ASTM B925-15(2022) - 1.3.2022
 
Significance and Use

5.1?Test specimens are used to determine the engineering properties of PM materials, for example, tensile strength, ductility, impact energy, etc.; property data that are essential to the successful use of PM material standards. Processing PM test specimens under production conditions is the most efficient method by which to obtain reliable PM material property data since in most cases it is impractical or impossible to cut test bars from sintered parts.

5.2?The performance characteristics of metal powders, for example, compressibility, green strength and dimensional changes associated with processing are evaluated using PM test specimens under controlled conditions. The data obtained are important to both metal powder producers and PM parts manufacturers.

5.3?PM test specimens play a significant role in industrial quality assurance programs. They are used to compare properties of a new lot of metal powder with an established lot in an acceptance test and are used in the part manufacturing process to establish and adjust production variables.

5.4?In those instances where it is required to present equivalent property data for a production lot of PM parts, standard test specimens compacted from the production powder mix to the same green density can be processed with the production PM parts and then tested to obtain this information.

5.5?Material property testing performed for industrial or academic research and development projects uses standard PM test specimens so the test results obtained can be compared with previous work or published data.

5.6?Powder metallurgy test specimens may have multiple uses. The dimensions and tolerances given in this standard are nominal in many cases. The user is cautioned to make certain that the dimensions of the test specimen are in agreement with the requirements of the specific test method to be used.

 
1. Scope

1.1?These standard practices cover the specifications for those uniaxially compacted test specimens that are used in ASTM standards, the procedures for producing and preparing these test specimens, and reference the applicable standards.

1.2?Basic tool design and engineering information regarding the tooling that is required to compact the test specimens and machining blanks are contained in the annexes.

1.3?This standard is intended to be a comprehensive one-source document that can be referenced by ASTM test methods that utilize PM test specimens and in ASTM PM material specifications that contain the engineering data obtained from these test specimens.

1.4?These practices are not applicable to metal powder test specimens that are produced by other processes such as cold isostatic pressing (CIP), hot isostatic pressing (HIP), powder forging (PF) or metal injection molding (MIM). They do not pertain to cemented carbide materials.

1.5?Detailed information on PM presses, compacting tooling and sintering furnaces, their design, manufacture and use are not within the scope of these practices.

1.6?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.

1.7?This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8?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.

 
2. Referenced Documents

A34/A34M-06(2021)

Standard Practice for Sampling and Procurement Testing of Magnetic Materials

E228-22

Standard Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer

A904-20

Standard Specification for 50 Nickel-50 Iron Powder Metallurgy Soft Magnetic Parts

A927/A927M-18(2022)

Standard Test Method for Alternating-Current Magnetic Properties of Toroidal Core Specimens Using the Voltmeter-Ammeter-Wattmeter Method

B215-20

Standard Practices for Sampling Metal Powders

A341/A341M-16(2022)

Standard Test Method for Direct Current Magnetic Properties of Soft Magnetic Materials Using D-C Permeameters and the Point by Point (Ballistic) Test Methods

B243-23

Standard Terminology of Powder Metallurgy

B312-20

Standard Test Method for Green Strength of Specimens Compacted from Metal Powders

B331-20

Standard Test Method for Compressibility of Metal Powders in Uniaxial Compaction

B438-21

Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)

A596/A596M-21

Standard Test Method for Direct-Current Magnetic Properties of Materials Using the Point by Point (Ballistic) Method and Ring Specimens

A773/A773M-21

Standard Test Method for Direct Current Magnetic Properties of Low Coercivity Magnetic Materials Using Hysteresigraphs

A811-15(2022)

Standard Specification for Soft Magnetic Iron Parts Fabricated by Powder Metallurgy Techniques

B963-22

Standard Test Methods for Oil Content, Oil-Impregnation Efficiency, and Surface-Connected Porosity of Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle

B595-21

Standard Specification for Materials for Aluminum Powder Metallurgy (PM) Structural Parts

B610-23

Standard Test Method for Measuring Dimensional Changes Associated with Processing Metal Powders Intended for Die Compaction

B528-16(2020)e1

Standard Test Method for Transverse Rupture Strength of Powder Metallurgy (PM) Specimens (Includes all amendments and changes 10/13/2020).

B439-21

Standard Specification for Iron-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)

B783-19

Standard Specification for Materials for Ferrous Powder Metallurgy (PM) Structural Parts

B817-08

Standard Specification for Powder Metallurgy (PM) Titanium Alloy Structural Components (Withdrawn 2013)

B823-20

Standard Specification for Materials for Copper Base Powder Metallurgy (PM) Structural Parts

B853-16(2021)e1

Standard Specification for Powder Metallurgy (PM) Boron Stainless Steel Structural Components (Includes all amendments and changes 9/17/2021).

B939-21

Standard Test Method for Radial Crushing Strength, K, of Powder Metallurgy (PM) Bearings and Structural Materials

B962-23

Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle

E18-22

Standard Test Methods for Rockwell Hardness of Metallic Materials

E23-23a

Standard Test Methods for Notched Bar Impact Testing of Metallic Materials (Includes all amendments and changes 4/13/2023).

E1876-22

Standard Test Method for Dynamic Young´s Modulus, Shear Modulus, and Poisson´s Ratio by Impulse Excitation of Vibration

Standard 56

Method for Determination of Rotating Beam Fatigue Endurance Limit in Powder Metallurgy Materials Available from MPIF, 105 College Road East, Princeton, NJ 08540.

E8-04

Standard Test Methods for Tension Testing of Metallic Materials

E9-19

Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature

A839-15(2023)

Standard Specification for Iron-Phosphorus Powder Metallurgy Parts for Soft Magnetic Applications