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Heat treatment method and application of high-carbon steel

A heat treatment method and technology for high carbon steel, applied in the field of carbon content detection, can solve problems such as deviation of decarburized layer depth measurement and difficulty in distinguishing grain boundary bainite morphology, and achieve the effect of avoiding deviation and avoiding influence

Pending Publication Date: 2022-04-22
ZHANGJIAGANG RONGSHENG SPECIAL STEEL CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the indistinguishable morphology between the grain boundary bainite formed on the surface of the wire rod and the grain boundary ferrite formed by decarburization in the prior art, resulting in difficulties in the measurement of the depth of the decarburized layer. Large deviation and other defects, thus providing a heat treatment method and application of high carbon steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] This embodiment provides a heat treatment method for high carbon steel, comprising the following steps,

[0032] Austempered high-carbon steel wire rod with a carbon content of 0.87%, its cross-section is made into a metallographic sample, and the metallographic method in GB / T224 is used to measure the depth of the decarburization layer in the high-carbon steel wire rod, and the depth is 0.2mm.

[0033] Take an austempered high-carbon steel wire rod with a length of 5 cm, put it into a muffle furnace protected by nitrogen gas, and heat it at a temperature of 815°C for 2 minutes, then put the high-carbon steel wire rod into the Quenching in quenching oil to room temperature, the quenching cooling rate is 60K / s, then place the high-carbon steel wire rod at 500 ° C for 10 minutes, take it out and cool it to room temperature, and make the high-carbon steel wire rod into a metallographic sample, adopt GB / The metallographic method in T224 measures the depth of the decarburiz...

Embodiment 2

[0036] This embodiment provides a heat treatment method for high carbon steel, comprising the following steps,

[0037] The austempered high-carbon steel wire rod with a carbon content of 1.0% is made into a metallographic sample from its cross section, and the thickness of the decarburized layer in the high-carbon steel wire rod is measured by the metallographic method in GB / T224, and the thickness is 0.3mm.

[0038] Take a 5cm-long austempering high-carbon steel wire rod, put it into a muffle furnace protected by nitrogen gas, and heat it at a temperature of 860°C for 2.5 minutes, then put the high-carbon steel wire rod into the Quenching in quenching oil to room temperature, the quenching cooling rate is 40K / s, then place the high-carbon steel wire rod at 550°C for 10 minutes, take it out and cool it to room temperature, and make the high-carbon steel wire rod into a metallographic sample, adopt GB / The metallographic method in T224 measures the depth of the decarburization...

Embodiment 3

[0041] This embodiment provides a heat treatment method for high carbon steel, comprising the following steps,

[0042] Austempered high-carbon steel wire rod with a carbon content of 0.92%, its cross-section is made into a metallographic sample, and the metallographic method in GB / T224 is used to measure the depth of the decarburization layer in the high-carbon steel wire rod, and the depth is 0.25mm.

[0043]Take a 5cm long austempering high carbon steel wire rod, heat it in a muffle furnace with nitrogen protection, the heating temperature is 950°C, and the heating time is 3min, and then put the high carbon steel wire rod into the quenching furnace within 3s Quenching in oil to room temperature, the quenching cooling rate is 45K / s, then place the high-carbon steel wire rod at 600 ° C for 5 minutes, take it out and cool it to room temperature, and make the high-carbon steel wire rod into a metallographic sample, using GB / T224 The metallographic method in the method measures ...

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Abstract

The invention belongs to the technical field of carbon content detection, and particularly relates to a heat treatment method and application of high-carbon steel. The treatment method comprises the following steps: (1) in an inert atmosphere or a vacuum state, heating the high-carbon steel to 10-20 DEG C above Acm temperature, and preserving heat for 2-3 minutes; or the high-carbon steel is placed in the salt bath to be heated to 10-20 DEG C above the Acm temperature, and heat preservation is conducted for 30-60 s; and (2) quenching to room temperature, placing the high-carbon steel at 500-560 DEG C, and preserving heat for 10-20 minutes to obtain the high-carbon steel subjected to heat treatment. According to the heat treatment method, a microstructure on the surface of the high-carbon steel can be austenitized again and subjected to phase change again, and grain boundary ferrite appearing on the surface of the high-carbon steel due to rapid cooling and too low phase change temperature in isothermal quenching is eliminated; and the high-carbon steel is subjected to short-time heat preservation treatment in an inert atmosphere or a vacuum state, so that new decarburization can be avoided, and the real depth of a decarburized layer in the decarburized steel can be obtained.

Description

technical field [0001] The invention belongs to the technical field of carbon content detection, and in particular relates to a heat treatment method and application of high-carbon steel. Background technique [0002] Metallographic method has become the most commonly used decarburization layer detection method in production because of its simple method and high detection efficiency. At present, according to the relevant provisions of the national standard GB / T224 "Measurement of Decarburization Depth of Steel", the metallographic method is suitable for steel types with annealed or normalized structures. Metallography is based on the reduction of the carbide content relative to the matrix. When using the metallographic method to measure the depth of the decarburization layer, it is necessary to measure the length from the surface of the wire rod to the position where the metallographic structure is the same as the matrix, and use this length as the total depth of the decarb...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D6/00C21D1/20C21D1/773
CPCC21D6/00C21D1/773C21D1/20
Inventor 王雷李月云喻智晨张宇
Owner ZHANGJIAGANG RONGSHENG SPECIAL STEEL CO LTD