ferri umm 54 machining study

8/15/2019 Ferri Umm 54 Machining Study

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Pankl Aerospace Systems

Machining Investigation of Ferrium M54

1

NAVAIR Public Release #2013-168

Distribution Statement A- "Approved for public release; distribution is unlimited"

Executive Summary

This study compared machining operations that are typically required to produce aircraft landing gear

components when using Ferrium® M54™ vs. AerMet ® 100 and developed quantitative and qualitative

results that will assist in determining initial manufacturing processes and cost comparisons. While no

limitations were found for machining either alloy, it was considerably easier to remove material through

outside diameter turning operations from Ferrium M54 vs. AerMet 100, reducing machining times by 30%

to 50% and while achieving superior or comparable surface finish. However, it was generally easier to drill

holes and thread an outside diameter in AerMet 100 vs. Ferrium M54. Other operations such as face

milling, inner diameter turning, and hole tapping were comparable. Deep bottle boring operations were

also investigated for Ferrium M54, and no limitations were found. In terms of net effect on the cost of

manufacturing components, the information obtained from this study can be applied to estimate the cost

of machining of a component. For example, a currently funded Navy program (Contract Number N68335-

11-C-0369) is evaluating T-45 hook shanks produced from Ferrium M54. For this case, it is estimated that

the cost to machine a T-45 hook shank component from Ferrium M54 is up to 15% less than one made

from AerMet 100, and up to 20% more than one made from 300M.


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I. Introduction

The goal of this study was to evaluate the machinability of Ferrium M54 and determine the initial machine

inputs for basic manufacturing processes. Ferrium M54 was initially conceived and developed to be an

ultrahigh-strength and high-toughness structural steel to replace AerMet 100 for the Navy's high strength,

high fracture toughness applications such as landing/arresting gear. And while the chemistry of this

material offers some reductions in cost, the main question surrounding this novel material is how it will

machine. Rapid tool wear, poor chip formation, and overheating of the work-piece are all common issues

with high alloy steels that contribute to manufacturing costs. Therefore, it is essential to know any

machining obstacles or benefits that Ferrium M54 will present over AerMet 100.

II. Approach of the Study

A square bar stock of Ferrium M54 at Rockwell C40 hardness with the dimensions of 3.750” x 3.750” x

7.500” served as the raw configuration of the test component. AerMet 100 in the same configuration was

used in the comparison study. The following processes were identified as conventional operations for

landing gear production.

Interrupted Turning, Square to Round Cross Section

Continuous Turning, Outer Diameter

Face Milling

Axial Hole Drilling, Inner Diameter

Continuous Turning, Inner Diameter

Hole Drilling and Tapping

External Thread Turning

Grinding, Outer Diameter

In the interest of efficiency and cost, each machining process was performed on the same test pieces in

sequence. However, each test piece was processed with a different combination of experimental inputs

to generate a broad cross-section of results. While it varies depending on the manufacturing technique,

the inputs included the machine settings (feed rate, spindle speed, depth of cut), cutting tools (style, size,

coatings), and heat treat condition. The results of each set of parameters were evaluated quantitatively

by the machining time and the surface finish of the test piece, as well as qualitatively by the chip formation

and the extent of the tool wear. It should be noted that two pieces were processed in the heat treated


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condition and two in the annealed condition. Heat treatment did not occur until after “Large Hole Drilling”

to optimize material removal prior to hardening. At the conclusion of this portion of the study, a set of

initial parameters for Ferrium M54 were ascertained for basic manufacturing.

