Materials and Their Characteristics # 1985 York
Since 1978 STUDSVIK has been testing a PEMoD-grade from Unifos Kemi AB for applications in the temperature range 30 - 60 C. The aim has been to study the long term properties of the material and thus to enable its life to be determined. Pressure testing has show; that the material is expected to last for 50 years at between 35 and 50 C, depending on the design stress. Fractography has shown that there are three main different types of initiation occurring for brittle fractures. A relationship has also been found between the width of the fracture surface and the results from the pressure testing. Chemical analysis has been used to measure the thermal stability in pipes which have failed and also to determine how much the stabilizer is consumed in the different cross sections of the pipes.