CN-122008089-A - Stress shot blasting process and equipment for high-strength spring

CN122008089ACN 122008089 ACN122008089 ACN 122008089ACN-122008089-A

Abstract

The application relates to the technical field of metal material surface treatment and high-strength spring manufacturing, and discloses a stress shot blasting process and equipment for a high-strength spring, wherein the process steps comprise the steps of hot shot blasting a quenching spring, and forming initial dislocation by using cast steel shots; the method comprises the steps of performing controllable water cooling on a spring, inducing phase change to construct a tissue foundation, constructing middle-layer stress by using fine steel shots and secondary cold shots, refining grains, constructing a deep gradient stress field by using modified tungsten carbide stress shots, cleaning and tempering the spring, protecting a coating, and performing quality detection, wherein the equipment comprises first hot shot blasting equipment, water cooling equipment, second cold shot blasting equipment, third stress shot blasting equipment and a control system. According to the application, through four-step cooperative treatment of hot shot blasting, controllable water cooling, cold shot blasting and final stress shot blasting, gradient residual compression stress fields with depth and stability are constructed on the surface layer and the subsurface layer of the spring, and the cyclic load tensile stress born by the spring in the service process is counteracted, so that the fatigue performance of the finished spring is improved.

Inventors

WANG HAIQUAN
HU SHAOTIAN
KANG GUOJUN
SU YUANLIN
LI WEI

Assignees

成都宁兴科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260402

Claims (10)

1. The stress shot blasting process of the high-strength spring is characterized by comprising the following steps of: s1, performing primary shot blasting treatment on a 55CrSi spring coiled by quenched and tempered steel wires, and adopting high-toughness cast steel shots as shot blasting media to form an initial dislocation structure and shallow residual compressive stress on the surface of the spring; S2, cooling the springs forming the initial dislocation structure and the shallow layer residual compressive stress by water, controlling the cooling rate and performing tissue regulation so as to construct a tissue foundation; s3, performing secondary cold shot blasting treatment on the springs constructed on the tissue basis, adopting fine steel shots as shot blasting media, refining the surfaces of the springs, optimizing the surface layer stress distribution, and constructing middle layer residual compressive stress on the tissue basis; S4, performing stress shot blasting treatment on the spring for constructing the middle layer residual compressive stress, adopting surface modified tungsten carbide particles as shot blasting media to induce deep bainite transformation, and constructing the deep layer residual compressive stress on the basis of the middle layer residual compressive stress so as to form a gradient optimized stress field; S5, cleaning and decontaminating the spring, tempering at low temperature, and performing quality detection treatment on the anticorrosive coating to obtain the high-strength spring after stress shot blasting.
2. The process for blasting the stress of the high-strength spring according to claim 1, wherein in the step S1, the first-stage blasting treatment is performed at 290-240 ℃, the grain size of the high-toughness cast steel shot ranges from 1.1 mm to 1.3mm, the hardness ranges from 610 HV to 670HV, the ejection speed ranges from 50 m/S to 70m/S, and the blasting strength is controlled to be 0.35-0.55A.
3. The process for blasting the stress of the high-strength spring according to claim 1, wherein the shot blasting treatment adopts a thermal shot blasting device formed by connecting a heating furnace with a centrifugal shot blasting device, and the water cooling is provided with a plurality of groups of high-pressure nozzles.
4. The process of claim 1, wherein the cold shot blasting process uses a cold shot blasting device equipped with a pneumatic shot-feed system, and the process uses a stress shot blasting device equipped with a hyperboloid impeller head.
5. A high strength spring stress ball blasting process according to claim 3, wherein in step S2, the cooling rate of the water cooling is controlled to 100-200 ℃ per S, cooling the spring to below 80 ℃.
6. The process for blasting the stress of the high-strength spring according to claim 1, wherein in the step S3, the cold blasting treatment is performed at normal temperature, the grain size of the fine steel shot ranges from 0.9 mm to 1.1mm, the hardness ranges from 610 HV to 670HV, the ejection speed ranges from 60 m/S to 80m/S, and the blasting strength is controlled to be 0.35-0.55mmA.
7. The process for blasting stress on a high-strength spring according to claim 1, wherein in the step S4, the blasting speed of the stress blasting treatment is 60-90m/S, the particle size of the surface-modified tungsten carbide particles is 0.5-0.7mm, and the hardness is 610-670HV.
8. The process of claim 1, wherein in step S5, the low temperature tempering is performed at 180-220 ℃, and the quality inspection step includes a fatigue limit inspection and a tensile test.
9. A stress shot blasting device for a high-strength spring, which is applied to the stress shot blasting process for the high-strength spring according to any one of claims 1 to 8, and is characterized by comprising the following steps: the steel wire storage device is provided with a steel wire straightening device and is used for storing or outputting steel wires and straightening the bent steel wires in cooperation with the steel wire straightening device; the first thermal shot blasting device is provided with a heating furnace and a centrifugal shot blasting machine and is used for performing first-stage shot blasting treatment on the quenched spring; A water cooling device provided with a plurality of groups of high-pressure nozzles for cooling the spring after the first-stage shot blasting treatment to below 80 ℃ at a cooling rate of 100-200 ℃ per second; The second cold shot blasting equipment is provided with a pneumatic shot feeding system and is used for carrying out second-stage cold shot blasting treatment on the cooled spring, wherein the shot blasting treatment is carried out at normal temperature; and the third stress shot blasting equipment is provided with a hyperboloid impeller shot blasting head and is used for performing stress shot blasting treatment on the spring, and the casting speed is 60-90m/s.
10. A high strength spring stress shot blasting apparatus according to claim 9, wherein the water cooling apparatus comprises a closed cooling channel having a plurality of groups of high pressure nozzle arrays densely arranged along the material conveying path inside the cooling channel.

