ISO 3506-2 Specification

This part of ISO 3506 specifies the mechanical properties of nuts 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 nuts: — with nominal thread diameter D 39 mm; — of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262; — of any shape; — with width across flats as specified in ISO 272; — with nominal heights in 0,5D. It does not apply to nuts requiring properties such as — locking abilities, and — weldability.

ISO 3506-2 Chemical Composition

Steel group Steel grade Chemical compositions
mass fraction, %		 Footnotes
c Si Mn p s Cr Mo Ni Cu
Austenitic A1 012 1 6.S 02 0,1Sto0.3S 16to 19 0.7 Sta 10 1,7S to2.2S bed
A2 010 1 2 O,OS 0.03 1S to 20   8 to 19 4 fg
A3 008 1 2 0,04S 0.03 17 to 19   9 to 12 1 h
A4 008 1 2 0,04S 0.03 16 to 18,S 2 to 3 10 to 1S 4 gi
AS 008 1 2 0,04S 0.03 16 to 18,S 2 to 3 10,S to 14 1 hi
Manensitic Cl 0,09 to 0,1S 1 1 O,OS 0.03 11,5 to 14 - 1 - i
C3 0,17 to 0,2S 1 1 004 003 16 to 18 - 1,Sto 2.S - -
C4 0,08 to 0,1S 1 1.S 006 0,1S to0.3S 12 to 14 06 1 - bi
Ferritic Fl 012 1 1 004 003 1S to 18 _j 1 - kt
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 *.s 5 x 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 i 10 x 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 a 5 x C up to 0,8 % maximum.
l. This may contain niobium (columbium) and/or tantalum 10 x C up to 1 % maximum.

ISO 3506-2 Mechanical properties for nuts — Austenitic steel grades

Steel group Steel grade Property class Stress under proof load
sp
min.
MPa
Nuts with
m ≥ 0,8D		 Nuts with
0,5D ≤ m < 0,8D		 Nuts with
      m ≥ 0,8D		 Nuts with
0,5D ≤ m < 0,8D
Austenitic A 1,A2,
A3,A4, AS		 50 025 500 250
70 035 700 350
80 040 800 400

ISO 3506-2 Mechanical properties for nuts — Martensitic and ferritic steel grades

Steel group Steel grade Property class Stress under proof load
sp
min.
MPa		 Hardness
Nuts with
m ≥ 0,8D		 Nuts with
0,5D ≤ m < 0,8D		 Nuts with
m ≥ 0,8D		 Nuts with
0,5D ≤ m < 0,8D		 HB HRC HV
Martensitic C1 50 025 500 250 147 to 209 - 155 to 220
70 - 700 - 209 to 314 20 to 34 220 to 330
110a 055a 1 100 550 - 36 to 45 350 to 440
C3 80 040 800 400 228 to 323 21to 35 240 to 340
C4 50 - 500 - 147 to 209 - 155 to 220
70 035 700 350 209 to 314 20 to 34 220 to 330
Ferritic F1,b 45 020 450 200 128 to 209 - 135 to 220
60 030 600 300 171 to 271 - 180 to 285
Note:

a. Hardened and tempered at a minimum tempering temperature of 275 °C.
b. Nominal thread diameter D 24 mm.