Q690 steel and material Q690M is a Chinese GB standard high strength low alloy structural steel and is divided into 3 quality grades: Q690C, Q690D and Q690E “Q” means yield strength, “690” refers to 690 Mpa, Tensile strength is 770-940 Mpa, “M” is the abbreviation of “TMCP” (thermal mechanical control processing), for data sheet and specifications, please refer to the following tables.
Steel plates made of Q690 material have high yield and tensile strength and are widely used in coal mine machinery and engineering machinery such as hydraulic support, port cranes, flatbed trucks and so on.
Chemical Composition of Q690 Steel
The chemical composition of Q690C, Q690D, Q690E is shown in the following table.
| Chemical Composition Q690 (%) | ||||||||||||||||
| Steel Grade | Quality grade | W | Yes | Mn | P | s | No. | V | You | Cr | No | Ass | N | Mo | B | Al |
| Q690 | Q690C | ≤ 0.18 | ≤ 0.60 | ≤ 2.00 | ≤0.030 | ≤0.030 | ≤ 0.11 | ≤ 0.12 | ≤ 0.20 | ≤ 1.00 | ≤ 0.80 | ≤ 0.80 | ≤ 0.015 | ≤ 0.30 | ≤ 0.004 | ≥ 0.015 |
| Q690D | ≤0.030 | ≤0.025 | ||||||||||||||
| Q690E | ≤0.025 | ≤0.020 | ||||||||||||||
Q690 Carbon Equivalent Value (CEV): ≤0.49% (including C, D, E; all diameters)
Mechanical Properties of Q690 Steel
| Yield strength Q690 (≥N/mm2); Thickness or Diameter. d (mm) | ||||||
| Standard | Steel Grade | Quality | d≤16 | 16 |
40 |
63 |
| GB/T 1591 – 2008 | Q690 | C, D, E | 690 | 670 | 660 | 640 |
| GB/T 1591 – 2018 | Q690M | C, D, E | 690 | 680 | 670 | 650 |
| Tensile strength Q690 (N/mm2); d (mm) | Stretching | |||||
| Standard | Steel Grade | Quality | d≤40 | 40 |
63 |
% |
| GB/T 1591 – 2008 | Q690 | C, D, E | 770-940 | 750-920 | 730-900 | ≥14 |
| GB/T 1591 – 2018 | Q690M | C, D, E | 770-940 | 750-920 | 730-900 | ≥14 |
1MPa = 1N/mm2
Q690M: “M” stands for TMCP (Mechanical Thermal Control Processing)
Welding crack sensitivity index (Pcm): ≤0.25% (only for bars)
Charpy Impact Test of Q690 Material
| Charpy Impact Test (V) – Test temperature and energy absorbed by impact | ||||
| Note | Quality grade | Test temperature. (℃) | Thickness | Absorbed Energy (KV2/J) |
| Q690 Steel | Q690C | 0 | 12mm-150mm | ≥55 |
| Q690D | -20 | ≥47 | ||
| Q690E | -40 | ≥31 | ||
| Impact test for collecting longitudinal samples. | ||||
