Microstructure of a Creep-Resistant 10 Pct Chromium Steel Containing 250 ppm Boron
Artikel i vetenskaplig tidskrift, 2011

The microstructure of a trial martensitic chromium steel containing a high content of boron (250 ppm) was characterized in detail in the as-tempered and aged conditions. This steel has a similar composition and heat treatment as the TAF steel that still is unsurpassed in creep strength among all 9 to 12 pct chromium steels. Characterization was performed by using scanning electron microscopy, energy-filtered transmission electron microscopy, secondary ion mass spectroscopy, and atom probe tomography. Focus was placed on investigating different types of precipitates that play a key role in improving the creep resistance of these steels. The low tempering temperature of 963 K (690 A degrees C) is enough for the precipitation of the full volume fraction of both MX and M23C6. A high boron content, more than 1 at. pct, was found in M23C6 precipitates and they grow slowly during aging. The high boron level in the steel results in metal borides rather than BN with the approximate formula (Mo0.66Cr0.34)(2)(Fe0.75V0.25)B-2. Two families of MX precipitates were found, one at lath boundaries about 35 nm in size and one dense inside the laths, only 5 to 15 nm in size.

Författare

Ardeshir Golpayegani

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Fang Liu

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Henrik Svensson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

MARCUS ANDERSSON

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Hans-Olof Andrén

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

1073-5623 (ISSN)

Vol. 42 940-951

Styrkeområden

Energi

Materialvetenskap

Ämneskategorier

Annan materialteknik

DOI

10.1007/s11661-010-0555-1