ASTM A355-89(2022)

Standard Specification for Steel Bars, Alloys, for Nitriding

ABSTRACT
This specification covers standard specification for alloy steel bars, suitable for surface hardening by nitriding, designated as Classes A, B, C, and D. Class A and Class D bars are general-purpose bars; Class B bars are free-machining bars; Class C bars contain nickel and are characterized by higher core strength. All classes shall be furnished in the hot-rolled, quenched, and tempered condition. The steel shall be made by the electric-furnace process only. The microstructure resulting from heat treatment shall not show free ferrite in amounts exceeding the prescribed values. The maximum depth of total and partial decarburization of hot-rolled bars and heat-treated bars shall not exceed the amounts prescribed. Heat or cast analysis shall be performed on four classes of steel, wherein the material shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, chromium, aluminum, molybdenum, selenium, and nickel. After quenching and tempering, the steel shall conform to one of the specified hardness ranges.
SCOPE
1.1 This specification covers alloy steel bars, suitable for surface hardening by nitriding, designated as Classes A, B, C, and D. Class A and Class D bars are general-purpose bars; Class B bars are free-machining bars; Class C bars contain 3.50 % nickel and are characterized by higher core strength. All classes are normally furnished in the hot-rolled, quenched, and tempered condition. However, centerless-ground or turned bars, in any of the classes, may be specified by the purchaser. Also, as-rolled, annealed, or unannealed bars suitable for forging may be purchased to this specification. When as-rolled, annealed, or unannealed bars are furnished, Sections 6, 10, and 11 are not applicable.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2022
• ICS: 77.140.60 - Steel bars and rods
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.15 - Bars

Relations

• Refers: ASTM A29/A29M-15 - Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
• Effective Date: 01-Nov-2015
• Refers: ASTM A29/A29M-12 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
• Effective Date: 01-May-2012
• Refers: ASTM A29/A29M-12e1 - Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
• Effective Date: 01-May-2012
• Refers: ASTM A29/A29M-11a - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
• Effective Date: 01-Oct-2011
• Refers: ASTM A29/A29M-11 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
• Effective Date: 01-Apr-2011
• Refers: ASTM A29/A29M-05 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
• Effective Date: 01-May-2005
• Refers: ASTM A29/A29M-04 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
• Effective Date: 01-Mar-2004
• Refers: ASTM A29/A29M-04e1 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
• Effective Date: 01-Mar-2004
• Refers: ASTM A29/A29M-03 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought and Cold-Finished, General Requirements for
• Effective Date: 10-Sep-2003
• Refers: ASTM A29/A29M-99e1 - Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought and Cold-Finished, General Requirements for
• Effective Date: 10-Aug-1999

Overview

ASTM A355-89(2022) - Standard Specification for Steel Bars, Alloys, for Nitriding is an international standard developed by ASTM International. This specification addresses alloy steel bars that are particularly designed for surface hardening by nitriding, an important process in industries requiring wear-resistant surfaces and enhanced fatigue life. The standard defines four steel bar classes - A, B, C, and D - each tailored for specific performance needs including general-purpose usage, free-machining, and applications requiring higher core strength.

ASTM A355-89(2022) establishes clear guidelines on the chemical composition, physical properties, manufacturing processes, and required mechanical properties for these nitriding steel bars. Steel covered by this standard must be produced by the electric-furnace process and supplied in various conditions including hot-rolled, quenched and tempered, centerless-ground, or turned.

Key Topics

• Steel Bar Classes:

  • Class A & D: General-purpose alloy steel bars.
  • Class B: Free-machining steel bars for easier fabrication.
  • Class C: Nickel-containing bars offering higher core strength.

• Manufacturing & Conditions:

  • Bars are typically supplied hot-rolled, quenched, and tempered.
  • Centerless-ground or turned bars can be specified.
  • Options for as-rolled, annealed, or unannealed bars exist, where specific requirements may not apply.

• Chemical Composition Requirements:

  • Precise limits for carbon, manganese, phosphorus, sulfur, silicon, chromium, aluminum, molybdenum, selenium, and nickel.
  • Four unique chemistry profiles corresponding to each class, providing predictable properties for end-use performance.

• Decarburization Control:

  • Maximum allowable depth of decarburization for both hot-rolled and heat-treated products is defined, ensuring surface integrity for effective nitriding.

• Hardness and Microstructure:

  • After heat treatment (quenching and tempering), bars must meet specified hardness ranges to guarantee mechanical performance.
  • The microstructure must show limited, controlled amounts of free ferrite, verified by metallographic examination.

• Dimensional Tolerances and Straightness:

  • ASTM A355 specifies strict tolerances for bar dimensions and straightness to ensure material consistency and suitability for machining or forging.

Applications

The standards and material properties outlined in ASTM A355-89(2022) are crucial for industries and applications that demand high surface hardness, wear resistance, and fatigue strength after nitriding. Notable applications include:

• Automotive: Gears, camshafts, crankshafts, and other engine components that require hardened surfaces for longevity.
• Aerospace: Shafts, bushings, and bearing components where wear resistance and core strength are critical.
• Manufacturing Equipment: Tooling, dies, and components subject to cyclic loading or abrasive environments.
• General Engineering: Heavy-duty machinery parts that must maintain a tough, durable surface while possessing a resilient core.

