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Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and crack following exposure to hydrogen. Detection of hydrogen embrittlement in welds and fabricated parts is more difficult than detection of oxidative corrosion (rust) because the process is not fully understood. Hydrogen cracking is sometimes said to pose a difficult engineering problem especially in the context of a hydrogen economy. However, commercially workable and safe technology exists globally in the hydrogen industry, which produces some 50 million metric tons per year. The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ...
General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...
Rust, the most familiar example of corrosion. ...
A blacksmith removing rust with sand prior to welding Rust damage in automobiles can cause hidden yet dangerous situations. ...
A hydrogen economy is a hypothetical future economy in which the primary form of stored energy for mobile applications and load balancing is hydrogen (H2). ...
Process The corrosion mechanism begins with hydrogen atoms diffusing through the metal as an interstitial. Hydrogen embrittlement is a room temperature phenomenon where hydrogen present inside the material makes it brittle. High-strength steels, aluminium, and titanium alloys are most susceptible. Interstitial is a generic term for referring to the space between other structures or objects. ...
The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ...
General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ...
General Name, Symbol, Number titanium, Ti, 22 Chemical series transition metals Group, Period, Block 4, 4, d Appearance silvery metallic Atomic mass 47. ...
Hydrogen embrittlement can happen during various manufacturing operations or operational use, anywhere where the material comes in contact with atomic or molecular hydrogen. Processes which can lead to this include cathodic protection, phosphating, pickling, and electroplating. A special case is arc welding, in which the hydrogen is released from moisture in the coating of the welding electrodes; to minimize this, special low-hydrogen electrodes are used for welding high-strength steels. Other mechanisms of introduction of hydrogen into metal are galvanic corrosion, chemical reactions of metal with acids, or with other chemicals (notably hydrogen sulfide in sulphide stress cracking, or SSC, a process of importance for the oil and gas industries). Aluminium anodes mounted on a steel jacket structure Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell. ...
Parkerizing (sometimes called phosphating) is a method of protecting steel surfaces from corrosion and thus increasing their durability. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
Electroplating is the coating of an electrically conductive item with a layer of metal using electrical current. ...
Manual Metal Arc welding, also known as stick or MMA welding is one of the most common forms of welding. ...
The Galvanic cell, named after Luigi Galvani, consists of two metals connected by an electrolyte which forms a salt bridge between the metals. ...
Flash point -82. ...
Sulphide stress cracking (SSC), or sulphide stress corrosion cracking (SSCC), is a special corrosion type, a form of stress corrosion cracking. ...
Counteractions If the metal has not yet started to crack, the condition can be reversed by removing the hydrogen source, causing the hydrogen within the metal to diffuse out and restoring ductility to the metal. Susceptible alloys after chemical or electrochemical treatments, where hydrogen is produced, are often subjected to baking heat treatment, in order to remove absorbed hydrogen. Ductility is the physical property of being capable of sustaining large plastic deformations without fracture (in metals, such as being drawn into a wire). ...
Hydrogen attack If steel is exposed to hydrogen at high temperatures, hydrogen will diffuse into the alloy and combine with carbon to form tiny pockets of methane at internal surfaces like grain boundaries and voids. This methane does not diffuse out of the metal, and collects in the voids at high pressure and initiates cracks in the steel. This process is known as hydrogen attack and leads to decarburization of the steel and loss of strength. The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ...
An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ...
General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ...
The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ...
Decarburization is the process opposite to carburization, namely aimed at decreasing the content of carbon in metals (usually steel). ...
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