QT-ESC Environmental Stress Cracking Tester is used to determine of the susceptibility of ethylene plastics, as defined in terminology D883, to environmental stress-cracking when subjected to the conditions specified in ASTM D1693-01, under certain conditions of stress and in the presence of environments such as soaps, wetting agents, oils, or detergents, ethylene plastics may exhibit mechanical failure by cracking.
Bent specimens of the plastic, each having a controlled imperfection on one surface, are exposed to the action of a surface-active agent. The proportion of the total number of specimens that crack in a given time is observed. ASTM D1693 Standard Test Method for Environmental Stress-Cracking of Ethylene Plastics. This test method covers the determination of the susceptibility of ethylene plastics, as defined in Terminology D 883, to environmental stress-cracking when subjected to the conditions herein specified. Under certain conditions of stress and in the presence of environments such as soaps, wetting agents, oils, or detergents, ethylene plastics may exhibit mechanical failure by cracking.
Environmental stress cracking is the formation of cracks in a material caused by relatively low tensile stress and environmental conditions. Environmental Stress-Cracking Resistance (ESCR) is the number of hours that 50% of the specimens tested exhibit stress cracks.
ESCR testing is performed by slowly bending the test specimens and placing them in a holding clamp. The clamp and specimens are then placed in a test tube and immersed in a specified reagent. The test tube is sealed and placed in a constant-temperature bath. Multiple test specimens are tested at one time.
Specimens are inspected periodically for failure. Cracks generally develop at the notch, perpendicular to the notch, and run to the edge of the specimen. Any cracks constitute failure, not just cracks that reach the edge of the specimen. Cracks sometimes appear beneath the surface and are visible as surface depressions. If a depression develops into a surface crack the time at which the depression was noted is taken as the time of failure.
Tester is designed with main focus on accuracy, perfect construction and flexibility to use.
Consists of specimen holder, specimen bending device, specimen transferring device and test bath.