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Dave Lutian
Semester Project
A Review of Alloy Steel Processing and Perspective on the Data used in
Tribological Decision Making
Alloy steel is the most common form of steel used in industry today (98% of annual
steep production in the United States is alloy steel). At Sikorsky, we use alloy steel
for many applications, especially for critically loaded components requiring high
strength such as drive train, rotor and landing gear components. Because alloy steel
plays such a critical role in our society, and in particular dynamic components at
Sikorsky, this class project has presented an opportunity to deepen my knowledge
in the field of alloy steel processing.
This project has three phases:
1. Review of ASM Handbook Volume 5 in order to quantify the number of
processes used in preparing alloy steel for tribological applications.
2. A summary of a specification of one of those processes
3. The perspective on the number of those processes required in order to make
one part.
To begin, there is more information in academia regarding the processing of alloy
steel then could ever be reasonably captured in a short semester project. Even a
review of carefully selected academic articles could create scope creep for a project
of this duration. With that in mind, I chose to selectively review some of the SAE
Specifications and ASM Handbooks that provide design guidance and criteria for
many of our designs at Sikorsky. As a boundary to this short project, I chose to focus
on specifications and handbooks that are used directly at Sikorsky. I performed a
brief review of the following specs with the intention of summarizing processes that
piqued my interest as an engineer:
ASM Handbook Volume 5: Surface Engineering of Carbon and Alloy Steels
SAE AIR4160: Alternatives to Cadmium Plating
SAE AIR5919: (R) Alternatives to Cadmium Plating
SAE ARP1631: Manufacturing Sequence for Fabrication of High-Strength
Steel Parts
SAE AMS2300: Steel Cleanliness, Premium Aircraft-Quality, Magnetic Particle
Inspection Procedure
SAE AMS2401: Plating, Cadmium, Low Hydrogen Content Deposit
SAE AMS2403: Plating, Nickel, General Purpose
SAE AMS2406: Plating, Chromium, Hard Deposit
SAE AMS 2419: Plating, Cadmium-Titanium
SAE AMS2423: Plating, Nickel Hard Deposit
SAE AMS2424: Plating, Nickel Low-Stressed Deposit
SAE AMS2426: Coating, Cadmium Vacuum Deposition
SAE AMS2427: Aluminum Coating Ion Vapor Deposition
SAE AMS2430: Shot Peening, Automatic
SAE AMS2460: Plating, Chromium
SAE AMS2630: Inspection, Ultrasonic Product over 0.5 Inch (12.5mm) Thick
SAE AMS2649: Etch Inspection of High Strength Steel Parts
SAE AMS2759/2: Heat Treatment of Low-Alloy Steel Parts
SAE AMS2759/9: Hydrogen Embrittlement Relief (Baking) of Steel Parts
SAE AMS2800: Identification, Finished Parts
SAE AMS6257: Steel Bars, Forgings, and Tubing 1.6Si 0.82Cr 1.8Ni 0.40Mo
0.08V (0.40-0.44C) Consumable Electrode Vacuum Remelted Normalized and
SAE AMS6417: Steel Bars, Forgings, and Tubing 1.6Si 0.82Cr 1.8Ni 0.40Mo
0.08V Consumable Electrode Vacuum Remelted
SAE AMS6419: Steel Bars, Forgings, and Tubing 1.6Si 0.82Cr 1.8Ni 0.40Mo
0.08V (0.40-0.45C) Consumable Electrode Vacuum Remelted
SAE AMS-C-8837: Coating, Cadmium (Vapor Deposited)
SAE AMS-QQ-C-320: Chromium Plating (Electrodeposited)
SAE AMS-S-13165: Shot Peening of Metal Parts
SAE AMS-STD-2154: Inspection, Ultrasonic, Wrought Metals, Process for
SAE AS1182: Standard Machining Allowance, Aircraft-Quality and Premium
Aircraft-Quality Steel Bars and Mechanical Tubing
SAE ARP4462: Barkhausen Noise Inspection for Detecting Grinding Burns in
High Strength Steel Parts
After briefly reviewing the following specs, I will summarize the three point of this
project referencing the following publications:
ASM Handbook Volume 5: Surface Engineering of Carbon and Alloy Steels
SAE AMS2460: Plating, Chromium
SAE ARP1631: Manufacturing Sequence for Fabrication of High-Strength
Steel Parts
ASM Handbook Volume 5: Surface Engineering of Carbon and Alloy Steels
It is obvious that we use a number of various methods to prepare steel parts for use
in tribological applications. ASM Handbook Vol. 5 provides an inclusive overview of
alloy steels, and includes the processes and corresponding methodologies for
preparing steel parts for contact. The handbook provides information on the
following processes:
 Cleaning, including: abrasive blasting, tumbling, brushing, acid pickling, salt
bath descaling, alkaline descaling, acid cleaning, hot emulsion hand slush,
spray emulsion, boiling alkaline, hot alkaline soak, hot rinse, vapor
degreasing, solvent wiping, alkaline dipping, steam, and surfactant spraying.
