ISO 8044:2020 download free.Corrosion of metals and alloys — Vocabulary.
3.7
corrosion failure
corrosion damage (16) characterized by the total loss of function of the technical system
3.8
corrosion product
substance tarmed as a result olcorrosion (11)
3.9
scale
solid layer of corrosion products (1) formed on a metal at high temperature
Note Ito entry: The term scale is also used In some countries for deposits from supersaturated water,
3.10
rust
visible corrosion products (is) consisting mainly of hydrated iron oxides
3.11
corrosion depth
distance between a point on the surface of a metal affected by corrosion (11) and the original surface of the metal
3.12
corrosion rate
corrosion effect (15) on a metal per unit time
Note ito entry: The unit used to express the corrosion rate depends an the technical system and on the type of corrosion effect. Thus, corrosion rate is typically expressed as an increase in corrosion depth (111) per unit time, or the mass of metal turned into corrosion products (La) per area of surface and per unit lime, etc. The corrosion effect may vary with time and may not be the same at all points of the corroding surface. Therefore, reports of corrosion rates are typically accompanied by information on the type, time dependency and location of the corrosion effect.
3.13
corrosion resistance
ability of a metal to maintain serwceability (116) In a given corrosion system (14)
3.14
corrosivity
ability of an environment to cause corrosion (11) of a metal in a given corrosion system (14)
3.15
corrosion likelihood
qualitative and/or quantitative expression of the expected corrosion effects (15) In a defined corrosion system (14)
3.16
serviceability
<corrosion> ability of a corrosion system (14) to perform its specified functions without impairment due to corrosion (ii)
3.17
durability
<corrosion> ability of a corrosion system (j4) to maintain serviceability (116) over a specified time when the specified requirements for use and maintenance have been fulfilled
3.18
service life
<corrosion> time during which a corrosion system (14) meets the requirements for serviceability (116)
4.13
impressed current corrosion
elect rochem ,ca corrosion (4J) due to the action of an external source of electric current
4.14
stray-current corrosion
Impressed current corrosion (4J.3) caused by current flowing through paths other than the intended circuits
4.15
pitting corrosion
ivcuhzed corrosion (4.10) resulting in pits. i.e. cavities extending from the surface into the metal
4.16
crevice corrosion
localized corrosion (LID) associated with, and taking place in or immediately around, a narrow aperture or clearance formed between the metal surface and another surface (metallic or non-metallic)
4.17
deposit corrosion
localized corrosion (Liii) associated with, and taking place under or immediately around, a deposit of corrosion products (3.) or other substance
4.18
water-line corrosion
corrosion (3.1) along, and as a consequence of the presence of, a gas/liquid boundary
4.19
selective corrosion dealloying
corrosion (11) of an alloy whereby the components react in proportions that differ from their proportions in the alloy
4.20
dezincllicatioii of brass
selective corrosion (4J.9) of brass resulting in the prelerential removal of zinc
4.21
graphitic corrosion
selective corrosion (4J.9) of grey cast iron resulting in the partial removal of metallic constituents and leaving graphite
4.22
Intergranular corrosion
corrosion (3d) in or adjacent to the grain boundaries of a metal
4.23
weld corrosion
corrosion (3,j) associated with the presence of a welded joint and taking place in the weld or its vicinity
4.24
knife-line corrosion
corrosion (3d) resulting in a narrow slit in or adjacent to the filler/parent boundary of a welded or brazed joint
4.25
erosion corrosion
process involving conjoint corrosion (ii) and erosion
Note 1 to entry: Erosion corrosion can occur in. for example. pipes with high fluid flow velocity and pumps and pipe lines carrying fluid containing abrasive particles in suspension or entrained in a gas flow.
4.37
microbiologwally influenced corrosion
MIC
corrosion (3J) influenced by the action of microorganisms
Note Ito entry: Compare with bocterkilcucroskin (41).
