阅读说明：本技术 通过内外部硬度分级提高稳定杆疲劳强度的方法 (Method for improving fatigue strength of stabilizer bar through internal and external hardness grading ) 是由 吕云飞 于 2020-05-26 设计创作，主要内容包括：本发明涉及一种通过内外部硬度分级提高稳定杆疲劳强度的方法,(1)将稳定杆加热到880℃；(2)将稳定杆浸入淬火介质水基淬火液中快速淬火,淬火时间8S-10S；(3)稳定杆回火,回火温度280℃,回火时间30min；(4)回火后的稳定杆,外层的金相组织为回火马氏体,硬度为57HRC-60HRC,芯部的金相组织为珠光体,硬度36HRC-38HRC；介于外层与芯部之间的过渡层的金相组织为回火屈氏体或回火索氏体,过渡层从外侧到内侧的硬度,从外层的硬度到芯部的硬度逐渐减小；(5)回火后的稳定杆的冯.米塞斯应力为910Mpa；(6)稳定杆扭力疲劳试验失效时的摆动次数≥20万次。(The invention relates to a method for improving the fatigue strength of a stabilizer bar by grading the internal hardness and the external hardness, which comprises the following steps of (1) heating the stabilizer bar to 880 ℃; (2) immersing the stabilizer bar into quenching medium water-based quenching liquid for rapid quenching, wherein the quenching time is 8-10S; (3) tempering the stabilizer bar, wherein the tempering temperature is 280 ℃, and the tempering time is 30 min; (4) in the tempered stabilizer bar, the metallographic structure of the outer layer is tempered martensite, the hardness is 57HRC-60HRC, the metallographic structure of the core part is pearlite, and the hardness is 36HRC-38 HRC; the metallographic structure of the transition layer between the outer layer and the core part is tempered troostite or tempered sorbite, the hardness of the transition layer from the outer side to the inner side is gradually reduced from the hardness of the outer layer to the hardness of the core part; (5) the von of the tempered stabilizer bar has a Misses stress of 910 Mpa; (6) the swing frequency of the stabilizer bar in the failure of the torsion fatigue test is more than or equal to 20 ten thousand times.)

1. A method for improving the fatigue strength of a stabilizer bar by grading the internal hardness and the external hardness is characterized in that (1) the stabilizer bar which is made of C45E and has the diameter of 20mm-25mm is heated to 875 ℃ to 885 ℃; (2) immersing the stabilizer bar into quenching medium water-based quenching liquid for rapid quenching, wherein the quenching time is 8-10S; (3) tempering the stabilizer bar at 275-285 ℃ for 28-32 min; (4) in the tempered stabilizer bar, the metallographic structure of the outer layer is tempered martensite, the hardness is 57HRC-60HRC, the metallographic structure of the core part is pearlite, and the hardness is 36HRC-38 HRC; the metallographic structure of the transition layer between the outer layer and the core part is tempered troostite or tempered sorbite, the hardness of the transition layer from the outer side to the inner side is gradually reduced from the hardness of the outer layer to the hardness of the core part; (5) the von of the tempered stabilizer bar has a Misses stress of 910 Mpa; (6) the swing frequency of the stabilizer bar in the failure of the torsion fatigue test is more than or equal to 20 ten thousand times.

2. The method of claim 1, wherein the fatigue strength of the stabilizer bar is improved by inner and outer hardness grading, wherein: the radial thickness of the outer layer is one sixth to one fourth of the diameter of the stabilizer bar, the diameter of the core is one fourth to one half of the diameter of the stabilizer bar, and the balance is the radial thickness of the transition layer.

3. The method of claim 1 or 2, wherein the fatigue strength of the stabilizer bar is improved by inner and outer hardness grading, wherein: the equipment for heating the stabilizer bar is medium-high frequency induction heating equipment capable of automatically controlling the heating temperature.

