ASTM E290-97a(2004)

Standard Test Methods for Bend Testing of Material for Ductility

SIGNIFICANCE AND USE
Bend tests for ductility provide a simple way to evaluate the quality of materials by their ability to resist cracking or other surface irregularities during one continuous bend. No reversal of the bend force shall be employed when conducting these tests.
The type of bend test used determines the location of the forces and constraints on the bent portion of the specimen, ranging from no direct contact to continuous contact.
The test can terminate at a given angle of bend over a specified radius or continue until the specimen legs are in contact. The bend angle can be measured while the specimen is under the bending force (usually when the semi-guided bend test is employed), or after removal of the force as when performing a free-bend test. Product requirements for the material being tested determine the method used.
Materials with an as-fabricated cross section of rectangular, round, hexagonal, or similar defined shape can be tested in full section to evaluate their bend properties by using the procedures outlined in these test methods, in which case relative width and thickness requirements do not apply.
SCOPE
1.1 These test methods cover bend testing for ductility of materials. Included in the procedures are four conditions of constraint on the bent portion of the specimen; a guided-bend test using a mandrel or plunger of defined dimensions to force the mid-length of the specimen between two supports separated by a defined space; a semi-guided-bend test in which the specimen is bent, while in contact with a mandrel, through a specified angle or to a specified inside radius (r) of curvature, measured while under the bending force; a free-bend test in which the ends of the specimen are brought toward each other, but in which no transverse force is applied to the bend itself and there is no contact of the concave inside surface of the bend with other material; a bend and flatten test, in which a transverse force is applied to the bend such that the legs make contact with each other over the length of the specimen.
1.2 After bending, the convex surface of the bend is examined for evidence of a crack or surface irregularity. If the specimen fractures, the material has failed the test. When complete fracture does not occur, the criterion for failure is the number and size of cracks or other surface irregularity visible to the unaided eye occurring on the convex surface of the specimen after bending, as specified by the product standard. Any cracks within one thickness of the edge of the specimen are not considered a bend test failure. Cracks occurring in the corners of the bent portion shall not be considered significant unless they exceed the size specified for corner cracks in the product standard.
1.3 The values stated in SI units are to be regarded as standard. Inch-pound values given in parentheses were used in establishing test parameters and are for information only.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2004
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.02 - Ductility and Formability

Relations

• Replaces: ASTM E290-97a - Standard Test Method for Bend Testing of Material for Ductility
• Effective Date: 01-Oct-2004
• Referred By: ASTM F3160-21 - Standard Guide for Metallurgical Characterization of Absorbable Metallic Materials for Medical Implants
• Effective Date: 01-Oct-2004
• Referred By: ASTM A675/A675M-14(2019) - Standard Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality, Mechanical Properties
• Effective Date: 01-Oct-2004
• Referred By: ASTM F3122-14(2022) - Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes
• Effective Date: 01-Oct-2004
• Referred By: ASTM A663/A663M-17 - Standard Specification for Steel Bars, Carbon, Merchant Quality, Mechanical Properties
• Effective Date: 01-Oct-2004
• Referred By: ASTM B317/B317M-07(2015)e1 - Standard Specification for Aluminum-Alloy Extruded Bar, Rod, Tube, Pipe, Structural Profiles, and Profiles for Electrical Purposes (Bus Conductor)
• Effective Date: 01-Oct-2004
• Referred By: ASTM B265-20a - Standard Specification for Titanium and Titanium Alloy Strip, Sheet, and Plate
• Effective Date: 01-Oct-2004
• Referred By: ASTM B551/B551M-12(2021) - Standard Specification for Zirconium and Zirconium Alloy Strip, Sheet, and Plate
• Effective Date: 01-Oct-2004
• Referred By: ASTM F2066-23 - Standard Specification for Wrought Titanium-15 Molybdenum Alloy for Surgical Implant Applications (UNS R58150)
• Effective Date: 01-Oct-2004
• Referred By: ASTM A720/A720M-02(2021) - Standard Test Method for Ductility of Nonoriented Electrical Steel
• Effective Date: 01-Oct-2004
• Referred By: ASTM A1123/A1123M-22 - Standard Specification for Carbon Steel Laser and Laser-Hybrid Welded, Sharp-Cornered Profile (SCP), Built-Up, Square, Rectangular, and Special Shape Tube
• Effective Date: 01-Oct-2004
• Referred By: ASTM A568/A568M-19a - Standard Specification for Steel, Sheet, Carbon, Structural, and High-Strength, Low-Alloy, Hot-Rolled and Cold-Rolled, General Requirements for
• Effective Date: 01-Oct-2004
• Referred By: ASTM B159/B159M-17 - Standard Specification for Phosphor Bronze Wire
• Effective Date: 01-Oct-2004
• Referred By: ASTM A1069/A1069M-19 - Standard Specification for Laser and Laser Hybrid Welded Stainless Steel Bars, Plates, and Shapes
• Effective Date: 01-Oct-2004
• Referred By: ASTM B272-12(2019) - Standard Specification for Copper Flat Products with Finished (Rolled or Drawn) Edges (Flat Wire and Strip)
• Effective Date: 01-Oct-2004

