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Transcript of The Impact of New Aerospace Materials, Manufacturing Strategies and Production Schedules on...
The Impact of New Aerospace Materials, Manufacturing Strategies and
Production Schedules on Machining Techniques and Control
SAE Webcast June 4, 2008
Carpenter Technology Corporation participated in a webinar delivered by SAE International’s Aerospace Engineering & Manufacturing magazine.
Carpenter’s manager of the Forged Bar and Billet Business Group presented a comparison of three major iron- and nickel-base alloy systems used in aerospace applications: stainless steels, high strength-high toughness alloys, and high temperature alloys. Tips were offered to help improve machining productivity of the non-stainless materials.
Copyright 2008 CRS Holdings, Inc.
Carpenter Produces Vacuum Melted and/or Remelted Aerospace Alloys
in Three Categories
1. High strength/high toughness steels – found in turbine shafts and structural components
2. Martensitic precipitation hardenable stainless steels - structural components and turbine compressor assemblies
3. Nickel-base superalloys - engine compressor and turbine sections
The information and data presented herein are typical or average values and are not a guarantee of maximum or minimum values. Applications specifically suggested for material described herein are made solely for the purpose of illustration to enable the reader to make his/her own evaluation and are not intended as warranties, either express or implied, of fitness for these or other purposes.
Examples of Two Aerospace High Strength/High Toughness Steels
AerMet® 100 Alloy
– Annealed Hardness RC38
– Aged Hardness RC54
– Toughness 110 ksi√in Maraging 250
– Annealed Hardness RC32
– Aged Hardness RC52
– Toughness 75 ksi√in
Increased hardness and toughness demand rigid machining setups and advanced tooling.
Registered trademarks are property of CRS Holdings, Inc., a subsidiary of Carpenter Technology Corporation.
Examples of Aerospace Stainless Steels
Relative strength and toughness of PH stainless steels
720718
31VNi-30
TEMPERATURE
TE
NS
ILE
YIE
LD
ST
RE
NG
TH
Wasp/901/Thermo-Span
X-750
80A/A-286X-750
41909706
75131V
Ni-30/80A/A-286
X-750
720
71841
909/706Thermo-Span
Wasp/901751/X-750
80AA-286X-750
75131V
Ni-30
706Waspaloy
901
720
41718
720
41
720
41Waspaloy
31V/751
Waspaloy
41
720
Waspaloy
Ni-3080A
751901/31V
75°F(24°C)
1500°F(815°C)
1200°F(650°C)
1300°F(705°C)
1400°F(760°C)
1600°F(870°C)
Age-Hardenable Superalloy Selectaloy Diagram (Yield Strength)Age-Hardenable Superalloy Selectaloy Diagram (Yield Strength)
Examples of Nickel-Base Superalloys
Characteristics of Machinability
Productivity
Tool life
Chip size/removal
Surface roughness
Cycle time
Consistency
Material Characteristics Affecting Machinability
High tensile strengths Large spreads between yield and tensile
strengths High ductility and toughness High work hardening rates Low thermal conductivity
Metallurgical properties responsible formachinability characteristics:
Difficulties Associated With Modern Aerospace Materials
Operating conditions in engines and aerospace structures demand higher strength, higher toughness and higher operating temperatures to improve aircraft efficiency.
The higher alloy content required to achieve these properties and the properties themselves lead to lower machining productivity, shorter tool life and more difficult chip formation and removal.
Effect of Thermal Conductivity
Temperature(F)
15Cr-5Ni PH Speed 400 SFM Feed 0.005 IPR
Project 70+® 15Cr-5Ni Speed 400 SFM Feed 0.005 IPR
Temperature(F)
Effect of Thermal Conductivity
Free Machining Additives in Stainless Steels
Type 303 - 200X Magnification
Effect and Limitations of Sulfur Additions
Tool Design Optimization
Project 70+® Type 303 chips vs. back rake angle 0.062” wide cut-off 180 SFPM,0.001 IPR
Angle - 4 degrees
12 degrees
8 degrees
14 degrees
Impact of Tool Design
Data on Speeds, Feeds and Tool Materials
Visit Carpenter’s Technical Information Database at www.cartech.com
Summary:
Materials are typically selected for their properties rather than their machinability.
Sulfurized alloys machine more economically but are limited to specific grades such as 17-4 and 15-5 stainless.
Wise tooling selection and setup, including tool angle and speed, are the keys to maximizing productivity.
Refer to the searchable technical information database at www.cartech.com for suggested speeds and feeds on more than 100 stainless steels and specialty alloys.
Modern Iron and Nickel Base Aerospace Alloys and Their Impact on Machinability
Thank you for your interest in machinability of alloys in the aerospace industry. More information is available on this site, including product literature, alloy datasheets, and technical articles.
To contact Carpenter, call 1-800-654-6543 in the U.S. or refer to the Contact Us page for the location nearest you.