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EN 10025-6 S620QL High Strength Steel Plate

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EN 10025-6 S620QL is a high-yield strength, quenched and tempered fine-grained structural steel.Mainly used for structural components that withstand high loads and complex stresses.

Standard :
EN 10025-6
Grade :
S620QL
Thickness :
3 - 100 mm
Width :
1500 - 2500 mm
Length :
3000 - 12000 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

EN 10025-6 S620QL is a high-strength, high-toughness, and easily weldable quenched and tempered structural steel plate. Its core advantage lies in balancing load-bearing capacity with low-temperature impact resistance, making it a key material for achieving "lightweight and high-reliability" designs in heavy engineering fields.

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: S620QL

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 the sub-grade and thickness).

Chemical Composition

The chemical composition of S690QL ensures hardenability, strength, and toughness. EN 10025-6 specifies the limits for key elements, with the following typical ranges:

Grade	S620QL
Element	C	Si	Mn	P	S	N	B	Cr	Cu	Mo	Nb	Ni	Ti	V	Zr
Content (max, %)	0.200	0.800	1.700	0.025	0.015	0.015	0.005	1.500	0.500	0.700	0.060	2.000	0.050	0.120	0.150

Carbon Equivalent of S620QL High Strength Steel Plate

Grade	Thickness (t) [mm]	CEV [max, %]
S620QL	t ≤ 63	0.65
	63 < t ≤ 100	0.77
	100 < t ≤ 150	0.83

* 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

Mechanical Properties

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

Grade	Thickness (t) [mm]	Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]	Impact Energy (KV) [min]
S620QL	3 ≤ t ≤ 50	620	700 - 890	15	30J (at -40°C, Longitudinal) 27J (at -40°C, Transverse)
	50 < t ≤ 100	580	700 - 890	15	30J (at -40°C, Longitudinal) 27J (at -40°C, Transverse)
	100 < t ≤ 150	560	650 - 830	15	30J (at -40°C, Longitudinal) 27J (at -40°C, Transverse)

Applications

S620QL high-strength structural steel plate is known for its "high strength, high toughness, and good weldability," making it primarily suitable for structural components that endure high loads, complex stresses, or low-temperature environments. Typical applications include:

Construction Machinery: Crane booms, excavator buckets, bulldozer frames, etc., where high strength reduces structural weight and enhances load-bearing capacity.

Mining Machinery: Dump truck bodies, crusher frames, etc., designed to withstand impact and abrasion.

Pressure Vessels and Storage Tanks: Shells of high-pressure vessels, heads of large storage tanks (requires supporting welding procedure qualification).

Bridges and Buildings: Load-bearing components of long-span bridges, steel core columns of high-rise buildings.

Special Vehicles: Protective armor or load-bearing structures for military vehicles and armored cars.

Other Information

Delivery Conditions

S620QL is typically delivered in the quenched and tempered condition, with surface treatments such as sandblasting and painting available as required.

Weldability

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

Grade	Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]	Impact Energy (KV) [min]
S620Q	620	700 - 890	15%	30J (at -20°C)
S620QL	620	700 - 890	15%	30J (at -40°C)
S620QL1	620	700 - 890	15%	30J (at -60°C)

Procurement and Acceptance

Material Test Certificate (MTC): The steel mill must provide a certificate compliant with EN 10204 Type 3.1 or 3.2, clearly stating mechanical properties, chemical composition, and non-destructive testing results (such as UT inspection).

Thickness Tolerance: Executed according to EN 10029, typically ±0.5mm (for thickness ≤10mm) or ±1.0mm (for thickness >10mm). Special tolerances must be negotiated in advance.

Surface Quality: Default is "as-rolled" surface. If anti-corrosion pretreatment (such as shot blasting or painting) is required, it must be specified in the order.

Non-Destructive Testing: For critical structures (e.g., wind power, bridges), it is recommended to require sheet-by-sheet UT inspection (compliant with EN 10160 Class 2 or higher) to detect internal defects.

Summary

EN 10025-6 S620QL steel plate is a high-strength, high-toughness, and easily weldable quenched and tempered structural steel plate. Its core advantage lies in balancing load-bearing capacity with low-temperature impact resistance, making it a key material for achieving "lightweight and high-reliability" designs in heavy engineering fields.

FAQ

Q1:

What are the weldability characteristics of high-strength low-alloy steel plates?

High-strength low-alloy steel plates offer excellent weldability. As their carbon content is typically low (below 0.2%), they present a lower risk of cracking during welding compared to standard high-strength steel plates and generally do not require complex preheating treatments.

Q2:

Why are high-strength low-alloy steels the preferred choice in construction and automotive manufacturing?

The key advantage of high-strength low-alloy steels is weight reduction. As they offer greater strength, thinner sheets can be used to withstand the same loads, thereby reducing the overall weight of the structure; in the automotive sector, this leads to improved fuel efficiency.

Q3:

What is high-strength low-alloy steel (HSLA)?

High-strength low-alloy steel (HSLA) is a type of steel in which small amounts of alloying elements (such as niobium, vanadium, titanium or copper) are added to enhance its mechanical properties. Compared to traditional carbon steel, it offers higher yield strength and better corrosion resistance whilst maintaining good weldability and formability.