Table 1: Ferrium M54 Material Condition for Initial Machinability Study

S/N 0001 S/N 0002 S/N 0003 S/N 0004

Operation

Annealed

(40 HRC)

Hardened

(54 HRC)

Annealed

(40 HRC)

Hardened

(54 HRC)

Annealed

(40 HRC)

Hardened

(54 HRC)

Annealed

(40 HRC)

Hardened

(54 HRC)

Interrupted Turning

(Square to Round

Cross Section)

Continuous Turning

(Outer Diameter)

Face Milling

Axial Hole Drilling

(Inner Diameter)

Continuous Turning

(Inner Diameter)

Hole Drilling and

Tapping

External Thread

Turning

Grinding

(Outer Diameter)

Another study focused on deep bottle boring, a common practice in landing gear production. Deep bottle

boring is the process of machining an ID that tapers out larger than the entrance hole and it provides its

own unique challenges in manufacturing. Unfortunately, this is difficult to replicate with the size

constraints of the test pieces, so another test piece with the raw configuration of 4.00” x 4.00” x 40.00”

was machined. Inputs were tested and evaluated as with the machining investigation for Ferrium M54.


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Figure 1: Finished Configuration of Ferrium M54 (Deep Bottle Bore) Test Piece.

After establishment of initial machining parameters, the second phase of this study was to determine

whether Ferrium M54 has any discernible advantages or disadvantages over AerMet 100 in regards to

machinability and cost. Two test samples of each material were manufactured concurrently to the finished

configuration. The parameters for Ferrium M54 was selected based on the recommendations from the

machining investigation and were kept constant for the multiple test pieces. The parameters for AerMet

100 were derived from prior experience and adjusted based on observations. Again, the metric for

machinability were the work time, chip formation, and tool wear. By running these two materials in

parallel, it was clear how the material affects each operation, and it can be definitively stated whether

parts can be manufactured more effectively with Ferrium M54 or AerMet 100.

Figure 2: Finished Configuration of Ferrium M54/AerMet 100 Test Piece.


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Table 2: Ferrium M54 and AerMet 100 Material Condition for Machinability Comparison Study

Ferrium M54 AerMet 100

Operation

Annealed

(40 HRC)

Hardened

(54 HRC)

Annealed

(40 HRC)

Hardened

(54 HRC)Interrupted Turning

(Square to Round

Cross Section)

Continuous Turning

(Outer Diameter)

Face Milling

Axial Hole Drilling

(Inner Diameter)

Continuous Turning

(Inner Diameter)

Hole Drilling and

Tapping

External Thread

Turning

Grinding

(Outer Diameter)

III. Machining Investigation of Ferrium M54

The following sections detail each machining operation conducted. Special considerations, experimental

machine parameters, results, and engineering recommendations are all included within each section.

A. Interrupted Turning, Square to Round Cross Section

The following table outlines the various test parameters used throughout interrupted turning. Since thepart needed to be fixtured on the machine, only one side of the part could be cut at a time. This allowed

for additional machine settings to be compared as each side can be processed differently. For this

operation, the recommended parameters lasted the entire roughing stage without insert breakage or

significant wear. Therefore, a robust, high-grade carbide insert is ideal. Brittle grades of carbide must be

avoided and the spindle speed kept low, because of the interrupted cut.


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Figure 3: Schematic of Input and Finished Stock for Interrupted Turning

Table 3: Machine Parameters for Interrupted Turning of Ferrium M54

Machine: CNC Lathe, Mori-Seiki SL-403C/2000

Coolant: Starchem Co., Starbright 485/Water Solution

Insert S/N Side

Pass

Type

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ingersoll

CNMG

432 MT

TT5030

0001

1Rough 409 0.010 0.080

20 64Finish 0.008 0.080

2 Rough 281 0.015 0.080 130Finish 0.012 0.080

0002

1Rough 250 0.012 0.100

60 125Finish 250 0.010 0.020

2Rough 250 0.018 0.100

45 125Finish 250 0.015 0.020

Seco

CNMG

432 M5TP1500

0003

1Rough 200 0.010 0.080

45 90Finish 200 0.008 0.030

2Rough 145 0.010 0.080

44 90Finish 218 0.008 0.030

0004

1Rough 250 0.012 0.100

60 64Finish 250 0.005 0.020

2Rough 250 0.006 0.100

80 64Finish 250 0.005 0.020

Bold font represents ideal machine settings from initial test matrix


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B. Continuous Turning, Outer Diameter

This operation does not produce much wear on the tool, but for feed rates greater than 0.015 inches/rev,

there were signs of excessive heat transfer on the outer diameter. The recommended parameters

achieved a good machined surface finish with a conservative machine time.