Description

Stress shot blasting process and equipment for high-strength spring Technical Field The application relates to the technical field of metal material surface treatment and high-strength spring manufacturing, in particular to a stress shot blasting process and equipment for a high-strength spring. Background Springs are used as key basic elements in mechanical systems, and are widely used in various equipment, and their main functions are cushioning, vibration damping or energy storage. The spring needs to bear high-frequency cyclic load during service, so the fatigue life and the working reliability of the spring are core indexes for measuring the quality and determining the safety performance of the whole equipment. In the existing spring manufacturing practice, after the spring steel wire is wound and formed, quenching and tempering (namely, quenching and tempering at medium and high temperature) are performed first, so that uniform tempered martensite or sorbite tissues are obtained in the material, and the strength and hardness of the foundation are provided for the spring. After the heat treatment is completed, the spring is fed into a shot blasting apparatus, and surface shot blasting is performed in a normal temperature environment. The step utilizes the impact of the high-speed projectile to form a layer of residual compressive stress on the surface layer of the spring so as to counteract the tensile stress generated during working, thereby improving the fatigue resistance. However, in the existing spring manufacturing technology, heat treatment is carried out to pursue hard and brittle structures such as martensite formed by high strength, and the like, the impact resistance of the whole spring is usually insufficient at the expense of toughness of materials, a residual compressive stress layer formed by normal-temperature shot blasting is usually shallow, the stress gradient is steep, and the fatigue protection effect is limited under the condition of high stress amplitude or surface defects, so that the invention provides a stress shot blasting process and equipment for the high-strength spring, and the defects in the prior art are overcome. Disclosure of Invention Aiming at the defects of the prior art, the application aims to provide a stress shot blasting process and equipment for a high-strength spring, and solves the problems that the toughness is often reduced when the strength is improved, and the residual compressive stress field with optimized depth and gradient is difficult to construct on the surface layer of the spring in the existing spring strengthening process, so that the fatigue life of the spring is limited. In order to achieve the above purpose, the invention is realized by the following technical scheme: The invention provides a stress shot blasting process of a high-strength spring, which is used for constructing a structure with a specific microstructure and a gradient residual compressive stress field on the surface of the spring through multistage and cooperative shot blasting treatment and cooling processes, so that the mechanical property of the spring is improved, and comprises the following steps: S1, performing first-stage thermal shot blasting treatment, namely performing first-stage shot blasting treatment on the quenched spring. The treatment is carried out at the temperature of 240-290 ℃, and the shot blasting medium is high-toughness cast steel shot with the grain diameter of 1.1-1.3mm and the hardness of 610-670 HV. The casting speed is 50-70m/s, and the shot blasting strength is controlled to be 0.35-0.55A in the arc height value of the Almen test piece. This step aims at the formation of initial dislocation structures and shallow residual compressive stress at the spring surface. S2, water cooling and tissue regulation, namely water cooling the spring after the first-stage shot blasting treatment. Cooling is performed by a plurality of groups of high-pressure nozzles, and the cooling rate is controlled to be 100-200 ℃ per second. The spring is cooled to below 80 ℃. The austenitizing degree is improved from 75% to 92% by controlling the cooling process, and bainite transformation is induced, so that a tissue foundation is constructed for subsequent treatment. S3, performing second-stage cold shot blasting treatment, namely performing second-stage cold shot blasting treatment on the cooled spring. The treatment is carried out at normal temperature, and the shot blasting medium is fine steel shot with the grain diameter of 0.9-1.1mm and the hardness of 610-670 HV. The casting speed is 60-80m/s, and the shot blasting strength is controlled to be 0.35-0.55A. The step constructs middle layer residual compressive stress on the basis of the structure by refining crystal grains on the surface of the spring and introducing nanometer twin crystals, and ensures that the dislocation density reaches 10 15m-2. And S4, stress shot blasting treatment, namely performing stress s