CN103071751B - Forging method for six throw crankshaft - Google Patents

Abstract

The invention discloses a forging method for a six throw crankshaft, comprising the step of pouring cylindrical blank. The cylindrical blank comprises the following chemical compositions in percentage by weight: 0.12-0.40 percent of C, 0.42-2.0 percent of Mn, 0.7-1.5 percent of Si, 0.09-0.15 percent of V, 0.11-0.22 percent of Ti, 0.4-1.4 percent of Cr, 0.4-1.5 percent of Ni, 0.15-0.30 percent of Mo, 0.4-0.8 percent of Li, 0.04-0.08 percent of Nb, 0.15-0.20 percent of Al, 0.15-0.50 percent of Mg, wherein the weight percentage of P is less than or equal to 0.030 percent, the weight percentage of S is less than or equal to 0.030 percent, and Fe accounts for the rest amount. According to the forging method for the six throw crankshaft, the defects in the prior art are overcome, energy sources are saved, the quality of heat treatment is improved, the production cycle is shortened, the production cost is reduced, and the radiation pollution to the workshop environment is reduced.

Description

A kind of forging method of six throw crankshaft

Technical field

The present invention relates to the manufacture field of location hook, specifically belong to a kind of forging method of six throw crankshaft.

Background technology

Six throw crankshaft it comprise some sections, crank throw is 120 °, and angle is uniformly distributed.Large-scale mulit-turning crankshaft is mainly used in big-block engine.Its major function is that the power transmitted by connecting rod becomes torque, is engine core position, is widely used in the engine of the industries such as big machinery, chemical industry, locomotive, boats and ships.Its forging method has full combined type, semi-built-up and solid forging method.Due to crank throw and labyrinth integrated, to forge fiber continuous, but solid forging is shaping more difficult, and forging quality requires high, and it is comparatively large thus to forge difficulty, complex-shaped in forging process, is easy to mass problem (as folding 120 ° of angle skews etc.).All take during current domestic solid forging mulit-turning crankshaft to offset, angle is preset etc., mostly carry out integral forged crankshaft by circle to six sides or to complicated technologies such as six sides from all directions, forging process fire is time many, and deformation process is complicated, and qualification rate is low.

Summary of the invention

The object of this invention is to provide a kind of forging method of six throw crankshaft, high temperature normalizing and forging are organically formed the quenching-and-tempering process of the location hook of tinuous production, overcome the defect of prior art, save the energy, improve thermal treatment quality, shorten the production cycle, reduce production cost, decrease the radiation pollution to workshop condition.

Technical scheme of the present invention is as follows:

A forging method for six throw crankshaft, comprises the following steps:

A, cast cylinder blank step

In cylinder blank, chemical component weight percentage is: C 0.12-0.40%, Mn 0.42-2.0%, Si 0.7-1.5%, V 0.09-0.15%, Ti 0.11-0.22%, Cr 0.4-1.4%, Ni 0.4-1.5%, Mo 0.15 ~ 0.30%, Li 0.4-0.8%, Nb 0.04-0.08%, Al 0.15 ~ 0.20%, Mg 0.15 ~ 0.50%, P≤0.030%, S≤0.030%, surplus is Fe;

B, forging step

1), will after forging jumping-up pulling to flat side, then according to the hop count triangular knife of the six throw crankshaft of required forging to the impression up and down of forging, forging is impressed out the hop count identical with six throw crankshaft;

2), according to the length of the six throw crankshaft of required forging, first comparatively length is wherein pulled out in advance with short anvil, and then whole forging is carried out entirety pulling to required size;

3), the six throw crankshaft blank obtaining required forging is reversed to the corresponding section of forging after pulling;

4), to six throw crankshaft blank carry out finish forge finishing, obtain the six throw crankshaft of required casting;

C, heat treatment step

1), by the workpiece after trimming, punching carry out normalized treatment, in heat-treatment furnace, be heated to 880 ± 10 DEG C, and air cooling of coming out of the stove after being incubated 3.5 ~ 4 hours;

2), by the workpiece Shot Blasting after heat treatment, apron type airless shot blasting machine is adopted to carry out surface treatment to forging, until the oxide skin that its surface produces all comes off;

3), by the workpiece after ball blast carry out the process of cold school, finally obtain finished product.

Described workpiece after trimming, punching is carried out normalized treatment, in heat-treatment furnace, be heated to 880 DEG C, and air cooling of coming out of the stove after being incubated 3.7 hours.