Figure 4: (left) Test Piece Fixtured in the Lathe.

(right) Schematic of Input and Finished Stock for Continuous Turning

Table 4: Machine Parameters for Continuous OD Turning of Ferrium M54

Machine: CNC Lathe, Mori-Seiki SL-403C/2000 Coolant: Starchem Co., Starbright 485/Water Solution

Insert S/N Side

Pass

Type

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Seco

DNMG

432 M3

TP2500

0001

1Rough 350 0.012 0.080

45 125Finish 350 0.010 0.020

2Rough 350 0.018 0.080

30 250Finish 350 0.015 0.020

00021

Rough 300 0.015 0.060

10 90Finish 300 0.008 0.015

2Rough 300 0.017* 0.060

7 125Finish 300 0.010 0.015

(Table is continued on the next page)


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Sandvik

DNMG

432 MF

Gr2015

0003

1Rough 350 0.012 0.080

15 90Finish 350 0.010 0.020

2Rough 350 0.010 0.080

12 64Finish 350 0.008 0.020

0004

1Rough 300 0.015 0.060

10 90Finish 300 0.008 0.015

2Rough 300 0.020 0.060

7 125Finish 300 0.012 0.015


* Feed rate initially set at 0.020 IPR but was reduced to 0.017 IPR

C. Face Milling

A large diameter cutting face would be the most efficient approach to this operation. It provides a more

stable machining set-up, each insert must remove less material, and the resulting finish is more consistent.

For the two-inch cutter, there was little to no wear on any of the inserts and it had less burrs on the exit

edge of the face. For the one-inch cutter, the operation generated lots of noise and vibration, which would

cause maintenance issues in the long term. Also, the chips cut were discolored purple and dark brown,

implying the inserts were beginning to dull and rub against the cutting surface. The recommended tools

could withstand very aggressive cuts, reducing lead time and insert wear.

Figure 5: Schematic of Input and Finished Stock for Face Milling


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Figure 6: (left) Test Piece Set-Up Prior to Face Milling. (right) Test Piece after Face Milling.

Figure 7: (left) 1-inch Face Milling Cutter and Inserts. (right) 2-inch Face Milling Cutter and Inserts

Table 5: Machine Parameters for Face Milling of Ferrium M54

Machine: CNC Vertical Mill, Mazak Super Velocity 2000L


Cutter

Body S/N

Tool

Diameter

(in)

Pass

Type

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Sandvik

R245-12 T3

E-PL 4230

0001

2.00

Rough 700 15.0 0.08013 32

Finish 700 10.0 0.050

0002

Rough 700 22.5 0.080

9 32Finish 700 15.0 0.050

Ingersoll

APKT120308R

IN2005

0003

1.00

Rough 800 14.0 0.06018 32

Finish 800 12.0 0.030

0004Rough 800 28.0 0.060

12 90Finish 800 24.0 0.030



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D. “Large” Hole Drilling on Axis

In order to drill a hole into the part in one pass, the diameter of the drill head must be equal to the

diameter of the hole generated. Also, there’s a limited amount of chip breakers and grades available for

this diameter, so this operation concentrated mainly on the machine settings instead of the cutting tools.

The feed rate for this part was relatively high for this tough material because the length of the bore was

short compared to the diameter. For longer parts, it is recommended that the feed rate be slowed down

to mitigate the need for tool changes.

Figure 8: Schematic of Input and Finished Stock for Hole Drilling

Table 6: Machine Parameters for Large Hole Drilling of Ferrium M54

Machine: NC Gun Drill Machine, Pratt & Whitney Gun Drill Machine

Coolant: W.S. Dodge Oil Company, Gun Drill Oil #5110

Gun Drill

Head S/N

Tool

Diameter

(in)

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Machine

Time

(min)

Surface

Finish

(μin)

EJ Co.

