Reducing bush malleable iron

  Datasheet (PDF)

The Georg Fischer reducing bush 241 provides a compact, heavy-duty axial diameter transition for industrial and building technology piping systems, enabling a direct step-down from a larger male connection to a smaller female port. Manufactured to EN 10242 and ISO 49 under designation symbol ISO/EN N4, the fitting is cast from decarburised annealed whiteheart malleable cast iron grade EN-GJMW-400-5, ensuring exceptional ductility, mechanical robustness, and high resistance to torsional tightening loads. Jointing is executed via pipe threads engineered to EN 10226-1 and ISO 7-1, combining a 1:16 taper external thread (R) with a parallel internal thread (Rp). The taper-to-parallel geometry achieves direct metallic flank contact under wrench torque, creating a dependable, pressure-tight seal when accompanied by suitable jointing compounds or PTFE thread sealants. Depending on the dimensional ratio between the primary nominal diameter d1 and the reduced outlet d2, the component is configured in Form I, Form II, or Form III profiles, ensuring optimized internal flow transitions and structural wall thickness across all diameters from 1/4 inch to 4 inches. The fitting body incorporates precision-formed external hexagon flats to guarantee slip-free wrench engagement and efficient torque transfer during assembly. Surface protection is provided by a uniform hot-dip galvanized zinc layer applied in accordance with EN 10242 standards, yielding high corrosion resistance and complete hygienic compliance for potable water distribution, heating and chilled water networks, industrial cooling loops, compressed air lines, and flammable gas conveying. The reducing bush operates reliably across a thermal envelope from -20 degrees Celsius to 120 degrees Celsius at working pressures up to 25 bar, and maintains service integrity up to 300 degrees Celsius at 20 bar, supporting long-term, maintenance-free performance in demanding process installations.