Stainless Steel Fastener Material Properties

Stainless steel grade and property classes regarding screws and nuts

Stainless steel fasteners available

Steel TypeMaterialAbbreviationAisi type
A11.4305X 8 CrNiS 18-9AISI 303
A21.43011.4303X 5 CrNi 18-10X 4 CrNi 18-12AISI 304AISI 305
A31.4541X 6 CrNiTi 18-10AISI 321
A41.44011.4404X 5 CrNiMo 17-12-2X 2 CrNiMo 17-12-2AISI 316AISI 316 L
A51.4571X 6 CrNiMoTi 17-12-2AISI 316 Ti

Crystalline Structure of Martensitic

C1.4122X 35 CRMo 17

The three principal material groups of stainless steel are:
austenic, martensitic, ferritic

Stainless Steel Fastener Material Properties

Stainless Steel Fastener Material Properties


Stainless Steel guidelines for assembling preload and tightening torques

Normal size thread

Steel grade property class 70

Steel Grade property class 80

Preload (N)

Tightening (Nm)

Preload (N)

Tightening (Nm)

M5

3.000

3.5

4.750

4.7

M6

6.200

6

6.700

8

M8

12.200

16

13.700

22

M10

16.300

32

22.000

43

M12

24.200

56

32.000

75

M16

45.000

135

60.000

180

M20

71.000

280

95.000

370

M24

105.000

455

14.000

605

M30

191.000

1050

255.000

1400

Material

A2/A4

Friction Coefficient

0.12

Proof Stress (Rp 0.2-A2/A4)

Rp 0.2 – A2/A4 – 70=450 N/mm2

                           80=600 N/mm2

Values

MA – Table *0.9 = MA – Max

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