Jul 24, 2018
The connection of ductile iron pipes is flexible. The inner and outer diameters of pipes or fittings can be connected to each other regardless of their size, as long as their nominal diameters are the same, and the joints are interchangeable. For example, the steel pipe connection method, the joint of the steel pipe mostly presents the threaded joint, welding, in addition to the Lap Joint Flange and various flexible joint types,such us Flexible Flange Adaptor. In urban water supply projects, small-diameter indoor feedwater galvanized steel pipes generally use a threaded joint.
Cast iron pipes generally use a rigid joint and a flexible joint.
1. Rigid joint: linoleum asbestos cement joint, rubber ring expansion cement joint.
2, Flexible joint: apron asbestos cement joint.
3, Semi-rigid semi-flexible joint: hemp-lead joint.
Plastic pipe connection method for ductile iron pipe. The rigid PVC water supply pipe can be of rubber ring joint, bonding joint, flange connection and the like. The most commonly used rubber ring and adhesive connection, the bonding joint is only suitable for the connection of pipes with an outer diameter of less than 160mm; the flange connection is generally used for the connection of other PVC valve parts such as hard polyvinyl chloride pipe and cast iron pipe. The high density polyethylene plastic pipe can be connected by hot melt. The polyethylene pipe is connected to the metal pipe and connected by a steel-plastic transition joint.
The main components of ductile iron pipes are carbon, silicon, manganese, sulfur, phosphorus and magnesium. A certain amount of spheroidal graphite is distributed on the ferrite and pearlite matrix. The proportion of ferrite and pearlite in the matrix is different according to the nominal diameter and the elongation requirement. The proportion of pearlite in small diameter is small. Generally not more than 20%, the general control of large diameter is about 25%. Minimum tensile strength: 420/Mpa, minimum yield strength 300/Mpa, minimum elongation 7%.