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E290–97a (Reapproved 2004)
Standard Test Methods for
1
Bend Testing of Material for Ductility
This standard is issued under the fixed designation E 290; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 2. Referenced Documents
2
1.1 These test methods cover bend testing for ductility of 2.1 ASTM Standards:
materials. Included in the procedures are four conditions of E6 Terminology Relating to Methods of Mechanical Test-
constraint on the bent portion of the specimen; a guided-bend ing
test using a mandrel or plunger of defined dimensions to force E8 Test Methods for Tension Testing of Metallic Materials
themid-lengthofthespecimenbetweentwosupportsseparated E8M Test Methods for Tension Testing of Metallic Mate-
by a defined space; a semi-guided-bend test in which the rials (Metric)
specimen is bent, while in contact with a mandrel, through a E18 Test Methods for Rockwell Hardness and Rockwell
specified angle or to a specified inside radius (r) of curvature, Superficial Hardness of Metallic Materials
measured while under the bending force; a free-bend test in E 190 Test Method for Guided Bend Test for Ductility of
which the ends of the specimen are brought toward each other, Welds
but in which no transverse force is applied to the bend itself
3. Summary of Test Methods
and there is no contact of the concave inside surface of the
bend with other material; a bend and flatten test, in which a 3.1 Four methods for ductility testing employing bending
are included in these test methods. Two methods have sub-
transverse force is applied to the bend such that the legs make
contact with each other over the length of the specimen. groups with specific procedures.
3.1.1 Guided-Bend
1.2 After bending, the convex surface of the bend is
examined for evidence of a crack or surface irregularity. If the 3.1.2 Semi-guided Bend:
3.1.2.1 Arrangement A, specimen held at one end.
specimen fractures, the material has failed the test. When
3.1.2.2 Arrangement B, for thin material.
complete fracture does not occur, the criterion for failure is the
number and size of cracks or other surface irregularity visible 3.1.2.3 Arrangement C, mandrel contact force in the bend.
3.1.3 Free-Bend:
to the unaided eye occurring on the convex surface of the
specimen after bending, as specified by the product standard. 3.1.3.1 Type 1, 180° bend.
3.1.3.2 Type 2, bend flat on itself.
Any cracks within one thickness of the edge of the specimen
are not considered a bend test failure. Cracks occurring in the 3.1.4 Bend and Flatten:
3.2 Aguided bend test for ductility of welds is described in
corners of the bent portion shall not be considered significant
unless they exceed the size specified for corner cracks in the Method E 190 and may be used for flat-rolled materials when
specified by the product standard. The essential features of this
product standard.
1.3 The values stated in SI units are to be regarded as bending method are employed in Method 1 Guided-Bend
(3.1.1).
standard. Inch-pound values given in parentheses were used in
establishing test parameters and are for information only. 3.3 Bend tests are made in one of two directions relative to
the principal working direction employed in production pro-
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the cessing of the material.
3.3.1 Longitudinal tests use a specimen with its long dimen-
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- sion aligned with the processing direction such that the bend is
formed across the processing direction, as shown in Fig. 1.
bility of regulatory limitations prior to use.
1
This test method is under the jurisdiction of ASTM Committee E28 on
2
Mechanical Testing and is the direct responsibility of Subcommittee E28.02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Ductility and Flexure Testing. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Current edition approved Oct. 1, 2004. Published October 2004. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1966. Last previous edition approved in 1997 as E 290 – 97a. the ASTM website.
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E290–97a (2004)
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