1、 STD-BSI BS EN IS0 L3920-ENGL 1777 LL2Libb7 057781b 7T3 W BRITISH STANDARD Welding - General tolerances for welded constructions - Dimensions for lengths and angles - Shape and position The European Standard EN IS0 13920 : 1996 has the status of a British Standard ICs 25.160 NO COPYING WITHOUT BSI P
2、ERMISSION EXCEPT AS PERMITTED BY COPYRIGH LAU BS EN IS0 13920 : 1997 STD.BS1 BS EN IS0 L3920-ENGL 1997 Lb; Dial gauges - Design and metrological requirements prEN IS0 1101 Techni cal drawings - Geometrical to1 eranci ng To1 erances of form, orientation, location and run-out - Generalities, definitio
3、ns, symbols, indications on drawings (ISO/DIS 1101: 1995) IS0 3599 Vernier callipers reading to 0,l and 0,05 mn IS0 6906 Vernier callipers reading to 0,02 mn IS0 8015 Technical drawings - Fundamental tolerancing principle STD-BSI BS EN IS0 13920-ENGL 1997 m Lb24bb7 0577824 87T m Ovor Ovor Ovor 2 30
4、120 400 to1 oranco to up to up to el ass 30 120 400 %o0 Page 6 EN IS0 13920 : 1496 Ovor Over Ovar Over Ovor Ovar ovar 1000 2000 4000 8ooo 12000 16000 20000 up to up to up to up to up ta :bot” 4000 8000 12000 16000 20000 Definitions A E , C - I EI - -D - I, = - For the purposes of this standard the d
5、efinitions of prEN IC0 1101 apply - Tolorancot t In m il il f2 i3 i4 i5 f6 i7 I f8 f9 i2 i2 i3 i4 f6 f8 f 10 i 12 i 14 f 16 *l i3 f4 i6 i8 i 11 i 14 i 18 i 21 i 24 f 27 i4 f7 i9 f 12 i 16 i 21 f 27 f 32 f 36 i 40 4 General tolerances 4.1 Tolerances for linear dimensions See table 1. Table 1: Toleran
6、ces for linear dimensions * rn 4.2 Tolerances for angular dimensions lhe length of the shorter angle leg shall be used to determine in accordance with table 2 which tolerances are to apply. The length of the leg may also be assumed to extend to a specified reference point. In this case, the referenc
7、e point concerned shall be indicated on the drawing. Jee table 2 for the relevant tolerances. Figures 1 to 5 show examples of how the shorter angle leg, 1, is represented. STD-BSI BS EN IS0 13720-ENGL 1977 m LbZqbb7 0577825 70b m Up to 400 Page 6 EN IS0 13920 : 1996 Over 400 up to 1000 Table 2: Tole
8、rances for angular dimensions f 20 f 45 i 1 Reference point Fiaun 1 i 15 f 10 f 30 i 20 i 45 f 30 Range of nominal sizes 1 in mn (length or shorter leg) i 130 f 115 f 1“ Over 1000 i 18 fol erance class A 6 C D A 6 C D l) The value indicated in mn/m corresponds to the tangent value of the general tol
9、erance. It is to be multiplied by the length, in m, of the shorter leg. f 13 i9 I I Tolerances Aa (in degrees and minutes) Calculated and rounded tolerances t, in mn/m) I I3 i6 I f 495 i 13 I f6 i 26 I f 22 I f 18 1 Reference point Fiaun 2 Reference point I I Fiin 3 -J I Reference point Tolarancat t
10、 In I E 0.5 . 1 1,s 2 3 4 5 6 7 8 F 1 1,5 3 4.5 6 8 10 12 14 16 G 1.5 3 5,s 9 11 16 20 22 25 2s H 2.5 5 9 14 18 26 32 36 40 40 I Figure 4 Page 7 EN IS0 13920 : 1996 F *rr 5. 4.3 Straightness, flatness and parallelism tolerances The straightness, flatness and parallelism tolerances as specified in th
11、e follo- wing table 3 apply both for the overall dimensions of a weldment, a welding assem- bly, or a welded structure, and also for sections for which the dimensions are i ndi cated. - Other tolerances of form and position, e.g. coaxiality and symnetry tolerances, have not been specified. If such t
12、olerances are required for reasons of func- _. - tion, they shall be indicated on the drawings as specified in prm ISO 1101. - _. i E * * Table 3: Straightness, flatness and parallel Ism tolerances rn I I Ranga of noriInal tlzar 1 .ln m (rolatar to longor tlda of tho surfaco) I t 1 I I I I i Page 8
13、EN IS0 13920 : 1996 5 Indications on drawings The designation of the selected tolerance class as specified in table 1 and table 2 (e.g. EN IS0 13920-8) or its combination with a tolerance class as spe- cified in table 3 (e.g. EN IS0 13920-BE), shall be entered in the appropriate area on the drawing.
14、 6 Testing 6.1 General Testing and measuring devices used shall be suitable and accurate for their intended purpose. - graduated steel straightedges; - tape measures; - straightedges; - squares; - vernier callipers (in accordance with IC0 1599 and IC0 6906); - dial gauges (in accordance with ISO/DIS
15、 463). Other testing and measuring devices may be used by agreement. The results of measurement may be influenced if they are obtained under unusual temperature or atmospheric conditions, e.g. large constructions in strong sun- 1 ight. The actual size of an angle shall be determined by applying suit
16、able measuring devices tangentially to the weldment, but away from the zone imnediately influ- enced by the weld. The deviation shall be derived from the difference between the nominal size and the actual size. The angular deviation may be measured in degrees and minutes, or in millimetres. 6.2 Stra
17、ightness The edge of the weldment and the straightedge shall be aligned in such a way that the greatest distance between the straightedge and the actual surface is at its miniinlrn!. The distance between the edge and the straightedge shall be measured (example see figure 6). Straightedge I hmax - hm
18、m s t 1 ,- Edge of weldment e Figure 6: Straightness test Page 9 EN IS0 13920 : 1996 6.3 Flatness The actual surface of the weldment and the measuring plane shall be aligned to each other in such a way that the greatest distance between the measuring plane and the actual surface is at its minimum. T
19、his may be effected, for example, with the aid of optical devices, tubular water levels, span wires, floor plates, surface plates, and machine beds. The distances between the actual surface and the measuring plane shall be measured (example see figure 7). p.* $(- Measuring plane Figure 7: Flatness t
20、est - - 6.4 Parallelism * The reference surface shall be aligned parallel to the reference plane. E m * A measuring plane shall be established parallel to the reference plane and apart from the weldment, using the measuring devices referred to in 6.3. lhe distances between the actual surface and the
21、 measuring plane shall be measured (example see figure 8). X Actual surface Figure 8: Parallelism test 7 Non-conform1 ties h, - h, S t Reference surface - Reference plane .- A decision on the acceptance of components not complying with this standard my be made on the basis of the suitability for the
22、ir intended purpose. - STD-BSI BS EN IS0 13920-ENGL 1997 m Lb24bb9 0579829 351 m BS EN IS0 13920 : 1997 List of references See national foreword o BSI 1996 BS EN IS0 13920 : 1997 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent Monal body responsibl
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