ISO 3506-1 Specification

This part of ISO 3506 specifies the mechanical properties of bolts, screws and studs made of austenitic, martensitic and ferritic steel grades of corrosion-resistant stainless steels, when tested over an ambient temperature range of 10 °C to 35 °C. Properties vary at higher or lower temperatures. This part of ISO 3506 applies to bolts, screws and studs ⎯ with nominal thread diameter d u 39 mm, ⎯ of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262, and ⎯ of any shape. It does not apply to screws with special properties, such as weldability.

ISO 3506-1 Chemical Composition

Steel group Steel grade Chemical Composition,a
mass fraction,%		 Footnotes
c Si Mn p s Cr Mo Ni Cu
Austenitic A1 0.12 1 65 02 0,15 to 0,35 16 to 19 07 S to 10 1,75 to 2,25 bed
A2 0.10 1 2 0.05 003 15 to 20 -e 8 to 19 4 fg
A3 0.08 1 2 0.045 003 17 to 19 -e 9 to 12 1 h
A4 0.08 1 2 0.045 003 16 to 18,5 2 to 3 10 to 15 4 gi
AS 0.08 1 2 0.045 003 16 to 18,5 2 to 3 10.5 to 14 1 hi
Martensitic C1 0,09 to 0.15 1 1 0.05 003 11.5 to 14 - 1 - i
C3 0,17to 0.25 1 1 0.04 003 16 to 18 - 1,5 to 2,5 - -
C4 0,08to 0.15 1 15 0.06 0,15 to 0,35 12 to 14 06 1 - bi
Ferritic F1 0.12 1 1 0.04 003 15 to 18 _j 1 - kl
Note:

a. Values are maximum, unless otherwise indicated.
b. Sulfur may be replaced by selenium.
c. If the nickel content is below 8 %, the minimum manganese content shall be 5 %. d. There is no minimum limit to the copper content, provided that the nickel content is greater than 8 %.
e. Molybdenum may be present at the discretion of the manufacturer. However, if for some applications limiting of the molybdenum content is essential, this shall be stated at the time of ordering by the purchaser.
f. If the chromium content is below 17 %, the minimum nickel content should be 12 %.
g. For austenitic stainless steels having a maximum carbon content of 0,03 %, nitrogen may be present to a maximum of 0,22 %.
h. This shall contain titanium W 5 × C up to 0,8 % maximum for stabilization and be marked appropriately as specified in this table, or shall contain niobium (columbium) and/or tantalum W 10 × C up to 1,0 % maximum for stabilization and be marked appropriately as specified in this table.
i. At the discretion of the manufacturer, the carbon content may be higher where required in order to obtain the specified mechanical properties at larger diameters, but shall not exceed 0,12 % for austenitic steels.
j. Molybdenum may be present at the discretion of the manufacturer.
k. This may contain titanium W 5 × C up to 0,8 % maximum.
l. This may contain niobium (columbium) and/or tantalum W 10 × C up to 1 % maximum.

ISO 3506-1 Mechanical properties for bolts, screws and studs — Austenitic steel grades

Steel group Steel grade Property
class		 Tensile
strength
Rm a
min.
MPa		 Stress at 0,2 °/o permanent strain
Rp0,2a min. MPa 		Elongation after
fracture Ab min.
mm
Austenitic A1,A2,
A3,A4,
AS		 50 500 210 0,6d
70 700 450 0,4d
80 800 600 0,3d
Note:

a. The tensile stress is calculated on the stress area (see Annex A).
b. This is determined according to 7.2.4, on the actual screw length and not on a prepared test piece.

ISO 3506-1 Mechanical properties for bolts, screws and studs — Martensitic and ferritic steel grades

Steel group Steel grade Property
class		 Tensile strength Rma
min.
MPa		 Stress at 0,2 % permanent strain
Rp0,2a min
MPa		 Elongation after fracture
Ab
min.
mm		 Hardness
HB HRC HV
Martensitic C1 50 500 250 0,2d 147 O 209 - 155 to 220
70 700 410 0,2d 209 to 314 20 to 34 220 to 330
110C 1 100 820 0,2d - 36 to 45 350 to 440
C3 80 800 640 0,2d 228 to 323 21 to 35 240 to 340
C4 50 500 250 0,2d 147 to 209 - 155 to 220
70 700 410 0,2d 209 to 314 20 to 34 220 to 330
Ferritic F1d 45 450 250 0,2d 128 to 209 - 135 to 220
60 600 410 0,2d 171 to 271 - 180 to 285
Note:

a. The tensile stress is calculated on the stress area (see Annex A).
b. This is determined according to 7.2.4, on the actual screw length and not on a prepared test piece.
c. Hardened and tempered at a minimum tempering temperature of 275 °C.
d. Nominal thread diameter d u 24 mm.