CN113618498A

CN113618498A - Steel billet grinding method applied to high-strength alloy spring steel

Info

Publication number: CN113618498A
Application number: CN202110783265.3A
Authority: CN
Inventors: 陈志亮; 金玉静; 王珍传; 张磊
Original assignee: Jiangsu Shagang Group Co Ltd; Jiangsu Shagang Iron and Steel Research Institute Co Ltd; Zhangjiagang Rongsheng Special Steel Co Ltd
Current assignee: Jiangsu Shagang Group Co Ltd; Jiangsu Shagang Iron and Steel Research Institute Co Ltd; Zhangjiagang Rongsheng Special Steel Co Ltd
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2021-11-09

Abstract

The invention provides a steel billet coping method applied to high-strength alloy spring steel, which comprises the working procedures of cogging treatment, coarse grinding, accurate grinding and flaw detection; a cogging treatment procedure, wherein the temperature of a heating high-temperature section is 1080-1150 ℃, and the surface decarburization depth of a billet is 0.5-1.1 mm; the rough grinding process and the accurate grinding process respectively comprise the decarburization grinding of the surface part of the steel billet and the decarburization grinding of the corner part of the steel billet. The steel blank grinding adopts a grinding method of 'cogging treatment, coarse grinding, fine grinding, flaw detection and point repair', so that the decarburized layer on the surface of the cogging square blank can be completely eliminated after high-temperature diffusion, and the surface smoothness of the blank is ensured.

Description

Steel billet grinding method applied to high-strength alloy spring steel

Technical Field

The invention belongs to the technical field of steel wire rolling, and particularly relates to a billet grinding method applied to high-strength alloy spring steel.

Background

During testing or working of the spring, the maximum stress mostly occurs on the surface layer of the spring material, and the surface quality of the spring material directly influences the fatigue service life of the spring. The fatigue fracture of the spring is usually started from a certain tiny surface defect, a tiny crack gradually appears under the action of alternating load, and the tiny crack leads to the fatigue fracture after a certain number of stress cycles. Surface defects, decarburization and the like formed in the smelting and cogging processes of the spring material often cause early fracture of a spring fatigue test, so that the quality of the spring material is severely restricted, and the surface quality of a billet is a key restriction link of the surface quality of the spring material. With the development of light weight of an automobile spring, higher requirements are put forward on the strength and toughness of a material, the strength of the automobile suspension spring after heat treatment is generally required to be within a range of 1860MPa to 1950MPa, the surface shrinkage is more than 40%, the strength of the high-strength automobile suspension spring after heat treatment is required to be within a range of 1960MPa to 2050MPa, the surface shrinkage is more than 40%, higher requirements are put forward on the surface quality of the material, particularly the full decarburization requirement on the surface of a rolled material, a full decarburized layer is composed of ferrite, microcracks are easily formed between the full decarburized layer and a matrix in the subsequent use process due to the tissue stress, in the aspect of blank finishing and coping, the surface decarburization and coping are ensured to be clean, additional defects of coping are avoided, and the surface quality is required to be controlled to be stable.

In order to meet the performance requirements of high-strength spring materials, the finishing and grinding of the surface of a casting blank need to be strictly controlled in the production process, and the defect-free and stable quality of the steel blank after grinding is ensured.

Disclosure of Invention

The invention aims to provide a billet polishing method applied to high-strength alloy spring steel, which can completely eliminate a decarburized layer on the surface layer of a spring steel billet.

A steel billet coping method applied to high-strength alloy spring steel comprises the working procedures of cogging, coarse grinding, fine grinding and flaw detection; in the cogging treatment procedure, the temperature of a heating high-temperature section is 1080-1150 ℃, and the surface decarburization depth of the billet is 0.5-1.1 mm; the rough grinding process and the accurate grinding process respectively comprise the decarburization grinding of the surface part of the steel billet and the decarburization grinding of the corner part of the steel billet.

Preferably, in the coarse grinding process, two times of grinding are carried out successively, and the initial feed amount of the first time of grinding is 12 mm; the initial feed for the first pass was 6 mm.

Preferably, in the coarse grinding process, a 12-mesh coarse grinding wheel is selected, and the coarse grinding depth is not less than 1.0 mm.

Preferably, in the fine grinding process, the grinding depth is not less than 0.3mm, the initial feed amount is 3mm, and the face finish is not less than 5 grades.

Preferably, the finish grinding process employs a 24 mesh wheel.

Preferably, the width of the rough grinding chamfer is not less than 12mm when the billet corner is subjected to decarburization grinding, and the angles of 22.5 degrees, 45 degrees and 67.5 degrees are adopted when the billet is subjected to finish grinding.

Preferably, the defective slab detected in the flaw detection process is spot repaired.

