ASTM A646/A646M-06
(Specification)Standard Specification for Premium Quality Alloy Steel Blooms and Billets for Aircraft and Aerospace Forgings
Standard Specification for Premium Quality Alloy Steel Blooms and Billets for Aircraft and Aerospace Forgings
ABSTRACT
This specification deals with the standard requirements for premium quality alloy steel semifinished rolled or forged blooms and billets for reforging into aircraft and aerospace critical parts such as landing-gear forgings. Covered here are three basic classifications of steel, namely: Class I, steel manufactured by vacuum-induction melting or consumable-electrode vacuum melting process; Class II, air-melted steel manufactured by electric-furnace vacuum degassing process; Class III, air-melted steel manufactured by electric-furnace ladle refining and vacuum degassing processes. Steel materials shall be heat-treated and hot-worked by either hot rolling or forging. Alloy steels shall be examined by heat and product analyses and hardenability tests, and shall conform to chemical composition and maximum annealed Brinell hardness requirements. Quality evaluation tests, such as macrotech, microcleanliness, and nondestructive ultrasonic (both immersion and contact examination) inspection, shall be performed as well.
SCOPE
1.1 This specification covers premium quality alloy steel semifinished rolled or forged blooms and billets for reforging into critical parts such as aircraft landing-gear forgings.
1.2 Blooms and billets, hereinafter referred to as blooms, are semifinished steel products, hot rolled or forged to approximate cross-sectional dimensions. Blooms may be square, round, hexagonal, octagonal, or rectangular in section. For the purposes of this specification, minimum bloom section size will be 16 in.2 [103 cm2].
1.3 This specification covers two basic classifications of steel:
1.3.1 Class I - Vacuum-induction melted or consumable-electrode vacuum melted, or other suitable processes which will satisfy the quality requirements of this specification.
1.3.2 Class II - Air-melted vacuum degassed.
1.3.3 Class III - Air melted electric furnace ladle refined and vacuum degassed
1.4 The values stated in either inch-pound or SI (metric) units are to be regarded separately as standards. Within the text and tables, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
1.5 Unless the order specifies the applicable "M" specification the material shall be furnished to the inch-pound units.
General Information
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Standards Content (Sample)
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Designation: A646/A646M – 06
Standard Specification for
Premium Quality Alloy Steel Blooms and Billets for Aircraft
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and Aerospace Forgings
This standard is issued under the fixed designationA646/A646M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* A788/A788M Specification for Steel Forgings, General Re-
quirements
1.1 This specification covers premium quality alloy steel
A604 Test Method for Macroetch Testing of Consumable
semifinished rolled or forged blooms and billets for reforging
Electrode Remelted Steel Bars and Billets
into critical parts such as aircraft landing-gear forgings.
E45 Test Methods for Determining the Inclusion Content of
1.2 Blooms and billets, hereinafter referred to as blooms,
Steel
are semifinished steel products, hot rolled or forged to approxi-
E114 Practice for Ultrasonic Pulse-Echo Straight-Beam Ex-
mate cross-sectional dimensions. Blooms may be square,
amination by the Contact Method
round, hexagonal, octagonal, or rectangular in section. For the
E127 Practice for Fabricating and Checking Aluminum
purposes of this specification, minimum bloom section size
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Alloy Ultrasonic Standard Reference Blocks
will be 16 in. [103 cm ].
E214 Practice for Immersed Ultrasonic Testing by the
1.3 This specification covers two basic classifications of
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Reflection Method Using Pulsed Longitudinal Waves
steel:
E381 Method of Macroetch Testing Steel Bars, Billets,
1.3.1 Class I—Vacuum-induction melted or consumable-
Blooms, and Forgings
electrode vacuum melted, or other suitable processes which
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2.2 AMS Standards:
will satisfy the quality requirements of this specification.
AMS 2300 Steel Cleanliness, Premium-Quality
1.3.2 Class II—Air-melted vacuum degassed.
AMS 2301 Steel Cleanliness, Aircraft-Quality
1.3.3 Class III—Air melted electric furnace ladle refined
AMS 2304 Steel Cleanliness, Special Aircraft-Quality
and vacuum degassed
1.4 The values stated in either inch-pound or SI (metric)
3. Terminology
units are to be regarded separately as standards.Within the text
3.1 In addition to the terminology requirements of Specifi-
andtables,theSIunitsareshowninbrackets.Thevaluesstated
cation A788/A788M, the following terms that are specific to
in each system are not exact equivalents; therefore, each
this specification apply:
system shall be used independently of the other. Combining
3.2 Definitions:
values from the two systems may result in nonconformance
3.2.1 air-melted vacuum-degassed steel—arc- or induction-
with the specification.
furnace-melted steel that is vacuum treated immediately prior
1.5 Unless the order specifies the applicable “M” specifica-
to or during the operation of pouring the ingot.
tion the material shall be furnished to the inch-pound units.
3.2.2 consumable-electrode vacuum-remelted steel—metal
2. Referenced Documents that has been remelted into a crucible in vacuum from single or
2 multiple electrodes.
2.1 ASTM Standards:
3.2.3 electroslag-melted steel—metal that has been re-
A255 Test Methods for Determining Hardenability of Steel
melted into a crucible from single or multiple electrodes
A388/A388M Practice for Ultrasonic Examination of Steel
utilizinganelectricaldischargethroughmoltenslagasasource
Forgings
of heat.
3.2.3.1 Discussion—For the purposes of this specification
the parent heat from which any electrode for remelting by the
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This specification is under the jurisdiction of ASTM Committee A01 on Steel,
electroslag process has been produced shall have been either
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
melted under vacuum or vacuum degassed immediately prior
A01.06 on Steel Forgings and Billets.
Current edition approved Dec. 1, 2006. Published January 2007. Originally
to or during pouring of the heat.
approved in 1971. Last previous edition approved in 2004 as A646/A646M – 04.
DOI: 10.1520/A0646_A0646M-06.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or Withdrawn. The last approved version of this historical standard is referenced
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM on www.astm.org.
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Standards volume information, refer to the standard’s Document Summary page on Available from Society of Automotive Engineers, 400 Commonwealth Drive,
the ASTM website. Warrendale, PA 15096.
*A Summary of Changes section appears at the end of this standard.
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A646/A646M – 06
3.2.4 vacuum induction me
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