Mechanical properties for bolts, screws and studs — Austenitic steel grades
ISO 3506-1:2009 (Externally Threaded Fasteners)

Group	Grade	Property Class	Size range	Min. Tensile Strength MPa	Stress at 0,2 % permanent strain min Mpa	Elongation after fracture min mm	Grade Identification Marking
Austenitic	A2	70	M6-M24	700	450	0.4d
Austenitic	A2	80	M6-M24	800	600	0.3d
Austenitic	A4	70	M6-M24	700	450	0.4d
Austenitic	A4	80	M6-M24	800	600	0.3d

 

 

Mechanical properties for nuts — Austenitic steel grades
ISO 3506-2:2009 (Internally Threaded Fasteners)

Metric Property Class	Grade	Property Class	Stress under proof load (Sp) min. Steel group Mpa	Grade Identification Marking
		Nuts with thk ≥ 0,8D	Nuts with thk ≥ 0,8D
Austenitic	A2	70	700
Austenitic	A2	80	800
Austenitic	A4	70	700
Austenitic	A4	80	800

 

 

Mechanical Properties Per ISO 898-1 (Externally Threaded Fasteners)

Group	Material	Size Range	Min. Proof Strength MPa	Min. Tensile Strength MPa	Core Hardness Rockwell		Min. Yield Strength MPa	Grade Identification Marking
					Min.	Max.
4.6	Low or medium carbon steel	M5 - M39	225	400 (58,000 PSI)	B67	B99.5	240
8.8	Medium carbon steel: quenched & tempered	M5 - M16 M18 - M39	580 600	800 (116,000PSI) 830 (120,000 , PSI)	C22 C23	C32 C34	640 660
10.9	Alloy steel: quenched & tempered	M5 - M39	830	1040 (150,800 PSI)	C32	C39	940
12.9	Alloy steel: quenched & tempered	M1.6 - M39	970	1220 (177,000 PSI)	C39	C44	1100

 

 

Mechanical Properties Per DIN 267 Part 4 (Internally Threaded Fasteners)

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