420.6-103

G24 D1.8

0001 1.800 148 0.0030 20 90

0002 1.800 155 0.0030 20 90

0003 1.800 155 0.0015 45 90

0004 1.800 155 0.0015 45 90



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E. Continuous Turning, Inner Diameter

For the annealed parts, we could be aggressive without any significant chip wear. Therefore, we settled

for a relatively high feed rate with a moderate speed. For the heat treated parts, the same parameters

would not be suitable for the increased hardness. It was necessary to slow the machine settings by fifty

percent, which almost doubles the machining time over the non-heat treated parts.

Figure 9: Schematic of Input and Finished Stock for Continous Turning

Table 7: Machine Parameters for Continuous ID Turning of Ferrium M54



Insert S/N

Heat

Treat

Pass

Type

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ingersoll

CNMGMT

SN-0001 ANRough 250 0.014 0.050

62 90Finish 250 0.010 0.010

SN-0002 HT

Rough 75% 0.014 0.050

30 100Finish 60% 0.010 0.010

SN-0003 HTRough 50% 0.014 0.050

140 100Finish 50% 0.010 0.010

Seco

CNMG

M5

SN-0004 ANRough 300 0.012 0.025

108 64Finish 250 0.008 0.010


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F. “Small” Hole Drilling and Tapping

For this operation, four end mills at the finished diameter were used to machine the four holes. The end

mills were made of carbide and did not have any surface coatings. Also prior to milling, a spot drill was

used to help locate the end mills on the work face of the test piece. To generate the appropriate pitch in

hole tapping, the feed rate must be a fixed value (the inverse of the pitch). Therefore, all trials were

conducted at the same feed rate. Next, for the Ø 0.1875” hole, a stop-off was built periodically into the

program to clear chips and reduces wear. This is crucial for smaller diameter holes to ensure chip build up

does not interfere with machining. Lastly, any machine time less than one minute in the following tables

were denoted as 1.

The R0.0938” hole presented some difficulty, because it required a small diameter hole be milled relatively

deeply. The result was there was some vibration at the tip causing rapid wear and chipping. The same

issue was observed for the ¼” tapping operation, which resulted in the tool breaking in the test piece. It

is recommended that for small diameter drilling, the cutting speed remain low to reduce the torque at

the end of the milling tool. For the heat treated pieces, both the spindle speed and the feed rate were

drastically reduced to account for the increase in hardness. Regardless, there is the potential risk of tool

breakage for this operation. Tool coatings should be explored for potentially extended tool life and wear

resistance.


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Figure 10: Schematic for Input and Finished Stock for Hole Drilling and Tapping

Figure 11: (left) Machine Set-Up for Hole Drilling. (right) Required End Mills and Taps

Table 8: Machine Parameters for Hole Drilling of Ferrium M54 (Annealed Condition)

Machine: CNC Vertical Mill, Mazak Super Velocity 2000L


Cutting

Tool

Drill

Diameter

(in)

Spindle

Speed

(RPM)

Feed

Rate

(IPM)

Machine

Time

(min)

M.A. Ford

Twister XD 3X (Ø 0.750 in) 0.7500 500 2.0 1

Guhring

DIN 6539 (Ø 9.40 mm)0.3701 500 2.5 1

Guhring

DIN 6539 (Ø 8.60 mm)0.3386 500 2.5 1

YG-1 (EDP 93198) 0.1875 500 1.5 1

Table 9: Machine Parameters for Hole Tapping of Ferrium M54 (Annealed Condition)

Cutting

Tool

Thread

Spec.

