Conventional screw testing relies on destructive tensile tests. Handling tiny fasteners is difficult, the effort is high and the screws are scrapped afterwards. Hardness testing with conversion tables helps in some cases. Testawell adds a third option: low-destructive screw testing with the Imprint Test – indentation plastometry per DIN SPEC 4864 / ASTM E3499. We create precise micro-indents on the screw head and derive RpI0.2 and RIm directly on the component – without compromising its function.
How does screw testing work and what makes it specific?
On-part testing: Directly on the screw head – no specimen preparation.
Gentle: Indent depth only a few dozen µm; the screw normally stays in service.
Direct metrics: RpI0.2, RIm and a stress-strain curve.
Automatable: Suitable for high volumes and 100% inspection.
Flexible: Works for many head geometries and metallic materials.
This is especially useful when batches must be compared quickly, incoming goods need a traceable release decision or complaint cases require evidence directly on real fasteners rather than on separately machined specimens.
Which use cases benefit from screw testing?
Incoming inspection and serial approval (100% control possible).
Traceable comparison of strength classes (e.g. 8.8–12.9).
Evaluating batches, heat treatments or coatings.
Resolving complaints without destroying parts.
Inline/at-line automation in assembly or production.
Which example results does screw testing provide?
Strength metric
Value
RIp0,2
1211 MPa
RIm
1250 MPa
Averaged stress-strain curve from several indents (internal Testawell data).
Fig. 2 – Screw after testing with five indents
How does low-destructive screw testing work under DIN SPEC 4864?
Whoever needs reliable data without scrap relies on the Imprint Test (DIN SPEC 4864). Micro-indents with depths of approx. 35 µm are applied to the screw head. The surrounding material pile-up contains enough information to determine RIp0,2 and RIm directly on the component.
“With Testawell’s support we rapidly characterised a batch of small parts and detected differences. The selection ensures the best possible properties within the assembly.”
#Customer #Motorsport #ScrewTesting·
The process is ideal for serial production and 100% inspections. A single measurement takes only seconds to a few minutes and can be automated completely. Throughput and process reliability rise while part and process costs decline. The fasteners remain reusable, which is a major economic advantage for high-value screws.
Compared with tensile testing there is no need for elaborate specimen preparation or destructive failure. Especially for small sizes or complex head geometries the strength evaluation on the real screw is faster and more meaningful because it captures the material response exactly at the point of use. The method is flexible to integrate and suitable for many screw types, strength classes (e.g. 8.8–12.9) and metallic materials including stainless steels.
Reports include RIp0,2, RIm and the stress-strain curve (averaged if required). This provides a robust basis for incoming inspection, serial release, batch comparison and claim clarification – fast, safe and without scrap.
Want to integrate screw testing into your line or check geometry feasibility? Get in touch with our team – we support you from feasibility to serial implementation.
Which questions are frequently asked about screw testing?
Is the test truly low destructive?
Yes. The indents are only a few µm deep. The screw typically remains functional and can be reused.
Which metrics do I get?
RpI0,2, RIm and the corresponding stress-strain curve including statistics over multiple indents.
Which screw sizes work?
From very small up to medium diameters. The decisive factor is the available surface on the head. We are happy to pre-check your geometry.
How does serial testing run?
Indents are applied and evaluated automatically. Results are available immediately; thresholds and release criteria can be configured.
Which standards or references exist?
The process follows DIN SPEC 4864 (Imprint Test / indentation plastometry). More on the test standard.
