Near Full Density Low Alloy Steel and Ductile Cast Iron by a New P/M Process Dennis Hammond Apex Advanced Technologies

Near Full DensityNear Full DensityLow Alloy Steel and Low Alloy Steel and

Ductile Cast Iron by a Ductile Cast Iron by a New P/M ProcessNew P/M Process

Dennis HammondDennis Hammond

Apex Advanced TechnologiesApex Advanced Technologies

Process OverviewProcess Overview Highly compressible, standard water Highly compressible, standard water

atomized powder, pre-alloyed and atomized powder, pre-alloyed and straight ironstraight iron

Special additive/lubricant master batchSpecial additive/lubricant master batch Conventional blending, standard Conventional blending, standard

tooling and conventional pressingtooling and conventional pressing Part pressing controlled to massPart pressing controlled to mass Compaction range 45-55 TSICompaction range 45-55 TSI Modified de-binding, controlledModified de-binding, controlled

temperature, time, and atmospheretemperature, time, and atmosphere

Process Overview Cont.Process Overview Cont. Modified sintering rate and temperatures Modified sintering rate and temperatures

up to 2500F for low alloy and 2200F for up to 2500F for low alloy and 2200F for castcast

Sintering atmosphere can be low % Sintering atmosphere can be low % hydrogen or vacuumhydrogen or vacuum

Heat treating similar to conventional Heat treating similar to conventional wrought and cast productswrought and cast products

Lower alloying additions to achieve Lower alloying additions to achieve properties verses conventional P/Mproperties verses conventional P/M

Sintered densities >96%; up to 99+Sintered densities >96%; up to 99+

Process Overview ContProcess Overview Cont..

Properties comparable/superior to Properties comparable/superior to wrought and cast productswrought and cast products

MPIF standards for P/M structural parts MPIF standards for P/M structural parts will not predict properties, technology will not predict properties, technology is more like a wrought/PM hybridis more like a wrought/PM hybrid

Not all conventional P/M alloy systems Not all conventional P/M alloy systems are feasible with this technology.are feasible with this technology.

Not all iron powders are suitableNot all iron powders are suitable

Key FeaturesKey FeaturesAdditive/Lubricant Master BatchAdditive/Lubricant Master Batch

Calculations for feasibility of full density, Calculations for feasibility of full density, desired lubrication, and needed additivesdesired lubrication, and needed additives

Target volume 98.5-99.5% of theoretical at Target volume 98.5-99.5% of theoretical at target green densitytarget green density

Need for a green compact free of density Need for a green compact free of density gradientsgradients

Need for excellent lubrication, Apex Need for excellent lubrication, Apex SuperlubeSuperlube®®

Need for mobile lubricant to achieve best fit Need for mobile lubricant to achieve best fit of metal particles during compaction and of metal particles during compaction and spread of additivesspread of additives


Need for excellent distribution of additives Need for excellent distribution of additives in powder mix and compactin powder mix and compact

Need for excellent dispersion of additivesNeed for excellent dispersion of additives Need for no segregation of additives, Need for no segregation of additives,

particles charged during making the master particles charged during making the master batchbatch

Master batch includes all additives including Master batch includes all additives including proprietary additives, pre-mixed and proprietary additives, pre-mixed and screened, ready to mix with iron powderscreened, ready to mix with iron powder


Easy blending of additive master Easy blending of additive master batch and metalbatch and metal

A.D. and flow of final mix may be A.D. and flow of final mix may be not the same as a conventional mixnot the same as a conventional mix

Static dissipative tubing should be Static dissipative tubing should be use between the hopper and press, use between the hopper and press, with groundingwith grounding

Scope Mo, Ni, C Scope Mo, Ni, C Low Alloy SteelsLow Alloy Steels

Molybdenum range from 0.3% to 1.5%Molybdenum range from 0.3% to 1.5% Nickel range from 2% to 6.6%Nickel range from 2% to 6.6% Graphite .65% to .9%Graphite .65% to .9%