Technical Field

The invention relates to the field of stabilizer bar production, in particular to a method for improving fatigue strength of a stabilizer bar through internal and external hardness grading.

Background

The stabilizer bar is called a transverse stabilizer bar, and is also called a Torsion bar spring, and the English name of the Torsion-bar spring is an important auxiliary elastic element in the automobile suspension. The structure of the stabilizer bar and the method of manufacturing the same are known from the stabilizer bar and the method of manufacturing the same related to the invention patent of the chinese patent application No. 201680015619.7; in the manufacturing process of the stabilizer bar, after cold forming, the performance of the stabilizer bar needs to be improved through heat treatment quenching and tempering, in the traditional stabilizer bar quenching and tempering process, the quenching is oil quenching, the quenching time is more than or equal to 4min, the quenching hardness is 50 HRC to 53 HRC, the tempered tissue is a tempered troostite or tempered sorbite, von, the Misses stress is 850Mpa, the swinging frequency of the stabilizer bar in the failure of a torsion fatigue test is 3-8 ten thousand, the quenching time is longer, the quenching hardness of the inner part and the outer part of the stabilizer bar is close, the von, the Misses stress is lower, and the fatigue strength is lower; therefore, it is an urgent need to solve the problem of designing a method for improving the fatigue strength of a stabilizer bar through grading of internal and external hardness, which has short quenching time, grading of internal and external quenching hardness of the stabilizer bar, high von mises stress and high fatigue strength.

Disclosure of Invention

The invention aims to overcome the defects of the prior quenching and tempering process of the stabilizer bar that the quenching time is longer, the quenching hardness of the inner part and the outer part of the stabilizer bar is close to that of the Von.

The specific technical scheme of the invention is as follows:

a method for improving the fatigue strength of a stabilizer bar by grading the internal hardness and the external hardness, (1) heating the stabilizer bar which is made of C45E and has the diameter of 20mm-25mm to 875 ℃ to 885 ℃; (2) immersing the stabilizer bar into quenching medium water-based quenching liquid for rapid quenching, wherein the quenching time is 8-10S; (3) tempering the stabilizer bar at 275-285 ℃ for 28-32 min; (4) in the tempered stabilizer bar, the metallographic structure of the outer layer is tempered martensite, the hardness is 57HRC-60HRC, the metallographic structure of the core part is pearlite, and the hardness is 36HRC-38 HRC; the metallographic structure of the transition layer between the outer layer and the core part is tempered troostite or tempered sorbite, the hardness of the transition layer from the outer side to the inner side is gradually reduced from the hardness of the outer layer to the hardness of the core part; (5) the von of the tempered stabilizer bar has a Misses stress of 910 Mpa; (6) the swing frequency of the stabilizer bar in the failure of the torsion fatigue test is more than or equal to 20 ten thousand times. The method for improving the fatigue strength of the stabilizer bar through grading the internal hardness and the external hardness is characterized in that the hardness of the outer layer, the transition layer and the core part of the stabilizer bar is graded through rapid quenching of rapid water-based quenching liquid, so that the Von and the Misses stress of the stabilizer bar are improved, the fatigue strength of the stabilizer bar is improved, and the quenching efficiency is improved; the radial thickness of the outer layer, the transition layer and the core part can be adjusted by adjusting the quenching time.

Preferably, the outer layer has a radial thickness of one sixth to one fourth of the stabilizer rod diameter, the core has a diameter of one fourth to one half of the stabilizer rod diameter, and the balance is the radial thickness of the transition layer. The von mises stress of the stabilizer bar and the fatigue strength of the stabilizer bar are high.

Preferably, the stabilizer bar heating equipment is medium-high frequency induction heating equipment capable of automatically controlling heating temperature. The heating is efficient and rapid, the power adjustment is stepless and continuous, and the power adjustment is facilitated according to the production requirement.

