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Control method for surface decarburization and ferrite distribution of steel disc bar of spring

A control method and spring steel technology, which is applied in the field of spring steel production, can solve the problems of increased production cost of 60Si2MnA spring steel, inability to achieve surface decarburization control, and reduced service life, so as to achieve reduced strength, increased surface shrinkage, and improved service life. Effect

Active Publication Date: 2013-04-17
TIANJIN IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] According to its application, 60Si2MnA spring steel is required to have good surface quality and high structure sorbite rate. The common problems in the production process are decarburization and ferrite network, which form the weak link of spring steel on the surface and inside. Under the action of external force, micro-cracks are formed, and the fracture rapidly expands. Macroscopically, it is characterized by low tensile strength and poor toughness.
[0003] The unresolved problems above can not achieve the unity of surface decarburization control and ferrite control, the production cost of 60Si2MnA spring steel is increased, and the service life is reduced

Method used

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  • Control method for surface decarburization and ferrite distribution of steel disc bar of spring
  • Control method for surface decarburization and ferrite distribution of steel disc bar of spring
  • Control method for surface decarburization and ferrite distribution of steel disc bar of spring

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] Example 1: 60Si2MnA, specification: φ13mm

[0062] 1) Raw material preparation

[0063] The melting composition is C=0.6%, Si=1.693%, Mn=0.783%, P=0.018%, S=0.003%; N=21ppm, O=14ppm, H=1.2ppm;

[0064] 5) Continuous casting

[0065] Center segregation: 0.5 level, center looseness: 0.5 level;

[0066] 6) Flaw detection and grinding

[0067] Slow cooling time for off-line stacking of slabs: 48 hours.

[0068] 7) Heating

[0069] A. Heating temperature: preheating, 820-860°C; heating, 1020-1055°C, heating time: 140min; soaking, 1075-1090°C;

[0070] 8) Rolling

[0071] Process control of wire rolling process:

[0072] A. The rolling temperature is 960℃~1000℃;

[0073] B. Finish rolling temperature: 915-935°C; rolling speed 30m / s;

[0074] 9) After rolling, the water cooling is controlled to 800 ℃ ~ 840 ℃ for spinning, reducing the spinning temperature, preventing the growth of austenite grains, reducing decarburization and secondary oxidation during the phase tran...

Embodiment 2

[0082] Example 2: 60Si2MnA, specification: φ10mm

[0083] 1) Raw material preparation

[0084] The melting composition is the melting composition: C=0.604%, Si=1.742%, Mn=0.794%, P=0.015%, S=0.002%; N=38ppm, O=11ppm, H=2.2ppm;

[0085] 5) Continuous casting

[0086] Center segregation: grade 0.5, center looseness: grade 0.5.

[0087] 6) Flaw detection and grinding

[0088] The slow cooling time of casting slab off-line stacking: 48 hours;

[0089] 7) Heating

[0090] Heating temperature: preheating, 850-880°C; heating, 1040-1065°C, heating time: 150min; soaking, 1055-1085°C;

[0091] 8) Rolling

[0092] Process control of wire rolling process:

[0093] A. The rolling temperature is 960℃~1000℃;

[0094] B. Finish rolling temperature: 910-935°C; rolling speed 54m / s;

[0095] 9) After rolling, the water cooling is controlled to 800 ℃ ~ 840 ℃ for spinning, reducing the spinning temperature, preventing the growth of austenite grains, reducing decarburization and secondary ...

Embodiment 3

[0103] Example three: 60Si2MnA, specification: φ15mm

[0104] 1) Raw material preparation

[0105] The melting composition is: C=0.602%, Si=1.703%, Mn=0.776%, P=0.010%, S=0.004%; N=34ppm, O=19ppm, H=2.1ppm;

[0106] 5) Continuous casting

[0107] Center segregation: 0.5 level, center looseness: 0.5 level;

[0108] 6) Flaw detection and grinding

[0109] The slow cooling time of casting slab off-line stacking: 48 hours;

[0110] 7) Heating

[0111] Process control of wire rolling process:

[0112] A. Heating temperature: preheating, 870-895°C; heating, 1035-1075°C, heating time: 145min; soaking, 1068-1095°C;

[0113] 8) Rolling

[0114] Process control of wire rolling process:

[0115] A. The rolling temperature is 960℃~1000℃;

[0116] B. Finish rolling temperature: 921-936°C; rolling speed 21m / s;

[0117] 9) After rolling, the water cooling is controlled to 800 ℃ ~ 840 ℃ for spinning, reducing the spinning temperature, preventing the growth of austenite grains, reduc...

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Abstract

The invention relates to a control method for surface decarburization and ferrite distribution of a steel disc bar of a spring. The method comprises the steps of raw material preparation,smelting in a converter, LF (Ladle Furnace), VD (Vacuum Degassing) treatment, continuously casting, flaw detection and coping, heating, rolling, spinning, wind cooling by stelmor, intensively coiling, detecting and putting in a storeroom, rolling wire rods to be 8-18 mm in diameter, ensuring that the tensile strength (ob) is 950-1100MPa and the percentage reduction of area (Z) is 30-50 percent after aging treatment, and organizationally adding a small amount of dispersedly distributed into sorbite. Compare with other processes, the strength is decreased to a certain extent, the reduction of area is improved to a certain extent, the variation range of the strength and reduction of area is smaller, the performance is more stable, pulling and reeding operation is facilitated, the production cost of spring steel is lowered, and the service life of the spring steel is prolonged.

Description

technical field [0001] The invention belongs to the technical field of spring steel production, in particular to a method for controlling surface decarburization and ferrite distribution of spring steel wire rods, in particular to a method for controlling surface decarburization and ferrite distribution of 60Si2MnA spring steel wire rods . Background technique [0002] According to its application, 60Si2MnA spring steel is required to have good surface quality and high structure sorbite rate. The common problems in the production process are decarburization and ferrite network, which form the weak link of spring steel on the surface and inside. Under the action of external force, microcracks are formed, and the fracture rapidly expands. Macroscopically, it is characterized by low tensile strength and poor toughness. Therefore, decarburization and ferrite network control become the key links in the production of 60Si2MnA spring steel. The patent No. is CN200810149557.6, and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/04C22C33/04C21C5/28C21C7/00B22D11/111C21D8/06
Inventor 孙伟梁云科刘学森徐龙庆信海喜
Owner TIANJIN IRON & STEEL GRP
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