Density DataDensity DataLow Alloy Mo, Ni, CLow Alloy Mo, Ni, C

MetalMetal NiNi CC G.DG.D S.DS.D

A -30 HPA -30 HP 2%2% .9%.9% 7.22-7.257.22-7.25 7.767.76

A -85 HPA -85 HP 2%2% .8%.8% 7.22-7.257.22-7.25 7.787.78

A-150 A-150 HPHP

6.6%6.6% .65%.65% 7.3-7.347.3-7.34 7.827.82

Astaloy Astaloy 85MO85MO

2%2% .65%.65% 7.25-7.297.25-7.29 7.797.79

Astaloy Astaloy 85 Mo85 Mo

2%2% .9%.9% 7.22-7.257.22-7.25 7.787.78

Low Alloy MO, Ni, CLow Alloy MO, Ni, Cwith Martensitic Heat Treatmentwith Martensitic Heat Treatment

AlloyAlloy Final Final DensityDensity

HardnessHardness

HRCHRCULT,ksiULT,ksi Y.S ksiY.S ksi

..3%Mo3%Mo

2% Ni, 2% Ni,

.9% C.9% C

7.707.70 4747 230.2230.2 214.7214.7

..85% Mo85% Mo

2% NI2% NI

.85% C.85% C

7.767.76 4949 231.9231.9 224.9224.9

1.5% Mo1.5% Mo

6.6Ni6.6Ni

.65% C.65% C

7.787.78 4545 217.4217.4 194.1194.1

Low Alloy MO, Ni, CLow Alloy MO, Ni, Cwith Martensitic Heat Treatmentwith Martensitic Heat Treatment

AlloyAlloy % Elong. % Elong.

ModulusModulusX 10X 10 PSI PSI

Un-Un-notchednotched

ft-lbsfft-lbsf

NotchedNotched

Ft-lbsfFt-lbsf

.3% Mo.3% Mo

2% Ni2% Ni

.9% C.9% C

2.22.2 29.329.3 5454 9.49.4

.85% Mo.85% Mo

2% Ni2% Ni

.85% C.85% C

1.21.2 29.729.7 43.843.8 9.19.1

1.5%Mo1.5%Mo

6.6%Ni6.6%Ni

.65%C.65%C

3.13.1 27.427.4 60.460.4 10.210.2

Low Alloy MO, Ni, C withLow Alloy MO, Ni, C with Three different Heat Treatments Three different Heat Treatments


HardnessHardness


..3%Mo3%Mo

2% Ni, 2% Ni,

.9% C.9% C

7.727.72 3838 181.4181.4 162.0162.0

.3% Mo.3% Mo

2% NI2% NI

.9% C.9% C

7.707.70 4747 230.2230.2 214.7214.7

.3% Mo.3% Mo

2% NI2% NI

.9% C.9% C

7.727.72 4343 211.7211.7 190.8190.8

Low Alloy MO, Ni, C withLow Alloy MO, Ni, C with Three different Heat Treatments Three different Heat Treatments

AlloyAlloy % Elong. % Elong.

ModulusModulusX 10X 10 PSI PSI

Un-Un-notchednotched

ft-lbsfft-lbsf

NotchedNotched

Ft-lbsfFt-lbsf

.3% Mo.3% Mo

2% Ni2% Ni

.9% C.9% C

4.24.2 26.826.8 68.868.8 11.811.8

.3% Mo.3% Mo

2% Ni2% Ni

.9% C.9% C

2.22.2 29.329.3 5454 9.49.4

.3% Mo.3% Mo

2% Ni2% Ni

.9% C.9% C

4.04.0 29.629.6 76.876.8 11.211.2

Properties ObservationsProperties Observations

Low alloy content gives properties Low alloy content gives properties comparable to higher alloy contentcomparable to higher alloy content

It is possible to save on high cost alloy It is possible to save on high cost alloy components Mo, Nicomponents Mo, Ni

Process gives properties far superior to Process gives properties far superior to comparable P/M conventional formulationscomparable P/M conventional formulations

