ASTM D790 Flexure Testing of Plastics | Kiyo R&D Lab

ASTM D790 Flexural Testing — Strength & Modulus | Kiyo R&D Lab

ASTM D790 Flexure Testing of Plastics — Kiyo R&D Lab

How stiff is your plastic, and how much load will it take before it bends too far or breaks? Flexural properties decide whether a housing flexes in the hand, a bracket holds its shape, or a panel sags in service. astm d790 flexural testing is the standard three-point bend method that measures exactly that — flexural strength and flexural modulus of plastics and composites. Kiyo R&D Lab tests the bending performance of your material with accuracy and confidence.

From rigid thermoplastics and filled compounds to laminates and composites, our astm d790 flexural testing delivers accurate flexural data, supporting analysis, and clear, audit-ready reports you can rely on.

ASTM D790 Flexure Testing of Plastics | Kiyo R&D Lab

What Is ASTM D790?

ASTM D790 is the standard test method for the flexural properties of unreinforced and reinforced plastics. A rectangular bar is supported at two points and loaded in the middle — a three-point bend — while the force and deflection are recorded. From that curve, astm d790 flexural testing gives the flexural strength (stress the material withstands in bending) and the flexural modulus (its stiffness).

The method defines two procedures: Procedure A uses a slow strain rate for materials that break at small deflections, while Procedure B uses a faster rate for more flexible ones. Choosing the right procedure and span-to-depth ratio is key to results that compare correctly against a specification.

What We Measure & Uses

Our astm d790 flexural testing captures the full set of bending properties your specification calls for.

Flexural Strength

Stress at break or yield.

Flexural Modulus

Stiffness in bending.

Stress at 3.5%

For non-breaking samples.

Load-Deflection

Full bending curve.

Procedure A / B

Correct strain rate.

Batch Comparison

Lot-to-lot consistency.

ASTM D790 Test Parameters

ParameterTypical Setup
LoadingThree-point bend
Span-to-depth16:1 (typical)
Procedure A0.01 mm/mm/min strain rate
Procedure B0.10 mm/mm/min strain rate
SpecimenRectangular bar, per thickness

Setup values are typical; exact span, rate, and specimen size follow the current ASTM D790 standard and your material thickness.

Who Uses This Test

  • Plastics Manufacturers: Grade & batch verification — a core use of astm d790 flexural testing.
  • Product Designers: Confirming stiffness for a part.
  • Composite Makers: Reinforced material performance.
  • Compounders: Effect of fillers on stiffness.
  • QC & R&D: Meeting datasheet & spec values.

Related Standards

Our astm d790 flexural testing sits alongside related flexural and mechanical methods, so results are accepted by auditors, buyers, and regulators alike.

ASTM ISO

StandardScope
ASTM D790Flexural properties of plastics
ISO 178Flexural — ISO equivalent
ASTM D6272Four-point bend flexural
ASTM D638Tensile properties (companion)
ASTM D7264Flexural of composites

Pair D790 flexural with D638 tensile and impact testing for a complete mechanical profile of your plastic — ask for a combined package.

Serving Chennai & Tamilnadu

Based in Chennai with branches in Chrompet and Oragadam, Kiyo R&D Lab makes plastic flexural testing easy to access for the Chennai–Oragadam industrial corridor, with convenient drop-off and courier-friendly collection.

Kiyo R&D Lab — Chennai (Chrompet & Oragadam)

Looking for astm d790 flexural testing? Our facilities measure flexural strength and modulus of plastics and composites with clear, accurate reporting.

Call 90420 86986 Request a Quote

Explore all our capabilities at www.kiyorndlab.com.

ASTM D790 Flexure Testing of Plastics | Kiyo R&D Lab

Know How Your Plastic Bends — Kiyo R&D Lab

Flexural strength and stiffness decide whether a part performs or fails in service. With accurate astm d790 flexural testing, we combine correct specimen preparation, the right procedure, and expert interpretation to give you data you can stand behind.

From a single flexural check to a full mechanical profile across tensile, flexural, and impact, the team at Kiyo R&D Lab is ready to help. Reach out today and turn your sample into a reliable, audit-ready report.

Frequently Asked Questions

What does astm d790 flexural testing measure?
It measures the flexural strength and flexural modulus of a plastic — how much stress it withstands in bending and how stiff it is. The sample is loaded in a three-point bend and the force-deflection curve gives both values.
What is the difference between Procedure A and B?
Procedure A uses a slower strain rate (0.01 mm/mm/min) and suits materials that break at small deflections; Procedure B uses a faster rate (0.10 mm/mm/min) for more flexible materials. Your specification usually states which to use.
What is flexural modulus?
Flexural modulus is a measure of stiffness in bending — how much a material resists deflection under load. A higher modulus means a stiffer material. It is one of the two key values reported from astm d790 flexural testing.
What if my sample does not break?
Many tough plastics bend without breaking. In that case the standard reports stress at a defined strain (commonly 3.5%) instead of a break point, so you still get a meaningful, comparable strength value.
How does D790 relate to ISO 178?
ISO 178 is the international equivalent of D790 — both measure flexural properties in a three-point bend, with small procedural differences. If your buyer specifies ISO 178, we can test to that instead. Tell us which your spec names.
How do I get started?
Simply request a quote on WhatsApp or visit www.kiyorndlab.com, tell us your material and thickness, and we’ll guide you through the rest.
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