Q550E High Strength Structural Steel Plate

Strictly Compliant with GB/T 16270-2009 | Quenched & Tempered State | Thickness Up to 150mm | Excellent Low-Temperature Toughness (-40℃) | Custom Sizes Available

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Product Overview

Q550E is a high strength structural steel plate specified in GB/T 16270-2009 High strength structural steel plates in the quenched and tempered condition standard, replacing the old GB/T 16270-1996 version. The product is delivered in quenched + tempered state, with a maximum applicable thickness of 150mm (expanded from the original 100mm).

Q550E is smelted by oxygen converter or electric furnace, with strict control of chemical composition and carbon equivalent (CEV ≤0.50%), ensuring excellent high strength and superior low-temperature toughness (-40℃ impact resistance). It is widely used in engineering machinery, construction structures, port machinery, bridge engineering and other fields that require high load-bearing capacity and ultra-low-temperature stability.

According to GB/T 16270-2009 Appendix A, Q550E has approximate equivalent grades in European standards, and is the preferred material for high-strength structural components working in ultra-low-temperature environments (-40℃) in domestic and international engineering projects.

★ Key Standard Update:

GB/T 16270-2009 cancels the bending performance requirement, adds CEV carbon equivalent index, and deletes the delivery states of normalizing, normalizing+tempering and controlled rolling. It also defines Q550E grade with -40℃ low-temperature impact requirement and Z-direction performance requirement for thickness ≥15mm.

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Technical Specifications (GB/T 16270-2009)

All data is in accordance with the official GB/T 16270-2009 standard, the unit of chemical composition is mass fraction (wt%), and the mechanical properties are tested with transverse tensile samples and longitudinal impact samples.

Chemical Composition (wt%, Max) & Carbon Equivalent CEV

Grade	Thickness mm	C	Si	Mn	P	S	Cu	Cr	Ni	Mo	B	V	Nb	Ti	CEV
Q550E	≤50	0.20	0.80	1.70	0.020	0.010	0.50	1.50	2.00	0.70	0.0050	0.12	0.06	0.05	0.65
	>50~100	0.20	0.80	1.70	0.020	0.010	0.50	1.50	2.00	0.70	0.0050	0.12	0.06	0.05	0.77
	>100~150	0.20	0.80	1.70	0.020	0.010	0.50	1.50	2.00	0.70	0.0050	0.12	0.06	0.05	0.83

Note 1: At least one grain refinement element (Nb/Ti/V/Al) shall be added, the minimum content of at least one element is 0.015% (Als for Al), or Alt can be used instead of Als with a minimum of 0.018%.
Note 2: CEV calculation formula (GB/T 16270-2009): CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15.
Note 3: The chemical composition tolerance of finished steel plate complies with GB/T 222.
Note 4: Q550E has stricter P/S control (P≤0.020%, S≤0.010%) than Q550D to ensure ultra-low-temperature toughness (-40℃) and Z-direction performance.
Note 5: Q550E requires Z-direction performance test (Z15/Z25/Z35) for thickness ≥15mm to prevent lamellar tearing.

Mechanical Properties (GB/T 16270-2009)

Grade	Yield Strength ReH (MPa) ≥	Yield Strength ReH (MPa) ≥	Yield Strength ReH (MPa) ≥	Tensile Strength Rm (MPa)	Tensile Strength Rm (MPa)	Elongation after Fracture A (%)	Impact Absorption Energy KV2 (J)
Grade	≤50mm	>50~100mm	>100~150mm	≤100mm	>100~150mm	All Thickness	-40℃ (Longitudinal)
Q550E	550	530	490	640~820	590~770	16	34

Note 1: When the yield phenomenon is not obvious, Rp0.2 is used instead of ReH.
Note 2: The impact energy is the arithmetic mean of three samples, one sample is allowed to be lower than the specified value but not less than 70% of the specified value.
Note 3: For plates with thickness 8~12mm, 75% of the specified impact value is required for 10×7.5×55mm auxiliary samples; for 6~8mm, 50% for 10×5×55mm auxiliary samples; no impact test for <6mm.
Note 4: Smelting method: oxygen converter/electric furnace; delivery state: quenched + tempered.
Note 5: Q550E impact test temperature is -40℃ (KV2≥34J), reflecting excellent ultra-low-temperature toughness (stricter than Q550D's -20℃ requirement).
Note 6: Q550E requires Z-direction performance test for thickness ≥15mm (Z15/Z25/Z35 grade optional) to ensure resistance to lamellar tearing.

International Standard Approximate Comparison

According to GB/T 16270-2009 Appendix A (informative appendix) and official international standard data, the approximate equivalent grades of Q550E are as follows:

Property	Q550E (GB/T 16270-2009) China \| Quenched & Tempered	S550QL1 (EN 10025-6:2004) EU \| Quenched & Tempered	ASTM A514 Gr.Q (ASTM A514) US \| Quenched & Tempered
Min Yield Strength (MPa)	550 (≤50mm)	550 (≤100mm)	690 (≤100mm)
Tensile Strength (MPa)	630~830	630~830	760~895
Min Elongation (%)	16	16	15
Impact Test Temperature (°C)	-40℃ (KV2≥34J)	-60℃ (KV≥40J)	-40℃ (KV≥27J)
Max Carbon Content (%)	0.20	0.20	0.21
Carbon Equivalent CEV ≤	0.50~0.55 (by thickness)	0.50	0.50
Max Thickness (mm)	150	150	100
Main Applications	Ultra-low-temperature engineering machinery, polar region structural components	Ultra-low-temperature high-rise structures, arctic cranes	Ultra-low-temperature heavy structural components

Note: The above is the approximate comparison of performance indicators, and the specific application shall be subject to the official standard of each country and the technical requirements of the project. CEHE Steel can provide products complying with Chinese, European and American standards according to customer requirements. Q550E is equivalent to S550QL1 in EN standard in terms of ultra-low-temperature performance (-40℃).

