Stress corrosion cracking

About: Stress corrosion cracking is a research topic. Over the lifetime, 11340 publications have been published within this topic receiving 138157 citations.

Composition and method for producing an aluminum alloy resistant to environmentally-assisted cracking

Abstract: A powder-derived aluminum alloy is provided which contains throughout its se aluminum alloy matrix a fine dispersion of elemental molybdenum particles. The articles formed from the alloy exhibit improved resistance to environmentally-assisted cracking, such as stress corrosion cracking and corrosion fatigue, at room and moderately elevated temperatures. An aluminum alloy powder of a composition usually used to produce high-strength aluminum alloys is blended with molybdenum powder to form a homogeneous powder blend containing up to about 1.0% by weight molybdenum. The powder blend is consolidated, including compacting it and extruding or otherwise hot working it to a total reduction ratio of at least 16 to 1. The hot-worked product is then heat treated in a conventional manner to maximize other desirable properties, such as strength.

Crack Chemistry Control of Intergranular Stress Corrosion Cracking in Sensitized Al-Mg

Abstract: Fracture mechanics experiments and occluded crack chemistry modeling validate the mechanism for intergranular stress corrosion cracking (IGSCC) of sensitized Al-Mg alloys: dissolution of discontinuous grain boundary β (Al3Mg2) precipitates activates Al-Mg (α) solid solution dissolution to acidify the crack solution for crack tip hydrogen embrittlement. Slow-rising displacement experiments with precracked specimens establish the strong effect of applied potential on IGSCC kinetics for sensitized AA5083-H131 (S-L orientation, 22 mg/cm2) in neutral NaCl solution. Anodic polarization increases growth rates through enhanced α dissolution for crack acidification and H uptake, whereas cathodic polarization below the pH-sensitive α breakdown potential reduces growth rates by limiting Al dissolution, and thus crack acidification and the overpotential for H production (ηH). Polarization below the β breakdown potential eliminates IGSCC by precluding β dissolution and crack acidification. Cathodic polarization could ...

Stress corrosion cracking of gas pipeline steels of different strength

Abstract: With the development of the natural gas industry, gas transmission pipelines have been developed rapidly in terms of safety, economy and efficiency. Our recent studies have shown that an important factor of main pipelines serviceability loss under their long-term service is the in-bulk metal degradation of the pipe wall. This leads to the loss of the initial mechanical properties, primarily, resistance to brittle fracture, which were set in engineering calculations at the pipeline design stage. At the same time stress corrosion cracking has been identified as one of the predominant failures in pipeline steels in humid environments, which causes rupture of high-pressure gas transmission pipes as well as serious economic losses and disasters. In the present work the low-carbon pipeline steels with different strength levels from the point of view of their susceptibility to stress corrosion cracking in the as-received state and after in-laboratory accelerated degradation under environmental conditions similar to those of an acidic soil were investigated. The main objectives of this study were to determine whether the development of higher strength materials led to greater susceptibility to stress corrosion cracking and whether degraded pipeline steels became more susceptible to stress corrosion cracking than in the as-received state. The procedure of accelerated degradation of pipeline steels was developed and introduced in laboratory under the combined action of axial loading and hydrogen charging. It proved to be reliable and useful to performed laboratory simulation of in-service degradation of pipeline steels with different strength. The in-laboratory degraded 17H1S and X60 pipeline steels tested in the NS4 solution saturated with CO 2 under open circuit potential revealed the susceptibility to stress corrosion cracking, reflected in the degradation of mechanical properties, and at the same time the degraded X60 steel showed higher resistance to stress corrosion cracking than the degraded 17H1S steel. Fractographic observation confirmed the pipeline steels hydrogen embrittlement caused by the permeated hydrogen.