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Stainless Steel Fastener Material Properties

 

 

 

 

 

Stainless steel grade and property classes regarding screws and nuts

Stainless steel fasteners available

Steel Type

Material

Abbreviation

Aisi type

A1

1.4305

X 8 CrNiS 18-9

AISI 303

A2

1.4301

1.4303

X 5 CrNi 18-10

X 4 CrNi 18-12

AISI 304

AISI 305

A3

1.4541

X 6 CrNiTi 18-10

AISI 321

A4

1.4401

1.4404

X 5 CrNiMo 17-12-2

X 2 CrNiMo 17-12-2

AISI 316

AISI 316 L

A5

1.4571

X 6 CrNiMoTi 17-12-2

AISI 316 Ti

 

Crystalline Structure of Martensitic

C

1.4122

X 35 CRMo 17

 

 

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

 

 

 

 

 

 

 

 

 

 

Steel Group

Austenic

 

Martensitic

 

Ferritic

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Steel Grade

A1

A2*

A3

A4*

A5

 

C1

    C4

 

C3

F1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Class

50

 

   70

 

80

 

50

70

110

 

50

70

 

80

45

60

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Property Resistance

Softened

Hardened

Strongly hardened

 

Softened

Tempered

Softened

tempered

Softened

Hardened

 

 

  • L  is added to the description of all stainless steel with  low carbon

 

                                                           

 

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