France · AFNOR NF

S 550 Q

NF EN 10025-6 — Hot-rolled products of structural steels - Part 6 : technical delivery conditions for flat products of high yield strength structural steels in the quenched and tempered condition.

Chemical composition

Element	min	max	Similar	Remarks
Al	0.013		The minimum grain-refining element content of 0	The minimum grain-refining element content of 0
B		0.006
C		0.22
CEV		0.65	For product thickness t <= 50 mm; for product thickness 50 < t <= 100 mm CEV=0.77%; for product thickness 100 < t <= 150 mm CEV=0.83%.	For product thickness t <= 50 mm; for product thickness 50 < t <= 100 mm CEV=0.77%; for product thickness 100 < t <= 150 mm CEV=0.83%.
Cr		1.6
Cu		0.55
Mn		1.8
Mo		0.74
N		0.016
Nb		0.07
Ni		2.1
P		0.03
S		0.017
Si		0.86
Ti		0.07
V		0.14
Zr		0.17

Mechanical properties

Heat treatment / condition	Yield strength	Tensile strength	Elongation	Reduction of area	Impact energy	Hardness
heavy plates and wide flats, quenched and tempered					≥27 Charpy V Notch; -20°C; (trans.)；≥30 Charpy V Notch; 0°C; (trans.)；≥30 Charpy V Notch; -20°C; (long.)
heavy plates and wide flats, quenched and tempered, > 100 <= 150 mm	≥490 Yield stress is Upper Yield Stress (Reh)	590–770	≥16 Lo = 5		≥40 Charpy V Notch; 0°C; (long.)
heavy plates and wide flats, quenched and tempered, > 50 <= 100 mm	≥530 Yield stress is Upper Yield Stress (Reh)	640–820	≥16 Lo = 5		≥40 Charpy V Notch; 0°C; (long.)
heavy plates and wide flats, quenched and tempered, >= 3 <= 50 mm	≥550 Yield stress is Upper Yield Stress (Reh)	640–820	≥16 Lo = 5		≥40 Charpy V Notch; 0°C; (long.)

High/low temperature

Impact energy Kv/Ku (J)

Condition	Temperature ℃	min	Remarks
heavy plates and wide flats quenched and tempered	-20	27	Charpy V Notch; trans.
heavy plates and wide flats quenched and tempered	-20	30	Charpy V Notch; long.