High-strength steels for cold-forming, thermomechanically-rolled

The steel grades of the S315MC to S700MC series are used for cold-formed components of the most varied designs. Their fields of application include the manufacture of:

• Longitudinal beams
• Frames
• Cold-pressed parts
• Cold-rolled sections
• Structural pipes

The user of these steel grades must make sure that his calculation, design and processing methods are appropriate for the material. The forming process used must be suitable for the intended application and comply with the state-of-the-art; it is of fundamental importance to the processing behaviour of these steel grades.

These low-perlite steel grades offer excellent bending, flanging, cold-bordering and folding properties in both longitudinal and transverse direction. The bending radii specified below should be observed as minimum values.

Europe	Material no.	D	F	I	GB	USA	Salzgitter Flachstahl	FK1)
EN 10149-2		SEW 092	NFA 36-231	UNI 8890	BS 1449 Sec. 1.4	ASTM A 1011/ SAE J 1392
S315MC	1.0972	-	E 315 D	-	HR 40F30	045 XLK	PSQ 32	B
	1.0974	QStE 340 TM	-	-	-	HSLAS-F Gr. 50 [340]/050 XLK	PSQ 34	B
S355MC	1.0976	-	E 355 D	Fe E 355 TM	HR 43F35	-	PSQ 36	B
	1.0978	QStE 380 TM	-	-	HR 46F40	-	PSQ 38	B
S420MC	1.0980	QStE 420 TM	E 420 D	Fe E 420 TM	-	HSLAS-F Gr. 60 [410]/060 XLK	PSQ 42	C
S460MC	1.0982	QStE 460 TM	-	-	HR 50F45	-	PSQ 46	C
S500MC	1.0984	QStE 500 TM	E 490 D	Fe E 490 TM	-	HSLAS-F Gr. 70 [480]/070	XLK PSQ 50	D
S550MC	1.0986	QStE 550 TM	E 560 D	Fe E 560 TM	-	HSLAS-F Gr. 80 [550]/080 XLK	PSQ 55	D
S600MC	1.8969	-	E 620 D	-	-	-	PSQ 60	D
S650MC	1.8976	-	-	-	-	-	PSQ 65	D
S700MC	1.8974	-	E 690 D	-	-	-	PSQ 70	D

¹⁾ FK = Tensile strength class

The following limitation shall additionally apply to all steel grades:
Nb ≤ 0,09 %, V ≤ 0,20 %, 
with the total of Nb, V and Ti not exceeding 0,22 %.

Grade	Smallest recommended bending radius bending angles ≤ 90°
	e1) ≤ 3	3 < e1) < 6	e1) > 6
S315MC	0,25 e	0,5 e	1,0 e
QStE 340 TM	0,25 e	0,5 e	1,0 e
S355MC	0,25 e	0,5 e	1,0 e
QStE 380 TM	0,25 e	0,5 e	1,0 e
S420MC	0,5 e 1	,0 e	1,5 e
S460MC	0,5 e	1,0 e	1,5 e
S500MC	1,0 e	1,5 e	2,0 e
S550MC	1,0 e	1,5 e	2,0 e
S600MC	1,0 e	1,5 e	2,0 e
S650MC	1,5 e	2,0 e	2,5 e
S700MC	1,5 e	2,0 e	2,5 e

¹⁾ Nominal thickness e [mm]

Grade	C	Si	Mn	P	S 1)	Altotal	Mo	Ti	B
	max.	max.	max.	max.	max.	min.	max.	max.	max.
S315MC	0,12	0,50	1,30	0,025	0,020	0,015	-	0,15	-
QStE 340 TM	0,12	0,50	1,30	0,025	0,010	0,015	-	-	-
S355MC	0,12	0,50	1,50	0,025	0,020	0,015	-	0,15	-
QStE 380 TM	0,12	0,50	1,50	0,025	0,010	0,015	-	-	-
S420MC	0,12	0,50	1,60	0,025	0,015	0,015	-	0,15	-
S460MC	0,12	0,50	1,60	0,025	0,015	0,015	-	0,15	-
S500MC	0,12	0,50	1,70	0,025	0,015	0,015	-	0,15	-
S550MC	0,12	0,50	1,80	0,025	0,015	0,015	-	0,15	-
S600MC	0,12	0,50	1,90	0,025	0,015	0,015	0,50	0,22	0,005
S650MC	0,12	0,60	2,00	0,025	0,015	0,015	0,50	0,22	0,005
S700MC	0,12	0,60	2,10	0,025	0,015	0,015	0,50	0,22	0,005

¹⁾ If agreed in the order, the sulphur content is 0,010 % max.

Grade	Min. yield strength	Tensile strength	Min. total elongation [%]
	MPa	MPa	L0 = 80 mm e2) < 3	L0 = 5,65 √S0 e2) ≥ 3
S315MC	315	390 - 510	20	24
QStE 340 TM	340	420 - 540	19	23
S355MC	355	430 - 550	19	23
QStE 380 TM	380	450 - 590	18	22
S420MC	420	480 - 620	16	19
S460MC	460	520 - 670	14	17
S500MC	500	550 - 700	12	14
S550MC	550	600 - 760	12	14
S600MC	600	650 - 820	11	13
S650MC	6502)	700 - 880	10	12
S700MC	7002)	750 - 950	10	12

¹⁾ The tensile test values apply to longitudinal samples for QStE 340 TM and QStE 380 TM in widths
    ≥ 600 mm tensile test values apply to transvers samples.
²⁾ In case the thickness is > 8 mm, the yield strength values may be reduced by 20 MPa.
³⁾ Nominal thickness e [mm]

If agreed in the order, the notch impact energy is proved using longitudinal samples at -20 °C. The average notch impact energy from 3 samples must be 40 J minimum. One individual value may fall short of the required minimum value by not more than 30 %. The sample width shall equal the product thickness if the latter is between 5 and 10 mm, the tests being performed using samples which are similar to Charpy-V samples. The required minimum values are to be reduced proportionally to the sample width.

Normalised and stress relief annealing above 580 °C with long holding times results in a reduction of yield strength and tensile strength as compared to the ‘as-delivered’ condition which is why such heat treatments should be avoided. It also follows that these steel grades are not suitable for hot-forming. If low-voltage annealing is necessary to compensate for the welding stresses, the recommended annealing time between 530 °C and 580 °C is 30 minutes for all product thicknesses and steel grades.

These steel grades can be welded both manually and using automatic equipment by means of all electrical welding processes provided the general technical rules are observed. No major hardness increases appear in the heat-affected zone. Preheating is not necessary under normal welding conditions and down to workpiece temperatures of +5 °C. Below +5 °C, pre-heating to 150 °C is recommended.

The welding wires and electrodes approved in the respective strength category must be used as filler metals.

In addition to this, the general meaning of the detailed information provided in ‘Stahl-Eisen-Werkstoffblatt’ (Iron and steel material sheet) 088 must be observed.