EP4097443A1 - Procede d'analyse de la fragilisation par l'hydrogene de pieces en aciers nus ou revetus utilisees dans les vehicules automobiles - Google Patents
Procede d'analyse de la fragilisation par l'hydrogene de pieces en aciers nus ou revetus utilisees dans les vehicules automobilesInfo
- Publication number
- EP4097443A1 EP4097443A1 EP20828045.3A EP20828045A EP4097443A1 EP 4097443 A1 EP4097443 A1 EP 4097443A1 EP 20828045 A EP20828045 A EP 20828045A EP 4097443 A1 EP4097443 A1 EP 4097443A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- parts
- rupture
- sample
- hydrogen
- threshold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 42
- 239000001257 hydrogen Substances 0.000 title claims abstract description 42
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 38
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 22
- 239000010959 steel Substances 0.000 title claims abstract description 22
- 238000009864 tensile test Methods 0.000 claims abstract description 18
- 238000012360 testing method Methods 0.000 claims description 13
- 238000004458 analytical method Methods 0.000 claims description 11
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 6
- 238000007654 immersion Methods 0.000 claims description 5
- ZNNZYHKDIALBAK-UHFFFAOYSA-M potassium thiocyanate Chemical compound [K+].[S-]C#N ZNNZYHKDIALBAK-UHFFFAOYSA-M 0.000 claims description 3
- 239000011780 sodium chloride Substances 0.000 claims description 3
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 claims description 2
- 230000000295 complement effect Effects 0.000 claims description 2
- 235000017281 sodium acetate Nutrition 0.000 claims description 2
- 238000000576 coating method Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 230000006399 behavior Effects 0.000 description 3
- 230000000977 initiatory effect Effects 0.000 description 3
- 208000035126 Facies Diseases 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 230000004807 localization Effects 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 238000004125 X-ray microanalysis Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000004451 qualitative analysis Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
- G01N2203/024—Corrosive
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
- G01N2203/0242—With circulation of a fluid
Definitions
- TITLE PROCESS FOR ANALYSIS OF HYDROGEN FRAGILIZATION OF BARE OR COATED STEEL PARTS USED IN MOTOR VEHICLES
- the invention applies to the field of analysis of the risks of hydrogen embrittlement in steel and / or to the steel / coating bond of parts used in the automotive industry.
- the invention relates, primarily, to a test method for characterizing the sensitivity and behavior of mechanical parts made of bare or coated steels vis-à-vis the risk of hydrogen embrittlement. (also known as FpH) and, alternatively, the use of this process to constitute a test standard for hydrogen embrittlement of mechanical parts in bare or coated steels intended for the automotive industry.
- ASTM F1624 which provide methods for testing the hydrogen sensitivity of serial screws in use. Most of these standards are based on testing tensile strengths performed on coated steel samples. However, these standards involve reproducing the fracture facies of these samples, which sometimes proves difficult or even impossible.
- patent EP3395989 describes an austenitic material whose resistance to hydrogen embrittlement is measured via an elongation at break according to tensile tests at 25 ° C under atmospheric conditions of 1 atm under a pressure of hydrogen of 70 MPa.
- Patent application WO2018 / 151974 describes a method for testing a hydrogen embrittlement of a steel alloy sample consisting essentially of applying a tensile load to the sample and supporting the load for a period of time. determined to promote and detect the appearance of potential embrittlement cracks if a sufficient quantity of hydrogen is present in the sample analyzed.
- the invention provides a technical solution consisting in characterizing the behavior of bare ferrous materials (heat treated or no) or made up of steel / coating pairs in screws and bolts set to the desired tension vis-à-vis the risk of hydrogen embrittlement.
- the invention aims, at the same time, to discriminate the risks of embrittlement by hydrogen of screw assembly elements intended to constitute safety parts of the vehicle (chassis, engine), and to assess these risks of embrittlement concomitantly and / or independently depending on: (i) the nature of the steel used and, where applicable, its associated heat treatment, (ii) the coating applied and, (iii) the voltage level applied.
- This object is achieved, according to the invention, by means of a method for analyzing the hydrogen embrittlement of mechanical parts made of bare or coated steels, comprising a preliminary tensile test on a first sample of parts. in the clamping position to determine their breaking point in air, characterized in that a second sample of identical parts in the clamping position is prepared which are at least partially immersed in a medium containing hydrogen where they are charged electrically, a tensile test is then carried out in said medium on the parts of the second sample by applying a tensile force to them in successive stages each corresponding to a fraction of the breaking threshold in air until a threshold of hydrogen rupture of said parts then their resistance to embrittlement is determined by comparison between their hydrogen rupture threshold and their air rupture threshold.
