HEAT TREATABLE PLATINUM
HOW TO COLD WORK OR FORM HEAT TREATABLE PLATINUM
PROPERTIES:
COMPOSITION: 95.2% PLATINUM 4.8% OTHER ELEMENTS
MELTING RANGE: LIQUIDUS: 165OC/ 3002 F SOLIDUS : 155OC/ 2822 F
CIELAB COLOUR COORDINATES: 83.1L* -0.1 a* 4.6b* DENSITY: 19.30
g/cm3
Alloy/ Treatment Hardness Tensile Strength Yield Strength
(HV) (psi) (psi)
95%Pt-5% HTA/Annealed @ 1100C with Quench 185 115,000 83,000
95% Pt - 5% Ru /Annealed @ 1100C 130 70,000 50,000
95% Pt - 5% HTA/ Aged @700C after anneal 350 145,000 117,000
95% Pt - 5% Ru Cold worked 75% by area 255 116,000 115,000
95%Pt-5% HTA Cold worked 50% 350 159,000 157,000
95%Pt-5%HTA aged @700C after50%cold work 425 183,000 174,000
APPLICATIONS:
* Stamped items such as clips and earnuts
* Formed wire shapes such as omega clips and post wire.
* Any assembly that requires superior spring properties with 95%
Pt content requirement.
MATERIALS & EQUIPMENT REQUIRED:
* Mechanically driven flat or shaped forming roll mill
* Mechanically driven wire draw bench with carbide dies
* Conventional press and die configurations will accomplish
stamping polish and chrome plate dies if
possible.
TECHNIQUES & METHODS:
* Yield strength must be exceeded to plastically deform the
metal. Stiffness is the same as other platinum alloys.
* Work hardening occurs quickly. Maximum thickness reduction
prior to anneal is approx. 60%
* Full anneal must involve heating to 1000-11OOC(1832 -
2012F)followed by quench in water.
* The cycle of cold work and anneal can be repeated several
times. Never use a slow cool from an atmosphere furnace prior to
cold working. This hardens the material and limits ductility.
HEAT TREATMENT HARDENING
* FOR BENCH WORK: Heat the platinum piece to a medium orange
color and allow it to slowly cool in air. Repeat the procedure a
second time. Do not quench if any visible color remains in the
piece.
* FURNACE PROCESSING: Regular atmospheres are suitable. Furnace
dwell time and fixturing should be adjusted to allow the piece to
attain 700C (1292F) for 15-30 minutes. Slow air cooling should
follow heating.
* If further cold work or shaping adjustment is required, reheat
the item to bright yellow (1000-11OOC/1832-2012F)and quickly quench
to restore softness and ductility. The heat treatment process is
reversible.
* Heat treatment after cold working provides maximum strength and
hardness obtainable (HV425)
HOW TO INVESTMENT CAST HEAT TREATABLE PLATINUM
PROPERTIES:
COMPOSITION: 95.2% PLATINUM 4.8% OTHER ELEMENTS
MELTING RANGE: LIQUIDUS: 165OC/ 3002 F SOLIDUS: 155OC/2822F
CIELAB COLOUR COORDINATES: 83.1L* -O.1a* 4.6 b*DENSITY: 19.30
g/cm3
Alloy/ Treatment Hardness Tensile Strength Yield Strength
HV) (psi) (psi)
95.2%Pt - 4.8% HTA As Cast 280 112,000 92,000
95.2%Pt - 4.8% Ru As Cast 130 66,000 35,000
95.2%Pt - 4.8% Co As Cast 135 64,000 35,000
95.2%Pt - 4.8% HTA/Aged@700C 318 125,000 104,000
APPLICATIONS:
* Cast four prongs or filigree settings where high strength in a
delicate design is required.
* Thin lightweight cast items where strength of conventional
alloys is insufficient
* Stone holding applications where the strength increase obtained
by heat treatment is beneficial
MATERIALS & EQUIPMENT REQUIRED:
* Platinum casting investment & ceramic crucibles
* Oxy-fuel torch heat or electric induction power
* Centrifugal force preferred to assist filling
* Electric kiln to heat ceramic flask from(65OC/1200F)for thick
items to (875C/1600 F) for thin items * Protective goggles and heat
resistant clothing used for regular Pt casting
TECHNIQUES & METHODS:
* Special care and attention to the feed of molten metal to the
casting during solidification should be given. The broad melting
range can make feeding more sluggish than regular platinum alloys.
* Casting temperature should vary by section thickness. Thin
items should receive 200-300C (400-500F) superheat to cast at
1850-1950C (3360-3500F). Thick sections can be cast with minimal
superheat around 1700C (3092F)
* All sprues should be as large as the thickest section located
there.
* The surface of the cast article will be frosted, indicative of
oxidation that is removed in finishing.
