Investigation on SCC and HE of STS 304 austenitic stainless steel for offshore structures

Abstract

The structural steel demands are surging by the industry development. Among them, the demands of stainless steel has excellent anti-corrosion properties are expanding to various fields including the ship, offshore structure, petrochemical industry and living appliance. The stainless steel has some advantages that can change the property due to add chemical elements, various heat treatments and processing. However, in the STS 304, which makes up the majority of demands currently, involves a lot of risks the possibility of occurring stress corrosion cracking and hydrogen embrittlement of marine structure exposed to external forces and lower corrosion protection properties as destruction of passive layer in chloride environment. In this paper, we discuss the results of our investigations using potentiostatic slow strain rate test to estimate the durability of STS 304 against stress corrosion cracking (SCC) and hydrogen embrittlement (HE) under corrosive conditions of chloride ion exposure and tensile stress applied from external force. The optimum corrosion protection range without stress corrosion cracking and hydrogen embrittlement was concluded with the potential range of -0.5 ~ -0.2 V (vs. Ag/AgCl).

Magnetocrystalline effects on the subsurface hydrogen diffusion in γ-Fe(0 0 1)

“…Austenitic steels are widely used in a range of technologies such as in nuclear power plants [1] and in offshore structures [2]. The face-centred cubic (fcc) austenite phase, i.e.…”

“…Three magnetically ordered phases are considered in the collinear approximation used in theoretical studies: the ferromagnetic (FM-↑↑↑↑ ...) phase, as well as multi-layered anti-ferromagnetic phases, namely the single (AFM1-↑↓↑↓ ...) and double (AFMD-↑↑↓↓ ...) layer phases [23][24][25][26]. The double-layer structure has been reported to be energetically most favourable, and provides a reasonable approximation of the spin-spiral state with a propagation vector ≈ 2 [001] [26][27][28], where a denotes the lattice parameter of the fcc crystal structure. The bulk magnetic ordering of γ-Fe extends to surface studies, in which γ-Fe films are grown on a Cu(100) substrate [9,29,30].…”

Energetics of hydrogen adsorption and diffusion for the main surface planes and all magnetic structures of γ-iron using density functional theory

“…This phase is stable in the range of temperatures of 1185-1665 K, 9 but can also be present as a metastable grain at lower temperatures by adding g-stabilising alloying elements such as nickel, manganese, carbon or nitrogen. 10,11 Such alloys are also used to form austenitic steels which nd application, amongst others, in the nuclear industry, 12,13 the offshore industry, 14 and the automotive industry. [15][16][17][18] The complex magnetic behaviour of the g-phase can also be tuned by varying the amount of alloying elements, thus changing the magnetic ground state and the critical temperature of g-Fe, 19,20 making this eld relevant to e.g.…”

Research on Oxygen Content and Crack Control of Oxygen-Free Copper Billet in Horizontal Continuous Casting Process

“…Second, it has the tendency of having serious cracks on large flakinessratio copper billet surface and its inner organization. Third, oxygen-free copper liquid has the characteristics of large viscosity and poor liquidity, which makes graphite crystallizer crystallization area easy to get oxidation prematurely and shorten working life [6] [7].…”