Ratnamani Metals and Tubes Ltd. Offer Helical Large Diameter Electric Fusion Welded SS Pipes. Ratnamani Metals and Tubes Ltd. Hold an ISO 9001:2000 quality assurance certification. Helical Large Diameter Electric Fusion Welded SS Pipes consists of a JCO forming press, helical / spiral mill, inside and outside welding system, heat treatment furnace and testing facilities. Helical Large Diameter Electric Fusion Welded SS Pipes are capable of manufacturing austenitic and various duplex grades. These pipes are used for oil and gas exploration, refineries & petrochemicals, fertilizer, LNG terminals, cross country pipe line for gas & water and pipes for general engineering purpose. The thickness of the pipes is 2.77mm to 9.52mm.