 Finishing, including: abrasive flow, abrasive blasting including shot peening,
barrel tumbling, grinding, brushing and buffing, centrifugal barrel,
electrochemical, electropolishing, hand deburring, spindle finishing, thermal
energy, and vibratory.
Conversion coatings, including: phosphate coatings (iron phosphate, zinc
phosphate, and manganese phosphates) and chromate coatings. The
handbook cites a typical chromate process. For an electrogalvanized strip:
electrogalvanizing, multiple stage warm water rinse, conversion coating
application, cold water rinse, post treatment. For a hot-dip galvanized strip:
Hot-dip galvanizing, surface conditioning (heat treatment), conversion
coating application, warm air-drying, and oiling.
Hot-dip coating processes, including: hot dip galvanizing and hot dip
aluminum coatings. The handbook discusses the nature of the coatings,
hardness and abrasion resistance, adhesion and impact resistance, corrosion
protection, consequences of atmospheric exposure (industrial and urban
environments, rural and suburban, and marine), effects of temperature,
performance in salt and fresh water, performance in soils, and paint adhesion
and performance.
Hot-dip aluminum zinc coatings, including: Microstructure of the 55Al-Zn
coating, protection of aluminum zinc alloys, atmospheric corrosion
resistance (corrosion mechanisms, aqueous corrosion resistance, corrosion
in natural waters, andcorrosion in soils)
Hot-dip Lead Alloy (Terne) Coatings, including: applications, forming,
corrosion characteristics, joining, painting and handling considerations,
nickel terne, and composite coatings.
Electrogalvanizing, including: Nature of the electrogalvanized coating,
advantages, limitations, and applications.
Electroplating, including: surface preparation, nickel plating, plating baths,
applications and properties for electroless nickel plating, chromium plating,
zinc plating, cadmium plating, and tin plating.
Metal cladding, including: the principal cladding techniques, noble metal clad
systems, transition metal systems and complex multi-layer systems.
Organic coatings, including: how paint films deter corrosion, prepaint
processing, differences between prepaint and postpaint, part design
considerations, selection guidelines, and advantages of prepainted steels.
Painting with zinc-rich paints, including: zinc dust/zinc oxide coatings, zincrich coatings (surface preparation, nature of zinc-rich coatings, organic zincrich coatings, and inorganic zinc-rich coatings), and a comparison between
zinc dust/zinc oxide paint and zinc-rich coatings.
Porcelain Enameling, including: coating materials, discussion on steel
substrates, and coating properties.
Thermal Spray Coatings, including: applicability to steel (buildings, bridges,
towers, radio and TV antenna masts, steel gantry structures, high-power
search radar aerials, overhead walkways, railroad overhead line support
columns, electrification masts, tower cranes, traffic island posts, and street
and bridge railings), corrosion protection by thermal spraying, service life
estimates, service life versus coating thickness for 90Al-10MMC coating,
wear coatings, coatings used for hardfacing applications (aluminum bronze;
soft bearing coatings: tobin bronze, Babbitt, and tin; hard bearing coatings:
Mo/Ni-Cr-B-Si blend, molybdenum, high-carbon steel, alumina/titania,
tubgsten carbide, Co-Mo-Cr-Si, Fe-Mo-C; aluminum oxide; chromium oxide;
tungsten oxide; chromium carbide; Cu-Ni-In; Cu-Ni; Co-Cr-Ni-W; WC/Ni-CrB-SiC; Ni-Cr-B-SiC-Al-Mo; Ni-Al/Ni-Cr-B-SiC), and oxidation protection.
