A quotation for “690 MPa plate” is incomplete until you confirm the EN 10025-6 grade, thickness-dependent strength, −40 °C impact result, +QT delivery condition and certificate traceability. By the end, you will be able to compare S690QL with S690QL1, S890QL, Strenx 700, S500MC and boiler-quality plate, then test an Indian supplier’s offer against fabrication and documentation requirements.
Key takeaways
- Confirm EN 10025-6, +QT condition and −40 °C Charpy results.
- Compare S690QL with S500QL, S890QL and equivalent design grades.
- Check yield strength by thickness, not the 690 MPa label alone.
- Require welding procedures that control heat input, preheat and hydrogen.
What S690QL means before you compare suppliers
S690QL identifies a quenched-and-tempered structural steel plate under EN 10025-6. “S” means structural steel, “690” identifies the minimum yield-strength class of 690 MPa, and “QL” means Charpy impact testing at −40 °C. S690QL is supplied in the +QT condition; it is not a generic name for every plate advertised as 690 MPa.
| Designation | Impact requirement | Selection meaning |
|---|---|---|
| S690QL | Charpy testing at −40 °C | Use when the design and service temperature are covered by the −40 °C subgrade |
| S690QL1 | Charpy testing at −60 °C | Select for colder service where the lower test temperature is required |
S690QL1 is a different toughness choice, not an automatic equivalent to S690QL. Before accepting it as interchangeable, confirm the exact designation, governing standard, test temperature and certificate; a lower-temperature impact result does not erase differences in specification or procurement requirements.
If you are searching for an s690ql plate supplier in india, specify the grade, subgrade, ordered thickness and minimum service temperature.
State “S690QL +QT under EN 10025-6, [thickness], Charpy at −40 °C” instead of requesting “high tensile 690.” Thickness matters because the applicable yield-strength band changes as plate thickness increases, so the certificate must match the plate you intend to use.
Which high-strength plate is the right comparison for your design
A higher yield strength reduces thickness only when buckling, stiffness, local stresses, corrosion allowance, connections and fabrication limits still pass. A 20 mm plate replaced by 16 mm offers a theoretical 20% weight saving; subtract the added cost of qualified welding, tighter forming control, inspection and possible reinforcement.
| Option | Strength and toughness | Fabrication, availability and documents |
|---|---|---|
| S690QL | 690 MPa yield up to 50 mm; 770–940 MPa tensile; Charpy at −40 °C | +QT, weldable only with a qualified procedure; widely traded; require EN 10025-6 and EN 10204 certificate |
| S890QL | 890 MPa yield class; higher tensile strength; verify the ordered thickness and −40 °C impact requirement | More sensitive to welding and forming; narrower supply; demand grade-specific WPS, PQR and inspection records |
| Strenx 700 | Product-specific yield, tensile and impact values; confirm the datasheet, thickness and test temperature | Strong documentation and consistent processing, but availability and substitution depend on the exact Strenx designation |
S890QL or Strenx 700 is worthwhile only if the calculated saving exceeds these demands. Forming radii, springback and heat input can erase the benefit.
S500MC is thermomechanically rolled for forming and structural work, not an automatic S690QL substitute. BQ 516 Grade 60 and Grade 70 are pressure-vessel choices governed by different design codes, toughness rules and heat-treatment expectations. Similar headline strength does not make structural, thermomechanically rolled and pressure-vessel plate interchangeable.
Ask an s690ql high tensile steel plate supplier in india for the exact standard, thickness-based properties, impact test temperature, delivery condition, heat number, forming limits and certificate before approving the comparison.
How to read S690QL strength and impact results on the certificate
The certificate proves compliance only when its results match the ordered thickness, standard edition and product range. Do not accept “690 MPa” as sufficient: EN 10025-6 sets different minimum yield strengths by thickness.
| Thickness range | Minimum yield strength |
|---|---|
| Up to 50 mm | 690 MPa |
| Over 50 to 100 mm | 650 MPa |
| Over 100 to 150 mm | 630 MPa |
| Over 150 to 200 mm | 610 MPa |
| Over 200 to 250 mm | 600 MPa |
For plate up to 50 mm, the tensile-strength range is typically 770–940 MPa. Compare the reported result with the applicable thickness band, not with the 690 MPa class name alone; confirm the standard edition and ordered product range before acceptance.