- This process is equally applicable to possibly heat-treated steels.
- the fraction of the air rupture threshold applied in stages to the parts of the second sample is between 2% and 10%.
- the immersion medium of the second sample comprises from 1% to 5% of NaCl, supplemented with 1 to 10 g / l of CH3COONa and less than 10g / l of KSCN, with a pH adjusted to between 1 and 4.
- the electrical charging of the parts of the second sample is carried out for 4 hours in galvanostatic mode with a current density of between -1 and -10 mA / cm 2 .
- the tensile test on the parts of the second sample is implemented in two steps, respectively, a first step of 2 hours with ten levels of mechanical tensile force followed by 'a second 8-hour stage with ten other levels of mechanical tensile stress.
- the first sample comprises at least 2 parts and the second sample comprises at least 3 parts. From a statistical point of view, it is of course strongly advised to increase their numbers.
- the hydrogen rupture threshold used for the parts corresponds to the average value of the rupture thresholds recorded for the last stage (n) before their rupture.
- the hydrogen rupture threshold used corresponds to the formula: [F (nl) + F (n)] x [Tr] / [Tn ] where F (nl) is the mean value of the forces of the plateau (n-1) preceding the break, F (n) is the mean value of the forces of the plateau n until the break, Tr is the duration of the plateau n up to 'at failure and Tn is the theoretical duration of the plateau n.
- a complementary fractographic analysis of the rupture is carried out, comprising the identification of the nature of the rupture and the location on the parts of the rupture zone.
- Another object of the invention is a use of the method defined above to constitute a test standard for hydrogen embrittlement of mechanical parts made of bare or coated steels, optionally heat-treated, and intended for automobile industry.
- the method of the invention applies very generally to mechanical parts of different types and, in particular, to the quality control of screwing elements intended for the assembly of various mechanical components installed in motor vehicles (safety parts such as chassis screws, engine screws,
- the method of the invention thus has normative applications for the automotive industry by supplementing existing standards such as those on phosphating, on electrolytic zinc coatings, on lamellar zinc coatings and makes it possible to validate new ones. solutions for steels with or without coatings used in automotive fasteners.
- FIG. 1 is a graph illustrating a preferred procedure of the method of the invention for determining the resistance to hydrogen of parts tested in accordance with ASTM F1624. For greater clarity, identical or similar elements are identified by identical reference signs in the description and in the figure.
- the invention relates to the field of the analysis of the sensitivity to hydrogen embrittlement of mechanical parts in bare or coated steels, optionally heat-treated and, in particular, of so-called safety parts, intended to ensure the assembly of various organs installed in motor vehicles.
- the analysis method of the invention is based on a series of tests carried out on samples of these mechanical parts by reproducing their operating conditions and the operating mode of which is described below.
- the method of the invention comprises a preliminary tensile test on a first sample of parts placed in the clamping position to simulate their operating conditions. The purpose of this first test is to determine the load corresponding to their breaking point in air according to standard NF EN ISO 898-1 (2013).
- the method of the invention is supplemented by a specific test relating to a second sample of parts identical to those of the first sample and always placed in the clamping position under conditions in accordance with their normal conditions of use.
- the submerged part will preferably be part of the threaded rod.
- a central section of the threaded rod will be exposed in the middle over a length of between 2 and 5cm while its end sections will be enclosed in a sheathed support lined with a hermetic silicone protection to avoid any galvanic coupling.
- the immersion medium of the parts of the second sample comprises between 1% and 5% of NaCl, added with 1 to 10 g / l of CH3C00Na and of less than 10g / l of KSCN, with a pH adjusted between
- the method of the invention provides then to perform, in the immersion medium, a tensile test on the parts of the second sample.
- This tensile test consists in exerting a tensile force on these parts in successive stages or increments, each stage applying a fraction of the load corresponding to the breaking threshold in air obtained during the preliminary test. According to a preferred embodiment of the invention, this incremental fraction is 5% of the breaking load in air.
- the sequential tensile test on the parts of the second sample is implemented in two steps, respectively, a first step of 2 hours with ten tensile stress levels followed by a second step of 8 hours with ten other tensile stress levels. This test is continued until the load threshold corresponding to the breakage of the parts is reached.
- the hydrogen rupture threshold used for the parts tested corresponds to the average value of the rupture thresholds recorded for the last level (n) before their rupture.
- the graphs in Figure 1 illustrate the method for determining the load increments as a function of different behaviors of a bare or coated steel part, optionally heat treated, placed under stress under the effect of a tensile force.