SpindleSpeed

(RPM)

FeedRate

(IPM)

MachineTime

(min)

OSG Tap

HY-PRO-2832001 7/16-14 150 0.0714 1

OSG Tap

EXO 1714301 1/4-28 150 0.0416 1


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Table 10: Machine Parameters for Hole Drilling of Ferrium M54 (Heat Treated Condition)

Cutting

Tool

Drill

Diameter

(in)

Spindle

Speed

(RPM)

Feed

Rate

(IPM)

Machine

Time

(min)

M.A. Ford

Twister XD 3X (Ø 0.750 in)0.7500 400 1.5 3

Guhring

DIN 6539 (Ø 9.40 mm)0.3701 500 1.0 2

Guhring

DIN 6539 (Ø 8.60 mm)0.3386 500 1.0 1

YG-1 (EDP 93198) 0.1875 500 0.5 5

Table 11: Machine Parameters for Hole Tapping of Ferrium M54 (Heat Treated Condition)

Cutting

Tool

Thread

Spec.

Spindle

Speed

(RPM)

Feed

Rate

(IPM)

Machine

Time

(min)

OSG Tap

HY-PRO-2832001 7/16-14 50 0.0714 1

OSG Tap

EXO 1714301 1/4-28 50 0.0416 1

G. External Thread Turning

A standard V-thread with a pitch of 10 was selected for this operation (2.500” - 10 UN CLASS 2A). Since

the part is short, the test piece was fixtured on a chuck and allowed to extend unsupported on the other

end. Also, the CNC lathe was initially programmed to turn this thread in a single pass due to the small

amount of material removal.

The most significant issue with the Ferrium M54 test piece observed was the presence of chatter on the

flanks of the thread. This indicates that either the set-up lacked rigidity or the machining parameters are

too aggressive causing the cutting tool to have uneven contact with the work-piece. In order to produce

a better surface finish, several actions were taken. Multiple spring passes were taken instead of a single

spring pass to reduce the depth of cut. The spindle speed was lowered for the heat treated pieces. And,

the part was fixtured more securely in the chuck to alleviate any vibration. The part was originally allowed


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to hang 4.0 in. from the face of the chuck jaws but this was incrementally decreased to 2.5 in. to improve

the rigidity of the test piece and reduce chatter. Overall, there were no major limitations found in external

thread turning.

Figure 12: Schematic of Input and Finished Stock for External Thread Turning

Table 12: Machine Parameters for External Thread Turning of Ferrium M54



Insert S/NHeatTreat

Spindle

Speed(RPM)

Feed

Rate(IPM)

Machine

Time(min)

Kennametal

Top Notch NT3R0001 AN 150 0.100 24

Kennametal

Top Notch NJ3014R120002 HT 100 0.100 43

Kennametal

Top Notch NT3R0003 HT 100 0.100 36

Kennametal

Top Notch NJ3014R120004 AN 150 0.100 26



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Figure 13: Chatter on Thread Flanks on Test Pieces

H. Grinding, Outer Diameter

Instead of a direct traverse feed, the grind wheel initially plunged three tracks with a diameter slightly

oversized of the nominal diameter. Then, it came in as a straight pass for the final dimension. This

intermediate step allowed for minimal material removal in the subsequent passes as well as ensures even

wear over the corners of the grind wheel. Overall, the CNC grinding cut the material very easily. There

were no issues of overheating and the wheel only needed to be dressed once for each test piece.

Figure 14: Schematic of Input and Finished Stock for Grinding


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Table 13: Machine Settings for OD Grinding of Ferrium M54

Machine: Shigiya CNC Grinder


Grind Wheel S/N

Heat

Treat

Spindle

Speed

(RPM)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Aluminum Oxide J SN-0001 HT 1750 0.004 23 16

545-J8VH Aluminum Oxide SN-0002 HT 965 0.002 12 16

545-J8VH Aluminum Oxide SN-0003 HT 965 0.002 38 16

Aluminum Oxide J SN-0004 HT 1750 0.004 35 16


IV. Deep Bottle Boring

The raw configuration of the test piece for the deep bottle bore was a 40.00 inch long solid bar with a

square cross section. For ease of fixturing, the two end sections were turned round. Additionally, the raw

material did not include a hole through its axis, so the part was gun-drilled through at a diameter of 2.250

inches. This allowed for 0.125 inches per side of stock material at the necked-down section and 0.250

inches of stock material at the bottled section.

