Papers by Keyword: Sulfide Stress Corrosion Cracking (SSCC)

Abstract: Laser shock processing (LSP) is a new technique for metal surface strengthening by which residual compressive stress in the superficial layer can be induced to greatly improve the stress corrosion resistance property. The effect of LSP on sulfide stress corrosion cracking (SSCC) of X70 pipeline steel welded joint has been studied in this paper. A convergent lens is used to deliver 20 J, 20 ns laser pulses by a Q switch Nd:YAG laser, operating at 10 Hz. The pulses are focused to a diameter of 3 mm onto samples. The power density of laser at the surface of the sample was about 5 GW/cm2. The surface residual stress level after LSP is much higher than before. SSCC behavior of X70 pipeline steel welded joint was investigated using slow strain rate testing (SSRT) in H2S solution. Morphology of X70 pipeline steel fracture surface was observed by scanning electron microscope (SEM). It has been demonstrated that LSP is an effective surface treatment technique to improve the stress corrosion cracking (SCC) resistance properties of X70 pipeline steel welded joints.

Abstract: As Pipeline in Wet H2S environment must consider its anti-hydrogen-induced cracking (HIC) and sulfide stress corrosion cracking (SSCC) performance, in this paper, to ensure L245A-pipe mechanical properties qualified under the premise, according to NACE TM 0284-2003 and NACE TM 0177-2005 standard conducted a test evaluation in Wet H2S in the context of anti-hydrogen-induced cracking performance (HIC) and sulfide stress corrosion cracking resistance (SSCC) and came L245A-pipe in standard Wet H2S environment didn’t produce hydrogen-induced cracking, occurred sulfide stress corrosion cracking, the design conditions and working conditions are no stress corrosion cracking conclusions. And make recommendations on the safe operation in Wet H2S.

Abstract: Electrochemical measurement techniques were applied to investigate the polarization and hydrogen permeation behavior of Cu-bearing CrMo steel in a H2S saturated aqueous brine solution. The observation on microstructure and precipitate phases of the steel was conducted by transmission electron microscopy (TEM), and the corrosion product was investigated by using X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). It is disclosed that copper addition could effectively influence the electrochemical behavior of the investigated steel, and the dissolution behavior of iron matrix and carbide precipitates in the H2S solution acts as a key role for the steel resistance to hydrogen sulfide corrosion.

Abstract: JIS-SPV50Q high strength steel is often employed in construction of liquid petroleum gas (LPG) spherical tanks due to its high strength and good ductility. In general, post weld heat treatment is not performed after welding of SPV50Q high strength steel and welding residual stress will be retained in weldment. Service experience and inspection indicate that higher H2S concentration and welding residual stress result in the environmental failure, such as blistering or hydrogen induced cracking (HIC), sulfide stress corrosion cracking (SSCC) and stress oriented hydrogen induced cracking (SOHIC). In the present paper, the cracking behavior of SPV50Q high strength steel weldment by manual electric arc welding has been investigated in various saturate solutions with different concentrations of H2S. The results of slow strain rate testing, performed at a strain of 1×10-6s-1, reveal the presence of SSCC and HIC in the base metal adjacent to HAZ. The ffects of the different temperatures of post weld heat treatment on cracking are discussed. The suitable post weld heat treatment could increase the resistance of SPV50Q weldment on SSCC or HIC and does not decrease the mechanical properties of SPV50Q weldment.