With the wide application of ductile iron, some enterprises are more and more cautious about the selection of ductile iron pipes. In many cases, the gas seal of nodular cast iron pipe plays an important role in product quality and service performance.
When all kinds of nodular cast iron parts are produced and formed, the air tightness monitoring is an essential process. Considering the particularity of the workpiece, the detection method of the gas seal of nodular cast iron pipe is also different from that of other pipe fittings. At present, the methods often used to check the air tightness of ductile iron pipes are bubble method, coating method, chemical gas tracing leak detection method, pressure change method, flow method, ultrasonic method and so on.
The bubble method is a more traditional method, which is to immerse the workpiece in water, fill it with compressed air, and then collect the bubbles out of it in a certain time to measure the leakage. The modification rule is to modify the bubble prone liquid on the surface of the workpiece filled with certain air pressure, and observe the bubble condition to detect the leakage. These two methods are relatively simple to operate, but there are still great uncertainties. Therefore, when consumers purchase ductile iron pipes, they should choose products from regular manufacturers, products and performance are well guaranteed.
At the same time, with the progress of science and technology, more scientific and technological elements are added to the production process of ductile iron, the quality will continue to improve, and they can be assured to purchase. In fact, in addition to air tightness inspection, it is also necessary to focus on the die, weight and hydrostatic test of ductile iron pipe. It is suggested that the die should be well maintained without obvious defects, so as to avoid affecting the surface quality of pipe fittings.
For the weight control system of nodular cast pipe, the process shall ensure that the weight of pipe fittings is within the standard tolerance range, and each nodular cast pipe fitting, regardless of its pipe diameter, shall be subject to hydrostatic test or equivalent effect test. In addition, the total quality management system should be carried out to ensure the quality of every ductile pipe.