S890Q is a high strength quenched and tempered structural steel plate with a minimum yield strength of 890 MPa in the as-delivered condition. It belongs to the EN 10025-6 family of thermomechanically and thermally treated structural steels, and it is chosen when a structure has to carry very heavy loads while keeping its own weight under control.
Designation and Delivery Condition
The grade name follows European nomenclature and can be read directly:
S - structural steel.
890 - minimum yield strength of 890 MPa over the thinner part of the delivery range.
Q - quenched and tempered delivery condition, so the plate is austenitised, quenched and then tempered to obtain a fine grained, tough microstructure.
The European material number for S890Q is 1.8940. The plate must be delivered in the quenched and tempered condition and is verified with tensile and Charpy V-notch impact testing at -20 °C, which is the property that separates S890Q from the colder S890QL and S890QL1 classes.
Chemical Composition of S890Q
EN 10025-6 sets the maximum limits that apply to the high strength quenched and tempered group. For S890Q the broad group maxima are as follows:
| Element, max % | EN 10025-6 limit | Commonly published supply limits |
|---|---|---|
| C | 0.20 | 0.20 |
| Si | 0.80 | 0.40 |
| Mn | 1.70 | 1.20 |
| P | 0.025 | 0.020 |
| S | 0.015 | 0.005 |
| Ni | 2.00 | 1.00 |
| Cr | 1.50 | 0.70 |
| Mo | 0.70 | 0.70 |
| Cu | 0.50 | 0.50 |
| Nb | 0.06 | 0.05 |
| V | 0.12 | 0.08 |
| B | 0.005 | 0.0020 |
The second column shows how mills typically restrict the analysis further than the standard requires: low phosphorus and sulphur improve toughness and reduce the risk of cold cracking, while a reduced carbon content widens the welding window. Vanadium, niobium and boron are used to secure strength in the quenched and tempered condition, and chromium, molybdenum and nickel support hardenability in thicker plate.
Mechanical Properties by Thickness
| Property | 3-50 mm | 50-100 mm |
|---|---|---|
| ReH, minimum yield strength | 890 MPa | 830 MPa |
| Rm, tensile strength | 940-1100 MPa | 880-1100 MPa |
| Elongation A, minimum | 11 % | 11 % |
| Charpy V-notch impact energy | 30 J at -20 °C | 30 J at -20 °C |
Mill test certificates frequently report higher absorption at warmer test temperatures, for example about 40 J at 0 °C, because the guaranteed figure is a minimum value and not a typical one. The reason for the reduced yield figure above 50 mm is straightforward: quench severity falls with thickness, so a slightly lower strength floor is accepted for heavy plate while toughness remains controlled.
Common supply covers plates from about 6 mm to about 150 mm depending on mill capability, with widths up to roughly 3200 mm and lengths up to roughly 12000 mm. Plate can be supplied cut to size, bevelled, shot blasted and primed.
Standards and Comparable Grades
EN 10025-6 - primary standard for hot rolled structural steel products in the quenched and tempered condition; S890Q and its L variants are covered by this part.
EN 10137-2 - the older European delivery condition specification for quenched and tempered plate and wide flats, still quoted on some drawings.
EN 10204 - inspection documents: type 3.1 as standard, type 3.2 or third party witnessed testing when the project demands it.
GB/T 16270 - Chinese standard for quenched and tempered high strength structural plate. Q890 is the corresponding strength level, and the suffix letters C, D, E and F indicate impact testing at 0 °C, -20 °C, -40 °C and -60 °C respectively, so Q890D is the closest match for S890Q.
EN 10149-2 S900MC - a thermomechanically rolled high yield steel at a similar strength level that can be considered where excellent formability is more important than the multi-temperature toughness guarantee of the quenched and tempered route.
S890Q is a structural steel and not a pressure vessel steel. Pressure equipment must be ordered against a pressure vessel specification such as EN 10028 or an equivalent code.
Welding, Cutting and Fabrication Notes
Weldability is manageable but demands discipline, because the carbon equivalent of an 890 MPa quenched and tempered plate is far above that of ordinary structural steel:
Qualify the welding procedure and follow the requirements of EN 1011-2 for high strength steels, including heat input control.
Preheating is usually required to prevent cold cracking, with the exact temperature taken from the qualified procedure rather than from a table.
Keep joints clean and dry, use low hydrogen consumables and control interpass temperature to protect the heat affected zone.
Post-weld heat treatment may be required for certain joints and applications; where it is applied, the temperature must stay below the tempering range of the parent plate.
Flame cutting, plasma cutting and machining can all be carried out with controlled parameters, and cut edges of thick plate are normally dressed before welding.
Standard dry storage is sufficient for the plate itself, with surface protection recommended for long outdoor storage.
Applications that benefit from this strength level include mining equipment such as hydraulic supports and dump truck bodies, heavy construction machinery, offshore structures and drilling rigs, high load bridge components and heavy duty vehicle frames, where a higher strength grade can replace a thicker lower strength plate and reduce the dead weight of the structure.
Frequently Asked Questions
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 with a guaranteed Charpy V-notch impact energy of 30 J at -20 °C.
Q: What is the material number of S890Q?
The European material number for S890Q is 1.8940.
Q: Is S890Q a non-alloy steel?
It is listed with the non-alloy structural steels in the EN classification, even though microalloying elements such as niobium, vanadium, titanium and boron are added to achieve the strength and toughness combination.
Q: What are the mechanical properties of S890Q plate?
Minimum yield strength of 890 MPa from 3 mm to 50 mm and 830 MPa from 50 mm to 100 mm; tensile strength of 940-1100 MPa and 880-1100 MPa for the same ranges; minimum elongation of 11 %; and impact energy of at least 30 J at -20 °C.
Q: What is the Chinese equivalent grade of S890Q?
GB/T 16270 Q890D is the closest equivalent, because the D suffix indicates impact testing at -20 °C, the same verification temperature as S890Q.
Q: Can S890Q be used for pressure vessels?
No. S890Q is a structural steel and is not intended for pressure vessel or boiler service, which requires a dedicated pressure equipment specification such as EN 10028 or an equivalent code.
Q: How thick is S890Q plate supplied?
Typical supply ranges from about 6 mm to about 150 mm depending on the mill, while the standard property guarantees are defined for the 3-50 mm and 50-100 mm bands.
