Forging method of single-throw crank shaft

Abstract

The invention discloses a forging method of a single-throw crank shaft. The forging method of the single-throw crank shaft comprises the following steps: a step a of pouring a cylindrical blank material, wherein the cylindrical blank material comprises chemical components, by weight percent: 0.12-0.40% of C, 0.42-1.0% of Mn, 0.7-1.5% of Si, 0.09-0.15% of V, 0.15-0.22% of Ti, 0.4-1.4% of Cr, 0.6-1.5% of Ni, 0.18-0.30% of Mo, 0.4-0.8% of Li, 0.04-0.08% of Nb, 0.18-0.24% of Al, 0.18-0.45% of Mg, no greater than 0.033% of P, no greater than 0.030% of S and the balance of Fe; and a step b of forging, wherein the sep b comprises the following steps: at first, heating the selectively-used cylindrical blank material to an initial forging temperature by adopting an intermediate frequency heating furnace; next, rolling the heated blank material in a cross wedge rolling mill through a cross wedge rolling die into a rough blank and forming shaft rod parts of two ends; subsequently, putting the rolled rough blank in a bending die for bending; and finally, upsetting and extruding the bent rough blank in an upsetting forging concave die in two directions for shaping. With the adoption of a quenching and tempering heat treatment technology for the single-throw crank shaft provided by the invention, the high temperature normalizing and the forging are caused to organically form a continuous production line; and therefore, the defects of the prior art are overcome, the energy resource is saved, the heat treatment quality is improved, the production period is shortened, the production cost is lowered and the radiation pollution to a workshop environment is reduced.

Description

technical field [0001] The invention relates to the processing field of positioning hooks, in particular to a forging method of a single throw crankshaft. Background technique [0002] The single-throw crankshaft includes several sections, the crankshaft is 120°, and the included angle is evenly distributed. Large multi-turn crankshafts are mainly used in large engines. Its main function is to convert the force transmitted from the connecting rod into torque. It is the core part of the engine and is widely used in engines in large machinery, chemical industry, locomotives, ships and other industries. Its forging methods include fully assembled, semi-assembled and integral forging methods. Due to the integration of the crankshaft and the curved diameter and the continuous forging fibers, the overall forging is difficult and the quality of the forgings is high, so the forging is difficult, the shape is complex during the forging process, and quality problems are easy to occu...

AI Technical Summary

Problems solved by technology

Due to the integration of the crankshaft and the curved diameter and the continuous forging fibers, the overall forging is difficult and the quality of the forgings is high, so the forging is difficult, the shape is complex during the forging process, and quality problems are easy to occur (such as folding 120 ° included angle offset, etc.)

At present, when the overall forging of multi-turn crankshafts is carried out in China, misalignment and angle presets are adopted. Most of the crankshafts are forged from a circle to a hexagon or from an octagon to a hexagon. The forging process requires many fires, the deformation process is complicated, and the pass rate is low.