CN103071751A - 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

It comprises some sections six throw crankshaft, and crank throw is 120 °, and angle evenly distributes.Large-scale mulit-turning crankshaft is mainly used in big-block engine.Its major function is that the power that connecting rod transmits is become torque, is the 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.Since crank throw and labyrinth integrated, to forge fiber continuous, but the solid forging moulding is difficult, forging quality requires high, thereby it is larger to forge difficulty, and is complex-shaped in the forging process, is easy to out quality problems (as folding 120 ° of angle skews etc.).Take all during present domestic solid forging mulit-turning crankshaft that offsetting, angle preset etc., mostly come integral forged crankshaft by circle to six sides or all directions to the complicated technologies such as six sides, the forging process fire is inferior many, the deformation process complexity, and qualification rate is low.

Summary of the invention

The forging method that the purpose of this invention is to provide a kind of six throw crankshaft, with high temperature normalizing and the quenching-and-tempering process that forges the location hook that organically forms tinuous production, overcome the defective of prior art, saved the energy, improved thermal treatment quality, shorten the production cycle, reduced production cost, reduced the radiation pollution to workshop condition.

Technical scheme of the present invention is as follows:

A kind of forging method of six throw crankshaft may further comprise the steps:

A, cast cylinder blank step

Chemical component weight percentage is in the cylinder blank: 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%, and surplus is Fe;

B, forging step

1), will be behind the forging jumping-up pulling to flat side, then according to the hop count of the six throw crankshaft of required forging with the up and down impression of triangular knife to 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,, and then whole forging carried out integral body pull out to required size first to pulling out in advance than length wherein with short anvil;

3), the corresponding section that pulls out rear forging is reversed the six throw crankshaft blank that obtains required forging;

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

C, heat treatment step

1), will cut edge, the workpiece after the punching carries out normalized treatment, is heated to 880 ± 10 ℃ in heat-treatment furnace, and the air cooling of coming out of the stove after being incubated 3.5～4 hours;

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

3), the workpiece behind the ball blast carried out cold school process, finally obtain finished product.

Describedly will cut edge, the workpiece after the punching carries out normalized treatment, is heated to 880 ℃ in heat-treatment furnace, and the 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 to get final product, and blank is repeatedly overturn, pulls out, and the defective of steel part inside can be compacted, and the blank internal modification is even, is not prone to the dead band, makes six throw crankshaft with this forging method, and 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 was reduced to 220-250 minute by original 440-550 minute, and the percent defective of product reduces 20%, produced the required energy and cost thereby can save.

 

The specific embodiment

A kind of forging method of six throw crankshaft may further comprise the steps:

A, cast cylinder blank step

Chemical component weight percentage is in the cylinder blank: 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%, and surplus is Fe;

B, forging step

1), will be behind the forging jumping-up pulling to flat side, then according to the hop count of the six throw crankshaft of required forging with the up and down impression of triangular knife to 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,, and then whole forging carried out integral body pull out to required size first to pulling out in advance than length wherein with short anvil;

3), the corresponding section that pulls out rear forging is reversed the six throw crankshaft blank that obtains required forging;

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

C, heat treatment step

1), will cut edge, the workpiece after the punching carries out normalized treatment, is heated to 880 ℃ in heat-treatment furnace, and the air cooling of coming out of the stove after being incubated 3.7 hours;

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

3), the workpiece behind the ball blast carried out cold school process, finally obtain finished product.

The 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. the forging method of a six throw crankshaft is characterized in that may further comprise the steps:

A, cast cylinder blank step

Chemical component weight percentage is in the cylinder blank: 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%, and surplus is Fe;

B, forging step

1), will be behind the forging jumping-up pulling to flat side, then according to the hop count of the six throw crankshaft of required forging with the up and down impression of triangular knife to 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,, and then whole forging carried out integral body pull out to required size first to pulling out in advance than length wherein with short anvil;

3), the corresponding section that pulls out rear forging is reversed the six throw crankshaft blank that obtains required forging;

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

C, heat treatment step

1), will cut edge, the workpiece after the punching carries out normalized treatment, is heated to 880 ± 10 ℃ in heat-treatment furnace, and the air cooling of coming out of the stove after being incubated 3.5～4 hours;

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

3), the workpiece behind the ball blast carried out cold school process, finally obtain finished product.

2. the forging method of six throw crankshaft according to claim 1 is characterized in that: describedly will cut edge, the workpiece after the punching carries out normalized treatment, is heated to 880 ℃ in heat-treatment furnace, and the air cooling of coming out of the stove after being incubated 3.7 hours.