Distortion Temperature (HDT) Dosage

Heat Deflection Temperature ( HDT ) is a standard thermal analysis used to assess the resistance of a polymer material to deformation under constant mechanical load. This test is particularly used in the plastics, composites and bio-based materials sector to predict their behavior under high temperatures, particularly under demanding service conditions.

ISO 75 / ASTM D648 standardized method: a rigorous and recognized protocol

The distortion temperature measurement is carried out according to international standards ISO 75 or ASTM D648. The principle of the test consists of applying a constant load to a standardized polymer sample, then gradually increasing the temperature until the deflection reaches a defined value. The temperature at which this deformation is reached constitutes the HDT.

Depending on the standards, several stress levels (e.g., 0.45 MPa, 1.8 MPa) can be applied to simulate different industrial use cases. This test provides critical information for material selection in thermomechanical applications.

Why measure the distortion temperature (HDT)?

HDT is an essential thermal performance criterion in many industrial sectors. It allows:

• To compare different grades of polymers in terms of temperature resistance
• To guide the selection of materials for parts subject to heat and mechanical stress (casings, covers, technical components, etc.)
• To validate formulations based on modified polymers or reinforcing fillers
• To evaluate the performance of bio-sourced materials compared to petroleum-based references
• To support a technical file (technical sheet, declaration of conformity, customer specifications)

Affected matrices and application sectors

The HDT test applies to a wide range of thermoplastic and thermoset materials:

• Standard plastics (PE, PP, PS, PVC, etc.)
• Technical polymers (PA, PBT, PC, PEEK, etc.)
• Thermosetting resins (epoxy, polyester, phenolic)
• Reinforced composites (fiberglass, carbon fiber)
• Bio-sourced or biodegradable materials
• Samples from recycling or experimental formulations

This test is used in many industrial sectors:

• Packaging: to ensure dimensional stability when hot (films, containers, lids, etc.)
• Automotive and transport: choice of materials for under-hood parts or interior elements
• Electrical/electronic: components subject to heating or thermal cycles
• Construction: insulation, pipes, joinery in polymer materials
• Research & development: improvement of formulations, substitution of materials

Specialized laboratories for controlled testing

YesWeLab relies on a network of partner laboratories that are experts in mechanical and thermal analysis of materials. All have calibrated equipment and procedures that comply with ISO 75 or ASTM D648 standards. We direct your request to the most appropriate laboratory based on:

• The type of material to be tested
• The specific mechanical constraints to be applied
• Normative or contractual requirements
• Delivery times and desired format of results

Tailor-made support for your materials projects

Thanks to our digital platform, you can submit your request online, select your services, track test progress, and securely retrieve results. Our scientific team also provides upfront advice on choosing the right test parameters, optimizing sample preparation, and interpreting results.

Further analyses recommended

For a complete characterization of your materials, consider combining the HDT test with other services:

• DSC Analysis – Glass Transition Temperature (Tg)
• ATG Analysis – Thermal Stability
• Tensile and bending tests

Get your quote now

Add this service to your quote request or contact our team to discuss your needs. YesWeLab has been supporting materials and polymer manufacturers since 2020, with an approach focused on quality, compliance, and responsiveness. Whether for quality control, product development, or technical expertise, we're here to help.