CN102989942A - Forging method of single-throw crank shaft - Google Patents

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

A kind of forging method of one-throw crankshaft

Technical field

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

Background technology

It comprises some sections one-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 one-throw crankshaft, with high temperature normalizing and the quenching-and-tempering process that forges the one-throw crankshaft 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 one-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 0.42-1.0%, Si 0.7-1.5%, V 0.09-0.15%, Ti 0.15-0.22%, Cr 0.4-1.4%, Ni 0.6-1.5%, Mo 0.18～0.30%, Li 0.4-0.8%, Nb 0.04-0.08%, Al 0.18～0.24%, Mg 0.18～0.45%, P≤0.033%, S≤0.030%, and surplus is Fe;

B, forging step

At first, adopt Medium Frequency Induction Heating Furnace to be heated to initial forging temperature the cylinder blank of selecting;

Then, the blank after the heating is rolled into blank by cross wedge rolling die, the shaft portion at moulding two ends in cross wedge rolling machine;

Afterwards, the blank after rolling is placed in the bending mould, carries out bending;

At last, with the blank after the bending in the upsetting die, two-way upsetting squeeze moulding;

C, heat treatment step

1), the workpiece after the upsetting moulding is carried out normalized treatment, in heat-treatment furnace, be heated to 880 ± 10 ℃, 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 one-throw crankshaft according to claim 1 is characterized in that: the workpiece after the described upsetting moulding 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 motor shaft 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 one-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.

Of the present invention PowerPerformance detection data is as follows:

Tensile strength sigma b (MPa): 〉=1110 (110)

Yield strength σ s (MPa): 〉=990 (95)

Percentage elongation δ 5 (%): 〉=13

Contraction percentage of area ψ (%): 〉=48

The specific embodiment

A kind of forging method of one-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 0.42-1.0%, Si 0.7-1.5%, V 0.09-0.15%, Ti 0.15-0.22%, Cr 0.4-1.4%, Ni 0.6-1.5%, Mo 0.18～0.30%, Li 0.4-0.8%, Nb 0.04-0.08%, Al 0.18～0.24%, Mg 0.18～0.45%, P≤0.033%, S≤0.030%, and surplus is Fe;

B, forging step

At first, adopt Medium Frequency Induction Heating Furnace to be heated to initial forging temperature the cylinder blank of selecting;

Then, the blank after the heating is rolled into blank by cross wedge rolling die, the shaft portion at moulding two ends in cross wedge rolling machine;

Afterwards, the blank after rolling is placed in the bending mould, carries out bending;

At last, with the blank after the bending in the upsetting die, two-way upsetting squeeze moulding;

C, heat treatment step

1), the workpiece after the upsetting moulding is carried out normalized treatment, in heat-treatment furnace, be heated to 880 ℃, 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.

Claims (2)

1. the forging method of an one-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 0.42-1.0%, Si 0.7-1.5%, V 0.09-0.15%, Ti 0.15-0.22%, Cr 0.4-1.4%, Ni 0.6-1.5%, Mo 0.18～0.30%, Li 0.4-0.8%, Nb 0.04-0.08%, Al 0.18～0.24%, Mg 0.18～0.45%, P≤0.033%, S≤0.030%, and surplus is Fe;

B, forging step

At first, adopt Medium Frequency Induction Heating Furnace to be heated to initial forging temperature the cylinder blank of selecting;

Then, the blank after the heating is rolled into blank by cross wedge rolling die, the shaft portion at moulding two ends in cross wedge rolling machine;

Afterwards, the blank after rolling is placed in the bending mould, carries out bending;

At last, with the blank after the bending in the upsetting die, two-way upsetting squeeze moulding;

C, heat treatment step

1), the workpiece after the upsetting moulding is carried out normalized treatment, in heat-treatment furnace, be heated to 880 ± 10 ℃, 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 one-throw crankshaft according to claim 1, it is characterized in that: the workpiece after the described upsetting moulding 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.