Process give properties superior to Process give properties superior to wrought and forged due to higher alloy wrought and forged due to higher alloy contentcontent

Properties ObservationsProperties Observations

Heat treatment variation opens doors to Heat treatment variation opens doors to modify properties to fit applicationsmodify properties to fit applications

A variety of surface treatments can A variety of surface treatments can now be used with this process due to now be used with this process due to the lack of porositythe lack of porosity

Costly operations such as resin Costly operations such as resin infiltration can now be eliminatedinfiltration can now be eliminated

Scope Cr,Mo,Mn,Ni,CScope Cr,Mo,Mn,Ni,C

Chromium .75%Chromium .75% Manganese up to .75%Manganese up to .75% Nickel up to 1%Nickel up to 1% Graphite .65% to .9%Graphite .65% to .9%

Density DataDensity DataLow Alloy Cr,Mo,Mn,Ni,CLow Alloy Cr,Mo,Mn,Ni,C

Cr %Cr % Mo % Mo % Mn/Ni Mn/Ni %%

C%C% G.D.G.D.

g/ccg/cc

S.DS.D

g/ccg/cc

.75%.75% .25%.25% .65%.65% 7.15-7.15-7.187.18

7.797.79

.75%.75% .25%.25% .9%.9% 7.15-7.15-7.187.18

7.747.74

.75%.75% .25%.25% .75Mn.75Mn .9%.9% 7.15-7.15-7.187.18

7.697.69

.75%.75% .25%.25% 1% Ni1% Ni .9%.9% 7.15-7.15-

7.187.18

7.707.70

Density DataDensity DataLow Alloy Mo, Ni, CLow Alloy Mo, Ni, C

Mo %Mo % Ni %Ni % C%C% G.D.G.D. S.D.S.D.

.9%.9% 7.297.29 7.707.70

.85%.85% .9%.9% 7.267.26 7.747.74

2%2% .9%.9% 7.257.25 7.797.79

Low Alloy Cr, Mo, CLow Alloy Cr, Mo, Cwith Heat Treatments with Heat Treatments


HardnessHardness


.75 Cr,.25% .75 Cr,.25% Mo, .85% CMo, .85% C

7.437.43 5757 99.499.4 99.499.4

. . 75 Cr,.25% 75 Cr,.25% Mo, .85% CMo, .85% C

7.437.43 4141 180.0180.0 163.6163.6

75 Cr,.25% 75 Cr,.25% Mo, .85% CMo, .85% C

7.417.41 1212 102.7102.7 86.786.7

Low Alloy Cr, Mo, CLow Alloy Cr, Mo, Cwith Heat Treatmentswith Heat Treatments

AlloyAlloy % Elongation% Elongation Un Notched Un Notched ImpactImpact

Ft-lbFt-lb.75 Cr,.25% .75 Cr,.25% Mo, .85% CMo, .85% C

<.5%<.5% 9.29.2

.75 Cr,.25% .75 Cr,.25% Mo, .85% CMo, .85% C

<1%<1% 11.511.5

.75 Cr,.25% .75 Cr,.25% Mo, .85% CMo, .85% C

6.5% 6.5% 61.161.1

Ductile Cast IronDuctile Cast Iron Base formula studied .7% silicon, 2% GraphiteBase formula studied .7% silicon, 2% Graphite Alloying components added with Alloying components added with

lubricant/additives as a master batchlubricant/additives as a master batch Formula pressed green 6.95 to 7.00g/ccFormula pressed green 6.95 to 7.00g/cc Sintering 2180 F 25%hydrogen/75% nitrogen Sintering 2180 F 25%hydrogen/75% nitrogen

mixture, 7.67 g/cc as sintered, gray cast ironmixture, 7.67 g/cc as sintered, gray cast iron Heat treated, similar to conventional cast Heat treated, similar to conventional cast

7.44g/cc after heat treatment (ductile cast)7.44g/cc after heat treatment (ductile cast)