These applications benefit from the precise control over chemical composition and heat treatment, allowing engineers to select and specify alloy steel bars that will respond reliably to nitriding processes.

Related Standards

• ASTM A29/A29M: General requirements for steel bars, both carbon and alloy, hot-wrought, referenced throughout ASTM A355 for dimensional and quality control.
• Other ASTM Alloy Steel Standards: Consider related specifications depending on unique fabrication, processing, or end-use requirements.
• International Equivalents: Similar standards may exist under ISO or EN designations for alloy steel products intended for nitriding.

Practical Value

Organizations adopting ASTM A355-89(2022) can ensure:

• Consistency in mechanical properties and surface hardenability.
• Reliable material performance in demanding nitrided applications.
• Clear communication between suppliers and purchasers through defined classes and ordering information.
• Compliance with international standardization principles and trade requirements.

By following this standard, manufacturers and end-users optimize their alloy steel selection and processing for critical, high-performance engineering applications requiring nitrided surfaces.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:A355 −89 (Reapproved 2022)
Standard Specification for
Steel Bars, Alloys, for Nitriding
This standard is issued under the fixed designation A355; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 Name of material (alloy steel bars, for nitriding),
3.1.3 Surface finish (Section 14),
1.1 This specification covers alloy steel bars, suitable for
3.1.4 Cross-sectional shape,
surface hardening by nitriding, designated as ClassesA, B, C,
and D. Class A and Class D bars are general-purpose bars;
3.1.5 Size,
Class B bars are free-machining bars; Class C bars contain
3.1.6 Length (Section 13),
3.50% nickel and are characterized by higher core strength.
3.1.7 Class (Section 1),
All classes are normally furnished in the hot-rolled, quenched,
3.1.8 Thermal treatment (Section 6),
and tempered condition. However, centerless-ground or turned
3.1.9 Hardness (Section 11),
bars, in any of the classes, may be specified by the purchaser.
3.1.10 Microstructure when desired (Section 7),
Also, as-rolled, annealed, or unannealed bars suitable for
3.1.11 Report of ladle analysis if desired (Section 9),
forgingmaybepurchasedtothisspecification.Whenas-rolled,
annealed,orunannealedbarsarefurnished,Sections6,10,and
3.1.12 Straightness (Section 10),
11 are not applicable.
3.1.13 ASTM designation A355, and
1.2 The values stated in inch-pound units are to be regarded 3.1.14 End use, exceptions to the specification, or special
as standard. The values given in parentheses are mathematical requirements.
conversions to SI units that are provided for information only
and are not considered standard. 4. Process
1.3 This international standard was developed in accor-
4.1 The steel shall be made by the electric-furnace process
dance with internationally recognized principles on standard-
only.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5. Discard
mendations issued by the World Trade Organization Technical
5.1 Sufficient discard shall be made from each ingot to
Barriers to Trade (TBT) Committee.
ensure freedom from injurious piping and undue segregation.
2. Referenced Documents
2 6. Quenching and Tempering
2.1 ASTM Standard:
A29/A29MSpecificationforGeneralRequirementsforSteel
6.1 The bars shall be given a liquid quench followed by a
Bars, Carbon and Alloy, Hot-Wrought
tempering treatment at a temperature not lower than 600°C
(1112°F) to produce a fine spheroidized structure.
3. Ordering Information
3.1 Orders under this specification should include the fol- 7. Microstructure
lowingasrequiredtoadequatelydescribethedesiredmaterials:
7.1 When specified the microstructure resulting from the
3.1.1 Quantity (weight or number of pieces),
heat treatment specified in Section 6 shall not show free ferrite
in amounts exceeding those prescribed in Table 1. Other
percentages of free ferrite may be supplied by agreement
This specification is under the jurisdiction ofASTM Committee A01 on Steel,
between the manufacturer and the purchaser.
Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee
A01.15 on Bars.
7.2 The amount of free ferrite shall be determined by
Current edition approved Sept. 1, 2022. Published September 2022. Originally
metallographic examination under suitable magnification of a
approved in 1952. Last previous edition approved in 2017 as A355–89 (2017).
DOI: 10.1520/A0355-89R22.
specimen from the bars in the quenched and tempered condi-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tion. The number and location of tests and details of the basis
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
of establishing free ferrite shall be as agreed upon between the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. manufacturer and the purchaser.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A355−89 (2022)
TABLE 1 Permissible Free Ferrite TABLE 4 Hardness Requirements
Permissible Free Hardness
Hardness Scale
Diameter or Thickness, in. (mm) Ferrite Area, Range 1 Range 2
max, % Brinell 223 to 269 248 to 302
Rockwell C 19 to 28 24 to 32
1.00 (25.4) and under 2
Rockwell B 98 to 104 101 to 107
Over 1.00 to 3.00 (25.4 to 76.2), incl 4
Over 3.00 (76.2) 6
12. Permissible Variations in Dimensions
TABLE 2 Per
...