Method for controlling surface decarburization of spring steel wires

A control method and spring steel technology, applied in the field of spring steel production, can solve the problems of affecting fatigue life, affecting fatigue performance, reducing spring fatigue strength and service life, etc., and achieving the effect of easy implementation, stable quality and low equipment requirements

Inactive Publication Date: 2012-07-11
NANJING IRON & STEEL CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003]The surface condition of spring steel has a great influence on its fatigue performance. If there is decarburization structure on the surface, the fatigue strength and service life of the spring will be seriously reduced
When there is a 0.1 mm decarburization layer on the surface of the spring, it will obviously affect the fatigue performance. If there is a full decarburization layer on the surface, it will affect the fatigue life by 50%.

Method used

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  • Method for controlling surface decarburization of spring steel wires
  • Method for controlling surface decarburization of spring steel wires
  • Method for controlling surface decarburization of spring steel wires

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment Example 1 The mass percentage of the chemical composition of the continuous casting slab is: C: 0.52%, Mn: 0.70%, Si: 1.50%, Cr: 0.72%, Ni: 0.35%, Cu: 0.25%, P: 0.0094%, S: 0.0023%, the balance is Fe.

[0023] The process flow of 55SiCr spring steel in this example is: acceptance of raw and auxiliary materials → batching → electric furnace smelting → LF refining → VD degassing → continuous casting → billet cooling inspection → billet acceptance → heating → descaling → rolling → spinning → cooling → Finished product inspection → bundling mark → weighing storage → delivery.

[0024] This embodiment is a continuous casting slab with a cross-sectional size of 150mm×150mm, rolling a 55SiCr spring steel wire rod with a diameter of 12mm, and the decarburization control method on the wire rod surface is as follows:

[0025] Heating furnace heating process: In order to reduce the thickness of the oxidation and decarburization layer during the heating process of the b...

Embodiment 2

[0030] Implementation Example 2 The mass percentage of the chemical composition of the continuous casting slab is: C: 0.52%, Mn: 0.68%, Si: 1.48%, Cr: 0.70%, Ni: 0.3%, Cu: 0.2%, P: 0.0076%, S: 0.0015%, the balance is Fe.

[0031] The process flow of 55SiCr spring steel in this example is: acceptance of raw and auxiliary materials → batching → electric furnace smelting → LF refining → VD degassing → continuous casting → billet cooling inspection → billet acceptance → heating → descaling → rolling → spinning → cooling → Finished product inspection → bundling mark → weighing storage → delivery.

[0032] This embodiment is a continuous casting slab with a cross-sectional size of 150mm×150mm, rolling a 55SiCr spring steel wire rod with a diameter of 10mm, and the decarburization control method on the wire rod surface is as follows:

[0033] Heating furnace heating process: In order to reduce the thickness of the oxidation and decarburization layer during the heating process of the...

Embodiment 3

[0038] Implementation Example 3 The mass percentage of the chemical composition of the continuous casting slab is: C: 0.54%, Mn: 0.67%, Si: 1.49%, Cr: 0.69%, Ni: 0.25%, Cu: 0.15%, P: 0.0096%, S: 0.0034%, the balance is Fe.

[0039] The process flow of 55SiCr spring steel in this example is: acceptance of raw and auxiliary materials → batching → electric furnace smelting → LF refining → VD degassing → continuous casting → billet cooling inspection → billet acceptance → heating → descaling → rolling → spinning → cooling → Finished product inspection → bundling mark → weighing storage → delivery.

[0040] This embodiment is a continuous casting slab with a cross-sectional size of 150mm×150mm, rolling a 55SiCr spring steel wire rod with a diameter of 18mm, and the decarburization control method on the wire rod surface is as follows:

[0041] Heating furnace heating process: In order to reduce the thickness of the oxidation and decarburization layer during the heating process of t...

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Abstract

The invention belongs to the technical field of spring steel production, in particular to a method for controlling the surface decarburization of spring steel wires. The steel comprises the chemical components by weight percentage that continuous casting billets comprise the chemical components by mass percent as follows: C accounts for 0.51 to 0.59 percent, Mn accounts for 0.50 to 0.80 percent, Si accounts for 1.20 to 1.60 percent, Cr accounts for 0.5 to 0.8 percent, Ni is less or equals to 0.35 percent, Cu is less or equals to 0.25 percent, and Fe and inevitable impurities in balancing amount. The method adopts the manufacturing technology that the continuous casting billets of 150 mm multiplied by 150 mm are adopted, the first zone furnace temperature of a heating furnace is controlled to range from 900 to 960 DEG C, the second zone furnace temperature of the heating furnace is controlled to range from 990 to 1050 DEG C, the soaking zone furnace temperature of the heating furnace is controlled to range from 1050 to 1100 DEG C, in-furnace time ranges from 90 to 150 minutes, the soaking zone air-fuel ratio is controlled to be about 0.8, the spinning temperature is controlled to be about 820 DEG C, and quick cooling is performed at the cooling speed of 10 DEG C / s after spinning so as to reach about 660 DEG C. Fully decarburized layers cannot be formed on the surfaces of 55SiCr spring steel wires that are produced by utilizing the technology of the method, and the thickness of a partly decarburized layer is less than 30 micrometers.

Description

technical field [0001] The invention belongs to the technical field of spring steel production, in particular to a method for controlling surface decarburization of spring steel wire rods, in particular to a method for controlling surface decarburization of 55SiCr spring steel. Background technique [0002] Spring is a very important mechanical part, which is widely used in national defense, industry, agriculture, technology and daily life. The production development level, quality and performance of spring steel play a very important role in the development of spring manufacturing, automobile, locomotive, machinery and other industrial sectors. The automotive, engine manufacturing and railway industries are major users of spring steel. In recent years, with the reduction in weight and performance of automobiles, it is urgently required to increase the strength of spring steel and increase the design stress of springs. At the same time, with the continuous improvement of t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/06C22C38/42C22C38/40C22C38/34C22C38/20C22C38/18
Inventor 王晓文李恒坤邱红雷尹雨群吴年春
Owner NANJING IRON & STEEL CO LTD
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