Application Cases

Ultra-low-temperature Engineering Machinery

Excavator arms, crane booms, loader buckets and hydraulic support components used in extreme cold regions (-40℃~-60℃). Q550E's high strength-to-weight ratio and excellent ultra-low-temperature toughness meet the load requirements of machinery in arctic environments.

Arctic Region Building Structures

Large-span bridge deck plates, high-rise building structural beams and columns in arctic regions, steel structure workshops in ultra-low-temperature areas. Q550E's excellent ultra-low-temperature toughness and stability adapt to harsh outdoor environments (-40℃).

Arctic Port Machinery

Port cranes, container handlers, ship unloaders and hoisting equipment in arctic ports. Q550E's high load-bearing capacity, wear resistance and ultra-low-temperature toughness meet the long-term heavy-duty operation requirements in extreme low-temperature environments.

Frequently Asked Questions

What are the core mechanical properties of Q550E high-strength steel plates? +

Q550E has the following core mechanical properties: 1. Yield strength (ReH): ≥550MPa (for thickness ≤16mm, decreases to ≥530MPa for 16-40mm, ≥510MPa for 40-63mm); 2. Tensile strength (Rm): 670-830MPa; 3. Elongation (A): ≥16%; 4. Low-temperature impact toughness: -40℃ Charpy V-notch impact energy (KV2) ≥34J; 5. Hardness: ≤260HB; 6. Carbon equivalent (CEV): ≤0.55% (for thickness ≤63mm) to ensure weldability; 7. All plates are supplied in quenched and tempered (QT) state to guarantee uniform performance.

What are the typical application scenarios of Q550E steel plates? +

Q550E is widely used in low-temperature and high-strength requirement scenarios: 1. Construction machinery: crane booms, excavator arms, loader frames (high strength + light weight); 2. Engineering machinery: offshore platform components, port machinery, lifting equipment; 3. Automobile industry: heavy truck frames, special vehicle chassis (low-temperature resistance for northern regions); 4. Bridge engineering: steel bridge structures in cold regions (-40℃ working environment); 5. Energy equipment: wind power tower flanges, hydraulic support columns for coal mines; 6. Military and aerospace: special vehicle armor components, low-temperature equipment shells. Its -40℃ low-temperature toughness makes it ideal for alpine region projects.

What are the key welding process requirements for Q550E? +

Q550E welding key technical requirements: 1. Preheating: 100~150℃ (thickness ≤25mm preheat 100℃, 25-40mm preheat 120℃, ≥40mm preheat 150℃); 2. Interpass temperature: ≤200℃ to prevent grain coarsening; 3. Welding materials: low-hydrogen type matching strength (such as E9018-G, ER90S-G) to ensure joint toughness; 4. Heat input control: 1.5~2.5 kJ/mm (avoid excessive heat input affecting low-temperature performance); 5. Post-weld treatment: stress relief annealing at 550~600℃ for thick plates (≥40mm) or complex structures; 6. Inspection: 100% UT (ultrasonic testing) for welds to ensure no internal defects.

What is the difference between Q550E and Q550C/Q550D grades? +

The core difference lies in low-temperature impact test requirements: 1. Q550C: 0℃ Charpy V-notch impact (KV2≥34J), suitable for normal temperature environments; 2. Q550D: -20℃ impact (KV2≥34J), for general low-temperature regions; 3. Q550E: -40℃ impact (KV2≥34J), for severe cold regions (northeast China, Russia, etc.). In chemical composition, Q550E has stricter control of harmful elements (P≤0.020%, S≤0.010%) and higher content of alloy elements (Ni/Cr/Mo) to improve low-temperature toughness, making it the top grade in Q550 series for low-temperature applications.

What are the customization capabilities of Q550E steel plates? +

CEHE Steel provides comprehensive customization for Q550E steel plates: 1. Size customization: thickness 8~120mm, width 1500~4000mm, length 3000~18000mm (custom cutting to required dimensions); 2. Performance customization: Z-direction performance (Z15/Z25/Z35) for thickness ≥15mm, impact energy upgrade (KV2≥40J at -40℃), higher strength tolerance; 3. Processing customization: CNC flame/plasma cutting, beveling (K/V/U type), shot blasting (Sa2.5 grade), anti-rust painting, edge rounding; 4. Certification customization: mill test certificate (MTC) per EN 10204 3.1/3.2, third-party inspection (SGS/BV/CCS) reports; 5. Delivery: stock available for standard sizes (3-5 days), customized production (18-28 days) with full traceability of production batch.

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