Compared with the prior art, beneficial effect of the present invention is as follows:

The present invention only needs a few fire, and repeatedly overturns blank, pulls out, and the defect of steel part inside can be compacted, and blank internal modification is even, not easily occurs dead band, and with this forging method making six throw crankshaft, the qualification rate of product is higher.

Beneficial effect of the present invention is as follows: the forging method of above-mentioned six throw crankshaft, its technique is simple, simple to operate, its corresponding forging time is reduced to 220-250 minute by original 440-550 minute, and the percent defective of product reduces 20%, thus can save the required energy of production and cost.

Detailed description of the invention

A forging method for six throw crankshaft, comprises the following steps:

A, cast cylinder blank step

In cylinder blank, chemical component weight percentage is: C 0.12-0.40%, Mn 1.42-1.8%, Si 0.7-1.5%, V 0.09-0.15%, Ti 0.11-0.22%, Cr 0.9-1.4%, Ni 0.9-1.5%, Mo 0.15 ~ 0.30%, Li 0.4-0.8%, Nb 0.04-0.08%, Al 0.15 ~ 0.20%, Mg 0.15 ~ 0.50%, P≤0.030%, S≤0.030%, surplus is Fe;

B, forging step

1), will after forging jumping-up pulling to flat side, then according to the hop count triangular knife of the six throw crankshaft of required forging to the impression up and down of forging, forging is impressed out the hop count identical with six throw crankshaft;

2), according to the length of the six throw crankshaft of required forging, first comparatively length is wherein pulled out in advance with short anvil, and then whole forging is carried out entirety pulling to required size;

3), the six throw crankshaft blank obtaining required forging is reversed to the corresponding section of forging after pulling;

4), to six throw crankshaft blank carry out finish forge finishing, obtain the six throw crankshaft of required casting;

C, heat treatment step

1), by the workpiece after trimming, punching carry out normalized treatment, in heat-treatment furnace, be heated to 880 DEG C, and air cooling of coming out of the stove after being incubated 3.7 hours;

2), by the workpiece Shot Blasting after heat treatment, apron type airless shot blasting machine is adopted to carry out surface treatment to forging, until the oxide skin that its surface produces all comes off;

3), by the workpiece after ball blast carry out the process of cold school, finally obtain finished product.

Main Mechanical index:

Tensile strength >=854 Mpa

Yield strength >=646 Mpa

Percentage elongation >=14%

The contraction percentage of area >=35%

Brinell hardness HB=237-259.

Claims (2)

1. a forging method for six throw crankshaft, is characterized in that comprising the following steps:

A, cast cylinder blank step

In cylinder blank, chemical component weight percentage is: C 0.12-0.40%, Mn 0.42-2.0%, Si 0.7-1.5%, V 0.09-0.15%, Ti 0.11-0.22%, Cr 0.4-1.4%, Ni 0.4-1.5%, Mo 0.15 ~ 0.30%, Li 0.4-0.8%, Nb 0.04-0.08%, Al 0.15 ~ 0.20%, Mg 0.15 ~ 0.50%, P≤0.030%, S≤0.030%, surplus is Fe;

B, forging step

1), will after forging jumping-up pulling to flat side, then according to the hop count triangular knife of the six throw crankshaft of required forging to the impression up and down of forging, forging is impressed out the hop count identical with six throw crankshaft;

2), according to the length of the six throw crankshaft of required forging, first comparatively length is wherein pulled out in advance with short anvil, and then whole forging is carried out entirety pulling to required size;

3), the six throw crankshaft blank obtaining required forging is reversed to the corresponding section of forging after pulling;

4), to six throw crankshaft blank carry out finish forge finishing, obtain the six throw crankshaft of required casting;

C, heat treatment step

1), by the workpiece after trimming, punching carry out normalized treatment, in heat-treatment furnace, be heated to 880 ± 10 DEG C, and air cooling of coming out of the stove after being incubated 3.5 ~ 4 hours;

2), by the workpiece Shot Blasting after heat treatment, apron type airless shot blasting machine is adopted to carry out surface treatment to forging, until the oxide skin that its surface produces all comes off;

3), by the workpiece after ball blast carry out the process of cold school, finally obtain finished product.

2. the forging method of six throw crankshaft according to claim 1, is characterized in that: described workpiece after trimming, punching is carried out normalized treatment, is heated to 880 DEG C in heat-treatment furnace, and air cooling of coming out of the stove after being incubated 3.7 hours.