Significance and Test Method
The requirements for materials in gas welding equipment, flame cutters or in related processes are very high. DIN EN ISO 9539 defines criteria for the evaluation of materials, including non-metallic materials such as elastomers, for these applications.
Resistance to solvents for non-metallic materials in contact with fuel gases must be verified by means of defined immersion and re-drying tests in acetone vapour, dimethylformamide vapour and n-pentane.
The special challenge is the polarity of these media:
Acetone and dimethyl formamide are strongly polar. They therefore require a non-polar or only weakly polar material, for example EPDM. Strongly polar elastomers will swell significantly in these media. n-Pentane, on the other hand, is a non-polar medium that requires a polar elastomer material, such as NBR, HNBR or FKM.
Other types of materials are therefore required in order to withstand all three media equally well. In addition to an FFKM materials or special FKM types, a CR elastomer has the best potential to fulfil the resistance criteria for all three substances mentioned.
Feel free to contact us, we will check the conformity of your materials in accordance with DIN EN ISO 9539.
