Method and device for progressive austempering heat treatment of bainite and martensite complex-phase steel/iron

A heat treatment method and technology of heat treatment device, applied in the direction of quenching device, heat treatment equipment, quenching agent, etc., can solve problems such as inability to overcome hardenability, and achieve the effect of preventing quenching cracking tendency, saving energy, and reducing the addition of alloying elements

Active Publication Date: 2015-04-29
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The present invention aims at the problem that the hardenability of workpieces with large wall thickness cannot be overcome when obtaining bainite, and obtains a bainite / martensite multiphase structure with superior performance through "serrated" graded austempering. The present invention adopts the following Implementation of technical solutions

Method used

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  • Method and device for progressive austempering heat treatment of bainite and martensite complex-phase steel/iron
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  • Method and device for progressive austempering heat treatment of bainite and martensite complex-phase steel/iron

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The bainite-martensitic composite phase steel / iron graded austempering heat treatment method first austenitizes the workpiece and puts it into circulating water for water cooling without cooling it through. , and then put the workpieces with similar internal and external temperatures into circulating water for water cooling, and each water cooling and waste heat recovery form a cyclic heat treatment process. The workpiece is cooled by waste heat or kept in an incubator for isothermal transformation of bainite; finally, it is air-cooled to room temperature to complete the transformation of martensite, and the bainite-martensite composite steel with bainite-martensite structure is obtained.

[0036] The workpiece is a steel ball, the composition of the steel ball is shown in Table 1 (mass percentage: wt%), and the diameter of the steel ball is 150mm.

[0037] Table 1

[0038]

[0039] The specific steps are as follows:

[0040] Step 1. First, the workpiece is austeni...

Embodiment 2

[0051] The bainite-martensitic composite phase steel / iron graded austempering heat treatment method first austenitizes the workpiece and puts it into circulating water for water cooling without cooling it through. , and then put the workpieces with similar internal and external temperatures into circulating water for water cooling, and each water cooling and waste heat recovery form a cyclic heat treatment process. The workpiece is cooled by waste heat or kept in an incubator for isothermal transformation of bainite; finally, it is air-cooled to room temperature to complete the transformation of martensite, and the bainite-martensite composite iron with bainite-martensite structure is obtained.

[0052] The workpiece is a ductile iron grinding ball, the composition of the steel ball is shown in Table 3 (mass percentage: wt%), and the diameter of the steel ball is 180mm.

[0053] table 3

[0054]

[0055] The specific steps are as follows:

[0056] Step 1. First, the workp...

Embodiment 3

[0068]The bainite-martensitic composite phase steel / iron graded austempering heat treatment method first austenitizes the workpiece and puts it into circulating water for water cooling without cooling it through. , and then put the workpieces with similar internal and external temperatures into circulating water for water cooling, and each water cooling and waste heat recovery form a cyclic heat treatment process. The workpiece is cooled by waste heat or kept in an incubator for isothermal transformation of bainite; finally, it is air-cooled to room temperature to complete the transformation of martensite, and the bainite-martensite composite steel with bainite-martensite structure is obtained.

[0069] The workpiece is a low-carbon alloy steel liner, the composition of the steel balls is shown in Table 5 (mass percentage: wt%), and the thickness of the liner is 180mm.

[0070] table 5

[0071]

[0072] The specific steps are as follows:

[0073] Step 1. First, austenitiz...

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Abstract

The invention relates to a method and device for progressive austempering heat treatment of bainite and martensite complex-phase steel/iron, and belongs to the technical field of metallic material heat treatment processes. The method comprises the following steps: performing water cooling on an austenitized workpiece for a certain period of time, taking out the workpiece for air cooling, and enabling the inner and outer temperatures of the workpiece to be close to each other by using waste heat temperature returning, thereby finishing a heat treatment cycle; putting the inner and outer parts of the workpiece into a lower bainite transformation temperature zone after finishing multiple heat treatment cycles; then performing isothermal transformation by using waste heat temperature returning or heat preservation by an insulation can; and finally performing air cooling to finish martensite transformation. By adopting the method, the defect that a workpiece with a relatively large wall thickness is easy to crack and generate early cracks during quenching can be overcome, and the obtained product is uniform in structure, good in comprehensive mechanical property, reliable in operation and low in cost and is green and environmentally-friendly.

Description

technical field [0001] The invention relates to a bainite-martensite multiphase steel / iron graded austempering heat treatment method and device, belonging to the technical field of metal material heat treatment technology. Background technique [0002] Cast (forged) steel or iron castings with bainite / martensite multiphase structure are widely used in many fields such as wear resistance, impact resistance, high strength and high toughness due to their excellent wear resistance and excellent comprehensive mechanical properties. Grinding balls and liners in various occasions. The main methods of transmission and weaving are: (1) Obtained by austenitic quenching process, that is, the austenitized workpiece is quenched to the lower bainite temperature zone for isothermal transformation, and then quenched to below the martensite transformation point to obtain bainite / martensitic complex structure. In this method, the isothermal medium is generally nitrate or quenching oil. T...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/20C21D1/60
CPCC21D1/20C21D1/60C21D1/62C21D2211/002C21D2211/008
Inventor 李祖来潘伟蒋业华山泉冯志扬周荣
Owner KUNMING UNIV OF SCI & TECH
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