Compared with the prior art, the invention has the advantages that: the steel billet is polished by adopting a polishing method of 'cogging treatment, coarse grinding, fine grinding, flaw detection and point repair', so that the decarburized layer on the surface of a billet which is cogging after high-temperature diffusion can be completely eliminated, and the surface smoothness of the billet is ensured.

Drawings

Fig. 1 is a flowchart of a billet coping method applied to a high-strength alloy spring steel according to an embodiment of the present invention.

Detailed Description

The present invention will now be described in more detail with reference to the accompanying schematic drawings, in which preferred embodiments of the invention are shown, it being understood that one skilled in the art may modify the invention herein described while still achieving the advantageous effects of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.

The steel billet coping method applied to the high-strength alloy spring steel comprises the working procedures of cogging, coarse grinding, fine grinding and flaw detection, and is shown in figure 1.

Firstly, a cogging treatment procedure is carried out, the temperature of a high-temperature section of a cogging heating furnace is controlled to be 1080-1150 ℃, the heating time is controlled to be 3-4 hours, and the air-fuel ratio in the furnace is controlled to be within 0.70, so that the surface decarburization depth of a steel billet after cogging is in the range of 0.5-1.1 mm.

And in the coarse grinding process, a coarse grinding wheel of 12 meshes is selected, the coarse grinding depth is not less than 1.0mm, and the feed rate is controlled to be about 12 mm. Specifically, two times of grinding are carried out in sequence, and the initial feed amount of the first grinding is 12 mm; the initial feed for the first pass was 6 mm. The steel billet is polished for two times, so that the phenomenon of 'wave' unevenness on the surface of the steel billet after being polished by the grinding wheel is eliminated.

And in the fine grinding process, a grinding wheel with 24 meshes is adopted, the grinding depth is not less than 0.3mm, the feed amount is controlled to be about 10mm, the initial feed amount is 3mm, and the finish degree of the face is not less than 5 grade.

The rough grinding process and the accurate grinding process respectively comprise the decarburization grinding of the surface part of the steel billet and the decarburization grinding of the corner part of the steel billet. During decarburization and grinding of steel billet corners, due to the fact that decarburization is accumulated on two sides of the corners when the steel billet is cogging, the width of the corner chamfer needs to be determined according to the decarburization condition of the original corner, the width of the rough grinding chamfer is controlled to be not less than 12mm so as to control the vertical depth of the corner chamfer to be more than 8.5mm, meanwhile, angle chamfers of 22.5 degrees, 45 degrees and 67.5 degrees are adopted during fine grinding, and accumulated decarburization on two sides of the corners when a subsequent heating furnace is heated is reduced.

And carrying out shot blasting after the steel billets are finely ground, then carrying out flaw detection, carrying out flaw detection by adopting automatic magnetic powder flaw detection identification and jet marking equipment, and carrying out point grinding on the detected defective steel billets, wherein the point grinding is smooth in transition. And repeating the steps of shot blasting, flaw detection and spot repair after point grinding until the flaw detection billet has no defects.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. a billet grinding method applied to high-strength alloy spring steel, is characterized in that, comprises billet processing, rough grinding, fine grinding and flaw detection operation; Wherein, described billet processing operation, heating high temperature section temperature 1080 ~ At 1150°C, the decarburization depth of the rear surface of the billet is 0.5-1.1 mm; the rough grinding process and the fine grinding process both include decarburization grinding of the billet face and decarburization grinding of the corner of the billet.

2. the billet grinding method applied to high-strength alloy spring steel according to claim 1, is characterized in that, described rough grinding process, carries out two times of grinding successively, and the initial feed amount of the first grinding is 12mm ; The initial feed for the first grinding is 6mm.

3 . The billet grinding method applied to high-strength alloy spring steel according to claim 1 , wherein, in the rough grinding process, a 12-mesh rough grinding wheel is selected, and the rough grinding depth is not less than 1.0 mm. 4 .

4. The billet grinding method applied to high-strength alloy spring steel according to claim 1, characterized in that, in the fine grinding process, the grinding depth is not less than 0.3mm, the initial feed is 3mm, and the face The finish is not less than grade 5.

5 . The billet grinding method applied to high-strength alloy spring steel according to claim 1 , wherein the fine grinding process adopts a 24-mesh grinding wheel. 6 .

6. The billet grinding method applied to high-strength alloy spring steel according to claim 1, characterized in that, when the billet corner is decarburized and ground, the chamfering width for rough grinding is not less than 12 mm, and 22.5 mm is used for fine grinding. Degree, 45 degree and 67.5 degree angle chamfers.

7 . The method for grinding a billet applied to high-strength alloy spring steel according to claim 1 , wherein spot repair is performed on the defective billet detected in the flaw detection process. 8 .