Effects of Ni on stress corrosion susceptibility of high-Cr ferritic stainless steels in hot Cl[sup [minus]] solution

Journal Article · Fri Oct 01 00:00:00 EDT 1993 · Corrosion (Houston); (United States)

DOI:https://doi.org/10.5006/1.3316003· OSTI ID:5842348

Kwon, H S; Jang, S P ^[1]

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1. Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of). Dept. of Materials Science and Engineering

Effects of nickel (Ni) on the stress corrosion susceptibility of high-chromium (Cr) ferritic stainless steels (SS) in boiling solution of 42% lithium chloride (LiCl) plus thiourea (NH[sub 2]CSHN[sub 2]) were investigated using a uniaxial tension-constant load tester. The influence of Ni on film breakdown potential, repassivation rate, creep behavior, and susceptibility to hydrogen (H)-induced failure of the alloys was evaluated. Commercial alloys of 29% Cr-4% molybdenum (Mo)(UNS S44700) and 29% Cr-4% Mo-2% Ni (UNS S44800) ferritic SS were compared. The 29% Cr-4% Mo alloy was immune to stress corrosion cracking (SCC) at open-circuit potential (OCP) but became susceptible when polarized anodically to critical potential (E[sub cc]) [minus]450 mV[sub sce] which was 20 mV[sub sce] more noble to the stabilized corrosion potential (E[sub corr], [minus]470mV[sub sce]). Addition of 2% Ni to the 26% Cr-4% Mo alloy did not affect E[sub cc], but did induce susceptibility to cracking by increasing E[sub corr] to a value 80mV[sub sce] nobel to E[sub cc]. The 2% Ni addition to 29% Cr-4% Mo alloy reduced film breakdown potential (E[sub b]) and the repassivation rate and significantly increased susceptibility to H embrittlement (HE).

• OSTI ID: 5842348
• Journal Information: Corrosion (Houston); (United States), Vol. 49:10; ISSN 0010-9312
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FERRITIC STEELS
CRACK PROPAGATION
STRESS CORROSION
NICKEL
METALLURGICAL EFFECTS
STAINLESS STEELS
CHLORIDES
CORROSIVE EFFECTS
ALLOYS
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
CORROSION
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
METALS
STEELS
TRANSITION ELEMENTS
360105* - Metals & Alloys- Corrosion & Erosion
360103 - Metals & Alloys- Mechanical Properties