ASTM E290
Bend Test of Metal Samples
Standard Test Methods for Bend Testing of Material for Ductility - PDF
ASTM E290, titled "Standard Test Methods for Bend Testing of Material for Ductility," is a mechanical test standard that evaluates the ductility and soundness of metal samples by subjecting them to bending deformation. It is commonly used in quality control, welding procedure qualification, and materials inspection processes.
This article will explain the ASTM E290 test method in detail, including the test procedure, required equipment (such as universal testing machines and bend test fixtures), specimen dimensions, and how to interpret the results. We’ll also mention related standards and applications across industries.
What Is ASTM E290?
ASTM E290 is a destructive bend test that determines a material’s ability to withstand plastic deformation without cracking. It is especially useful for metallic products, including steel, stainless steel, aluminum, copper alloys, and weld test coupons.
In this test, a sample is bent through a specified angle—often 90° or 180°—around a mandrel or former of known diameter, and the material is inspected for surface cracks or other signs of failure.
This method helps ensure the integrity of base materials and welded joints, especially in structural and pressure-containing applications.
Scope and Applications
ASTM E290 is used for:
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Evaluating metal ductility
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Qualifying welding procedures and personnel
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Inspecting welded joints for defects
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Assessing heat treatment effects
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Supporting material certification and quality assurance
The standard is applicable to sheet, plate, wire, bar, tube, and weld test specimens.
Specimen Preparation
Bend test specimens must meet the dimensions and tolerances specified in ASTM E290. These dimensions can vary based on the form of the metal and specific material standards (such as ASTM A370 or AWS D1.1).
General Specimen Guidelines:
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Width: Typically 1.5 in (38 mm), or match the thickness of the plate or pipe section
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Length: Sufficient to allow secure clamping and full bend angle without slippage
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Thickness: Varies by material but must allow for full plastic deformation
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Edge Condition: Smooth and free of notches or surface defects
For welds, the specimen may be notched to position the weld root or face at the bend apex.
Required Testing Equipment
1. Universal Testing Machine (UTM) or Bend Test Frame
A UTM or a manually operated bend test machine is used to apply the bending force. For larger sections, hydraulic or servo-driven systems are preferred.
2. Guided Bend Test Fixture
A typical guided bend fixture consists of:
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A mandrel or plunger that applies force at the specimen’s center
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Two support rollers or anvils spaced at a standard span
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Interchangeable components to vary the mandrel diameter and span
Bend fixtures must prevent slippage and allow uniform stress distribution during the test.
ASTM E290 Test Procedure
The bend test is performed using one of the following methods:
a) Face Bend Test
The weld face is placed in tension during the bend.
b) Root Bend Test
The root of the weld is placed in tension during bending.
c) Side Bend Test
The weld cross-section is oriented so the entire thickness bends around the mandrel.
Standard Procedure:
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Place the specimen in the guided bend fixture with correct orientation (face, root, or side).
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Apply force to bend the specimen over the mandrel at a constant speed.
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Continue bending until a specified angle (usually 180°) is reached or until failure occurs.
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Remove and inspect the specimen visually for cracks or discontinuities.
Pass/Fail Criteria
The specimen is evaluated based on the appearance and size of any cracks:
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Acceptable: No cracks larger than a specified length (e.g., 3 mm or 1/8 in) on the tension side.
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Failure: Cracks or tears exceeding the allowable length, especially in critical weld zones or parent material.
Some material specifications (e.g., ASME, AWS, API) will define acceptable defect sizes.
Note: Small surface imperfections or flaws at specimen edges are often disregarded if they fall within permissible tolerances.
Calculations (Plain Text Format)
While ASTM E290 is a qualitative (pass/fail) test, it is helpful to calculate the bend radius and inside diameter of the mandrel.
Bend Radius = Mandrel Radius
Bend Angle = Typically 90° or 180°, depending on the application
Distance Between Supports = 4 to 6 times the specimen thickness, depending on setup
For consistent testing, ensure that the mandrel size and span match the required specification for the material type and thickness.
Advantages of ASTM E290
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Quick and effective evaluation of ductility and weld soundness
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Inexpensive and requires no strain measurement devices
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Common across industries like construction, oil & gas, power generation, aerospace, and shipbuilding
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Essential for welder and procedure qualification (e.g., AWS, ASME Section IX)
Related Standards
Other testing methods related to metal ductility and weld evaluation include:
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ASTM A370 – Mechanical testing of steel products
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AWS D1.1 – Structural welding code, includes bend test procedures
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ASTM E8 – Tension testing of metallic materials
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ASME Section IX – Welding procedure and performance qualification
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ISO 5173 – Bend testing of fusion welded joints
Conclusion
ASTM E290 is a straightforward and effective method for assessing the ductility and integrity of metal components and welds under bending deformation. It serves as a cornerstone for welding qualification and material compliance in critical applications across construction, transportation, pressure vessels, and more.
The test's simplicity, speed, and strong relevance to real-world mechanical behavior make it a widely trusted standard in metalworking industries.
Need ASTM E290 Testing Equipment?
We provide complete guided bend fixtures, universal testing machines, and custom jigs for weld test programs. Contact us to set up a reliable and code-compliant testing station in your lab.
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Similar Specifications:
ASTM D790 - Plastics Bend Test
ASTM D5459 - Plane Strain Bend Test