New process of forging and drawing of the hottest

  • Detail

With the increase of the weight and size of forgings required by steel, energy and petrochemical industry, the weight of steel ingots continues to increase, making it more difficult to prevent or reduce metallurgical defects in steel ingots. On the other hand, due to the increase of ingot weight and size, the tonnage of hydraulic press is relatively reduced, and the quality standard of forgings is constantly improving. The traditional upsetting and drawing deformation process can not meet the quality requirements of forgings by breaking the internal casting structure of ingots and repairing the internal metallurgical defects. Drawing and upsetting are the two most widely used steps in the forging of large forgings. Compared with upsetting, drawing and upsetting firmly fix the hammer body and handle on the electronic universal experimental machine, because the blank on this basis has small volume, large deformation and high stress in the defect area; Therefore, drawing is the main step to break the casting structure and repair metallurgical defects. Here is a new process of forging and drawing of Large Forgings: concave anvil drawing plastic metal separator

in the process of forging deformation, due to the influence of friction and temperature gradient, there is always a difficult deformation area near the contact area between the tool and the forging stock, either large or small. The size and shape of the hard deformation zone have an important influence on the deformation distribution and stress state inside the forging, thus affecting the quality of the forging. During drawing, there is a difficult deformation area near the contact area between the anvil and the forging stock, and its pressing direction is perpendicular to the axis. Because the metallurgical defects of the ingot can obtain the stripping force and the minimum force exist near the axis, during the drawing step, a large amount of deformation and a good stress state should be formed in the area near the axis, which is conducive to the repair of the metallurgical defects of the ingot. There is a hard deformation area in the contact area between the forging stock and the anvil, which is just in line with the deformation characteristics of the drawing step. From the perspective of deformation, when there is a hard deformation area in the contact area between the forging stock and the anvil, the deformation of the core area is bound to be large; From the point of view of stress, in the drawing step, due to the rigid end constraint, in order to maintain the continuity of the deformation body, the upper and lower dilemma deformation area must hinder the metal flow near the axis through the rigid end, thus causing a large axial compressive stress in the center, when the metal flow speed in the heart is large. Therefore, it is beneficial to repair the metallurgical defects of the ingot that there is a difficult deformation zone in the contact area between the forging billet and the anvil, and the larger the difficult deformation zone is, the more obvious the effect is. According to the above analysis, changing the bottom plane of the anvil to a slightly concave surface in the middle can increase the difficult deformation area at the bottom of the anvil. This kind of anvil with concave surface at the bottom is called concave anvil drawing. Research shows that concave anvil lengthening is better than ordinary anvil lengthening in loose compaction and cavity volume closure. Compared with other existing special forging methods, concave anvil lengthening has the advantages of convenient application and wide application range

Copyright © 2011 JIN SHI