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Large forging plant about the main features of large forging parts:

First of all, the main and fundamental characteristics of large size and weight forgings are their large size and weight. Due to the large size and weight, large forgings need to be forged directly from large ingots. As we all know, the segregation, ryukyu, shrinkage, non-metallic impurities and various organizational inhomogeneities in large steel ingots are very serious, and the gas content is relatively high, and these defects are difficult to remove in the subsequent forging process. Therefore, in large forgings, there is often a significant chemical composition of non-uniformity: a variety of tissue defects and excessive amount of harmful gases. As a result, the heat treatment process of large forgings is often complicated, time-consuming and expensive. Therefore, it needs to be carried out carefully.

Secondly, due to the large size and weight, the heat capacity of the workpiece must be very large, which makes it impossible for large forgings to obtain relatively large heating and cooling speeds during the heat treatment process. Therefore, for the performance, quality requirements are higher, the need for quenching and tempering or quenching to make a significant change in the internal structure of the steel forgings.

large forging plant

Furthermore, large size and heavy weight, large forging plant will inevitably make large workpieces in the heating and cooling process to produce a huge surface and heart temperature difference and organizational transformation of the different simultaneity and the development of large internal stress in the workpiece. In large forgings, the huge compressive stress will hinder the internal organizational transformation of large forgings, delaying or reducing the transformation. The huge amount of tensile stress will lead to cracks in the workpiece, or even overall fracture. In addition, after the end of the heat treatment process, the huge internal stress will be converted into residual stress permanently residing in the large workpiece, and its value can sometimes reach tens or hundreds of MPa, and can be combined with other harmful factors (such as hydrogen in steel, large-size non-metallic inclusions in cold climate, etc.), causing large workpieces to fracture during storage or transportation, which is called cracking. When the value of the internal stress is small, although it does not cause the occurrence of fracture, it will cause the instability of the size and shape of the large workpiece. And it will be converted into a part of the load that the workpiece bears during normal operation, so that the effective carrying capacity of the workpiece is reduced.