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Intrinsic non-net secondary cementite steel and application method thereof

A technology of cementite steel and carbon steel, applied in the field of high carbon steel and bearing steel, to achieve the effect of simple spheroidizing process, shortening spheroidizing time and increasing hardness

Inactive Publication Date: 2010-01-06
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the longer life obtained by the above methods is not always satisfactory, especially when used under severe conditions such as high loads, so there has been a strong demand for the development of a steel with a longer life

Method used

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  • Intrinsic non-net secondary cementite steel and application method thereof
  • Intrinsic non-net secondary cementite steel and application method thereof
  • Intrinsic non-net secondary cementite steel and application method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment example 1

[0032] Implementation case 1, an intrinsic non-network secondary cementite steel, according to the weight percentage, the chemical composition of the cementite steel is shown in Table 1:

[0033] Table 1 chemical composition

[0034] the element

[0035] figure 1 It shows that the material is vacuum-heated at 1100°C for 4 hours and furnace-cooled for 4 hours after being rolled in a vacuum capacity. There is no reticular cementite in the structure, and there are flocculent and dispersed precipitates between the cementite strips. See figure 1 -b, figure 2 It is a TEM photo, which more clearly shows the distribution of dispersed precipitates and cementite strips, and is observed and analyzed by a high-resolution electron microscope (see image 3 ), these precipitates are a kind of AM decomposition. This kind of structure is easy to spheroidize. After heating at 850°C for 15 minutes and cooling at 1°C / min to 750°C, the ideal spheroidized structure is obtained. See ...

Embodiment example 2

[0036] Implementation case 2: An intrinsic non-network secondary cementite steel, according to the weight percentage, the chemical composition of the cementite steel is shown in Table 1:

[0037] Table 1 chemical composition

[0038] the element

[0039] The chemical composition is the same as that of Example 1. The material is subjected to conventional heat quenching and tempering treatment. The specific process is heating (salt bath furnace) to 840±10°C for heat preservation, tempering temperature is 155±5°C, and tempering for 2-2.5 hours. Figure 5 It is a quenched structure, and the structure is martensite and retained austenite plus residual carbide. Image 6 In comparison with the structure of GCr15 after the same heat treatment, it can be seen from the comparison that the structure of the present invention is obviously finer, and the amount of retained austenite is also relatively small. These characteristics are very beneficial to improving the performance of...

Embodiment example 3

[0040] Implementation case 3, an intrinsic non-network secondary cementite steel, according to the weight percentage, the chemical composition of the cementite steel is shown in Table 2:

[0041] Table 2 chemical composition

[0042] the element

[0043] The composition of Example 1 contains Al, which may bring difficulties to the control of inclusions in smelting. The composition given in Example 3 does not contain Al, but the content of Si is increased to more than 1.0. Figure 8 The results given show that there is still no reticular cementite in the as-cast structure.

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Abstract

The invention discloses an intrinsic non-net secondary cementite steel and an application method thereof; the steel comprises the following components by weight percent: 0.8-1.8% of C, 0-3.0% of Al, 0-2.5% of Cr, 0.2-0.8% of Mn, 0-2.0% of Si, 0-0.8% of Mo, 0-0.1% of Nb, 0-0.1% of V, 0-0.1% of Ti, 0-0.05% of Re and the balance Fe. The steel does not have net-shaped secondary cementite in common casting state, annealed state and normalized state, secondary cementite is precipitated in pearlite in a dispersive form and the form of organization is pearlite and dispersive spinodal decomposition organization. The organization is easy for nodulizing which can be realized by heating the organization at 800 DEG C for 1-2h after the routine forging technology. The steel can be widely applied in the fields such as tools, abrasive tools, bearings, rail steels and the like and the steel can improve the carbon content, hardness and wear resistance and service life of traditional materials.

Description

Technical field: [0001] The invention belongs to the technical field of steel materials and heat treatment processes thereof, and particularly relates to high-carbon steel and bearing steel. Background technique: [0002] When the carbon content of the steel is greater than 0.77%, it becomes a hypereutectoid steel. The normal structure of the hypereutectoid steel in the cast state, annealed state and normalized state is reticular secondary cementite and pearlite (Shi Deke Material Science Foundation, Mechanical Industry Press 1999). Cementite has high hardness and good wear resistance, and increasing cementite can obviously improve the hardness and wear resistance of the material. However, the existence of network form is the main reason for the steel to become brittle. In order to reduce brittleness and avoid more network cementite, the carbon content of steel is generally less than 1.0. Higher carbon content will lead to subsequent forging 1. It is difficult to break the...

Claims

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Application Information

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IPC IPC(8): C22C38/04C22C38/36C22C38/28C22C38/26C22C38/24C22C38/22C22C38/18C22C38/14C22C38/12
Inventor 柳永宁陈秀明张贵一朱杰武
Owner XI AN JIAOTONG UNIV
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