The role of phosphorus in precipitation behavior and its effect on the creep properties of alumina-forming austenitic heat-resistant steels

Min Ho Jang, Jun Yun Kang, Jae Hoon Jang, Tae Ho Lee, Changhee Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The precipitation behavior and creep properties of lower phosphorus (P) alumina-forming austenitic (AFA LP ) heat-resistant steel were investigated and compared to those of AFA. The creep rupture time and hardness of the investigated steels were improved with the decrease of the P content. The TEM and EELS analyses confirmed an enhanced P concentration in the M 23 C 6 precipitates along the grain boundaries. The P promoted the precipitation of M 23 C 6 and also suppressed the precipitation of secondary NbC in the earlier stage of aging. The creep rupture time of AFA became shorter compared to AFA LP due to the reduction in the fraction of secondary NbC which acts as a dominant strengthening phase during creep. The suppression of secondary NbC precipitation by P increased the Nb content in the austenite matrix and accelerated the precipitation of the Laves phase in the intermediate stage. However, the difference in Vickers hardness caused by Laves phase was not large in both alloys because the volume fraction of Laves phase strongly depended on the nominal content of Mo rather than Nb. The Vickers hardness at the earlier stage is determined by the precipitation of secondary NbC and the difference of the hardness maintained at the final stage. Thus, it is found that P degrades the creep rupture time and P is a detrimental element in terms of creep and precipitation hardening in AFA steels.

Original languageEnglish
Pages (from-to)14-21
Number of pages8
JournalMaterials Science and Engineering A
Volume684
DOIs
StatePublished - 2017 Jan 27

Fingerprint

creep properties
Aluminum Oxide
Steel
Phosphorus
phosphorus
Creep
Alumina
aluminum oxides
steels
heat
Laves phases
Vickers hardness
hardness
Hardness
precipitation hardening
Age hardening
Electron energy loss spectroscopy
austenite
hardening
Austenite

Keywords

  • Alumina-forming austenitic heat-resistant (AFA) steel
  • Creep test
  • Phosphorous
  • Precipitation behavior

Cite this

@article{cc310cee3ddf4af692bef4f697f30044,
title = "The role of phosphorus in precipitation behavior and its effect on the creep properties of alumina-forming austenitic heat-resistant steels",
abstract = "The precipitation behavior and creep properties of lower phosphorus (P) alumina-forming austenitic (AFA LP ) heat-resistant steel were investigated and compared to those of AFA. The creep rupture time and hardness of the investigated steels were improved with the decrease of the P content. The TEM and EELS analyses confirmed an enhanced P concentration in the M 23 C 6 precipitates along the grain boundaries. The P promoted the precipitation of M 23 C 6 and also suppressed the precipitation of secondary NbC in the earlier stage of aging. The creep rupture time of AFA became shorter compared to AFA LP due to the reduction in the fraction of secondary NbC which acts as a dominant strengthening phase during creep. The suppression of secondary NbC precipitation by P increased the Nb content in the austenite matrix and accelerated the precipitation of the Laves phase in the intermediate stage. However, the difference in Vickers hardness caused by Laves phase was not large in both alloys because the volume fraction of Laves phase strongly depended on the nominal content of Mo rather than Nb. The Vickers hardness at the earlier stage is determined by the precipitation of secondary NbC and the difference of the hardness maintained at the final stage. Thus, it is found that P degrades the creep rupture time and P is a detrimental element in terms of creep and precipitation hardening in AFA steels.",
keywords = "Alumina-forming austenitic heat-resistant (AFA) steel, Creep test, Phosphorous, Precipitation behavior",
author = "Jang, {Min Ho} and Kang, {Jun Yun} and Jang, {Jae Hoon} and Lee, {Tae Ho} and Changhee Lee",
year = "2017",
month = "1",
day = "27",
doi = "10.1016/j.msea.2016.12.021",
language = "English",
volume = "684",
pages = "14--21",
journal = "Materials Science and Engineering A",
issn = "0921-5093",

}

The role of phosphorus in precipitation behavior and its effect on the creep properties of alumina-forming austenitic heat-resistant steels. / Jang, Min Ho; Kang, Jun Yun; Jang, Jae Hoon; Lee, Tae Ho; Lee, Changhee.

In: Materials Science and Engineering A, Vol. 684, 27.01.2017, p. 14-21.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The role of phosphorus in precipitation behavior and its effect on the creep properties of alumina-forming austenitic heat-resistant steels

AU - Jang, Min Ho

AU - Kang, Jun Yun

AU - Jang, Jae Hoon

AU - Lee, Tae Ho

AU - Lee, Changhee

PY - 2017/1/27

Y1 - 2017/1/27

N2 - The precipitation behavior and creep properties of lower phosphorus (P) alumina-forming austenitic (AFA LP ) heat-resistant steel were investigated and compared to those of AFA. The creep rupture time and hardness of the investigated steels were improved with the decrease of the P content. The TEM and EELS analyses confirmed an enhanced P concentration in the M 23 C 6 precipitates along the grain boundaries. The P promoted the precipitation of M 23 C 6 and also suppressed the precipitation of secondary NbC in the earlier stage of aging. The creep rupture time of AFA became shorter compared to AFA LP due to the reduction in the fraction of secondary NbC which acts as a dominant strengthening phase during creep. The suppression of secondary NbC precipitation by P increased the Nb content in the austenite matrix and accelerated the precipitation of the Laves phase in the intermediate stage. However, the difference in Vickers hardness caused by Laves phase was not large in both alloys because the volume fraction of Laves phase strongly depended on the nominal content of Mo rather than Nb. The Vickers hardness at the earlier stage is determined by the precipitation of secondary NbC and the difference of the hardness maintained at the final stage. Thus, it is found that P degrades the creep rupture time and P is a detrimental element in terms of creep and precipitation hardening in AFA steels.

AB - The precipitation behavior and creep properties of lower phosphorus (P) alumina-forming austenitic (AFA LP ) heat-resistant steel were investigated and compared to those of AFA. The creep rupture time and hardness of the investigated steels were improved with the decrease of the P content. The TEM and EELS analyses confirmed an enhanced P concentration in the M 23 C 6 precipitates along the grain boundaries. The P promoted the precipitation of M 23 C 6 and also suppressed the precipitation of secondary NbC in the earlier stage of aging. The creep rupture time of AFA became shorter compared to AFA LP due to the reduction in the fraction of secondary NbC which acts as a dominant strengthening phase during creep. The suppression of secondary NbC precipitation by P increased the Nb content in the austenite matrix and accelerated the precipitation of the Laves phase in the intermediate stage. However, the difference in Vickers hardness caused by Laves phase was not large in both alloys because the volume fraction of Laves phase strongly depended on the nominal content of Mo rather than Nb. The Vickers hardness at the earlier stage is determined by the precipitation of secondary NbC and the difference of the hardness maintained at the final stage. Thus, it is found that P degrades the creep rupture time and P is a detrimental element in terms of creep and precipitation hardening in AFA steels.

KW - Alumina-forming austenitic heat-resistant (AFA) steel

KW - Creep test

KW - Phosphorous

KW - Precipitation behavior

UR - http://www.scopus.com/inward/record.url?scp=85003443638&partnerID=8YFLogxK

U2 - 10.1016/j.msea.2016.12.021

DO - 10.1016/j.msea.2016.12.021

M3 - Article

AN - SCOPUS:85003443638

VL - 684

SP - 14

EP - 21

JO - Materials Science and Engineering A

JF - Materials Science and Engineering A

SN - 0921-5093

ER -