Hardfacing, including: welding processes, hardfacing materials, and
composition, hardness, and abrasion data for build-up alloys and metal-tometal wear alloys
Vapor deposition coatings, including a brief discussion on Physical Vapor
Deposition (PVD) and Chemical Vapor Deposition (CVD) processing and a
discussion on ion plating for the aircraft industry (landing gear, fastener
Surface modification, including: ion implantation and laser surface
processing including a discussion on laser surface heat treatment (as
discussed in class on December 2).
Surface hardening, including: a brief description of the benefits of common
surface hardening processes (carburizing, carbonitriding, nitriding, induction
hardening, and flame hardening), discussion of flame, induction, and highenergy beam methods (flame hardening, induction hardening, and highenergy beam methods), discussion of diffusion methods (carburizing,
nitriding, and carbonitriding), a discussion of carburizing methods (gas
carburizing, vacuum carburizing, plasma carburizing, salt bath carburizing,
and pack carburizing), and brief descriptions of carbonitriding and ferritic
The ASM Handbook provides a wealth of data regarding surface treatments for steel
applications. Eighty-eight process types are identified in the summary above. As
part of this project, I began to think about how to capture this data in a quick, useful
way for engineering needing to make decisions with regard to surface treatments
when designing steel components. In order to quickly gain access to the data for the
purposes of making an engineering design decision, it would be useful for this data
to be stored in database format. In this type of format, engineers could input a set of
design requirements, and a database could pull all applicable data from the ASM
Handbook in order to provide the applicable process options to the engineer
instantly. While this is not a technical breakthrough, this convenience could enable
engineers to become more familiar with the processes and procedures suitable for
their applications without looking through the ASM Handbook.
I have applied this methodology to the “Cleaning” section of the AMS Handbook
only, as a template for what this sort of database might look like. It is an excel file
with all cleaning methods used for steel for a variety of applications (removal of
pigments oils, scaling, machining debris, etc.) and frequencies (seldom in the
process vs. high rate production). The excel file itself uses the autofilter function to
select the desirable cleaning processes for the application and frequency required
for the engineer. This sort of database might be expanded and enhanced in order to
provide engineers with a quick, seamless reference to the otherwise verbose ASM
handbook. I am confident that there are many types of engineering volumes in
which this sort of tool could be useful. The excel file has been included as a
deliverable for this project.
SAE AMS2460: Plating, Chromium
The purpose of the summary is to provide the reader with a basis for the structure
of AMS specifications. Specification exist for the majority of the processes listed in
the AMS Handbook, and demonstrate the attention detail and the level of data that
engineers need to access in order to make sounds technical decisions with regard to
parts in tribological applications.
This particular specification reviews the requirements for chromium plating for all
materials. As chromium plating has multiple applications for steel (wear resistant
coatings for tribological surfaces and decorative coatings), I felt that this was an
appropriate specification to summarize. The summary of the spec’s content is
1. Scope
1.1. Purpose
1.2. Application
1.2.1. Restriction
1.3. Safety-Hazardous Materials
1.4. Classification
1.4.1. Classes
1.4.2. Appearance
2. Applicable documents
2.1. SAE Publications
2.2. ASTM Publications
2.3. Aerospace Industries Association Publications
3. Technical Requirements
3.1. Material
3.1.1. Basis Metal Quality
3.1.2. Parts dimensions shall be met after plating
3.1.3. Pening
3.2. Preparation
3.2.1. Stress Relief Treatment
3.2.2. Cleaning
3.2.3. Electrical Contact Points
3.2.4. Zincate treatment for aluminum alloys
3.3. Procedure
3.3.1. Parts shall be plated by electrodeposition onto a properly prepared
surface. Procedures and parameters shall meet all requirements in this
3.3.2. Underplating Class 1 plating shall be applied over an intermediate nickel
plating Class 2 plating shall be applied directly onto the substrate
material (with exceptions) Underplate shall not be substituted for any of the chromium
plate thickness
3.3.3. All plating re-start procedures shall have prior approval
