Method for determining reverse austenite by adopting expansion method

A technology of reverse transformation of austenite and expansion method, applied in the field of material metallurgy, to achieve the effects of ensuring smooth development, improving analysis efficiency, and simplifying the calculation process

Active Publication Date: 2020-09-08
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a method for measuring the content of reverse transformed austenite using a thermal simulation testing machine using the expansion method, and to solve the rapid determination of the content of reverse transformed austenite in the heat treatment process question

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  • Method for determining reverse austenite by adopting expansion method
  • Method for determining reverse austenite by adopting expansion method
  • Method for determining reverse austenite by adopting expansion method

Examples

Experimental program
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Embodiment 1

[0062] Using the Gleeble3800 thermal simulation testing machine, two groups of tests were carried out on the TRIP steel containing 5% Mn. The test temperatures were 650°C and 680°C respectively. The specific test process is as follows:

[0063] Step (1): Select a 60mm thick Mn5 steel plate to take a quarter of the steel plate and process it into a Φ6×76mm sample;

[0064] Step (2): Weld a thermocouple on the sample of Mn5 steel processed in step (1). The welding position of the thermocouple is the middle position of the sample axial direction, and ensure that the plane where the thermocouple is located is perpendicular to the axial direction of the sample. , put it into the Gleeble3800 thermal simulation test chamber, install the dilatometer, and the measuring blade of the dilatometer and the thermocouple are on the same plane.

[0065] Step (3) Use the Gleeble3800 thermal simulation testing machine to heat the sample installed in step (2) to a temperature of 800°C for 10 minu...

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Abstract

The invention discloses a method for determining reverse austenite by adopting an expansion method. A sample is subjected to complete austenitizing heat treatment and partial austenitizing heat treatment respectively; a relation curve of volume expansion and temperature under two conditions is recorded; the volume shrinkage amount caused by austenitizing the sample and the volume expansion of tissue transform of the sample in the cooling process are calculated; and the percentage composition of heating and heat preservation austenitizing of the sample and the content of transformation again during cooling in the partial austenitizing heat treatment process are calculated by using a lever law formula, and the difference value between the percentage composition and the content of transformation again during cooling is the content of reverse transformation austenite. By adopting the method disclosed by the invention, the reversed austenite can be directly measured in the heat treatment process, the content of the reversed austenite can be quickly obtained after simple analysis according to a measurement result, and the method is used for adjusting a field process scheme, so that the analysis efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of material metallurgy, and relates to a method for directly and quickly measuring reverse transformed austenite in steel during heat treatment using an expansion method. Background technique [0002] High-manganese-high-nickel alloy steel has excellent low-temperature toughness after quenching and tempering heat treatment, and this excellent low-temperature toughness is closely related to the reverse transformed austenite formed during tempering. During the heat treatment process, there are fluctuations in the composition of the steel. Due to the enrichment of manganese, nickel, carbon and other elements in the local area, the austenite transformation temperature point in the local area is reduced, and the austenite phase transformation occurs. No martensite transformation or partial martensite transformation occurs, and the remaining austenite is reverse transformed austenite. [0003] At present, the mea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N25/12
CPCG01N25/12
Inventor 钦祥斗张华伟赵亚娟李建宾郭志春
Owner NANJING IRON & STEEL CO LTD
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