* Divesting by hydrofluoric acid or bead blasting applies based
on platinum investment
* Regular finishing techniques and methods can be applied
HEAT TREATMENT HARDENING
* Heat the cast platinum piece to a medium orange color and allow
it to slowly cool in air. Repeat the procedure a second time. Do not
quench if any visible color remains in the piece.
* If further cold work or shaping adjustment is required, reheat
the item to bright yellow 1000-11OOC (1832-2012F) and quickly quench
to restore softness.
* A protective flux will minimize formation of an oxide layer.
'FREE MACHINING' HEAT TREATABLE PLATINUM
PROPERTIES:
COMPOSITION: 95.2% PLATINUM 4.8% OTHER ELEMENTS
MELTING RANGE: LIQUIDUS : 165OC/ 3002 F SOLIDUS: 155OC/2822F
CIELAB COLOUR COORDINATES: 83.1L* -0.1a* 4.6b* DENSITY : 19.30
g/cm3
Alloy/ Treatment Hardness Tensile Strength Yield Strength
(HV) (psi) (psi)
95%Pt-5%HTA/Annealed @ 1100C with Quench 185 115,000 83,000
95%Pt-5%HTA/'Free Machining'heat treated 230 112,000 85,000
95%Pt-5%Ru /Cold worked 75% by area 255 116,000 115,000
DEFINITION:
The unique microstructure produced from a specific combination of
mechanical work and heat treatment that provides superior
performance during machining operations based on metal shear such as
stamping, cutting, lathe turning, drilling, milling or facetting.
The same alloy composition can be heat treated to achieve spring
properties, maximum ductility, maximum machinability or maximum
hardness as desired. This behavior is more typical of a tool steel
than a precious metal.
APPLICATIONS:
* Drilled pieces of plate for pave settings
* Thick walled tube for diamond machining of seamless bands
* Facetting and engraving of flat or round surfaces.
* Any assembly that requires superior machining properties that
exceed conventional platinum performance
MATERIALS & EQUIPMENT REQUIRED:
* Conventional flex shaft or CNC drilling capabilities with
HSSteel tools
* Conventional manual lathes or CNC centers with standard diamond
tools, feeds, speeds, lubricants etc for seamless band machining.
TEST PERFORMANCE DATA:
* The material must be ordered as 'free machining platinum', as
opposed to conventional heat treatable,
* Regular platinum machining methods must be deployed.
* A single 0.0625" drill cut over 700 holes in 0.080" thick 'free
machining platinum' sheet compared to 5 drills for 49 holes in
95%Pt-5%Ru sheet of the same thickness during controlled CNC tests.
* A single diamond tool cut over 400 plain rectangular seamless
bands without breakage or sharpening on a manual lathe using 'free
machining platinum' tube compared to an average of 125 bands cut
with 95%Pt-5%Ru
* Lathe chips from 'free machining platinum' are 60% thinner
compared to 95%Pt-5%Ru
POST MACHINING HEAT TREATMENT:
* Maximum ductility can be restored through heating to IOOOC
(1832F) followed by a rapid quench in cold water. This allows a
machined item such as a seamless band to be stretched.
* The quenched structure can be heat treated @700C (1292F) with
an air cool to achieve a hardness of 35OHV for superior wear
resistance at the consumer level after the completion of
manufacturing.
* A harder material can be finished to a higher polish easier.
HOW TO SOLDER/BRAZE HEAT TREATABLE PLATINUM
PROPERTIES:
COMPOSITION: 95.2% PLATINUM 4.8% OTHER ELEMENTS
MELTING RANGE: LIQUIDUS : 165OC/ 3002 F SOLIDUS: 155OC/2822 F
CIELAB COLOUR COORDINATES: 83.1L* -0.1a* 4.6 b* DENSITY: 19.30
g/cm3
Alloy/ Treatment Hardness Tensile Strength Yield Strength
(HV) (psi) (psi)
95%Pt-5% Ru/Annealed @ 1100C 130 70,000 50,000
Joint between 0. 170" diameter 95%Pt-5%Ru pieces 60,000 ----
Using 0.010" 95% Pt HTA foil
APPLICATIONS:
* Joining work where the 95% Pt marking requirement cannot be
compromised
* Situations where laser welding a joint is not possible
* Welding investment cast pieces of heat treatable platinum.
MATERIALS & EQUIPMENT REQUIRED:
* Conventional oxy-fuel bench torch apparatus
* Tungsten carbide working tools to minimize contamination.
TECHNIQUES & METHODS:
* Small pieces of foil cut to fit the joint can be put in place,
fluxed and heated to form a metallurgical bond.
* Exposure of the joint during finishing should be minimized due
to high hardness.
* No special considerations of hiding the joint are required
because of the close color match to conventional platinum materials.
HEAT TREATMENT HARDENING:
* The joint can be hardened just like an investment cast article,
if required
* Heat the platinum piece to a medium orange color (70OC/1292F)
and allow it to slowly cool in air.
* Repeat the procedure a second time. Do not quench if any
visible color remains in the piece.
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