High-strength steels for cold-forming, thermomechanically rolled

Usage

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.

Standards

Europe Material no. DE US Salzgitter Flachstahl FK1)
EN 10149-2 SEW 092 VDA239-100 ASTM A 1011/ SAE J 1392
S315MC 1.0972 - HR300LA 045 XLK PSQ 32 B
1.0974 QStE 340 TM - HSLAS-F Gr. 50
[340]/050 XLK 		PSQ 34 B
S355MC 1.0976 - HR340LA - PSQ 36 B
1.0978 QStE 380 TM - - PSQ 38 B
S420MC 1.0980 QStE 420 TM HR420LA HSLAS-F Gr. 60
[410]/060 XLK 		PSQ 42 C
S460MC 1.0982 QStE 460 TM HR460LA - PSQ 46 D
S500MC 1.0984 QStE 500 TM HR500LA HSLAS-F Gr. 70
[480]/070 		XLK PSQ 50 D
S550MC 1.0986 QStE 550 TM - HSLAS-F Gr. 80
[550]/080 XLK 		PSQ 55 D
S600MC 1.8969 - - - PSQ 60 D
S650MC 1.8976 - - - PSQ 65 D
S700MC3) 1.8974 QStE 690 TM2) - - PSQ 70 D
  1. FK = Tensile strength class
  2. Based on DIN EN 10149-2

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.

Smallest bending radius

Grade Smallest recommended bending radius bending angles ≤ 90°1)
e ≤ 3 3 < e ≤ 6 e > 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]

Chemical composition in percent by weight [%] (Heat analysis)

Grade C Si Mn P S1) Altotal Mo Nb2) V2) Ti2) B
max. max. max. max. max. min. max. max. max. max. max.
S315MC 0.12 0.50 1.30 0.025 0.020 0.015 - 0.09 0.20 0.15 -
QStE 340 TM 0.12 0.50 1.30 0.025 0.010 0.015 - 0.09 - - -
S355MC 0.12 0.50 1.50 0.025 0.020 0.015 - 0.09 0.20 0.15 -
QStE 380 TM 0.12 0.50 1.50 0.025 0.010 0.015 - 0.09 - - -
S420MC 0.12 0.50 1.60 0.025 0.015 0.015 - 0.09 0.20 0.15 -
S460MC 0.12 0.50 1.60 0.025 0.015 0.015 - 0.09 0.20 0.15 -
S500MC 0.12 0.50 1.70 0.025 0.015 0.015 - 0.09 0.20 0.15 -
S550MC 0.12 0.50 1.80 0.025 0.015 0.015 - 0.09 0.20 0.15 -
S600MC 0.12 0.50 1.90 0.025 0.015 0.015 0.50 0.09 0.20 0.22 0.005
S650MC 0.12 0.60 2.00 0.025 0.015 0.015 0.50 0.09 0.20 0.22 0.005
S700MC 0.12 0.60 2.10 0.025 0.015 0.015 0.50 0.09 0.20 0.22 0.005
  1. If agreed in the order, the sulfur content is 0,010 % max.
  2. The total of Nb, V und Ti must not exceed 0.22 %.

Mechanical properties1)

Grade Yield strength Tensile strength Min. total elongation [%]2)
[MPa] [MPa] L0 = 80 mm L0 = 5,65 √S0
e < 3 e ≥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 ≥ 6503) 700 - 880 10 12
S700MC ≥ 7003) 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. e = Nominal thickness in mm 
  3. In case the thickness is > 8 mm, the yield strength values may be reduced by 20 MPa.

Notch impact energy

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 or 27 J at -40°C. 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.

Heat treatment

Normalized 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.

Welding

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, preheating 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.

Condition of delivery, scope of testing and certificate

The provisions of EN 10149-2 shall apply for delivery and inspection.
The products are delivered in a thermomechanically rolled condition.

Certificates according to DIN EN 10204 can be supplied as follows: IT, DUN, FAX, e-mail, paper.