ISO 3384 / 6914 / ASTM D6147 — Predict Material Life Under Constant Load

A Stress Relaxation Tester — also known as a Creep Tester — is a precision laboratory instrument that measures how rubber, elastomer, and plastic materials behave when held under constant deformation (stress relaxation) or constant load (creep) for extended periods of time. These two complementary measurements are fundamental to predicting service life: every gasket, every seal, every rubber-bonded component, every elastomeric bushing in service is slowly losing the sealing force or accumulating deformation that defines whether it will continue to perform — or fail prematurely. By accelerating those long-term phenomena under controlled laboratory conditions, stress-relaxation and creep testing transforms what would take years of field service into reliable predictive data delivered in days or weeks.

The physics is straightforward but powerful. In compressive stress relaxation, a specimen is compressed to a constant deformation and the compressive force is monitored over time — the gradually decreasing force, expressed as a percentage of the initial force, is the stress-relaxation curve. In creep testing, a constant stress is applied and the gradually increasing deformation needed to sustain that stress is recorded. Both physical processes (polymer chain rearrangement) and chemical processes (oxidation, cross-link breakdown) drive these effects — and at different temperatures, different mechanisms dominate. This is why Qualitest offers four distinct platforms, each engineered for a specific temperature range and application demand.

Qualitest's comprehensive portfolio covers the full operational spectrum: the Stress Relaxation Test Rig for room-temperature ISO 3384 testing of vulcanized and thermoplastic rubber; the Low Temperature Stress Relaxation / Creep Tester (−50 °C to 0 °C) for sub-ambient automotive, outdoor, and refrigeration-seal applications with adjustable 0–30 mm displacement and 0–10 kN force; the mid-range Stress Relaxation / Creep Tester (0 °C to 150 °C) for ambient and elevated-temperature mainstream applications; and the flagship Stress Relaxation / Creep Tester (−70 °C to +250 °C) for the most demanding extreme-environment applications spanning a full 320 °C range — supporting aerospace, automotive, and high-performance R&D programs.

What is Stress Relaxation Tester - Creep Tester?

A stress relaxation tester, also known as a creep tester, is used to determine the amount of deformation a material experiences over time while under a continuous tensile or compressive load at a constant temperature. Creep tests are fundamental for materials that are needed to withstand certain operation temperatures under load

Applications in Industries

• Rubber & Elastomer Manufacturing — Service-life prediction of O-rings, gaskets, seals, vibration mounts, and rubber-bonded components per ISO 3384 / 6914 / ASTM D6147.
• Automotive & Heavy-Duty Vehicle — Sealing-force retention testing of weather seals, engine gaskets, suspension bushings, and rubber-isolation components across full automotive temperature range.
• Aerospace & Defense — Sealing & elastomer qualification across the full −70 °C to +250 °C aerospace temperature spectrum for fuel systems, hydraulics, and structural seals.
• Pipeline, Offshore & Oil & Gas — Long-term sealing behavior of elastomeric components under sustained compressive loads in pipelines, valves, and offshore equipment.
• HVAC & Refrigeration — Sub-ambient stress-relaxation testing of seal compounds for refrigeration, cryogenic, and cold-climate applications using the Low Temp model.
• Construction & Building Products — Durability prediction of weather sealants, expansion-joint elastomers, geomembrane materials, and structural rubber components.
• Medical & Pharmaceutical Devices — Long-term mechanical-behavior testing of medical-grade elastomers, pharmaceutical-packaging seals, and biocompatible polymers.
• Plastics & Polymer R&D — Creep characterization of engineering plastics, fiber-reinforced compounds, and novel polymer formulations.
• Universities & Research Institutes — Fundamental research into viscoelastic behavior, cross-link characterization, and polymer-aging mechanisms.

Product Comparison Table

Why Choose Qualitest for Your Stress Relaxation & Creep Testing Needs

Qualitest is a globally recognized supplier of advanced rubber, polymer, and materials-testing instruments, serving customers across more than 80 countries with one of the most comprehensive stress relaxation and creep testing portfolios available worldwide.

Four-Tier Portfolio Covering −70 °C to +250 °C

From room-temperature ISO 3384 testing through the sub-ambient −50 °C/0 °C model, ambient-to-elevated 0 °C/150 °C platform, and the flagship −70 °C/+250 °C extended-range system, Qualitest delivers a coordinated portfolio matched to every temperature regime, application demand, and analytical-sophistication requirement.

Both Stress Relaxation AND Creep Modes

Every Qualitest creep platform supports both constant-deformation stress relaxation (compressive and tensile) and constant-load creep (static creep with full displacement/time curves) — delivering the complete viscoelastic-characterization capability that modern rubber and polymer research requires.

Full International Standards Compliance

Engineered to meet ISO 3384 (rubber compression stress relaxation), ISO 6914 (tension stress relaxation), and ASTM D6147 — ensuring every test result is universally accepted, audit-ready, and defensible in customer certifications and regulatory submissions.

Precision Force, Displacement & Time Data

Adjustable pre-compression displacement (0–30 mm) and pre-compression force (0–10 kN), full force/time and displacement/time curve detection, and computer-controlled data acquisition together deliver the precise, repeatable data quality that demanding material-qualification programs require.

Cost-Effective Value & Global Support

Qualitest delivers premium stress-relaxation and creep testing performance at a transparent, competitive price point — backed by global service, training, calibration support, and replacement parts. Worldwide presence ensures expert support wherever your laboratory operates.

Predict Service Life. Prevent Field Failures.

Every rubber and elastomeric component in service is slowly losing its sealing force or accumulating creep deformation — and the only way to know when that will translate into field failure is to test it before installation. A poorly characterized stress-relaxation profile means gaskets that lose seal in 2 years instead of 20, vibration mounts that bottom out, and O-rings that leak fuel in safety-critical aerospace applications. The laboratories that consistently deliver durable, reliable, regulator-compliant elastomeric products are the ones equipped with stress-relaxation testers built for precision, repeatability, and full temperature-range coverage — and the Qualitest stress-relaxation/creep tester portfolio gives you exactly that.

Whether you are qualifying weather seals for an automotive OEM, developing aerospace fuel-system elastomers, testing geomembrane materials for civil infrastructure, or running fundamental viscoelastic research, Qualitest has the platform engineered to meet your exact needs. From the entry-level Stress Relaxation Test Rig to the flagship −70 °C / +250 °C extended-range platform, every Qualitest stress-relaxation and creep tester delivers world-class predictive performance backed by industry-leading service and support.