③ 标准/对比页
Q690D vs Q690E: Same Strength, Colder Rating
Q690D and Q690E are the two common quality levels of Q690 high-strength steel under GB/T 1591-2018, delivered quenched-and-tempered or TMCP. Both guarantee 690 MPa minimum yield; they differ only in the temperature at which 34 J Charpy energy is verified — −20 ℃ for D, −40 ℃ for E.
Strength Floor and Tensile BandBoth variants hold a minimum yield of 690 MPa in the thinnest range, with tensile typically 770–940 MPa per GB/T 1591 — actual values on the mill test certificate govern. Plate runs 4–60 mm in our supply window, the thickness range where QT high-strength plate keeps its strength-to-toughness balance.
The D/E Split Is Pure TemperatureD verifies 34 J KV2 at −20 ℃; E pushes the same 34 J requirement down to −40 ℃. Chemistry and rolling route are engineered around that test temperature. For boom, pump-truck and carrier structures that work winters in Central Asia or on high plateaus, E is the safer call; temperate-market equipment runs D comfortably.
Delivery Condition MattersQ690 reaches its numbers in the quenched-and-tempered or TMCP route — this is not an as-rolled grade. Downstream flame cutting and welding need preheat and controlled cooling discipline; keep forming above the recommended temperature and plan for springback, because at the 690 MPa class the material punishes casual cold work.
Versus EN S690QLBuyers often map Q690 against EN S690QL. The honest framing: similar strength class, different delivery-condition systems — substitution needs design review, not a like-for-like swap. If the drawing says S690QL, send it over; we quote the GB route with full MTC traceability so the engineer can judge.
Ordering From YunhaoQ690D and Q690E ship in 4–60 mm, widths 1500–3200 mm, MOQ 25 t, 15–30 days from Tianjin or Qingdao, mill test certificate with each heat. Tell us the grade letter, thickness list and end use — crane boom, pump truck or carrier — and we confirm rolling route and test temperature before quoting.
| Item | Q690D | Q690E |
|---|---|---|
| Standard | GB/T 1591-2018 | GB/T 1591-2018 |
| Yield ReH (≤16 mm) | ≥690 MPa | ≥690 MPa |
| Tensile Rm | 770–940 MPa (per MTC) | 770–940 MPa (per MTC) |
| Charpy KV2 | ≥34 J at −20 ℃ | ≥34 J at −40 ℃ |
| Thickness (Yunhao) | 4–60 mm | 4–60 mm |