New Testing Standard in the Portfolio: Cracked Round Bar Test (CRB) in Accordance with ISO 18489
With the commissioning of the ZwickRoell LTM 3, our testing laboratory has expanded its range of services. In conjunction with the new testing system and the associated advanced training of our personnel, we now perform the Cracked Round Bar Test (CRB) in accordance with ISO 18489.
Pipe materials of the PE 80 and PE 100 classes exhibit high resistance to Slow Crack Growth (SCG). The failure mechanism associated with SCG occurs at stress levels significantly below the yield stress. The assessment of this resistance to stress cracking is often associated with extended testing durations.
The Cracked Round Bar Test (CRB) is a dynamically cyclic test method performed on notched round bar specimens and is used to determine resistance to slow crack growth (SCG). Similar to the ANPT and SHT methods, the CRB is part of the test scope specified in DIN EN ISO 12201 and DIN EN ISO 1555 for drinking water and gas pipes of manufacturing groups 3 and 4 (DN 250 to DN 800).
The characterization of stress crack resistance, combined with optimized operational procedures and rapid specimen preparation, enables us to provide our customers with reliable test results in accordance with ISO 18489.
With the CRB test method, we offer:
- Standard-compliant testing in accordance with ISO 18489 for quality verification and material approval.
- Reliable and dependable results regarding crack initiation tendency and damage mechanics.
- High testing speed and efficiency through the use of advanced testing technology.
- Evaluation by qualified specialist personnel with expertise in material fatigue and fracture mechanics.

Figure 1: cylindrical bar in clamping mechanism



