ASTM E855 Bend Testing of Flat Metals for Spring Applications Involving Static Loading

ASTM E855 is a standard test method that determines the modulus of elasticity in bending, bending proof strength, and offset yield strength of metallic strips or sheets used in flat springs. Three methods are described in this test: Test Method A - cantilever beam, Test Method B - three-point loaded beam, and Test Method C - four-point loaded beam.

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ASTM E855 Bend Testing of Flat Metals for Spring Applications Involving Static Loading

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Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

ASTM E 855 bend testing is the standardized test method for evaluating the bend performance of flat metallic materials used in spring applications involving static loading — measuring the stress relaxation, permanent set, and elastic recovery characteristics of flat metal strip and sheet specimens under defined bending conditions. ASTM E 855 defines the specimen preparation, bending fixture configurations, and measurement procedures required to assess the spring performance of flat metallic materials — providing materials engineers, spring designers, and manufacturers with reliable bend performance data for material selection, spring design validation, and supplier assessment programs.

Scope, Applications, and Benefits

Scope

ASTM E 855 is a test standard that determines bend properties of flat metallic spring materials through a procedure involving bending a specimen to a particular deflection or stress, holding it at this deflected state for a particular period of time, and then measuring the permanent set as well as elastic recovery upon removal of the deflection, which is essential in static load spring materials.

ASTM E 855 bend testing evaluates:

Permanent set and elastic recovery of flat metallic materials under static bending conditions
Stress relaxation behavior of flat metal strip and sheet in spring bending applications
Comparative bend performance of metallic spring materials across defined bending conditions
Effect of material temper, thickness, and alloy composition on flat spring bend performance
Compliance with permanent set and elastic recovery requirements for spring material specifications

Applications

Flat metallic spring materials for electrical contact, connector, and switch applications
Steel, copper, brass, and beryllium copper strip materials for spring component design
Automotive and industrial flat spring components requiring static load bend performance data
Electronic and precision instrument spring materials require a bend performance assessment
Material suppliers and spring manufacturers requiring ASTM E 855 bend test data

Benefits

Provides reliable bend performance data for flat metallic spring material selection and design
Supports spring material specification compliance and supplier assessment programs
Identifies permanent set and relaxation deficiencies in spring materials before production
Delivers traceable bend test records for engineering and research submissions
Reduces spring design risk by verifying flat metal bend performance early in the approval cycle

Test Process

Sample Preparation

Flat metal strip specimens prepared to defined dimensions and conditioned per ASTM E 855 requirements.

Bending Fixture Loading

Specimens loaded in defined bending fixture to specified deflection or stress level.

Static Load Maintenance

Bent specimens maintained at defined deflection for specified hold period per ASTM E 855.

Data Analysis & Reporting

Permanent set and elastic recovery measured and assessed against criteria for test compliance result.

Technical Specifications

Parameter	Details
Applicable Materials	Flat metallic strip and sheet spring materials including steel, copper, brass, and beryllium copper
Specimen Geometry	Flat strip specimen dimensions per ASTM E 855 bending fixture configuration requirements
Bending Conditions	Defined deflection or stress level and hold period per ASTM E 855 static loading requirements
Measured Parameters	Permanent set, elastic recovery, and stress relaxation under static bending conditions
Measured Outputs	Permanent set values, elastic recovery data, and test compliance result

Instrumentation Used for Testing

ASTM E 855 bending fixture with defined geometry and deflection control
Precision deflection measurement system for specimen bending and recovery measurement
Specimen conditioning chamber with temperature and humidity control
Calibrated load application system for defined stress level bending
Precision dimensional measurement tools for permanent set determination
Data acquisition and test reporting system

Results and Deliverables

Bending deflection and permanent set measurement data for all tested flat metal specimens
Elastic recovery values and stress relaxation observations per ASTM E 855 conditions
Statistical summary of bend performance results across the test specimen set
Test compliance result assessed against spring material permanent set requirements
ASTM E 855 bend test report

Why Choose Infinita Lab for ASTM E 855?

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Frequently Asked Questions

ASTM E855 includes bend angle, mandrel diameter, specimen thickness, loading rate, and surface condition. It evaluates how well flat metal spring materials can resist static bending without cracking or failing.

ASTM E855 uses flat metal samples that have controlled thickness and width. These samples are usually made from spring materials. This approach ensures a uniform shape for reliable bending tests under static loads.

ASTM E855 applies a static bending load around a specified mandrel at a controlled rate. This process ensures gradual deformation of the specimen. It helps evaluate flexibility, ductility, and resistance to cracking.

ASTM E855 checks for cracks, surface defects, and deformation behavior after bending. It helps determine if flat metal materials are suitable for spring applications that need dependable performance under static loads.

ASTM E855 testing involves bending fixtures, mandrels of specific diameters, and mechanical loading devices. These tools apply controlled static bending forces to evaluate flat metal spring materials.