Figure 15: Schematic of Input and Finished Stock for Deep Bottle Boring


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Figure 16: (left) Machine Set-Up for Deep Bottle Boring.

(right) Packed Chips from Inner Diameter of Deep Bottle Bore

The length of the bore relative to the inner diameter presented the need for a thick boring bar to maintain

its rigidity as tool pressure deflects the bar over long distances. In this instance, the 1.75 in boring bar

used to bore 2.40 inch I.D allowed for very little clearance limiting chip evacuation and coolant flow during

machining. Consequently, there is a risk of overheating the part, increased stress on the inserts, and work

hardening the machining surface. Therefore, conservative parameters are recommended.

Table 14: Machine Parameters for Deep Bottle Boring



Insert

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Sandvik

DCMT11T304

FGTT5030

250 0.004 0.020 85 36

The operation initially produced long, thick, and loosely-coiled chips. Also, the leading edge of the chips

where the insert initially cut into the material was jagged, indicating a rough break. The depth of cut was

reduced and an insert with a chip breaker was employed. It is essential for this material not to approach

the machining too aggressively. Also, for the deep bottle bore, there were issues with clogging of the inner

diameter with chips. Ensure that there is a clear, unobstructed flow of coolant at the cutting surface to

flush the chips out the chucked end. All cuts produced a good 36 micro-inch surface finish over the inner


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diameter surface. Improvements to this operation may be possible in time with advancements in

machining technologies to promote chip breaking and removal of chips from the work piece.

V. Comparison of Ferrium M54 and AerMet 100

The objective of this study is to compare the initial machining parameters for Ferrium M54 to that of

typical machining parameters for AerMet 100. This comparison is meant to supply quantitative feedback

for differences in machining between the two alloys. The machining operations selected follow the same

path as the initial study completed and outlined in Section III above. The initial machining parameters for

the Ferrium M54 pieces were based on the initial established results. The machinist/operator was then

allowed to adjust the parameters further to reduce the machining time. The initial parameters for AerMet

100 were selected based on prior experience and adjusted by the machinist/operator as necessary.

A. Interrupted Turning, Square to Round Cross Section

The insert was changed halfway through the operation for both materials. There were similar wear

patterns on all inserts corners. Improvements from the initial machining parameters identified for Ferrium

M54 were increased speed, feed, and depth of cut which led to a reduction in machine time as well as

improved surface finish.

Table 15: Material Comparison for Interrupted Turning

Material

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ferrium M54 250 0.012 0.100 43 64

AerMet 100 150 0.012 0.100 90 90

B. Continuous Turning, Outer Diameter

The ideal machine parameters for Ferrium M54 worked well for AerMet 100. There was some significant

chip wear even though there was no breaking. The spindle speed was dialed down slightly for the AerMet

100.

Table 16: Material Comparison for Continuous OD Turning


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Material

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ferrium M54 350 0.010 0.080 22 90

AerMet 100 280 0.010 0.080 31 90

C. Face Milling

The face cutting inserts showed signs of slightly more wear, however this operation does not cause much strain on

the cutting tool. It is predicted that, over multiple production lots, Ferrium M54 would require less tooling compared

to AerMet 100.

Table 17: Material Comparison for Face Milling

Material

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ferrium M54 700 22.500 0.080 9 32

AerMet 100 700 22.500 0.080 9 32

D. “Large” Hole Drilling on Axis

There was no appreciable difference between Ferrium M54 and AerMet 100 for this operation.

Table 18: Material Comparison for Axial Hole Drilling

Material

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Machine

Time

(min)

Surface

Finish

(μin)

Ferrium M54 155 0.0030 20 90

AerMet 100 155 0.0030 20 90

E. Continuous Turning, Inner Diameter

There was no appreciable difference between Ferrium M54 and AerMet 100 for this operation.