4.38
environmentally assisted cracking
cracking of a susceptible metal oralloy due to the coriloint action ofan environment and mechanical stress
4.39
hydrogen-Induced cracking
HIC
planar cracking that occurs in metals due to induced stresses when atomic hydrogen diffuses Into the metal and then combines to form molecular hydrogen at trap (3.23) sites
4.40
hydrogen stress cracking
HSC
cracking that results from the presence of hydrogen in a metal and tensile stress (residual or applied or both)
Note I to entry: HSC describes cracking in metals that are not sensitive ta sulfide stress corrosion cracking (SSCC) (4A3) but which may be embrittled by hydrogen when galvanically coupled, as the cathode (LL3J. to another metal that is corroding actively as an u’,vde (7,.j.4). The term galvanlcally Induced HSC’ has been used for this mechanism of cracking.
4.41
Irradiation-assisted stress corrosion cracking
lntergranular cracking of austenitic stainless steels resulting from a reduction In the chromium concentration in a very narrow band at the grain boundaries following exposure to high neutron irradiation doses exceeding one displacement per atom, which causes the migration of point defects to the grain boundaries
4.42
stepwise cracking
swC
cracking that connects hydrogen -induced cracking (HIC) (4,39) on adacent planes in a metal
Note ito entry: This term describes the crack appearance. the linking of hydrogen-Induced cracks to produce stepwisr cracking is dependent upon local strain between the cracks and cmbrlttlcmcnt of the surrounding steel by dissolved hydrogen. HIC/SWC Is usually associated with low-strength plate steels used In the production of pipes and vessels.
4.43
sulfide stress corrosion cracking
ssCc
cracking of metal involving corrosion (ii) and tensile stress, residual and/or applied, in the presence ol water and hydrogen sulfide
Note I to cntry SSCC Is a form of lrydrogen stress cracking (HSC) (4.4l) and involves the embrittlement of the metal by the atomic hydrogen that is produced by acId corrosion on the metal surface. Hydrogen uptake is promoted in the presence of sulrides. The atomic hydrogen can diffuse into the metal, reduce ductility and increase susceptibility to cracking. High strength metallic materials and hard weld zones are prone to SSCC.
7.4.10
galvanic anode sacrificial anode
metallic component used as an anode (2.1.4) for galvanic protection [7.4.4) and cathodic protecuon (7j3)
Note I to entry: The galvank anode must have a lower corrosion potential (7.1.20) than the metal that Ls to be protected.
7.4.11
insoluble anode
DEPRECATED: dimensionally stable anode
anode (7J..4) used [or cathodic protection (Zi) by impressed current protection (Z4) where the anode Is not significantly consumed
EXAMPLE Platinized titanium.
7.5 Electrochemical corrosion tests
7.5.1
patentlostatic test
electrochemical test in which the electrode potent to? (ZIJ.8J is constantly maintained
7.5.2
patentlodynamic test
DEPR ECATED: potentiokinetic test
electrochemical test in which the elea rode potential (7.1.18) is varied continuously at a pre-set rate
7.5.3
potentlostep test
electrochemical test in which the electrode potential (2.1.18) is varied step-wise with time in a pre set manner
7.5.4
potentiostaircase test
DEPRECATED: quasi-potentiostatic test
pot entiostep test (7.13) in which the tame duration and potential increments or decrements arc equal for each step
7.5.5
galvanostatic test
DEPRECATED intensiostatic test
electrochemical test in which the current density (7.2.6) is maintained constant
7.5.6
galvanodynamic test
elect rochemical test in which the current density (7.2.6) is varied continuously with time at a pre-set rate
7.5.7
galvanoslep test
elect rochemical test in which the current density (2.2.6) is varied stepwise with time in a pre-set manner
7.5.8
galvanostaircase test
DEPR E(;ATEI): quasi-galvanostatic test
DEPRECATED: quasi-intensiostatic test
galvanostep test (7.5.7) In which the time duration and current increments or decrements are equal for each step.