Updated 2026 · Test technology · Indentation plastometry
Indentation plastometry: Imprint Test for yield strength, tensile strength and flow curves
Indentation plastometry is an indentation-based method for determining yield strength, tensile strength and plastic flow curves
directly from a local imprint on the component surface. The Imprint Test according to DIN SPEC 4864 and ASTM E3499
enables fast, low-destructive testing of steels, aluminium, magnesium, nickel, titanium and copper alloys. Compared with
conventional tensile testing, it reduces specimen effort while still providing
decision-ready mechanical data on real parts and local strength gradients.
The Imprint Test is an indentation plastometry method according to DIN SPEC 4864 and ASTM E3499.
Instead of preparing tensile specimens, a defined indent is deformed into the surface and measured in 3D.
From this imprint, a plastic stress–strain curve is determined using finite element simulations and
inverse evaluation. The method delivers:
comparative yield strength RIp0,2,
comparative tensile strength RIm,
hardening exponent n,
ductility descriptor D,
plastic flow curves for direct use in material models.
A single imprint typically takes between 30 and 90 seconds. This makes the method ideal for
fast screening, mapping of strength gradients and local characterisation on real components. For production-oriented
implementation, see our i3D® PRO system.
Which key features define indentation plastometry?
Locally
Locally resolved testing of mechanical properties – directly on components, welds or small parts.
Automated
Fully automated characterisation of strength fields with programmed grids and high point density.
Fast & easy
Results available within about 45 seconds per imprint, including 3D measurement and evaluation.
Multi-sample
Efficient multi-sample screening – for example, 200+ measurement points across several specimens.
Why use indentation plastometry?
Determine yield strength and tensile strength locally on real components.
Obtain plastic stress–strain curves without machining standard tensile specimens.
Run high-throughput campaigns for alloy screening, welds and strength gradients.
Reduce destructive effort compared with classic tensile testing.
Which applications benefit from indentation plastometry?
Application #1 – Multisample screening in alloy development
In the early phases of alloy development, quickly accessible data including mechanical properties is crucial.
Indentation plastometry accelerates iteration loops between parameter adjustment and data acquisition:
rapid feedback on the impact of composition and process parameters,
plastic flow curves for many positions within minutes,
high-throughput testing: in approx. 30 minutes, around 30 plastic flow curves can be recorded.
This shortens development cycles and supports data-driven optimisation of alloys and processes.
Fig. – High-throughput indentation plastometry for alloy screening.
Application #2 – Weld seam examination
In research projects, weld joints were characterised for their mechanical properties in:
base material,
transition region,
heat-affected zone,
weld seam.
Traditionally, Vickers hardness testing is used, with lines of measurement points along the weld.
Indentation plastometry goes a step further and determines:
tensile strength and yield strength locally,
ductility and hardening behaviour across the weld,
strength gradients in heat-affected zones with high spatial resolution.
This provides a physically stronger alternative to simple hardness-to-strength conversion
when local mechanical properties matter.
Fig. - Indentation plastometry across a weld joint with strength gradients.
Which application pages explore indentation plastometry in more detail?
The core method page explains how indentation plastometry works. The following pages go deeper into the strongest commercial and engineering use cases already reflected in our application material.
DIN SPEC 4864 – the first standard of its kind, developed together with national
institutes and industry partners; published by Beuth Verlag in November 2019.
Measurement principle
Imprints are introduced with a defined load; the resulting pile-up geometry is measured using a
vertical scanning interferometer or similar 3D optical system. The 3D imprint shape
reflects the unique mechanical response of the material.
Numerical evaluation
Real measured data (pile-up profile) is matched with finite element simulations via inverse modelling.
When simulated and measured geometries match, the underlying material parameters and the
plastic stress–strain curve are identified.
Automation
The procedure has been developed from laboratory setups to fully automated systems.
Today, measurements can be completed in less than a minute – in the lab, inline or using mobile devices.
How does indentation plastometry compare with classic materials testing methods?
Indentation plastometry complements and partly replaces conventional methods such as hardness conversion
and tensile testing.
Aspect
Indentation plastometry (Imprint Test)
Hardness → tensile strength conversion
Tensile test
Specimen / preparation
Flat surface, basic grinding/polishing; no tensile specimen required.
Flat, prepared surface for hardness impressions.
Standardised tensile specimen; machining and geometry according to norms.
Test effort
Approx. 30–90 s per imprint; low-destructive.
Approx. 15–60 s per hardness test.
Typically 15–45 min including preparation and testing.
Reference data, qualification tests, full material characterisation.
Which standards, developments and industrial use cases shape indentation plastometry?
DIN SPEC 4864 is published by Beuth Verlag (Germany) under the title:
“Test method for the determination of flow curves and benchmark characteristic values for tensile testing by means of minor destructive indentation, 3D measurement and finite element material models.”
The method significantly contributes to the fast and cost-effective determination of mechanical properties.
It enables:
testing of components and thin/small parts,
characterisation of strength gradients (welded joints, heat-affected zones, strain hardening),
high-throughput campaigns in development and quality assurance.
Typical sectors include aerospace, automotive, civil engineering, oil & gas, construction, medical devices,
mechanical engineering and the energy sector – wherever reliable strength data is needed with minimal specimen effort.
Need indentation plastometry data for components, welds or alloy screening? We support everything from
feasibility studies to fully automated campaigns. Contact us to discuss your project.
Which questions are frequently asked about indentation plastometry?
What is indentation plastometry used for?
Indentation plastometry is used for local determination of yield strength, tensile strength and plastic flow curves on components,
welds, small parts and development samples. It is particularly useful when conventional tensile specimens are difficult or costly to prepare.
How accurate are results compared to a tensile test?
For many metals, the comparative tensile strength RIm and comparative yield strength
RIp0,2 show good agreement with tensile test results when surface preparation and
test conditions are controlled. Indentation plastometry is not intended to replace all tensile tests,
but to complement them – especially when local, fast or low-destructive testing is required.
Can small or complex components be tested?
Yes. Only a local surface area is required for an imprint. This makes the method suitable for small components,
thin sections, additively manufactured parts, welded joints and regions that are difficult to sample for tensile tests.
Can indentation plastometry replace tensile testing?
It can replace tensile testing in many local, comparative or high-throughput tasks, especially on finished components.
For full qualification programs, it is often best used alongside tensile tests and
hardness testing.
How do I start a project with indentation plastometry?
Define your materials, target properties and number of measurement points. We support you in designing a suitable
test matrix – from single-point verification up to high-throughput campaigns. Contact us
to discuss your use case and data requirements.
