Si-containing medium carbon steel and thermal treatment method for Si-containing medium carbon steel to obtain high strength and elasticity

A heat treatment method and high plasticity technology, which is applied in the field of medium carbon steel, can solve the problems of no heat treatment process reports, etc., and achieve the effects of process stability, process optimization, and good strength and toughness

Active Publication Date: 2012-08-01
SHOUGANG CORPORATION
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although there are many studies on the bainite transformation and austempering of steel at home and abroad, there is no report on the heat treatment process for medium-carbon Si-containing steel to obtain lower bainite + stable austenite

Method used

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  • Si-containing medium carbon steel and thermal treatment method for Si-containing medium carbon steel to obtain high strength and elasticity
  • Si-containing medium carbon steel and thermal treatment method for Si-containing medium carbon steel to obtain high strength and elasticity
  • Si-containing medium carbon steel and thermal treatment method for Si-containing medium carbon steel to obtain high strength and elasticity

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Effect test

Embodiment 1

[0029] The heat treatment process is completed in three steps:

[0030] The first step, austenitizing treatment, is to heat the material to 850°C for 20 minutes in a conventional resistance furnace under air conditions, so that the material can obtain a uniform austenite structure.

[0031] The second step, salt bath treatment after austenitization, is to quickly cool the material from 850°C to the lower bainite transformation temperature range, and keep it warm for 40 seconds to obtain uniform supercooled austenite.

[0032] The third step is the transformation of lower bainite and stabilized austenite. The material cooled in the salt bath is placed in an air holding furnace at 300°C for 5 minutes, and the transformation of lower bainite and the stabilization of austenite (such as figure 1 and Figure 7 ), and then water-cooled to room temperature, the strength reaches about 1600Mpa, and the elongation is 10.8% ( Figure 4 ), the area shrinkage rate reaches 45% ( Figure 6...

Embodiment 2

[0035] The heat treatment process is completed in three steps:

[0036] The first step, austenitizing treatment, is to heat the material to 900°C for 10 minutes in a conventional resistance furnace under air conditions, so that the material can obtain a uniform austenite structure.

[0037] The second step, salt bath treatment after austenitization, is to quickly cool the material from 850°C to the lower bainite transformation temperature range, and keep it warm for 60 seconds to obtain uniform supercooled austenite.

[0038] The third step is the transformation of lower bainite and stabilized austenite. The material cooled in the salt bath is placed in an air holding furnace at 250°C for 20 minutes, and the transformation of lower bainite and stabilization of austenite occurs ( figure 2 ), and then water-cooled to room temperature, the strength reaches about 1700Mpa, and the elongation is 10.5% ( Figure 4 ), the area shrinkage rate reaches 37%.

[0039] The three steps me...

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Abstract

The invention discloses Si-containing medium carbon steel and a thermal treatment method for Si-containing medium carbon steel to obtain high strength and elasticity, which belongs to the technical field of medium carbon steel. The Si-containing medium carbon steel comprises the following chemical components in percentage by weight: 0.5-0.7% of C, 1.2-1.8% of Si, 0.4-0.8% of Mn, 0.2-0.4% of Cr, less than or equal to 0.013% of P, less than or equal to 0.005% of S, and the balance of Fe. The thermal treatment method comprises the following steps: austenitizing the components at the temperature of between 850 and 900 DEG C for 10-20 minutes; quickly putting the austenitized materials in salt liquid at 250-350 DEG C and performing salt bath quenching for 20-60 minutes; fetching the materials from the salt liquid at 250-350 DEG C and putting in an air furnace at 250-350 DEG C and preserving heat for 10-20 minutes; and fetching the materials and cooling with water to room temperature. The invention has the advantages: high-strength and high-elasticity lower bainite and stable austenite structure are obtained from the materials; relatively high toughness is realized; the complicated thermal treatment of users is replaced; the heat-preservation part of a resistor furnace replaces the isothermal time of isothermal quenching in the salt bath furnace; the pressure in the salt bath furnace is reduced; the salt bath quenching technique is optimized; the steel strength exceeds 1,500 Mpa; and the area reduction is over 40%.

Description

technical field [0001] The invention belongs to the technical field of medium-carbon steel, and in particular relates to a Si-containing medium-carbon steel and a heat treatment method for obtaining high-strength and high-plasticity. Background technique [0002] The heat treatment of medium carbon steel has always been a key research in engineering and production. The traditional heat treatment process is mainly quenching + tempering process, the most typical one is quenching and tempering for cold heading fasteners and salt bath treatment for abrasive tools and cutting tools. This heat treatment can obtain tempered martensite, tempered troostite and tempered sorbite according to the process requirements and the use environment. According to the user's requirements, adjusting the process parameters of quenching and tempering can make the structure have high strength and high plasticity. , Good impact toughness and relaxation and other excellent properties. This involves th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/18C22C38/34C21D1/18
Inventor 王猛王立峰王全礼王丽萍崔京玉张玮
Owner SHOUGANG CORPORATION
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