- P in particular, during the rupture phase, as a function of time T; Pi being the initiating load of the rupture and Pth the load corresponding to the rupture threshold.
- the threshold level considered is the level (n ).
- the threshold load level to be taken into account is then the average value of the load level of the bearing (n).
- the threshold load level to be taken into account corresponds to the formula [F (nl) + F (n)] x [Tr] / [Tn]; where F (nl) is the mean value of the forces of the bearing (n-1) preceding the break, F (n) is the mean value of the forces of the bearing (n) until the break, Tr is the duration of the soak ( n) until failure and Tn is the theoretical duration of the plateau (n).
- the following operation may consist of classifying and / or prioritizing the different parts tested exhibiting the variations in the resistance to hydrogen embrittlement (in%) with reference to the breaking strength (in air ambient).
- the method of the invention can provide for carrying out additional analyzes such as a fractographic analysis of the rupture comprising the identification of the nature of the rupture and the localization on the parts of the rupture zone.
- these last analysis operations can consist, in particular, in locating the rupture plane (on or outside the part of the part immersed in the middle), the part of the part where it is located and where, if necessary, initiates the break
- additional operations can also include a check for the presence or absence of an identifiable necking phenomenon on the scale.
- the localization of the primer zone (s) by fractographic analysis carried out with a binocular magnifying glass and a scanning electron microscope. If necessary, a prior pickling of the part with acid will allow the removal of the oxides present on the break.
- the method can also provide for an identification of the relief of the break at the level of the rupture initiation zone and, depending on the result, an identification by elemental analysis, typically by EDS (Energy Dispersive Spectrometry) , of the nature of the inclusion on which the rupture initiation was initiated) as well as a qualitative analysis by X-ray microanalysis to identify the chemical elements constituting the inclusion.
- EDS Electronic Data Dispersive Spectrometry
- results obtained by the implementation of the method of the invention can be supplemented or refined by an estimate of the extent (in two or three dimensions) of the rupture zone exhibiting a characteristic break microrelief d 'a process of hydrogen embrittlement.
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR2000909A FR3106898B1 (fr) | 2020-01-30 | 2020-01-30 | Procede d’analyse de la fragilisation par l’hydrogene de pieces en aciers nus ou revetus utilisees dans les vehicules automobiles |
PCT/FR2020/052267 WO2021152222A1 (fr) | 2020-01-30 | 2020-12-03 | Procede d'analyse de la fragilisation par l'hydrogene de pieces en aciers nus ou revetus utilisees dans les vehicules automobiles |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4097443A1 true EP4097443A1 (fr) | 2022-12-07 |
Family
ID=70228256
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20828045.3A Pending EP4097443A1 (fr) | 2020-01-30 | 2020-12-03 | Procede d'analyse de la fragilisation par l'hydrogene de pieces en aciers nus ou revetus utilisees dans les vehicules automobiles |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4097443A1 (fr) |
FR (1) | FR3106898B1 (fr) |
WO (1) | WO2021152222A1 (fr) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3615624A (en) | 1968-01-29 | 1971-10-26 | Eastman Kodak Co | Peptizers for silver halide emulsions useful in photography |
WO2014109402A1 (fr) * | 2013-01-11 | 2014-07-17 | 株式会社神戸製鋼所 | Métal soudé ayant une excellente résistance à la fragilisation par l'hydrogène, et fil solide pour un soudage à l'arc submergé |
WO2017111489A1 (fr) | 2015-12-22 | 2017-06-29 | 주식회사 포스코 | Matériau en acier austénitique présentant une excellente résistance à la fragilisation par l'hydrogène |
AU2018220685A1 (en) | 2017-02-17 | 2019-07-25 | Goff Omega Holdings, Llc | Testing method for hydrogen embrittlement |
EP3591375A1 (fr) * | 2018-07-04 | 2020-01-08 | TesTneT Engineering GmbH | Appareil, échantillon et procédé pour des essais de traction, en particulier sous hydrogène |
-
2020
- 2020-01-30 FR FR2000909A patent/FR3106898B1/fr active Active
- 2020-12-03 EP EP20828045.3A patent/EP4097443A1/fr active Pending
- 2020-12-03 WO PCT/FR2020/052267 patent/WO2021152222A1/fr unknown
Also Published As
Publication number | Publication date |
---|---|
WO2021152222A1 (fr) | 2021-08-05 |
FR3106898A1 (fr) | 2021-08-06 |
FR3106898B1 (fr) | 2022-10-07 |
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Owner name: STELLANTIS AUTO SAS |