A Forging Process of Large Locomotive Connecting Rod

Abstract

The invention discloses a large-scale locomotive connecting rod forging technology which comprises the steps of blanking, lathing, anti-decarburization coating application, blank heating, surface oxidation layer removal, roll forging of blanks, pre-forging, finish forging, trimming, punching and calibration, anti-decarburization coating application and heat treatment. According to the large-scale locomotive connecting rod forging technology, forming can be achieved through one time of heating only. Compared with the traditional technology that heating needs to be conducted twice or more, the technology has the advantages that surface oxidation and decarburization of a connecting rod are effectively reduced, the mechanical performance of the connecting rod is guaranteed, and time and energy resources are saved. Due to the adoption of roll forging of blanks, speed is high, labor is saved, the consistency of manufactured blanks is high, and time and labor are saved during forging in later periods. Due to the fact that high-temperature-resistant and oxidation-resistant anti-decarburization coating application is conducted twice during the whole technology, the decarburized layer on the surface of a final forged piece is thinner than 0.3 mm, and product quality is improved effectively. Due to the fact that the connecting rod forged piece is vertically hoisted for heat treatment, bending deformation of the forged piece is effectively prevented during heat treatment.

Description

technical field [0001] The invention relates to a forging process, in particular to a large-scale locomotive connecting rod forging process, and belongs to the technical field of forging process. Background technique [0002] At present, the forging process of domestic large-scale locomotive connecting rods mainly includes: blanking, heating, free forging billet, grinding defects, heating, pre-forging, final forging, edge trimming / punching, correction, heat treatment. [0003] The disadvantages of the above process are obvious: [0004] (1) At least two or more times of heating are required before final forging. Multiple heatings will cause: oxidation and decarburization of the connecting rod surface, the depth of the decarburization layer reaches 1.0-1.5mm, and the mechanical properties of the connecting rod are reduced; [0005] (2) There is no special treatment for heat treatment in the traditional process, and the bending degree of the connecting rod after heat treatmen...

AI Technical Summary

Problems solved by technology

[0004] (1) At least two or more times of heating are required before final forging. Multiple heatings will cause: oxidation and decarburization of the connecting rod surface, the depth of the decarburization layer reaches 1.0-1.5mm, and the mechanical properties of the connecting rod are reduced;

[0005] (2) There is no special treatment for heat treatment in the traditional process, and the bending degree of the connecting rod after heat treatment is greater than 2mm;

[0006] (3) The defects need to be polished after the free forging billet is drawn out, and if the grinding is not clean, it will cause defects such as folding;

[0007] (4) Forgings are re-calibrated after trimming / punching. There are many process steps, the process is cumbersome, and the labor intensity of workers is relatively high.

[0008] Based on the above reasons, currently large-scale locomotive connecting rod forgings are mainly imported products, and the cost is relatively high. However, the connecting rods forged by the traditional domestic forging process have disadvantages such as low mechanical properties, large depth of decarburization layer, large weight deviation, and large bending degree. It is also difficult to achieve the purpose of replacing imported connecting rod forgings

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