Method for producing steel with retained austenite

a technology of austenite and steel, applied in the field of method for producing steel, can solve the problems of time/temperature/alloying approaches that are quite challenging, processing constraints that are needed to control the bainite transformation, etc., and achieve the effect of convenient or less costly processing

Inactive Publication Date: 2006-01-19
COLORADO SCHOOL OF MINES
View PDF3 Cites 129 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0005] The present invention recognizes that the carbon partitioning and growth of the body-centered phase are decoupled in martensite transformations and that this decoupling provides a mechanism for controlling the austenite fraction and its carbon concentration (the kinetics of carbon partitioning are separate from the mechanisms

Problems solved by technology

The problem is to enrich some austenite in the microstructure with carbon, by controlling microstructure evolution and carbon partitioning, without having to use a much higher carbon-containing steel, which is usually undesired for reasons such as reduced weldabilit

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for producing steel with retained austenite
  • Method for producing steel with retained austenite
  • Method for producing steel with retained austenite

Examples

Experimental program
Comparison scheme
Effect test

example

[0014] The present invention is described with respect to the production of retained austenite in one transformation induced plasticity (TRIP) sheet steel. TRIP sheet steels are of great current interest for automotive sheet applications and high strength products that make use of controlled amounts of retained austenite, typically on the order of 10% austenite. TRIP sheet steel with retained austenite, such as that produced by processes that use bainite transformation, typically in excess of 1% carbon (by weight) in the austenite, are capable of undergoing martensite transformation during deformation. This capability provides several advantages that are useful in various applications. For example, TRIP sheet steel with retained austentite has improved formability, and increased energy absorbance (such as would apply to a vehicle collision in automotive application).

[0015] The microstructures for the TRIP sheet steel of this example also contain equiaxed ferrite, along with differe...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
Temperatureaaaaaaaaaa
Mobilityaaaaaaaaaa
Login to view more

Abstract

The present invention relates to a process for producing steel with retained austenite. In one embodiment, the process comprises the steps of heating a steel alloy to produce austenite, quenching the steel to produce martensite, and carbon partitioning to transfer carbon from the martensite to the austenite.

Description

FIELD OF THE INVENTION [0001] The invention is directed to a method for producing steels with microstructures containing retained austenite. BACKGROUND OF THE INVENTION [0002] The difficulty that this invention seeks to address is that of creating a microstructure in steel, (e.g., but not limited to, low carbon sheet steel) that contains austenite at the ambient temperature at which the steel is to be used in some application, typically room temperature. Without substantial additions of expensive alloying elements such as nickel, austenite usually must be enriched with carbon (or sometimes nitrogen) in order to stabilize it to room temperature. (Actually, it is metastable, and undergoes subsequent transformation to martensite during deformation, a key component of its utility in service.) The problem is to enrich some austenite in the microstructure with carbon, by controlling microstructure evolution and carbon partitioning, without having to use a much higher carbon-containing ste...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C21D6/00C21D1/18C21D1/19C21D1/20C21D8/02
CPCC21D1/18C21D1/185C21D1/19C21D1/20C21D2211/008C21D6/00C21D8/0273C21D2211/001C21D2211/005C21D1/22
Inventor SPEER, JOHN G.MATLOCK, DAVID K.GALLAGHER, MATTHEW F.
Owner COLORADO SCHOOL OF MINES
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap