CN103846634A - Method for forging single-throw crank shaft - Google Patents

Abstract

The invention discloses a method for forging a single-throw crank shaft. The method comprises the following steps: casting a cylindrical blank, wherein the cylindrical blank comprises the following chemical components in percentage by weight: 0.22-0.36 percent of C, 0.22-1.3 percent of Mn, 1.7-2.5 percent of Si, 0.09-0.15 percent of V, 0.085-0.12 percent of Ti, 1.2-2.4 percent of Cr, 0.46-0.86 percent Ni, a trace amount to 0.30 percent of Mo, 0.4-0.8 percent of Li, 0.04-0.08 percent of Cu, a trace amount to 0.14 percent of Al, a trace amount to 0.25 percent of Mg, less than or equal to 0.033 percent of P, less than or equal 0.030 percent of S and the balance of Fe. In the method, a tempering thermal treatment process for single-throw crack shafts on a continuous production line is constructed organically by high-temperature normalizing and forging, so that the defects in the prior art are overcome, energy is saved, the thermal treatment quality is improved, the production period is shortened, the production cost is reduced, and radiation pollution of the workshop environment is lowered.

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 is uniformly distributed.Large-scale mulit-turning crankshaft is mainly used in big-block engine.Its major function is that the power that connecting rod is transmitted 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 moulding is more difficult, forging quality requires high, thereby it is larger to forge difficulty, complex-shaped in forging process, is easy to out quality problems (as folding 120 ° of angle skews etc.).When current domestic solid forging mulit-turning crankshaft, all take to offset, angle is preset etc., mostly by circle to six sides or carry out integral forged crankshaft to complicated technologies such as six sides from all directions, forging process fire is time many, deformation process complexity, and qualification rate is low.

Summary of the invention

The object of this invention is to provide a kind of forging method of one-throw crankshaft, by high temperature normalizing and the quenching-and-tempering process that forges the one-throw crankshaft that organically forms tinuous production, overcome the defect of prior art, save the energy, improve 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 forging method for one-throw crankshaft, comprises the following steps:

A, cast cylinder blank step

In cylinder blank, chemical component weight percentage is: C 0.22-0.36%, Mn 0.22-1.3%, Si 1.7-2.5%, V 0.09-0.15%, Ti 0.085-0.12%, Cr 1.2-2.4%, Ni 0.46-0.86%, Mo trace～0.30%, Li 0.4-0.8%, Cu 0.04-0.08%, Al trace～0.14%, Mg trace～0.25%, P≤0.033%, S≤0.030%, surplus is Fe;

B, forging step

1) described cylinder blank is heated to 800 ℃, insulation 2h, heats afterwards 3h and makes its temperature reach 1180 ℃, and insulation 1.5h also pulls out ejection;

2) by step 1) in the workpiece that generates be heated to 1180 ℃, and pull out, jumping-up, round as a ball, alignment afterwards, correction size make forging ratio be not less than 4, to forge the base substrate for described bent axle;

3) by step 2) in the institute's workpiece that generates employing hot charging stove expansion hydrogen mode cooling;

C, heat treatment step

1), the workpiece after upsetting moulding is carried out to 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), by the workpiece Shot Blasting after heat treatment, adopt apron type airless shot blasting machine forging is carried out to surface treatment, until its surface produce oxide skin all come off.

Workpiece after 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, and blank is repeatedly overturn, pulled out, and the defect of steel part inside can be compacted, and blank internal modification is even, is not prone to 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 is reduced to 220-250 minute by original 440-550 minute, and the percent defective of product reduces 20%, produces the required energy and cost thereby can save.

The specific embodiment

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

A, cast cylinder blank step

In cylinder blank, chemical component weight percentage is: C 0.22-0.36%, Mn 0.22-1.3%, Si 1.7-2.5%, V 0.09-0.15%, Ti 0.085-0.12%, Cr 1.2-2.4%, Ni 0.46-0.86%, Mo trace～0.30%, Li 0.4-0.8%, Cu 0.04-0.08%, Al trace～0.14%, Mg trace～0.25%, P≤0.033%, S≤0.030%, surplus is Fe;

B, forging step

1) described cylinder blank is heated to 800 ℃, insulation 2h, heats afterwards 3h and makes its temperature reach 1180 ℃, and insulation 1.5h also pulls out ejection;

2) by step 1) in the workpiece that generates be heated to 1180 ℃, and pull out, jumping-up, round as a ball, alignment afterwards, correction size make forging ratio be not less than 4, to forge the base substrate for described bent axle;

3) by step 2) in the institute's workpiece that generates employing hot charging stove expansion hydrogen mode cooling;

C, heat treatment step

1), the workpiece after upsetting moulding is carried out to 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), by the workpiece Shot Blasting after heat treatment, adopt apron type airless shot blasting machine forging is carried out to surface treatment, until its surface produce oxide skin all come off.

Claims (2)

1. a forging method for one-throw crankshaft, is characterized in that, comprises the following steps:

A, cast cylinder blank step

In cylinder blank, chemical component weight percentage is: C 0.22-0.36%, Mn 0.22-1.3%, Si 1.7-2.5%, V 0.09-0.15%, Ti 0.085-0.12%, Cr 1.2-2.4%, Ni 0.46-0.86%, Mo trace～0.30%, Li 0.4-0.8%, Cu 0.04-0.08%, Al trace～0.14%, Mg trace～0.25%, P≤0.033%, S≤0.030%, surplus is Fe;

B, forging step

1) described cylinder blank is heated to 800 ℃, insulation 2h, heats afterwards 3h and makes its temperature reach 1180 ℃, and insulation 1.5h also pulls out ejection;

2) by step 1) in the workpiece that generates be heated to 1180 ℃, and pull out, jumping-up, round as a ball, alignment afterwards, correction size make forging ratio be not less than 4, to forge the base substrate for described bent axle;

3) by step 2) in the institute's workpiece that generates employing hot charging stove expansion hydrogen mode cooling;

C, heat treatment step

1), the workpiece after upsetting moulding is carried out to 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), by the workpiece Shot Blasting after heat treatment, adopt apron type airless shot blasting machine forging is carried out to surface treatment, until its surface produce oxide skin all come off.

2. the forging method of one-throw crankshaft according to claim 1, is characterized in that: the workpiece after 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.