Compared with the prior art, the invention has the beneficial effects that: the method for improving the fatigue strength of the stabilizer bar through grading the internal hardness and the external hardness is characterized in that the hardness of the outer layer, the transition layer and the core part of the stabilizer bar is graded through rapid quenching of rapid water-based quenching liquid, so that the Von and the Misses stress of the stabilizer bar are improved, the fatigue strength of the stabilizer bar is improved, and the quenching efficiency is improved; the radial thickness of the outer layer, the transition layer and the core part can be adjusted by adjusting the quenching time. The radial thickness of the outer layer is one sixth to one fourth of the diameter of the stabilizer bar, the diameter of the core is one fourth to one half of the diameter of the stabilizer bar, the rest is the radial thickness of the transition layer, and the von-mises stress of the stabilizer bar and the fatigue strength of the stabilizer bar are high. The equipment for heating the stabilizer bar is medium-high frequency induction heating equipment capable of automatically controlling the heating temperature, the heating is efficient and rapid, the power regulation is stepless continuous regulation, and the power regulation is facilitated according to the production requirement.

Drawings

Fig. 1 is a schematic view of the stabilizer bar of the present invention showing radial dimension versus stiffness.

Detailed Description

The invention will be further described with reference to the drawings.

A method for improving the fatigue strength of a stabilizer bar by grading the internal hardness and the external hardness, (1) heating the stabilizer bar which is made of C45E and has the diameter of 20mm-25mm to 875 ℃ to 885 ℃; (2) immersing the stabilizer bar into quenching medium water-based quenching liquid for rapid quenching, wherein the quenching time is 8-10S; (3) tempering the stabilizer bar at 275-285 ℃ for 28-32 min; (4) in the tempered stabilizer bar, the metallographic structure of the outer layer is tempered martensite, the hardness is 57HRC-60HRC, the metallographic structure of the core part is pearlite, and the hardness is 36HRC-38 HRC; the metallographic structure of the transition layer between the outer layer and the core part is tempered troostite or tempered sorbite, the hardness of the transition layer from the outer side to the inner side is gradually reduced from the hardness of the outer layer to the hardness of the core part; (5) the von of the tempered stabilizer bar has a Misses stress of 910 Mpa; (6) the swing frequency of the stabilizer bar in the failure of the torsion fatigue test is more than or equal to 20 ten thousand times. The radial thickness of the outer layer is one sixth to one fourth of the diameter of the stabilizer bar, the diameter of the core is one fourth to one half of the diameter of the stabilizer bar, and the balance is the radial thickness of the transition layer. The equipment for heating the stabilizer bar is medium-high frequency induction heating equipment capable of automatically controlling the heating temperature.

In the embodiment, the diameter of the stabilizer bar is 23mm, the heating temperature of the stabilizer bar is 880 ℃, the quenching time is 9S, the tempering temperature is 250 ℃, and the tempering time is 30 min;

the radial thickness of the outer layer is 4.8mm of the diameter of the stabilizer bar, the diameter of the core part is 7.7 mm, and the balance is the radial thickness of the transition layer.

The relationship curve of the radial dimension and the hardness of the stabilizer bar of the invention is shown in the attached figure 1, wherein: a-outer layer, B-transition layer, C-core.

The method for improving the fatigue strength of the stabilizer bar through grading the internal hardness and the external hardness is characterized in that the hardness of the outer layer, the transition layer and the core part of the stabilizer bar is graded through rapid quenching of rapid water-based quenching liquid, so that the Von and the Misses stress of the stabilizer bar are improved, the fatigue strength of the stabilizer bar is improved, and the quenching efficiency is improved; the radial thickness of the outer layer, the transition layer and the core part can be adjusted by adjusting the quenching time.

In addition to the above embodiments, the technical features or technical data of the present invention may be reselected and combined to form new embodiments within the scope of the claims and the specification of the present invention, which are all realized by those skilled in the art without creative efforts, and thus, the embodiments of the present invention not described in detail should be regarded as specific embodiments of the present invention and are within the protection scope of the present invention.