Behavior of type 316 austenitic stainless steel under slow strain rate technique conditions in lithium bromide heavy brine environments

Journal Article · Sun Dec 31 23:00:00 EST 1995 · Corrosion

DOI:https://doi.org/10.5006/1.3292098· OSTI ID:187044

Itzhak, D; Elias, O; Greenberg, Y ^[1]

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1. Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Materials Engineering

Lithium bromide (LiBr) heavy brines are used in absorption refrigeration and heating systems. The corrosion and stress corrosion cracking (SCC) behavior of type 316 (UNS S31600) austenitic stainless steel (SS) in a 55% lithium bromide (LiBr) environment was investigated using slow strain rate testing (SSRT) and potentiodynamic polarization measurements. The experiments were performed at temperatures from 80 C to 140 C and from pH 4 to 11.6. The effect of 1 wt% potassium iodide and potassium chromate addition was evaluated. The ultimate tensile stress (UTS) and the elongation were decreased by raising the temperature from 80 C to 140 C in the LiBr environments. Scanning electron microscopy revealed environmental embrittlement features on the lateral surface, the free surface of the specimen, in all the tested environments. Addition of 1 wt% KI to 55% LiBr brine of pH = 4 acted as an inhibitor to SCC and improved mechanical properties. In this case, fracture occurred by microvoid coalescence. In the presence of 1 wt% K{sub 2}CrO{sub 4} high cathodic overpotential was recorded potentiodynamically and evaluated. Inhibition of the passivation process because of high cathodic activation energy resulted in a low cathodic exchange current density. This resulted in a corrosion potential located in the active zone of the anodic polarization curves. SEM showed intergranular and transgranular modes of fracture in this case, instead of microvoid coalescence. Additional of 1 wt% K{sub 2}CrO{sub 4} enhanced the SCC sensitivity of type 316 SS in 55% LiBr environments, resulting in reduced mechanical properties and formation of a typical brittle fracture surface.

• Sponsoring Organization: USDOE
• OSTI ID: 187044
• Journal Information: Corrosion, Journal Name: Corrosion Journal Issue: 1 Vol. 52; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
ABSORPTION REFRIGERATION CYCLE
CHROMATES
CORROSION INHIBITORS
CORROSIVE EFFECTS
CRACK PROPAGATION
LITHIUM BROMIDES
MATERIALS TESTING
MECHANICAL TESTS
POTASSIUM COMPOUNDS
POTASSIUM IODIDES
STAINLESS STEEL-316
STRESS CORROSION
TENSILE PROPERTIES