TECHNO BOLTS INDUSTRIESL.L.C.

Technical Information

Mechanical property reference tables for bolts, screws, studs and nuts, per the applicable ISO and DIN standards.

ISO 3506-1:2009

Bolts, Screws & StudsAustenitic Steel Grades

Externally threaded fasteners.

Grade	Property Class	Size Range	Min. Tensile Strength	Stress at 0.2% Permanent Strain, Min	Elongation After Fracture, Min	Grade Marking
A2	70	M6 – M42	700 MPa	450 MPa	0.4D
A2	80	M6 – M42	800 MPa	600 MPa	0.3D
A4	70	M6 – M42	700 MPa	450 MPa	0.4D
A4	80	M6 – M42	800 MPa	600 MPa	0.3D

ISO 898-1

Bolts, Screws & StudsCarbon & Alloy Steel Grades

Externally threaded fasteners.

Property Class	Material	Size Range	Min. Proof Strength	Min. Tensile Strength	Core Hardness (Rockwell)	Min. Yield Strength	Grade Marking
4.6	Low or medium carbon steel	M5 – M39	225 MPa	400 MPa	B67 – B99.5	240 MPa
8.8	Medium carbon steel, quenched & tempered	M5 – M16 M18 – M39	580 MPa 600 MPa	800 MPa 830 MPa	C22 – C32 C23 – C34	640 MPa 660 MPa
10.9	Alloy steel, quenched & tempered	M5 – M39	830 MPa	1040 MPa	C32 – C39	940 MPa
12.9	Alloy steel, quenched & tempered	M1.6 – M39	970 MPa	1220 MPa	C39 – C44	1100 MPa

ISO 3506-2:2009

NutsAustenitic Steel Grades

Internally threaded fasteners, nuts with thickness ≥ 0.8D.

Grade	Property Class	Stress Under Proof Load, Min	Grade Marking
A2	70	700 MPa
A2	80	800 MPa
A4	70	700 MPa
A4	80	800 MPa

DIN 267 Part 4

NutsCarbon Steel Grades

Internally threaded fasteners.

Property Class	Typical Material	Proof Stress	Core Hardness (Rockwell), Min	Grade Marking
Class 8	Low to medium carbon steel	800 MPa	C30
Class 10	Medium carbon steel, quenched & tempered	1000 MPa	C36
Class 12	Medium carbon steel, quenched & tempered	1200 MPa	C36

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