Total Elongation to Fracture

Deformation continues in the local neck until fracture occurs. The amount of additional strain that can be accommodated in the necked region depends on the microstructure. Inclusions, particles, and grain boundary cracking can accelerate early fracture. Total elongation is measured from start of deformation to start of fracture. Two extensometer gauge lengths are commonly used: A50 (50mm or 2 inches) and A80 (80 mm).

In the past, limited automation and measurement equipment necessitated the use of a non-repeatable technique defined in ASTM E8A-24 and ISO 6892-1I-7 as “elongation after fracture.” Here, the operator attempts to position the two fractured strips back together and hand measures the distance between two gauge marks on the sample.

Tensile testing combined with data acquisition systems are much more commonplace today. According to ASTM E8, the elongation at fracture shall be taken as the strain measured just prior to when the force falls below 10 % of the maximum force encountered during the test. Both elastic strains and plastic strains are included in the measurement.

 

Figure 1: Tensile Strength is the Strength at the Apex of the Engineering Stress – Engineering Strain Curve

Figure 1 : Total elongation is measured from start of deformation to start of fracture.

 

Related Posts
Filter by
Post Page
Mechanical Properties homepage-featured-top main-blog Blog Simulation Tube Forming Testing and Characterization Steel Grades AHSS 1stGen AHSS Press Hardened Steels
Sort by

What are 3rd Gen AHSS?

One of the tasks we took great care in completing during the update of the AHSS Application Guidelines was to

8

Conventional Rule-of-Thumb Calculations Lead to Inaccurate Press Tonnage Predictions

The rule of thumb estimates used in 1989 during my internship with an automotive stamping supplier were simple

8

Tube Forming

Manufacturing precision welded tubes typically involves continuous

8

Improvement by Metallurgical Approaches

The Hole Expansion test (HET) quantifies the edge stretching capability of a sheet metal grade having a specific

8

A New Global Formability Diagram

Bubble chart. Banana diagram. Steel strength ductility diagram—it’s been called a lot of things over the years. But t

8

Vision for Industry 4.0 in Sheet Metal Forming

There is interest in the sheet metal industry on how to adopt Industry 4.0 into their legacy forming practices to

8