Defects and Countermeasures of Large Forging Parts
Defects of forging parts vary according to the character of materials and process parameters. They often appear in form of folds, piping, core collapse, poor roundness, poor shrinkage, poor consistency and white spots. Large forging parts often contain faults due to improper control of parameters, which will affect the performance and quality of the product. In this paper, defects and countermeasures of large forging parts are discussed.
The main cause of white spots in large forging parts is slag inclusions from the smelting process. White spots are distributed in the matrix of the forging parts and are suspicious for potential cracks. Due to poor slag removal process, this kind of problem is commonly encountered in large forge parts. To solve this problem, firstly, it is necessary to control the furnace temperature and slag components reasonably to ensure the quality of steel smelting. Secondly, improvement should be made on the equipment and technology of slag removal to make it reach an automatic running condition. Thirdly, it is also important to construct a sound inspection system to check the surface of forge parts regularly.
The piping defect of large forging parts is caused by the misalignment between the original billet and the forging frame, which results in the misalignment between the top and bottom surfaces of the forging parts. The pipeline defect form is mainly round, with a diameter of 6-12 mm and a depth of about 2-4 mm. To reduce the possibility of pipeline defects, the first step is to properly adjust the furnace temperature when forging steel billets. In this way, it can effectively reduce the plasticity of the steel material, reduce the occurrence of misalignment, and reduce the probability of self-aligning and piping defects.In addition, in the actual production process, it is necessary to modify the mold reasonably, reduce the gap between the cover plate and the body, and select the appropriate forged hammer for forging.
Core collapse defect refers to the occurrence of improper strength at the inner surface of large forging parts. The main reasons for this kind of defect are too low forging temperature, too much gap at the starting end, and too small inner strength. In order to solve this problem, one should first pay attention to controlling the temperature of the billet before forging. Secondly, attention should be paid to the reasonable filling of the punch and the design of the forming die and the appropriate forging force. Last but not least, it is necessary to use more advanced heat treatment technology to further improve the mechanical properties of the parts.
In a word, the defects of large forging parts can be solved by controlling the process parameters and improving the equipment and technological processes. However, the most important point is to construct a sound inspection system and improve the training of personnel to better prevent the defects from happening. By doing this, large forging parts of high quality can be provided for subsequent processing and manufacturing. 。