Table 19: Material Comparison for Continuous ID Turning


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Material

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ferrium M54 250 0.014 0.050 62 90

AerMet 100 250 0.014 0.050 65 90

F. “Small” Hole Drilling and Tapping

For the hole drilling, the surface finish was slightly better for the AerMet 100. The machine produced a similar sound

and vibration but it seemed AerMet 100 could be machined more aggressively. There were no major limitations

indentified for Ferrium M54, however slightly reduced feed rates allowed for reduced vibration which will improve

tool life.

Table 20: Material Comparison for Hole Drilling

Drill

Diameter

(in) Material

Spindle

Speed

(RPM)

Feed

Rate

(IPM)

Machine

Time

(min)

0.7500

Ferrium M54 400 1.5 3

AerMet 100 400 1.5 2

0.3701

Ferrium M54 500 1.0 2

AerMet 100 500 1.5 1

0.3386

Ferrium M54 500 1.0 1

AerMet 100 500 1.0 1

0.1875

Ferrium M54 500 1.5 5

AerMet 100 500 1.5 4

For the hole tapping, AerMet 100 cut much more easily. The chips produced were longer as well as tightly-curled

and there was less wear and damage on the milling tools. While the feed rate had to be kept constant for the thread

pitch, there was much less risk of the tool tap breaking or wearing down.

Table 21: Material Comparison for Hole Tapping


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Thread

Spec Material

Spindle

Speed

(RPM)

Feed

Rate

(IPM)

Machine

Time

(min)

7/16 - 14

Ferrium M54 50 0.0714 1

AerMet 100 100 0.0714 1

1/4 - 28

Ferrium M54 50 0.0416 1

AerMet 100 100 0.0416 1

G. External Thread Turning

Using the same parameters for Ferrium M54 produced threads with a severe degree of surface finish issues for

AerMet 100. In general, turning threads on AerMet 100 was tougher and resulted in unwanted chatter. Note that

more spring passes were taken on the Ferrium M54 to reduce chatter and improve surface finish as identified in the

initial study.

Table 22: Material Comparison for Thread Turning

Material

Spindle

Speed

(RPM)

Feed

Rate

(IPR)

Machine

Time

(min)

Ferrium M54 100 0.100 36

AerMet 100 150 0.100 21

H. Grinding, Outer Diameter

The grinding of the Ferrium M54 test piece was performed somewhat more quickly than AerMet 100, however this

was due to set-up considerations and not attributable to any material considerations.

Table 23: Material Comparison for OD Grinding

Grind Wheel

Spindle

Speed

(RPM)

Depth

of Cut

(in)

Machine

Time

(min)

Surface

Finish

(μin)

Ferrium M54 965 0.002 17 16

AerMet 100 965 0.002 25 16

VI. Conclusion


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The initial machinability study for Ferrium M54 was able to establish initial recommended parameters for

various machining operations. There were no limitations found in machining Ferrium M54 for typical

machining processes identified for the various landing gear manufacturing operations. The parameters

established should be considered a good starting point for the various machining operations, but as shown

in the comparison study, improvements can be made as more experience is gained with the alloy which

will allow for further improvements in the machining process and reduction in the machining times.

The deep bottle boring of Ferrium M54 allowed for establishment of initial recommended parameters.

The chip formation observed indicates that an insert with a chip breaker will allow for improved

machinability. There were no limitations found in deep bottle boring of Ferrium M54.

The comparison study between Ferrium M54 and AerMet 100 for typical landing gear operations provided

quantitative feedback that will allow for initial manufacturing processes and costs to be compared. While

no limitations were found for either alloy, Ferrium M54 was easier to turn, while AerMet 100 was easier

to drill small holes and thread. An example of applying the information obtained from this study and

applying it to an example component, such as machining a T-45 hook shank (to support cost analysis under

Navy Contract Number N68335-11-C-0369), the estimated cost to machine a component from Ferrium

M54 is up to 15% less than one made from AerMet 100, and up to 20% more than one made from 300M.

ferri umm 54 machining study

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