Special Steel For Semi-Trailer
From the forming methods, commercial vehicles beams can be divided into stamping beam, rolling beam, and welding beam. For stamping beam and rolling beam, the steels should have high cold forming performance. For welding beam, the steels should show good weldability.
Representataive Standard
The first pinyin letter of "Bao" in Baosteel Co., Ltd. is "B", and it also stipulates the value of the minimum tensile strength (unit MPa). The first letter "L" in Pinyin stands for beam."ST" stands for "Semi-trailer"
Mechanial Property
| Grade | Tensile Testa | 180° Bend Testb | |||
|---|---|---|---|---|---|
| Yield Strength ReL (MPa) | Tensile Strength Rm (MPa) | Elongation % | |||
| <3 | ≥3 | ||||
| B610L(B600L) | ≥500 | 610～760 | ≥15 | ≥18 | D=1.5a |
| B650L | ≥550 | 650～820 | ≥13 | ≥16 | D=1.5a |
| B700Ld | ≥600 | 700～880 | ≥12 | ≥14 | D=2a |
| B750Ld | ≥650 | 750～950 | ≥11 | ≥13 | D=2a |
a Transverse specimens are used for the tensile test. For nominal thickness <3 mm, elongation is measured on L0=80mm, b=20mm specimen; for ≥3 mm on L0=5.65√S0.
b Transverse specimens are used for the bend test. Bend specimen width b≥20mm; b=20mm for referee tests. D—mandrel diameter; a—specimen thickness.
c When the yield phenomenon is not obvious, Rp0.2 shall be used.
d When thickness t＞8mm, the specified minimum yield strength is allowed to decrease by 20MPa.
| Grade | Tensile Testa | 180° Bend Testb | V-notch Impact Testd | |||
|---|---|---|---|---|---|---|
| Yield Strength ReH (MPa)c | Tensile Strength Rm (MPa) | Elongation % | Test Temp. (℃) | Impact Energy KV2 (J) | ||
| BST700L | ≥650 | ≥700 | ≥15 | D=2a | -20 | ≥40 |
| BST750L | ≥700 | ≥750 | ≥14 | D=2a | -20 | ≥40 |
a Transverse specimens are used for the tensile test.
b Transverse specimens are used for the bend test. Bend specimen width b≥20mm; b=20mm for referee tests. D—mandrel diameter; a—specimen thickness.
c When the yield phenomenon is not obvious, Rp0.2 shall be used. Elongation is measured on L0=5.65√S0 specimen. When thickness t＞8mm, the specified minimum yield strength is allowed to decrease by 20MPa.
d Longitudinal specimens are used for the impact test.
Chemical Composition
| Grade | Chemical composition (mass fraction), % | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| C | Mn | Si | P | S | Alta | Nba | Va | Tia | |
| B590L | ≤0.12 | ≤1.80 | ≤0.50 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.15 |
| B610L(B600L) | ≤0.12 | ≤1.80 | ≤0.50 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.15 |
| B650L | ≤0.12 | ≤1.90 | ≤0.50 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.22 |
| B700L | ≤0.12 | ≤2.00 | ≤0.60 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.22 |
| B750L | ≤0.12 | ≤2.10 | ≤0.60 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.22 |
| BST700L | ≤0.20 | ≤1.80 | ≤0.50 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.22 |
| BST750L | ≤0.20 | ≤2.10 | ≤0.60 | ≤0.025 | ≤0.015 | ≥0.015 | ≤0.09 | ≤0.20 | ≤0.22 |
a One or several alloying elements among Nb, V and Ti may be added to the steel; in this case the lower limit of Alt is not required, but Nb+V+Ti≤0.22.
Fabrication and Delivery Conditions
For these aspects, they depend on your specific requirements. Please contact us and we will provide you with professional advice and services.
