What Is S690QL Plate?
S690QL plate is a high-yield-strength structural steel grade produced in accordance with EN 10025-6. The material number is 1.8928. The designation works as follows: S means structural steel, 690 is the minimum yield strength in MPa, Q denotes the quenched and tempered delivery condition, and L means impact energy is tested at −40 °C.
The grade provides an excellent combination of high strength, toughness, abrasion resistance and weldability. Because of its high strength, structures can be designed lighter; for mobile applications such as cranes and lifting equipment, this translates into increased payload and operational efficiency.
Mechanical Properties
Table 1 shows the mechanical requirements commonly quoted for S690QL by nominal thickness.
| Nominal thickness (mm) | Min. yield strength (MPa) | Tensile strength (MPa) | Min. elongation (%) | Min. impact energy @ −40 °C |
|---|---|---|---|---|
| 3 ≤ t ≤ 50 | 690 | 770 – 940 | 14 | 30 J longitudinal / 27 J transverse |
| 50 < t ≤ 100 | 650 | 760 – 930 | 14 | 30 J longitudinal / 27 J transverse |
| 100 < t ≤ 150 | 630 | 710 – 900 | 14 | 30 J longitudinal / 27 J transverse |
Chemical Composition
Table 2 lists the maximum element contents for S690QL. The quenched and tempered fine-grain design with low carbon equivalent (CEV max 0.83%) supports strength, toughness and weldability.
| Element (max, %) | Value |
|---|---|
| Carbon (C) | 0.20 |
| Silicon (Si) | 0.80 |
| Manganese (Mn) | 1.70 |
| Nickel (Ni) | 2.0 |
| Phosphorus (P) | 0.020 |
| Sulfur (S) | 0.010 |
| Chromium (Cr) | 1.50 |
| Molybdenum (Mo) | 0.70 |
| Vanadium (V) | 0.12 |
| Niobium (Nb) | 0.06 |
| Titanium (Ti) | 0.05 |
| Copper (Cu) | 0.50 |
| Zirconium (Zr) | 0.15 |
| Boron (B) | 0.005 |
| Nitrogen (N) | 0.015 |
| CEV | 0.83 |
Standard Equivalents
The table below lists the commonly quoted standard equivalents of S690QL (1.8928). Equivalences are approximate and acceptance is defined by the governing standard of the order.
| Region | Standard | Equivalent grade |
|---|---|---|
| EU | EN | S690QL (1.8928) |
| USA | ASTM | A709-100 |
| Germany | DIN, WNr | TStE690V |
| France | AFNOR | E690T, S690T, E690TFP |
| European old | EN | FeE690VKT |
| Sweden | SS | 2625 |
| International | ISO | E690 |
Fabrication: Bending and Welding
S690QL can be bent and formed using equipment rated for high-strength steel. Minimum bend radii and forming forces are larger than for ordinary structural steel, and springback must be considered. Hot forming should follow the limits recommended for quenched and tempered steels, typically not above about 600 °C, to preserve the mechanical properties.
Welding requires qualified procedures: matching or slightly under-matching consumables, controlled preheat and interpass temperatures, and limited heat input to avoid softening of the heat-affected zone. The low carbon equivalent (max 0.83%) keeps the weldability acceptable when these controls are applied.
Typical Applications
Earthmoving equipment
Dump trucks
Mobile cranes
Drilling rigs
High-speed fans
Bridges
Heavy transportation
Machine building and steel constructions
Lifting equipment
Frequently Asked Questions
What is the difference between S690QL and S690Q?
Both are quenched and tempered 690 MPa steels. S690Q is impact tested at −20 °C (30 J), while S690QL is tested at −40 °C (30 J longitudinal). QL is the better choice for cold-climate and offshore service.
What is S690 grade steel?
S690 is a high-yield, fine-grain, quenched and tempered structural steel with a minimum yield strength of 690 MPa, used in structures that must withstand very heavy loads where weight saving is important.
What is the material number of S690QL?
The material number is 1.8928 under EN 10025-6.
What are the equivalents of S690QL?
Commonly quoted standard equivalents are ASTM A709-100 (USA), TStE690V (Germany), E690T (France), SS 2625 (Sweden) and E690 (ISO).
Is S690QL weldable?
Yes, with qualified procedures for quenched and tempered steels: matched consumables, controlled preheat and heat input, and a limited carbon equivalent keep the joint sound.
What impact energy does the L designation guarantee?
At least 30 J longitudinal (27 J transverse) at −40 °C for the common thickness range.
