Ball/pin impression

ISO 4600 ISO 6252 ISO 4599 Resistance to ESC-BALL/PIN impression method Resistance to ESC-constant-tensile stress method Resistance to ESC-bent-strip method... 

In the ball/pin impression test according to ISO 22088, Part 4 [274], a hole with a... 

ISO 4600, Plastics - Determination of environmental stress cracking (ESC) - Ball or pin impression method, 1992. 

ISO 4600 details a ball or pin impression method for determining the ESCR. In this procedure, a hole of specified diameter is drilled in the plastic. An oversized ball or pin is inserted into the hole, and the polymer is exposed to a stress cracking agent. The applied deformation, given by the diameter of the ball or pin, is constant. The test is multiaxial, relatively easy to perform, and with not very well-defined specimens, and the influence of the surface is limited. Drawbacks are the small testing surface and the undefined stress state. After exposure, tensile or flexural tests may be performed on the specimens. This leads to the determination of either the residual tensile strength or the residual deformation at break. 

ISO 4600 1981 Determination of Environmental Stress Cracking - Ball or Pin Impression (see also DIN 53499 Part 1). 

In the usual tests on stress crack resistance (see Sect. 5.3.2), e.g. the pin impression test EN ISO 4600 1998 Plastics - Determination of Environmental Stress Cracking (ESC) - Ball or Pin Impression Method, or in the so-called bend strip test or Bell-test as per ASTM D1693-97a Standard Test Method for Environmental Stress-Cracking of Ethylene Plastics, no failure of HDPE geomembranes is observed under the test conditions required by the standards. These index tests therefore cannot be used for the assessment of stress crack resistance of plastic geomembranes. The requirements are simply too low. 

General instructions Tensile creep test Bending strip test Ball or pin impression test... 

The ball and/or pin impression method is suitable in particular for thermoplastics with little creep tendency and can be used very easily to test large components with virtually any geometry and wall thickness. 

Plastics — Determination of environmental stress cracking (ESC) — Ball or pin impression method, 1998 retracted 2006, succeeded by DIN EN ISO 22088-4 Plastics — Determination of resistance to environmental stress cracking (ESC)-Part 4 Ball or pin impression method, 2006... 

The method of caustics has also been used to study the formation of cracks and crazes formed by exposure of PMMA to solvents (259). ISO 4599 (260) has been developed to better control the application of stress using a jig having the curve of the arc of a circle for shaping the specimen and maintaining a set curvature during exposure to the agent. After a predetermined time the specimen is tested for tensile or flexural properties and compared to preexposure test values. ISO 4600 (261) uses the technique of impressing an oversized ball or pin into a hole drilled in the specimen to apply a strain. 

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