Stress Relaxation Tester - TT-SR Series

ASTM E328, ISO 15630-3

Application

Torontech's Stress Relaxation Tester - TT-SR Series is used to determine stress-relaxation of metals, such as pre-stressed concrete strand, pre-stressed concrete bar, steel rope...etc. To determine stress-relaxation of a material the specimen is deformed a given amount and decrease in stress is recorded over prolonged period of exposure at constant elevated temperature.

ASTM E328 Standard Test Methods for Stress Relaxation Tests for Materials and Structures. This method covers the standard test methods for stress relaxation tests for materials and structures. Stress relaxation in a material is an important characteristic to consider when designing with mechanical fasteners that must hold with a permanent tightness. Long term failure of fastener might occur if stress relaxation is not considered.

According to ASTM, applications that are often tested with this standard include, bolted of riveted assemblies, press of shrink-fit components, rolled-in tubes, gaskets tightness, constraining force of springs, and stability of wire in pre-stressed concrete. This test is also valid for measuring stress relaxation of a material an area of high stress concentration. The test environment must be highly controlled to prevent changes to the material due to environmental conditions.

Features

• Real-time display load versus time, temperature versus time and relaxation rate versus time curves
• Automatic calculate 1000 hours tensile stress relaxation rate.
• High-precision temperature recorder attached to record the influence of room temperature variations
• Servo-controlled drive system ensures the high precision load/displacement/strain close-loop control as well as low noise
• User configurable test methods and customizable report template
• Self-alignment design on specimen anchorage to ensure the high accuracy
• Patent calibration system is mounted on machine to calibrate not only the load cell but also the whole system without disassembly the load cell from machine

Technical Specifications