Q800E 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

Q800E 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).

Q800E is smelted by oxygen converter or electric furnace, with strict control of chemical composition and carbon equivalent (CEV ≤0.55%), 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 low-temperature stability (-40℃ working environment).

According to GB/T 16270-2009 Appendix A, Q800E has approximate equivalent grades in European standards, and is the preferred material for high-strength structural components working in 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 Q800E 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
Q800E ≤50 0.20 0.80 2.00 0.020 0.010 0.50 1.50 2.00 0.70 0.0050 0.12 0.06 0.05 0.72
>50~100 0.20 0.80 2.00 0.020 0.010 0.50 1.50 2.00 0.70 0.0050 0.12 0.06 0.05 0.82
>100~150 0.20 0.80 2.00 0.020 0.010 0.50 1.50 2.00 0.70 0.0050 0.12 0.06 0.05 -

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: Q800E has strict P/S control (P≤0.020%, S≤0.010%) to ensure low-temperature toughness (-40℃) and structural stability.
Note 5: Q800E 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) 
≤50mm >50~100mm >100~150mm ≤50mm >50~100mm All Thickness -40℃ (Longitudinal)
Q800E 800 740 - 840~1000 800~1000 13 27

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: Q800E impact test temperature is -40℃ (KV2≥34J), reflecting excellent low-temperature toughness (GB/T 16270-2009 standard requirement).
Note 6: Q800E 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 Q800E are as follows:

Property Q800E (GB/T 16270-2009)
China | Quenched & Tempered		 S890QL (EN 10025-6:2004)
EU | Quenched & Tempered		 ASTM A514 Gr.Q (ASTM A514)
US | Quenched & Tempered
Min Yield Strength (MPa) 800 (≤50mm) 890 (≤100mm) 690 (≤100mm)
Tensile Strength (MPa) 870~1040 960~1100 760~895
Min Elongation (%) 12 10 15
Impact Test Temperature (°C) -40℃ (KV2≥34J) -40℃ (KV≥40J) -40℃ (KV≥27J)
Max Carbon Content (%) 0.20 0.20 0.21
Carbon Equivalent CEV ≤ 0.65~0.83 (by thickness) 0.55 0.50
Max Thickness (mm) 150 150 100
Main Applications High-load engineering machinery, heavy structural components in ultra-low temperature regions (-40℃) High-rise building structures, heavy crane components in cold regions Ultra-high strength structural components in low-temperature environments

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. Q800E is equivalent to S890QL in EN standard in terms of strength grade and has good low-temperature toughness (-40℃).

Application Cases

High Load Engineering Machinery with Q800E Steel

High Load Engineering Machinery

Heavy excavator arms, large crane booms, hydraulic support components and mining machinery in ultra-cold regions. Q800E's ultra-high strength (yield ≥800MPa) and excellent -40℃ low-temperature toughness meet the extreme load requirements of heavy engineering machinery in ultra-cold environments.

Heavy Building Structures with Q800E Steel

Heavy Building Structures

Large-span bridge structural components, high-rise building core columns, large stadium steel structures and industrial factory heavy load-bearing beams in ultra-cold regions. Q800E's high strength-to-weight ratio and -40℃ toughness reduce structural weight while ensuring safety in ultra-low-temperature environments.

Port Heavy Machinery with Q800E Steel

Port Heavy Machinery

Large port cranes, ship unloaders, container gantry cranes and bulk cargo handling equipment in polar coastal areas. Q800E's ultra-high strength, wear resistance, structural stability and -40℃ toughness meet the long-term heavy-duty operation requirements in ultra-low-temperature port environments.

Frequently Asked Questions

What are the key updates of GB/T 16270-2009 compared to the old version? +

GB/T 16270-2009 has the following key updates: 1. Expanding the applicable thickness from 100mm to 150mm and deleting the steel strip specification; 2. Canceling Q420 grade and adding Q800/Q890/Q960 grades; 3. Adding quality grade C/F and adjusting composition and performance; 4. Canceling bending performance requirements and adding CEV carbon equivalent index; 5. Deleting delivery states such as normalizing and controlled rolling, and only retaining quenched + tempered state; 6. Adding Q800E grade with -40℃ low-temperature impact requirement and Z-direction performance requirement.

Why is Q800E suitable for low-temperature (-40℃) applications? +

Q800E is specially designed for low-temperature environments for the following reasons: 1. Strict control of impurity elements (P≤0.020%, S≤0.010%) to avoid cold brittleness; 2. CEV carbon equivalent ≤0.55% (for thickness ≤50mm) to ensure weldability and low-temperature toughness; 3. Mandatory -40℃ impact test (KV2≥34J) to verify low-temperature performance; 4. Addition of grain refinement elements (Nb/Ti/V/Al) to refine grains and improve low-temperature toughness; 5. Z-direction performance requirement (Z15/Z25/Z35) for thickness ≥15mm to prevent lamellar tearing in low-temperature welding.

What are the welding requirements for Q800E steel plates? +

Q800E welding key points: 1. Preheating temperature: 100~200℃ (adjust according to thickness, ≥50mm needs 150~200℃); 2. Interpass temperature ≤250℃ to avoid overheating affecting toughness; 3. Recommended welding materials: matching strength grade (yield ≥800MPa) low-hydrogen electrodes/wires (such as E11018-G, ER110S-G); 4. Post-weld heat treatment: generally not required, but stress relief annealing (580~620℃) is recommended for thick plates or complex structures; 5. Welding process: use low heat input, multi-layer multi-pass welding to reduce welding stress and deformation.

What is the difference between Q800E and Q500C/Q500D/Q500E grades? +

The core difference lies in strength grade and low-temperature impact requirements: 1. Q500C: 0℃ impact (KV2≥34J), yield strength ≥500MPa; 2. Q500D: -20℃ impact (KV2≥34J), yield strength ≥500MPa; 3. Q500E: -40℃ impact (KV2≥34J), yield strength ≥500MPa; 4. Q800E: -40℃ impact (KV2≥34J), yield strength ≥800MPa (higher strength grade). In addition, Q800E has stricter P/S control (P≤0.020%, S≤0.010%) and higher carbon equivalent limit (CEV≤0.55%) than Q500 series, and mandatory Z-direction performance requirement for thickness ≥15mm, making it suitable for high-strength low-temperature (-40℃) applications in heavy engineering equipment.

What are the customization capabilities of Q800E steel plates? +

CEHE Steel provides full customization for Q800E: 1. Size customization: thickness 6~100mm (max thickness for Q800 grade), width 1500~4000mm, length 3000~18000mm (can be cut to custom size); 2. Performance customization: Z-direction performance (Z15/Z25/Z35), impact energy upgrade (KV2≥40J), surface quality grade (A/B/C/D); 3. Processing customization: flame cutting, plasma cutting, beveling, shot blasting, painting, anti-rust oil coating; 4. Certification customization: provide mill test certificate (MTC) according to EN 10204 3.1/3.2, third-party inspection (SGS/BV/ABS) report; 5. Delivery cycle: stock for common sizes (5-7 days), customized production (20-30 days) (longer cycle due to high-strength heat treatment process).

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