1、CEN ENa283L 93 m 3404589 0042656 T95 m EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 2831:1993 February 1993 UOC 669.14:621.793/794:620.177:629.7 Descriptors: Airdt indwt, steels, hydrogen embriement, band tests English version Aerospace series - Hydrogen embrittiernent of steels - Test by sl
2、ow bending Srie arospatiale - Fragilisation des aclers par lhydrogne - Essa par flexion lente Luft- und Raumfahrt - Wasserstoffversprdung von Sthlen - Langsamer Biegeversuch This European standard was apptoved by CEN on 1993-02-19. CEN members are bound to comply with the =N/CENELEC Internal Regulat
3、ions which stipulate the conditions for giving this European Standard the status of a national standard withart any alteration. Up-to-date lists and bibliographic81 references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. The Europ
4、ean Standards exist in three official versions (English. French. German). A version in any other language made by translation under the responsibillty of a CEN member into Its own language and notified to the Central Secretariat has the same status as the official versions. - CEN members are the nat
5、ional standards bodies of Austria, Belgium, Denmark, Finland, France. Germany, Greece, Iceland. Ireland, Italy, Luxembourg, Netherlands. Noway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Gmnittee for Standardization hit Europen de NonMlisation Europisches Komitee fur Normu
6、ng CenLral Su-etariat: rue de stascart.36 B-1050 the fixed chuck shall be fitted with an interchangeable bending block the diameter of which may be between 2 mm and 6 mm (see figure 1) ; the movable chuck shall have a deflection rate which can be adjusted between 4 O /min and 18 Olmin, - be fitted w
7、ith a device allowing to measure the angles ao, a fl and a f2 (see figures 2 to 41 with a precision of f 0,5O, - be fitted with a magnifier of 1 O times in order to reveal the occurence of the first crack. 3 lest specimens They shall : - be cut from a bar or sheet along the grain direction, - have t
8、he following dimensions : . length : 180 mm to 200 mm . width : 15 mm to 20 mm . thickness : 1,8 mm to 4 mm . straightness deflection over the length : 0.25 mm, - be machined along the grain direction to a surface roughness Ra s1,6 pm, then submitted to a stress relief of at least 2 h at 150 OC with
9、out decarburization. 4 Procedure Each bending angle (ao, a fl, if specified, and a f2) is determined successively on the same test specimen (see figures 2 to 4). At least three test specimens shall be used. The test specimens shall be in the same condition as the parts they represent. Page 4 EN 2831
10、:1993 CEN ENr2831 93 3404589 0042b59 7T4 = NOTE 1 : Test specimens, possibly of a different steel grade, with a higher strength than the pieces may be used: NOTE 2 : The fracture angle of the test specimens per bending shall not exceed the defiection angle of the movable chuck. The diameter of the b
11、ending block and the deflection rate of the movable chuck shall be determined according to the material and thickness of the test specimen. - Place the test specimen in the test machine (see figure 11. Bend the test specimen under the specified deflection rate of the movable chuck until the first cr
12、ack occurs in the centre part of the test specimen and measure the bending angles ao, a fl , if sgecified, and a f2. Angle a fl shall be measured within max. 1 h after surface treatment. 6 Expression of results - ductility after surface treatment : - final ductility : afl /ao x 100. in % af2 /ao x 1
13、00, in % 6 Fault sanction The value of final ductility shall be specified in the process standard. 7 Test report It shall include the following : - reference to this standard; - reference numbers of the test specimens; - nature of the coating; - thickness of the coating; - diameter of the bending bl
14、ock and deflection rate of the movable chuck; - values of bending angles measured; - test result. . I CEN EN12831 93 3404583 0042bb0 4Lb = Block 1 Ten specimen l i -3- EN 2831:1993 Block I - . Fixed *u& Movable chuck R of the bending block Figure 1 - Placing of the test specimen before testing * /- Detail W I- 1 Fiure 2 - Bending angle prior to chemical or electrolytic treatment (TJ Detail W - Mirror-view r, Detail W I - L I 7 Figure 3 - Bending angle after surface treatment
