Boron-alloyed quenched and tempered steel
General Information
These steel grades belong according to DIN EN ISO 683-2 to the product category of quenched & tempered steels, and features outstanding forming properties in the soft delivery state and high strength after heat treatment (hardening). The materials strength is propagated by adding a small fraction of boron to the carbon, manganese and chromium composition. Currently, Salzgitter Flachstahl can supply manganese-boron Steels of 10MnB5 to 46MnB5 and customer-specific analysis variants by arrangement.
Form of delivery
This steel grade is available as hot rolled coil (pickled, unpickled) in nominal thicknesses of 2.0 to 12.70 mm and in widths according to the Salzgitter Flachstahl delivery program.
Chemical composition (melt analysis in percent by weight)
Range of chemical composition guaranteed
(differing ranges by prior Agreement)
Steel grade | C | Mn | Si | P | S | Cr | Cu | Ti | B | |
max. | max. | max. | ||||||||
10MnB5 | 0,06 - 0,12 | 0,60 - 1,00 | 0,10 - 0,35 | 0.02 | 0.007 | 0,25 - 0,55 | 0.150 | 0,010 - 0,045 | 0,0010 - 0,0050 | |
20MnB5 | 0,15- 0,22 | 1,05 - 1,40 | 0,30 - 0,45 | 0.02 | 0.007 | 0,20 - 0,40 | 0.180 | 0,010 - 0,045 | 0,0010 - 0,0050 | |
20MnB51) | 0,17 - 0,23 | 1,10 - 1,40 | ≤ 0,40 | 0.025 | 0.035 | - | 0.400 | - | 0,0008 - 0,0050 | |
22MnB5 | 0,20 - 0,27 | 1,10 - 1,40 | 0,15 - 0,35 | 0.02 | 0.007 | 0,10 - 0,25 | 0.150 | 0,010 - 0,045 | 0,0008 - 0,0050 | |
26MnB5 | 0,22 - 0,29 | 1,15 - 1,45 | 0,15 - 0,35 | 0.02 | 0.006 | 0,05 - 0,25 | 0.150 | 0,010 - 0,045 | 0,0010 - 0,0050 | |
27MnCrB5-21) | 0.24 - 0.30 | 1.10 - 1.40 | ≤ 0.40 | 0.025 | 0.035 | 0.30 - 0.60 | 0.4 | - | 0.0008 - 0.0050 | |
27MnCrB5-2 | 0.25 - 0.30 | 1.15 - 1.40 | 0.15 - 0.35 | 0.02 | 0.007 | 0.30 - 0.50 | 0.15 | 0.015 - 0.050 | 0.0010 - 0.0050 | |
30MnB51) | 0.27 - 0.33 | 1.15 - 1.45 | ≤ 0.40 | 0.025 | 0.035 | - | 0.4 | - | 0.0008 - 0.0050 | |
30MnB5 | 0.27 - 0.33 | 1.15 - 1.45 | 0.15 - 0.35 | 0.02 | 0.007 | 0.05 - 0.25 | 0.15 | 0.015 - 0.045 | 0.0010 - 0.0050 | |
34MnB5 | 0.32 - 0.38 | 1.15 - 1.45 | 0.15 - 0.35 | 0.02 | 0.006 | 0.05 - 0.25 | 0.15 | 0.015 - 0.045 | 0.0008 - 0.0050 | |
37MnB52) | 0.34 - 0.40 | 1.15 - 1.45 | 0.15 - 0.35 | 0.02 | 0.007 | ≤ 0.25 | 0.15 | 0.030 - 0.060 | 0.0008 - 0.0050 | |
39MnB51) | 0.36 - 0.42 | 1.15 - 1.45 | ≤ 0.40 | 0.025 | 0.035 | - | 0.4 | - | 0.0008 - 0.0050 | |
40MnB5 | 0.36 - 0.43 | 1.05 - 1.40 | 0.15 - 0.35 | 0.02 | 0.005 | 0.35 - 0.60 | 0.2 | 0.020 - 0.055 | 0.0008 - 0.0050 | |
46MnB4 | 0.43 - 0.51 | 0.50 - 1.0 | ≤ 0.25 | 0.02 | 0.015 | 0.10 - 0.40 | 0.18 | 0.015 - 0.045 | 0.0008 - 0.0050 | |
33MnCrB5-21) | 0.30 - 0.36 | 1.20 - 1.50 | ≤ 0.40 | 0.025 | 0.035 | 0.30 - 0.60 | 0.4 | - | 0.0008 - 0.0050 |
Typical mechanical properties derived from tensile tests transversal to rolling direction (reference value for a hot rolled coil)
Steel grade | Yield strength Rp0.21) | Tensile strength Rm1) | Total elongation A1) | Yield strength Rp0,22) | Tensile strength Rm2) | Total elongation A52) | |
[MPa] | [MPa] | A80 [%] | A5 [%] | [MPa] | [MPa] | [%] | |
10MnB4 | 280 - 490 | 470 - 570 | ≥ 16 | ≥ 20 | 270 - 460 | 450 - 550 | ≥ 18 |
20MnB5 | 310 - 530 | 500 - 700 | ≥ 15 | ≥ 19 | 300 - 520 | 480 - 680 | ≥ 16 |
22MnB5 | 330 - 600 | 520 - 750 | ≥ 12 | ≥ 15 | 320 - 580 | 480 - 730 | ≥ 14 |
26MnB5 | 350 - 580 | 580 - 740 | ≥ 10 | ≥ 14 | 340 - 570 | 500 - 720 | ≥ 11 |
27MnCrB5-2 | 350 - 700 | 580 - 850 | ≥ 10 | ≥ 12 | 350 - 630 | 570 - 800 | ≥ 10 |
30MnB5 | 380 - 600 | 610 - 780 | ≥ 10 | ≥ 12 | 340 - 590 | 580 - 760 | ≥ 11 |
34MnB5 | 330 - 620 | 600 - 820 | ≥ 9 | ≥ 11 | 320 - 620 | 600 - 800 | ≥ 10 |
37MnB5 | 380 - 640 | 630 - 830 | ≥ 12 | 380 - 620 | 630 - 810 | ≥ 11 | |
40MnB5 | 390 - 800 | 600 - 950 | ≥ 7 | ≥ 11 | 380 - 700 | 600 - 900 | ≥ 9 |
(46MnB4) | 420 - 800 | 690 - 960 | ≥ 10 | 400 - 780 | 670 - 900 | ≥ 9 | |
33MnCrB5-2 | 330 - 600 | 550 - 820 | ≥ 12 | 320 - 580 | 520 - 790 | ≥ 11 |
Microstructure
These boron-alloyed quenched and tempered steel grades in hot rolled state usually have a ferritic-pearlitic microstructure with a typical grain size of > 9 according to DIN EN ISO 643.
Examples of usage
Thanks to the combination of formability and temperability, the automotive industry takes advantage of these steel grades especially for the production of supporting body parts (motor vehicles) and other safety-relevant components. Examples are the B-pillar, side impact protection, chassis components or bumpers.
Within the automotive industry, welded precision tubes made of these steel grades are, for instance, used to make stabilizers, axle driving or gearbox shaft and other parts relevant to passive security. Another application field for them is the production of boiler tubes.
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