EN 10025-6 S620QL1 is a quenched and tempered high-strength structural steel plate under the European Standard (EN) system, primarily used in heavy machinery, infrastructure engineering, and other fields that require stringent material strength, low-temperature toughness, and structural safety.

Standard and Grade Designation

1. Standard: EN 10025-6

The full title is "Hot-rolled structural steels - Part 6: Technical delivery conditions for flat products of high yield strength structural steels in the quenched and tempered condition," which is a unified European standard for high-strength structural steel.



2. Grade: S620QL1

S: Structural steel.

620: The specified minimum yield strength is 620MPa.

Q: The delivery condition is Quenched and Tempered.

L: Low temperature impact toughness (Tested at -60°C or -40°C, depending on thickness).

1: The quality class or impact toughness level(Impact Energy Test at -60°C).

The chemical composition of S620QL1 (Heat Analysis, wt. %, maximum) is shown in the table below.

Carbon Equivalent of S620QL1 High Strength Steel Plate

* The carbon equivalent value varies depending on the thickness.For detailed information, please contact us for inquiries.

* Carbon equivalent (CEV) is calculated using the International Institute of Welding (IIW) formula:

CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

* The mechanical properties of S620QL high-strength structural steel plate vary with thickness.

S620QL1 is primarily used for structural components that bear heavy loads, complex stresses, or operate in harsh environments due to its high strength, low-temperature resistance, and impact toughness. Common applications include:

Construction Machinery: Crane booms, excavator arms, loader frames.

Transportation: Frames for special vehicles (heavy-duty trucks, tankers), bogies for railway freight cars.

Building and Bridge Construction: Load-bearing structures for long-span bridges, steel columns/beams for high-rise buildings (especially in cold regions).

Pressure Vessels and Special Equipment: High-pressure storage tanks, wind turbine tower flanges (requiring wind load and low-temperature resistance).

Marine Engineering: Secondary load-bearing structures for offshore platforms (requiring low-temperature toughness and certain corrosion resistance, typically used with coatings).

Delivery Conditions of S620QL1 High Strength Steel Plate

Quenched and Tempered(Q&T)

Weldability of S620QL1 High Strength Steel Plate

EN 10025-6 S620QL high-strength steel plate is weldable. However, due to its high carbon and alloy element content, preheating is required before welding (typically at 100-150°C), and stress relief heat treatment (such as tempering at 200-300°C) is necessary after welding to avoid welding cracks. It is recommended to use low-hydrogen electrodes or welding wires with matching strength.

The Differences Between Grades Within The Same Series

Summary

EN 10025-6 S620QL1 is a high-strength, high-toughness structural steel plate. Its core advantage lies in meeting the structural safety requirements for harsh working conditions in low-temperature environments, making it a key material in fields such as heavy machinery and infrastructure engineering.