3.3.4. Notes on Hydrogen Embrittlement relief
3.4. Properties
3.4.1. Thickness Restriction on thicknesses for recessed surfaces Class 1 minimum thickness (0.00001 in) Class 2 minimum thickness (0.002 in)
3.4.2. Adhesion requirements and testing (knife-chisel or blend test) Class 2 Adhesion evaluation – optional method
3.4.3. Hardness (Class 2 only)
3.4.4. Porosity (Class 2 only) Class 2 plating, criteria for passing the testing in,. Description of Potassium Ferricyanide (Ferroxyl) Porosity Test
3.4.5. Hydrogen Embrittlement
3.5. Quality
3.5.1. Surface texture and appearance requirements Boundary requirements Luster requirements
4. Quality Assurance Provisions
4.1. Responsibility for Inspection
4.2. Classification of Tests
4.2.1. Acceptance Tests include thickness, adhesion, and quality of samples
from each lot. Hardness, porosity, and hydrogen embrittlement may
also be acceptance test criteria
4.2.2. Description of Periodic Tests Process Control Records Interruption of production
4.2.3. Preproduction tests Requirement to pass hydrogen embrittlement tests before
plating production parts
4.3. Sampling - definition of “lot”
4.3.1. Nondestructive tests - description
4.3.2. Destructive tests – description
4.3.3. Sample configuration Samples for thickness, adhesion and hardness tests Samples for porosity tests Samples for Hydrogen Embrittlement tests Periodic and Preproduction Test Specimens for Thickness,
Adhesion, Hardness, and Porosity
4.4. Approval
4.4.1. Approval of process and control factors Records of test results
4.4.2. Test requirements and approvals for process changes
4.4.3. Description of control factors
4.5. Reports – requirements for shipment
4.6. Resampling and Retesting
4.6.1. Requirements for retesting parts after a failed test Specification of stripping method and criteria
4.6.2. Definition of nonconforming process per test results and follow-on
Preparation for Delivery
5.1. Packaging and Handling
5.2. Shipment preparation
Acknowledgement of specification
Rejections – definition
8.1. Notes on document revision
8.2. Notes on compliance with dimensions
8.3. Notes on part delivery and processibility
8.4. Guidance
8.4.1. Guidance on shot peening
8.4.2. Guidance on hydrogen embrittlement Control and testing Alkaline cleaning Acid dip Final step in cleaning Plating of nickel alloys
8.4.3. Class 1 Chromium Plating Function Deposition
Note on plating thickness
8.4.4. Class 2 Chromium Plating Description Designations Plating by electrodisposition Recommended maximum thickness Note on grinding
8.5. Compliance with ARP4992
8.6. Test Specimen material – acceptance criteria
8.6.1. Transformation Hardening Steels
8.6.2. CRES
8.6.3. High Alloy Steels
8.6.4. Tool Steels
8.6.5. Heat Resistant Alloys
8.6.6. Aluminum Alloys
8.6.7. Titanium Alloys
8.6.8. Copper Alloys
8.7. Note on Hydrogen Embrittlement for certain alloys
8.8. Terms used for reference
8.9. Units of measurement
SAE ARP1631 Manufacturing Sequence for Fabrication of High-Strength Steel
This final section of the project will provide true perspective on the amount of data
that needs to be obtained in order to make just one part. The sheer number of
processes in the ASM Handbook and having seen the summary of a specification for
one of those processes, the reader should have grasped an understanding of just
how much information is out there. Now – for all practical applications, how do we
find it? While we will not be summarizing ARP1631 in its entirety, this section of
the report aims to show the quantity of engineering information required to make
one part. I intend to bring full circle the concept that in order to make a sound
engineering decision, a large amount of data from multiple sources is required. A
database to consolidate even a part of this data would be extremely helpful in
assisting our engineers in streamlining their decision-making processes.
The following is a summary of the flow chart listed as “Figure 1” in ARP1631:
As the reader can see, there are many decisions that need to be made in order to
properly process one component, along with several iterations and “do loops” in the
This study has taught me two things.
1. There is a massive amount of data available for technical decision making,
2. A company’s ability to manage the available data and making sound technical
decisions quickly will enable that company to find an advantage.
I look forward to implementing these lessons as a M.Eng project that tackles (a
portion) of the data listed herein in order to produce a useable database for
tribological surface treatments. I have hope that a tool like this could be useful to a
company like Sikorsky or others.
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