What Is S890Q Steel Plate?
S890Q is a quenched and tempered high strength structural steel plate specified in EN 10025-6, the part of the European standard that covers flat products with high yield strength in the quenched and tempered condition. The designation reads in three parts: S for structural steel, 890 for the minimum yield strength expressed in MPa, and Q for the quenched and tempered delivery condition. The grade is registered under material number 1.8940 and is normally supplied in thicknesses from 6 mm to 150 mm, depending on mill capability and rolling width.
During production the plate is austenitised, water quenched into a martensitic structure and then tempered at a controlled temperature. The result is a tempered martensite or tempered bainite microstructure that delivers a very high yield strength while retaining enough ductility and fracture toughness for welded heavy duty structures. That balance is what allows a designer to replace a thick S355 or S460 section with a much thinner S890Q section and still carry the same load.
Mechanical Properties and Chemical Composition
The values below reflect the minimum requirements of EN 10025-6 for S890Q. Yield strength is thickness dependent, so heavier plates are permitted slightly lower values than thin plates.
| Property | Requirement |
|---|---|
| Minimum yield strength ReH, t ≤ 50 mm | 890 MPa |
| Minimum yield strength ReH, 50 < t ≤ 100 mm | 830 MPa |
| Minimum yield strength ReH, 100 < t ≤ 150 mm | 780 MPa |
| Tensile strength Rm | 940 - 1100 MPa |
| Elongation A5 | ≥ 10 % |
| Charpy V impact, S890Q | ≥ 30 J at −20 °C |
| Charpy V impact, S890QL and S890QL1 | ≥ 30 J at −40 °C and −60 °C |
| Typical hardness | 290 - 350 HB |
The chemistry is a low alloy, low impurity balance rather than a heavily alloyed one. Sulphur and phosphorus are tightly restricted to keep toughness and weldability predictable, and the carbon equivalent is controlled to a maximum of about 0.65 for plates up to 50 mm thick.
| Element (ladle analysis) | Maximum, % |
|---|---|
| Carbon C | 0.20 |
| Silicon Si | 0.80 |
| Manganese Mn | 1.70 |
| Phosphorus P | 0.020 |
| Sulphur S | 0.010 |
| Chromium Cr | 1.50 |
| Nickel Ni | 2.00 |
| Molybdenum Mo | 0.70 |
Design Benefits: Strength to Weight and Weight Reduction
Because the allowable stress of S890Q is roughly two and a half times that of S355, a component can be redesigned with far less cross sectional area. In crane booms, lifting frames, excavator arms and heavy transport equipment, moving from a conventional structural grade to S890Q typically removes 20 to 40 percent of the steel weight while maintaining or increasing the rated load.
Thinner plates at equal load bearing capacity
Lower dead load transferred to foundations, supports and axles
Higher payload for mobile cranes and trailer mounted equipment
Smaller weld volumes and shorter fabrication time
Reduced fuel consumption and lower life cycle emissions for transport equipment
The savings go beyond material cost. Lighter structures need smaller bearings, lighter slewing rings and less powerful drives, which compounds the benefit through the whole machine design.
Weldability and Fabrication Practice
S890Q sits at the practical upper end of weldable structural steels. It is easier to fabricate than S960Q because its carbon equivalent and hardness are lower, which widens the safe welding window and reduces the risk of hydrogen induced cold cracking.
Use low hydrogen consumables matched to the parent plate strength and keep them dry.
Apply preheat according to plate thickness, ambient temperature and joint restraint.
Control heat input and interpass temperature so the heat affected zone keeps its toughness.
Avoid sharp weld toes and other stress raisers in highly loaded details.
Use flame or plasma cutting with controlled parameters, then grind cut edges where fatigue matters.
Qualified welding procedure specifications are normal practice for this grade, and they should always be confirmed against the actual plate thickness and joint design before production starts.
Typical Applications and Grade Comparison
S890Q is chosen where dead weight must be minimised and loads are very high.
Crane booms, lattice masts and lifting equipment
Mining trucks, excavator booms and drilling rig masts
Mobile concrete pumps and heavy trailer frames
Bridge bearing zones, link plates and heavy connection nodes
Wind turbine installation equipment and offshore handling frames
| Grade | Minimum yield strength | Tensile strength | Relative notes |
|---|---|---|---|
| S690Q | 690 MPa | 770 - 940 MPa | Widely available, higher ductility |
| S890Q | 890 MPa | 940 - 1100 MPa | Best balance of strength and weldability |
| S960Q | 960 MPa | 980 - 1150 MPa | Highest strength, narrower fabrication window |
Compared with S690Q, upgrading to S890Q allows further thickness reduction at unchanged load capacity. Compared with S960Q, S890Q accepts a more forgiving welding procedure, which is often worth more on site than the last 70 MPa of yield strength.
Inspection, Certification and Frequently Asked Questions
Plates are normally delivered with an EN 10204 3.1 inspection certificate covering heat analysis, tensile results and impact testing. Ultrasonic testing, dimensional reports, third party witness and 3.2 certification can be arranged before shipment for projects that require independent verification. Marking includes the steel grade, heat number and plate identity, and plates should be stored dry with edge protection for long term outdoor storage.
Q: What is S890Q steel plate?
S890Q is a quenched and tempered structural steel plate to EN 10025-6 with a minimum yield strength of 890 MPa, supplied in thicknesses up to about 150 mm.
Q: What is the EN material number of S890Q?
S890Q corresponds to the European material number 1.8940.
Q: What is the difference between S890Q, S890QL and S890QL1?
All three have the same strength class. S890Q is impact tested at minus 20 degrees Celsius, S890QL at minus 40 degrees Celsius and S890QL1 at minus 60 degrees Celsius.
Q: Can S890Q steel plate be welded?
Yes. Welding is routine when procedures use low hydrogen consumables, suitable preheat, controlled heat input and qualified welding procedure specifications.
Q: Is S890Q suitable for pressure vessels?
No. S890Q is a structural steel. Pressure equipment must use grades specified in dedicated pressure vessel standards such as EN 10028.
Q: Can S890Q replace S690Q to save weight?
Yes. The higher yield strength allows thinner plates for the same load capacity, which is particularly valuable in mobile and lifting equipment.
Q: How should S890Q plates be cut and machined?
Flame cutting, plasma cutting and machining are all possible. Parameters must be controlled so that the cut edge and heat affected zone keep acceptable hardness and toughness.
