Q690D high-strength steel plate is a high-yield-strength structural steel that has undergone quenching and tempering (Q&T) treatment. Renowned for its exceptional mechanical properties and low-temperature impact toughness, this steel grade is widely utilized in engineering machinery, mining equipment, and bridge construction. In international trade, the precise control of tolerances is critical for ensuring structural integrity and facilitating weight calculations.
What Is Q690D High-Strength Steel Plate?
Q690D is a low-alloy, high-strength structural steel plate that has been quenched and tempered; it features a minimum yield strength of 690 MPa and is specifically designed for heavy-load applications and low-temperature environments (down to -20°C). Renowned for its high strength, excellent toughness, and superior weldability, this steel plate is widely utilized in the lightweight manufacturing of large-scale construction machinery, lifting equipment, and mining machinery.
Chemical Composition of Q690D High-Strength Steel Plate
| Element | Q690D Max Content (wt%) |
|---|---|
| Carbon (C) | ≤ 0.18 |
| Silicon (Si) | ≤ 0.60 |
| Manganese (Mn) | ≤ 2.0 |
| Phosphorus (P) | ≤ 0.030 |
| Sulfur (S) | ≤ 0.025 |
| Nickel (Ni) | ≤ 0.80 |
| Chromium (Cr) | ≤ 1.00 |
| Molybdenum (Mo) | ≤ 0.30 |
| Niobium (Nb) | ≤ 0.11 |
| Vanadium (V) | ≤ 0.12 |
| Titanium (Ti) | ≤ 0.020 |
| Boron (B) | ≤ 0.004 |
| Aluminum (Al) | ≥ 0.015 |
Mechanical Properties of Q690D High-Strength Steel Plate
| Plate Thickness (mm) | Yield Strength, min (MPa) | Tensile Strength (MPa) | Elongation, min (%) | Impact Energy AKV at -20°C, min (J) | Cold Bend 180° |
|---|---|---|---|---|---|
| ≤ 16 | ≥ 690 | 770–940 | ≥ 14 | ≥ 47 | d = 3a |
| 16–40 | ≥ 670 | 770–940 | ≥ 14 | ≥ 47 | d = 3a |
| 40–63 | ≥ 660 | 770–940 | ≥ 14 | ≥ 47 | d = 3a |
| 63–80 | ≥ 640 | 730–940 | ≥ 14 | ≥ 47 | d = 3a |
Why Tolerance Matters Q690D High-Strength Steel Plate?
Structural Integrity and Fatigue Resistance: Small variations in thickness can lead to significant stress concentrations. Because high-strength steels are often more sensitive to defects, maintaining tight gauge tolerances is essential to prevent fatigue crack growth and brittle fractures.
Load-Bearing Performance: Q690D is designed for high-stress applications such as bridge engineering and crane booms. Inaccurate thickness (usually required within a precise ±5% for heavy plates) can weaken the effective cross-sectional area,reducing the overall safety factor.
Assembly and Weight Reduction: Q690D allows for thinner, lighter structures. Tight tolerances guarantee that large, prefabricated steel parts fit together accurately, preventing costly modifications on-site.
Low-Temperature Safety (Grade D): Q690D is tailored for low-temperatureapplications (impact tested at -20°C). Dimensional precision is crucial to ensure thatthe material's structural behavior remains consistent, avoiding failure in harshenvironments.
Thickness Tolerance Standards of Q690D High-Strength Steel Plate
Our Q690D steel plates are manufactured strictly according to GB/T 709 (equivalent to EN 10029). The thickness tolerance is generally divided into four classes (Class A, B, C, D).
Class A (Standard): Most common for general engineering.
Class B (Tight): Narrower negative tolerance.
Class C (Positive Only): Guaranteed no negative tolerance (Thickness ≥ Nominal thickness).
Class D (Symmetrical): Even distribution of positive and negative values.
Typical Tolerance Table (Reference)
| Nominal Thickness (mm) | Class A Tolerance (mm) | Class C Tolerance (mm) |
| 10mm - 15mm |
±0.45 |
-0.0 / +0.90 |
| 15mm - 25mm |
±0.55 |
-0.0 / +1.10 |
| 25mm - 40mm |
±0.70 |
-0.0 / +1.40 |
| 40mm - 60mm |
±0.85 |
-0.0 / +1.70 |
Width and Length Tolerances of Q690D High-Strength Steel Plate
For hot-rolled Q690D plates, the width and length tolerances are typically positive to ensure the customer has sufficient material for final machining
Width Tolerance: Usually -0mm / +20mm (Mill edge) or -0mm / +5mm (Trimmed edge).
Length Tolerance: Usually -0mm / +30mm depending on the plate length.
If you require further details regarding our Q690D high-strength steel plate, please do not hesitate to contact us.
As a leading manufacturer of Q690D high-strength steel plate in China, GNEE boasts over 20 years of extensive industry experience. Our warehouses maintain a standing inventory of over 50,000 tons year-round, ensuring that orders can be dispatched in as little as seven days. In terms of quality assurance, we are a dual-certified supplier holding both API and ISO certifications, and we welcome inspections by third-party agencies such as SGS, BV, and Lloyd's.
By choosing our Q690D high-strength steel plate products, you will benefit from our comprehensive, customer-centric support services, as well as our extensive value-added processing capabilities. We would be delighted to provide full-scale support and assistance for your project.
Contact now to get Q690D high-strength steel plate
| Specification | Width: 600-3000mm Thickness:2mm-100mm or as customers' special requirements; |
| Length | Length 1000-12000mm or as customers' special requirements |
| Grade | Q690D |
| Standards | GB/T24186-2009, Q/OHAC 839-2021, GB/T709-2006, ASTM A36, JIS G4051,DIN EN10083, SAE 1045, ASTM A29M |
| Surface | Smooth, straight, bright, no blur on both ends |
| Packaging | Standard exporting packing or as client's requirement |
| Certificate | ISO9001:2008 |
| Processing technique |
1.Heat treatment facilities for hot-rolled, controlled rolling,normalizing. 2.Annealing, tempering, quenching, normalizing plus tempering, quenching and tempering. 3. Other delivery states are available as customers' requirement. |
| Feature of hot rolled steel plate |
1.Heat conduction. 2.Excellent freezing, even structure with pressure resistance. 3.Good mechanical properties |
| Excellent performances |
1.High strength, good toughness. 2.Easy for molding process and good weld ability. |
| Main application |
1.Automobile, Bridges, Buildings. 2.Machinery, Pressure vessel industries. 3.Ship building, Engineering construction. 4.Mechanical manufacturing, Pavement slab, ect. |
What are the equivalent grades of Q690D in international standards?
Its equivalent grades include S690QL (EN standard), ASTM A514 (certain grades) in the US, and JIS SHY685 in Japan.
What are the main application fields of Q690D?
It is widely used in coal mining machinery, construction machinery (such as crane booms), offshore platforms, pressure vessels, bridge structures, and heavy-duty truck chassis.
What should be noted when cutting Q690D steel plates?
Laser or plasma cutting is recommended. If oxy-fuel cutting is used, preheating the thick plates is advised to prevent cold cracking at the cut edges.
What is the typical hardness of Q690D?
The hardness of Q690D after quenching and tempering is typically around 230-280 HBW (for reference only, as standards primarily focus on strength indicators).