Cold forging processing method of hardened and tempered structural steel

A processing method and technology of structural steel, applied in the field of steel cold forging, can solve problems such as incomplete metal streamlines, poor mechanical properties of parts, and influence on use safety, and achieve the effects of reducing dependence, improving fatigue strength, and saving energy

Inactive Publication Date: 2011-04-20
SHANGHAI JIAO TONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional processing method of this kind of parts is quenching and tempering first and then cutting. The disadvantages of this method are: long processing hours, low production efficiency, high product cost, and lack of competitiveness; the metal flow line is cut off and incomplete, and the mechanical properties of the parts Poor, short life, affect the use of safety
This traditional processing method has a long process route, wastes energy, and the cost of parts is high

Method used

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  • Cold forging processing method of hardened and tempered structural steel
  • Cold forging processing method of hardened and tempered structural steel
  • Cold forging processing method of hardened and tempered structural steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Taking the forming process of positive extrusion parts as an example, the process flow is:

[0029] 1. For billet making, choose a hot-rolled round bar with a diameter of φ30.0mm, the material grade is 40Cr, and cut it by sawing, and the cutting length is controlled at 29.9-30.1mm.

[0030] 2. Quenching and tempering. According to the performance requirements of forged extrusion parts, the quenching and tempering process is as follows: heating to 850°C for quenching, then tempering at 580°C, holding for 2 hours and then leaving the furnace for air cooling.

[0031] 3. Conventional shot blasting process.

[0032] 4. Conventional phosphorus saponification process.

[0033] 5. Cold forging is formed by cold extrusion through a positive extrusion die. The diameter of the extruded part is φ20.0 mm, and the degree of deformation is about 55.6%.

[0034] The metal streamlines of the obtained positive extrusion are continuously distributed, and there is no defect of center bu...

Embodiment 2

[0036] Taking the forming process of reverse extrusion parts as an example, the process flow is as follows:

[0037] 1. For billet making, choose a hot-rolled round bar with a diameter of φ25.0mm, the material grade is 40Cr, and cut it by sawing, and the cutting length is controlled at 24.9-25.1mm.

[0038] 2. Quenching and tempering. According to the performance requirements of forged extrusions, the quenching and tempering process is as follows: heating to 850°C for quenching, and then tempering at 630°C. After holding for 2 hours, it is out of the furnace and air-cooled.

[0039] 3. Conventional shot blasting process.

[0040] 4. Conventional phosphorus saponification process.

[0041] 5. Cold forging is formed by cold extrusion through a reverse extrusion die. The diameter of the inner hole of the reverse extrusion is φ15.8 mm, the bottom thickness is 10.0 mm, and the degree of deformation is about 40.0%.

[0042] The metal streamlines of the obtained back-extruded part ...

Embodiment 3

[0044] Take the forming process of an automobile hub locking sleeve as an example. The automotive hub locking sleeve is a functional element used to lock the connection between the hub and the axle. The locking force to be borne reaches 100kN, so there are certain requirements for its strength, that is, small End surface hardness should be in the range of 25HRC ~ 29.5HRC.

[0045] The technological process of the present embodiment is:

[0046] 1. Billet, because there is no pipe material that meets the size specifications, choose a hot-rolled round bar with a diameter of φ50.0mm, the material grade is 20MnMoB, and preformed by sawing, upsetting, reverse extrusion, and thinning and stretching After the process, a tube blank with an inner diameter of φ47.0 mm and an outer diameter of φ57.0 mm is obtained.

[0047] 2. Quenching and tempering. Since the locking sleeve needs to bear a certain locking force when used, there are certain requirements for the hardness of the end face...

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Abstract

The invention discloses a cold forging processing method of hardened and tempered structural steel, which belongs to the technical field of steel cold forging. The method comprises the following steps of: firstly, performing corresponding blank forming treatment on different blanks and performing quenching treatment and high-temperature tempering treatment so as to obtain a structural steel hardened and tempered blank; secondly, blowing steel shots out of a barrel-type shot blasting machine by using compressed air, continuously impacting the steel shots onto the hardened and tempered structural steel blank and phosphating and saponifying the structural steel blank; and lastly, deforming the structural steel blank by using a cold forging mold in a cold extruding or cold heading way so as to obtain a precision forming part. The classical cold forging process is changed completely, softening treatment is not performed before cold forging of a steel material, a mechanical part with high size accuracy and high comprehensive mechanical property is processed by material hardening and tempering treatment and cold forging deformation and reinforcement, and subsequent thermal treatment is not needed after cold forging forming.

Description

technical field [0001] The invention relates to a method in the technical field of steel cold forging, in particular to a cold forging processing method of quenched and tempered structural steel. Background technique [0002] In the processing and manufacturing process of mechanical parts, in order to improve the processing performance of metal parts and the mechanical properties of parts, heat treatment is often used as an important process in the processing process, and quenching and tempering treatment is the most common and most convenient and practical A method of heat treatment. There is a class of mechanical parts that need to be used in a quenched and tempered state to meet the strength and rigidity requirements, such as various transmission shafts, connecting rods, gears, high-strength connectors, etc. The traditional processing method of this kind of parts is quenching and tempering first and then cutting. The disadvantages of this method are: long processing hour...

Claims

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Application Information

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IPC IPC(8): B21J5/00B21J1/00B21J13/02
Inventor 赵震胡成亮徐祥龙
Owner SHANGHAI JIAO TONG UNIV
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