Page 678 - Mastik®

Typical values for allowable surface Surface pressure when mounted
pressures for different materials

The limit pressure per unit area should based on VDI 2230, edition of 2003 with typical values determined experimentally
not be exceeded when tightening the
screw or the nut otherwise the threaded Abbreviated term for Tensile strength Surface
connection can loosen as a result of the material EN designation Material number Rm min. pressure 1) 2)
2
2
seating effects. [N/mm ] PG [N/mm ]
USt 37-2 (S235 JRG1) 1.0036 340 490
St 50-2 (E295) 1.0050 470 710
Based on VDI 2230, 1986 edition, with
St 52-3U (S355 JO) 1.0553 510 760
proven limiting values
Cq 45 1.1192 700 630*
The values given apply to holes without 34 CrMo 4 1.7720 1000 870*
chamfers and with sufficiently large ex-
34 CrNiMo 6 1.6582 1200 1080*
ternal diameter for the tensioned part at
38 MnSi-VS 5-BY 1.5231 900 810*
room temperature.
16 MnCr 5 1.7131 1000 900*
X5 CrNi 18 12 1.4303 500 630
X5 CrNiMo 17 12 2 1.4401 510 460*
Materials Tensile Surface X5 NiCrTi 26 15 1.4980 960 860*
for the locking strength pressure 2)
NiCr20TiAl 2.4952 1000 700
parts Rm [N/mm ]PG [N/mm ]
2
2
GG-25 (GJL-250) 0.6020 250 900
St 37 370 260
GGG-40 (GJS-400-15) 0.7040 400 700*
St 50 500 420
C 45 800 700 GGG-50 (GJS-500-7) 0.7050 500 900*
GGG-60 (GJS-600-3) 0.7060 600 1000*
42 CrMo 4 1000 850
AlMgSi 1 F31 (AW-6082) 3.2315.62 290 260*
30 CrNiMo 8 1200 750
AlMgSi 1 F28 3.2315.61 260 230*
X 5 CrNiMo 18.10 500 to 700 210
AlMg4.5Mn F27 (AW-5083) 3.3547.08 260 230*
X 10 CrNiMo 18 9 500 to 750 220
AlZnMgCu 1.5 (AW-7075) 3.4365.71 540 410*
Titan, unlegiert 390 to 540 300
GK-AlSi9Cu3 3.2163.02 180 220*
GG 15 150 600
GD-AlSi9Cu3 3.2163.05 240 290*
GG 25 250 800
GK-AlSi7Mg wa 3.2371.62 250 380*
GG 35 350 900
AZ 91 (3.5812) 310 280*
GG 40 400 1100
TiAl6V4 3.7165.10 890 890*
GGG 35,5 350 480
DG MgAl 9 300 220
* Figures in italics have not yet been checked against the latest results from research and practice
GK MgAl 9 200 140
(TU Darmstadt).
AlZnMg Cu 0,5 450 370
1) Tightening procedures, supporting effects or the behaviour of anisotropic materials can often mean that a significantly higher value for pressure can be
permitted than the pressure liquid limits for the particular material. The much higher limiting surface pressures are supported by experience gained in
practice and should be checked for each specific case of application.
2) Boundary conditions which affect the surface pressure
Chamfer Chamfers at the hole (contact Power-operated screwdriver When tightening using a power
surfaces with the fastening screwdriver, for steels the
element) can for steels result permissible limiting value of
in permitted values for surface surface pressure can be up to
pressure up to 25% higher 25% lower!
being achieved (supporting
effect).
Guide values for surface condition in area of contact surfaces
(Roughness, shape and position tolerance)
Thread M4 M5 M6 M8 M10 M12 M16 M20
Rec. minimum edge distance c [mm] 6 7,5 9 12 15 18 24 30
maximum deviation from 0,04 0,08 0,08 0,09 0,11 0,13 0,17 0,21
rectangularity z [mm]
maximum roughness Ra x [μm] 3,2 3,2 3,2 3,2 3,2 3,2 3,2 6,3