Ductile Cast IronDuctile Cast IronHeat Treated Gray Cast IronHeat Treated Gray Cast Iron

Easily machined Easily machined Low porosity, near full densityLow porosity, near full density For machine applications with fair degree For machine applications with fair degree

of toughness with high yield strengthof toughness with high yield strength Nodular cast iron possibleNodular cast iron possible Many micro structures variations based on Many micro structures variations based on

different heat treatments, ferritic, pearlitic, different heat treatments, ferritic, pearlitic, or martensiticor martensitic

Gray cast iron as sintered, etched

Heat treated, etched

Dimensional Control VariablesDimensional Control Variables

Green density gradients - highly effective Green density gradients - highly effective mobile lubricant, volume at G.D. mobile lubricant, volume at G.D.

Elephant foot- caused by friction forces on Elephant foot- caused by friction forces on support medium- reduced friction mediumsupport medium- reduced friction medium

Temperature –tendency to slump with Temperature –tendency to slump with temperature and time- controlled time and temperature and time- controlled time and temperaturetemperature

Liquid phase components- uniformity of Liquid phase components- uniformity of component and temperature component and temperature

Dimensional Stability ExamplesDimensional Stability Examples

High Nickel 4%,Mo,CHigh Nickel 4%,Mo,C Part design, bushing 1.5 In. O.D.,1in I.D. Part design, bushing 1.5 In. O.D.,1in I.D.

height ~1inch height ~1inch Ave. Density green 7.28g/cc Ave. Density green 7.28g/cc Ave. Density Sintered 7.79g/ccAve. Density Sintered 7.79g/cc Max. roundness Max. roundness

top .002,mid .001,btm .002 inchestop .002,mid .001,btm .002 inches Max taper .003 inchesMax taper .003 inches


Nickel 2%,Mo,CNickel 2%,Mo,C Part design, bushing 1.5 In. O.D.,1in I.D. Part design, bushing 1.5 In. O.D.,1in I.D.

height ~1inch height ~1inch Ave. Density green 7.24g/cc Ave. Density green 7.24g/cc Ave Density Sintered 7.75g/ccAve Density Sintered 7.75g/cc Max. roundness Max. roundness

top .001,mid .001,btm .002 inchestop .001,mid .001,btm .002 inches Max. taper .002 inchesMax. taper .002 inches


.75%Chromium, .25%Mo, .85%C.75%Chromium, .25%Mo, .85%C Part design, modified bushing 2.295 O.D., Part design, modified bushing 2.295 O.D.,

1.186 I.D. .780 height 1.186 I.D. .780 height Ave. Density green 7.16g/cc Ave. Density green 7.16g/cc Ave. Density Sintered 7.65g/ccAve. Density Sintered 7.65g/cc Max. roundness top .002, mid.003, Max. roundness top .002, mid.003,

btm .002btm .002 Max taper .003Max taper .003

ConclusionsConclusions

New net shape processes may open New net shape processes may open significantly new applications for P/Msignificantly new applications for P/M

High levels of alloy content are not needed High levels of alloy content are not needed to get excellent physical propertiesto get excellent physical properties

Properties allow for favorable comparison Properties allow for favorable comparison to cast, wrought and forged applicationsto cast, wrought and forged applications

Heat treatments can significantly modify Heat treatments can significantly modify propertiesproperties

ConclusionsConclusions

A variety of wrought surface treatments A variety of wrought surface treatments will be able to be used with this technologywill be able to be used with this technology

Modifications to de- binding and sintering Modifications to de- binding and sintering will slow introduction to the marketwill slow introduction to the market

Combining heat treating with the sintering Combining heat treating with the sintering process will lead to higher flexibility, process will lead to higher flexibility, customizing properties and cost savingcustomizing properties and cost saving

Forward thinkers will be neededForward thinkers will be needed

Documents

Near Full Density Low Alloy Steel and Ductile Cast Iron by a New P/M Process Dennis Hammond Apex Advanced Technologies