Grain Refinement by Rapid Transformation Annealing of Cold Rolled Low Carbon Steels

A novel heat treatment, rapid transformation annealing (RTA) is introduced, which uses the refining effect of the phase transformation during recrystallization annealing. The RTA is comprised of rapid heating including the full or partial phase transformation of cold-rolled, nonrecrystallized, or partly recrystallized a microstructure to c microstructure combined with subsequent rapid cooling to ambient temperature. In this way, a substantial grain refinement compared to conventional industrial annealing of cold-rolled strip can be realized. Minimum homogeneous grain sizes of 2.3 lm are produced in microalloyed high-strength low-alloy (HSLA) steels. A plain low-carbon steel shows despite any microalloying grain sizes of about 2.5 lm. Grain refinement results in a substantial increase in strength and in a pronounced strain hardening in the H IV stage. Simultaneously, the uniform and total elongation slightly decrease, which is a physical consequence of Conside`reÕs instability criterion. By a refinement from 4.2 to 2.3 lm, the yield and tensile strength of a HSLA grade can be increased by about 130 MPa to 535 and 650 MPa, while the total elongation is reduced by about four percentage points to 21 pct, i.e., a still moderate formability is provided. In general, the ductility-strength relationship remains similar to the conventional behavior. For all investigated steel grades, the HallPetch (HP) relationship is fulfilled. Furthermore, it is proved that RTA cycles can be realized in pilot scale as far as induction heating devices are applied.

show abstract

Rapid Transformation Annealing: a Novel Method for Grain Refinement of Cold-Rolled Low-Carbon Steels

Lesch

Álvarez

Bleck

et al. 2007

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

A Novel Heat Treatment Line for Processing of Tailored Small Batch Steels

Järvenpää

Lämsä

Patard

et al. 2014

KEM

View full text Add to dashboard Cite

This study describes design and construction of a novel flexible heat treatment line for processing customer-oriented small batch steels. The induction heater (600 kW) developed is suitable for the sheet thickness in the range 3.2 30 mm and the width of 85 1250 mm. Sheets are fed using an electrical motor (1.5 kW) and a chain drive, the speed being in the range 0.3 7 m/min, depending on the power and the sheet dimensions. At this study, 4.5 (WR-1) and 10 mm (WR-2) thick wear resistant steels were tempered at different peak temperatures to compare the effect of rapid tempering on mechanical properties. Results showed that the heat treatment line is capable of producing tempered steel grades with adequate properties at industrial product rate. For example, 4.5 thick WR-1 tempered at 550 oC provided a yield strength (YS) over 1000 MPa with minimum bending radius of 6 mm (in the delivered condition YS = 1605 MPa and Rmin = 12). Tempering of WR-1 at 700 oC provided YS of 762 MPa and Rmin of 1 mm. Results were similar between two test materials, but the enhancement in bendability was slightly more effective with the thinner sheet.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Grain Refinement by Rapid Transformation Annealing of Cold Rolled Low Carbon Steels

Cited by 2 publications

References 0 publications

Rapid Transformation Annealing: a Novel Method for Grain Refinement of Cold-Rolled Low-Carbon Steels

Rapid Transformation Annealing: a Novel Method for Grain Refinement of Cold-Rolled Low-Carbon Steels

A Novel Heat Treatment Line for Processing of Tailored Small Batch Steels

Contact Info

Product

Resources

About