worked then age hardened | Pick for the hardest, most wear-resistant contact wire and brush stock where forming is complete and ductility is no longer needed. | 1,100 | 1,240 | 2 | 32 HRC | 6 % IACS |
What is B563-SR?
B563-SR is B563 heat treated to SR — pick when formed springs and contact arms need dimensional stability and relaxation resistance without the full strength gain (or distortion) of a full ageing cycle. B563-SR has a yield strength of 820 MPa (119 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 100% of precious metal grades. Elongation at break is 5% and the elastic modulus is 116 GPa (16.8 Msi). B563-SR has a density of 11.7 g/cm³ (0.423 lb/in³), heavier than 63% of precious metal grades. It melts at 1,010°C (1,850 °F). SA is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High strength — 820 MPa (119 ksi), better than 100% of precious metal grades
- Easy to machine — 55/100, better than 86% of precious metal grades
- Polishes to a fine finish — 95/100, better than 86% of precious metal grades
- Good corrosion resistance — 95/100, better than 82% of precious metal grades
- Stiff — 116 GPa (16.8 Msi), better than 78% of precious metal grades
Limitations
- Low electrical conductivity — 5.2 % IACS, worse than 95% of precious metal grades
- Limited ductility — 5%, worse than 93% of precious metal grades
- Poor heat conductor — 31 W/m·K (17.9 BTU/hr·ft·°F), worse than 92% of precious metal grades
- Limited formability — 35/100, worse than 92% of precious metal grades
B563-SR properties
Typical room-temperature values for B563-SR; 12 are specific to this condition. Other listed values are B563 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
B563-SR has a density of 11.7 g/cm³ (0.423 lb/in³), heavier than 63% of precious metal grades. It melts at 1,010°C (1,850 °F).
Mechanical12
B563-SR has a yield strength of 820 MPa (119 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 100% of precious metal grades. Elongation at break is 5% and the elastic modulus is 116 GPa (16.8 Msi).
Thermal5
B563-SR is rated for continuous service to 300°C (572 °F). It conducts heat at 31 W/m·K (17.9 BTU/hr·ft·°F), worse than 92% of precious metal grades. Thermal expansion is 14.5 µm/m·K (8.06 µin/in·°F).
Electrical3
B563-SR conducts electricity at 5.2 % IACS, worse than 95% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (95/100), better than 82% of precious metal grades.
Sustainability4
Producing a kilogram of B563-SR takes about 90,000 MJ of energy and emits 6,000 kg of CO₂ — more than 66% of precious metal grades. Typical recycled content is 60%.
Manufacturability8
B563-SR's machinability is good (55/100, better than 86% of precious metal grades); weldability very good (70/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with B563-SR
Is B563 easy to machine?
Machines like a gummy noble alloy — sharp carbide or diamond tooling, high speed, light feeds, flood coolant; swarf and coolant must be captured for refining.
Can B563 be welded?
Resistance, laser and micro-TIG welding to contact carriers are routine; avoid overheating that dissolves the ordered structure and softens age-hardened parts.
Can B563 be formed, bent or molded?
Excellent cold formability in the annealed condition (drawing, stamping, coining, cladding); form first, then age harden, since hard/aged tempers have only a few percent elongation.
What surface finishes work on B563?
Not anodizable; take a mirror polish for slip-ring surfaces and can be gold or rhodium flash plated where extra lubricity or low fretting is wanted.
B563 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 |
|---|---|---|
| Pdprimary noble base, gives tarnish immunity | 34 – 36 | 35 |
| Ag | 29 – 31 | 30 |
| Cuprincipal age-hardening/ordering element | 13 – 15 | 14 |
| Aupresent in the commercial Pd-Ag-Cu contact alloy of this class | 9.5 – 10.5 | 10 |
| Ptwear and arc-erosion resistance | 9.5 – 10.5 | 10 |
| Zndeoxidiser / hardness | 0.5 – 1.5 | 1 |
| other (total impurities)per ASTM B563 purity limits | ≤ 0.15 | — |
B563-SR — frequently asked
What is B563-SR used for?
B563-SR is typically used for slip rings, potentiometer contacts and wiping contacts. In short: age-hardenable palladium alloy; wear-resistant sliding contact; higher service temperature, 500 °C.
What is the yield strength of B563-SR?
B563-SR has a typical yield strength of 820 MPa (119 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 100% of precious metal grades. Strength varies by condition: see the 5 listed tempers.
Is B563-SR easy to machine?
Reasonably — machinability is rated good (55/100, better than 86% of precious metal grades). Machines like a gummy noble alloy — sharp carbide or diamond tooling, high speed, light feeds, flood coolant; swarf and coolant must be captured for refining.
Can B563-SR be welded?
Yes — weldability is rated very good (70/100). Resistance, laser and micro-TIG welding to contact carriers are routine; avoid overheating that dissolves the ordered structure and softens age-hardened parts.
What surface finishes work on B563-SR?
Not anodizable; take a mirror polish for slip-ring surfaces and can be gold or rhodium flash plated where extra lubricity or low fretting is wanted.
Can B563-SR be formed, bent or molded?
Excellent cold formability in the annealed condition (drawing, stamping, coining, cladding); form first, then age harden, since hard/aged tempers have only a few percent elongation.
What is the maximum service temperature of B563-SR?
B563-SR is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between B563-SA and B563-H?
SA is the default condition — standard mill supply condition for wire, strip and rivet stock that must be formed, drawn, coined or deep-drawn before final ageing. H: pick for spring-loaded contact fingers and brush wire where elastic limit matters and no further heat treatment is planned. Yield strength is 250 MPa in SA versus 850 MPa in H.
Sources
- ASTM B563 Standard Specification for Palladium-Silver-Copper Electrical Contact Alloy — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (precious metal contact alloys) — ASM International (1990)
- Palladium-silver-copper contact alloy (Paliney-type) technical data — Deringer-Ney (2022)
- Electrical Contacts: Principles and Applications — CRC Press (2014)
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.