Check the certificate for:
- Chemical analysis and heat number
- Yield strength, tensile strength and elongation
- Charpy V-notch absorbed energy at −40 °C
- Specimen direction and +QT delivery condition
- Ordered thickness, width, length and dimensional tolerances
- EN 10204 Type 3.1, or purchaser-required Type 3.2 documentation
A room-temperature tensile result cannot prove cold-service suitability because strength at ambient temperature does not demonstrate impact toughness at −40 °C. The certificate must show the specified Charpy result and test temperature.
EN 10025-6 does not automatically include EN 10160 ultrasonic testing, through-thickness quality or special surface-quality classes. Specify those separately, including the required UT acceptance class, when internal discontinuities or Z-quality performance matter.
How to compare an Indian supplier’s plate offer beyond price per tonne
A quotation is comparable only after you fix the material and service scope. Ask for the actual heat number, original mill certificate, unused and traceable status, mill origin, quantity, dimensions and S690QL +QT delivery condition—not merely “high tensile 690.”
| Role | What the seller does | What changes for you |
|---|---|---|
| Manufacturer | Produces and certifies the plate | Mill responsibility, production lead time and usually higher minimum quantity |
| Stockist | Holds previously produced plate and resells it | Immediate availability depends on verified stock and certificate control |
| Service centre | Cuts or processes mill plate | Cut-piece lead time, minimum order and responsibility for dimensional conformity |
Before accepting an offer from an s690ql plate stockist in india, require these quotation fields:
- Thickness, width, length, quantity and cut-piece tolerance
- Impact-test temperature, certificate type, original mill certificate and heat number
- EN 10160 ultrasonic-testing requirement, surface quality and EN 10029 dimensional tolerance
- Mill origin, unused status, traceability method and +QT delivery condition
- Freight, GST and Incoterms
Cutting a mother plate does not create individually certified material. Accept cut pieces only when each piece carries its heat number, or the supplier provides a traceability map transferring the original certificate to every piece or bundle.
Shyam Metals & Alloys can provide these details for a Mumbai quotation, but a catalogue listing proves neither live stock, mill origin nor compliance. Normalize every offer to the same grade, thickness, dimensions, test scope, certificate, tolerance, quantity, freight, GST and Incoterms before comparing price per tonne.
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What the approved welding procedure must control
A compliant S690QL certificate does not make the plate ready for fabrication. The approved welding procedure controls preheat, interpass temperature, heat input, cooling time, joint restraint, hydrogen-controlled consumables and post-weld inspection for the actual thickness and joint detail.
Obtain the heat analysis and have the fabricator’s welding engineer calculate carbon equivalent and confirm the WPS and PQR. Nominal chemistry cannot predict cold-cracking risk without thickness, restraint, hydrogen level and thermal-cycle information.
Severe cold forming can reduce local toughness, while uncontrolled flame straightening can temper the quenched-and-tempered condition. Define forming radii, heating limits and post-forming tests in the purchase specification before fabrication.
Use this checklist when comparing an S690QL plate manufacturer in India:
- Confirm that the WPS and PQR apply to the ordered thickness, steel condition, joint type and welding process.
- Record the qualified preheat and interpass-temperature range, including the required cooling time and heat-input limits.
- Specify hydrogen-controlled consumables and sealed storage, rebaking and issue controls.
- Name the weld inspection method: visual testing, magnetic-particle testing, radiography or ultrasonic testing, as applicable.
- State thickness, flatness and dimensional tolerances under EN 10029 instead of relying on the grade designation.
- Add any required EN 10160 ultrasonic-testing class and acceptance level to the order.
Frequently asked questions
What does S690QL mean?
S690QL is quenched-and-tempered structural steel under EN 10025-6, with a 690 MPa minimum yield-strength class and Charpy impact testing at −40 °C.
Which steel grades should you compare with S690QL?
Compare S690QL with S500QL when you need lower strength and easier fabrication, or S890QL when higher strength justifies stricter welding controls.
What should you check on an S690QL material certificate?
Check the heat number, plate thickness, +QT condition, chemical analysis, tensile results, yield strength, elongation and Charpy impact energy at −40 °C.
What must an approved S690QL welding procedure control?
Control preheat, interpass temperature, heat input, consumable hydrogen level, joint preparation, cooling conditions and post-weld inspection.
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