Nodular Graphite Iron Castings pipe is imported from abroad, a large rolling equipment, the core components of the machine, its quality directly affects the performance of the equipment. The geometry of the pipe is a cylinder。 The length of the slide tube is 1685mm, the upper and lower diameters are 336mm, 327mm, the average wall thickness is 86mm, the weight of the casting blank is 765kg, the material grade is QT600-3. Chemical composition control range see table. Ball Level 2. Pearlite number 80% to 90%, tensile strength of 570 ~ 600MPa, is a difficult large castings. The casting not only on the material, mechanical performance requirements are very strict, and casting does not allow cracks, loose, slag, shrinkage and stomata and other mechanical properties and performance defects. Casting heat treatment quenching and tempering hardness of 275 ~ 320HBW, after heat treatment must also be aging treatment, shall not be caused by heat treatment deformation. In order to ensure the inherent quality of Nodular Graphite Iron Castings castings, customers explicitly require the use of induction furnace melting. Fully taking into account the casting process is easy to occur in the process, after receiving the pattern, the author carried out a careful planning, the process of using a rotary stepped pouring system and with the shape of the edge of the plumbing riser, plus the whole process of casting Of the strict control, and ultimately a successful casting, the merchants get the approval.
Nodular Graphite Iron Castings production technology has experienced more than 60 years of continuous development, innovation and improvement, according to the requirements of production components, from a relatively simple variety of materials, the development of today's dozens of different grades of Nodular Graphite Iron Castings, such as ferrite Nodular Graphite Iron Castings , Pearlite Nodular Graphite Iron Castings, austenitic Nodular Graphite Iron Castings, bainitic Nodular Graphite Iron Castings and austenite-bainitic Nodular Graphite Iron Castings, Nodular Graphite Iron Castings defects has been a casting worker and foundry concern and research of hot topics.
Ductile cast iron in addition to the general casting defects, the production of casting defects often occur: shrink loose, slag, graphite floating, subcutaneous stomata, spheroidization and spheroidization and other Nodular Graphite Iron Castings casting defects; according to different production processes, Nodular Graphite Iron Castings prone to casting defects are often different, but the impact of the most direct impact on the casting, the greatest impact is the graphite floating, spheroidization and spheroidization, if the test results, the emergence of the three casting defects, There is no effective measure to save, can only be scrapped, and may be the whole product of the product scrapped.
With the continuous development of science and technology, the improvement of smelting equipment, the improvement of dosing agent and inoculant, and the extensive application of rare elements in the production of Nodular Graphite Iron Castings, the quality of Nodular Graphite Iron Castings production is improved and the production rate of Nodular Graphite Iron Castings defects is reduced But also to improve the production costs; how to take effective measures, not substantially increase the cost of production under the premise of the Nodular Graphite Iron Castings defects to a minimum, is the pursuit of every manufacturer. Among them, Nodular Graphite Iron Castings graphite floating defects is easy to appear, it is difficult to determine a casting defects.