Malleable iron union Rp

  Datasheet (PDF)

Georg Fischer malleable iron union flat seat 331 (ISO/EN U2) provides a robust, detachable transition joint designed for connecting rigid threaded pipelines in demanding industrial, heating, gas, and potable water distribution systems. Engineered in accordance with EN 10242 and ISO 49 under Design Symbol A, the fitting is manufactured from premium decarburised annealed white malleable cast iron grade EN-GJMW-400-5, ensuring exceptional mechanical toughness, structural integrity, and resistance to deformation under stress. The three-piece assembly comprises a flat-face union bush 370 featuring a parallel internal thread Rp, a flat-face union end 371 with a taper external thread R compliant with EN 10226-1 and ISO 7-1, and a robust union nut 374 utilising standard fastening threads G to ISO 228-1. Sealing across the joint interface relies on a flat compressible gasket compressed squarely between the finely machined planar sealing faces when tightening the union nut, ensuring positive leak-tight containment while isolating the fastening threads from fluid contact. This detachable flat-seat configuration permits rapid installation, straightforward disassembly, and seamless inline component servicing or pipeline inspection without requiring the rotation or lateral displacement of adjacent pipe sections. Available in both black finish and high-purity hot-dip galvanised execution suitable for drinking water installations, the fitting withstands operating temperatures from -20 degrees Celsius up to 120 degrees Celsius at a maximum permissible working pressure of 25 bar, and up to 300 degrees Celsius at 20 bar. Dimensioned across nominal sizes from 1/4 inch to 3 inch, the union incorporates precision hexagonal and octagonal wrench flats for positive tool engagement and controlled torque application during assembly, delivering dependable, long-term performance across industrial utility, cooling, compressed air, and building services networks.