This part of ISO 3506 specifies the mechanical properties of set screws and similar fasteners not under tensile stress made of austenitic stainless steel, 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 set screws and similar fasteners: — with nominal thread diameter 1,6 mm d ‘, 24 mm; — of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262; — of any shape. It does not apply to screws with special properties, such as weldability.
| Steel group | Steel grade | Chemical Composition ,a mass fraction,% | Footnotes | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| c | Si | Mn | p | s | Cr | Mo | Ni | Cu | |||
| Austenitic | A1 | 012 | 1 | 6,5 | 02 | 0,15 to 0,35 | 16 to 19 | 0.7 | 5 to 10 | 1,75 to 2.25 | bcd |
| A2 | 010 | 1 | 2 | 0,05 | 0.03 | 15 to 20 | 8 to 19 | 4 | fg | ||
| A3 | 008 | 1 | 2 | 0,045 | 0.03 | 17 to 19 | 9 to 12 | 1 | h | ||
| A4 | 008 | 1 | 2 | 0,045 | 0.03 | 16 to 18,5 | 2 to 3 | 10 to 15 | 4 | gi | |
| AS | 008 | 1 | 2 | 0,045 | 0.03 | 16 to 18,S | 2 to 3 | 10,S to 14 | 1 | hi | |
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 5 x C up to 0.8 % maximum for stabilization and be marked apvopnately as specified in this table. or shall contain niobium (columbium) and/or tantalum _ff 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 %.
| Nominal thread diameter d |
Minimum lengtha of set screws for test mm |
Hardness class | ||||
|---|---|---|---|---|---|---|
| 12H | 21H | |||||
| Flat point | Cone point | Dog point | Cup point | Proof torque,min. Nm |
||
| 16 | 25 | 3 | 3 | 25 | 003 | 005 |
| 2 | 4 | 4 | 4 | 3 | 006 | 01 |
| 25 | 4 | 4 | 5 | 4 | 018 | 03 |
| 3 | 4 | 5 | 6 | 5 | 025 | 042 |
| 4 | 5 | 6 | 8 | 6 | 08 | 14 |
| 5 | 6 | 8 | 8 | 6 | 17 | 28 |
| 6 | 8 | 8 | 10 | 8 | 3 | 5 |
| 8 | 10 | 10 | 12 | 10 | 7 | 12 |
| 10 | 12 | 12 | 16 | 12 | 14 | 24 |
| 12 | 16 | 16 | 20 | 16 | 25 | 42 |
| 16 | 20 | 20 | 25 | 20 | 63 | 105 |
| 20 | 25 | 25 | 30 | 25 | 126 | 210 |
| 24 | 30 | 30 | 35 | 30 | 200 | 332 |
a. The minimum lengths to be tested are the lengths below the dotted line in the product standard. i.e. the lengths having the normal hexagon socket depth.