Q620D High Strength Structural Steel Plate

Strictly Compliant with GB/T 16270-2009 | Quenched & Tempered State | Thickness Up to 150mm | Excellent Low-Temperature Toughness (-20℃) | Custom Sizes Available

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Product Overview

Q620D 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).

Q620D 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 (-20℃ 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 (-20℃ working environment).

According to GB/T 16270-2009 Appendix A, Q620D has approximate equivalent grades in European standards, and is the preferred material for high-strength structural components working in low-temperature environments (-20℃) 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 Q620D grade with -20℃ 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
Q620D ≤50 0.20 0.80 1.70 0.025 0.015 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 0.025 0.015 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 0.025 0.015 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: Q620D has stricter P/S control (P≤0.020%, S≤0.010%) than Q620C to ensure low-temperature toughness (-20℃) and structural stability.
Note 5: Q620D 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 ≤100mm >100~150mm All Thickness -20℃ (Longitudinal)
Q620D 620 580 560 700~890 650~830 15 47

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: Q620D impact test temperature is -20℃ (KV2≥34J), reflecting excellent low-temperature toughness (GB/T 16270-2009 standard requirement).
Note 6: Q620D 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 Q620D are as follows:

Property Q620D (GB/T 16270-2009)
China | Quenched & Tempered		 S620QL (EN 10025-6:2004)
EU | Quenched & Tempered		 ASTM A514 Gr.S (ASTM A514)
US | Quenched & Tempered
Min Yield Strength (MPa) 620 (≤50mm) 620 (≤100mm) 690 (≤100mm)
Tensile Strength (MPa) 720~900 720~900 760~895
Min Elongation (%) 15 15 15
Impact Test Temperature (°C) -20℃ (KV2≥34J) -20℃ (KV≥40J) -40℃ (KV≥27J)
Max Carbon Content (%) 0.20 0.20 0.21
Carbon Equivalent CEV ≤ 0.50~0.58 (by thickness) 0.55 0.50
Max Thickness (mm) 150 150 100
Main Applications High-load engineering machinery, heavy structural components in cold regions High-rise building structures, heavy crane components Ultra-high strength 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. Q620D is equivalent to S620QL in EN standard in terms of strength grade and low-temperature toughness.

Application Cases

High Load Engineering Machinery with Q620D Steel

High Load Engineering Machinery

Heavy excavator arms, large crane booms, hydraulic support components and mining machinery in cold regions. Q620D's ultra-high strength (yield ≥620MPa) and excellent -20℃ low-temperature toughness meet the extreme load requirements of heavy engineering machinery in cold environments.

Heavy Building Structures with Q620D 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 cold regions. Q620D's high strength-to-weight ratio and -20℃ toughness reduce structural weight while ensuring safety in low-temperature environments.

Port Heavy Machinery with Q620D Steel

Port Heavy Machinery

Large port cranes, ship unloaders, container gantry cranes and bulk cargo handling equipment in cold coastal areas. Q620D's ultra-high strength, wear resistance, structural stability and -20℃ toughness meet the long-term heavy-duty operation requirements in low-temperature port environments.

Frequently Asked Questions

What are the core performance indicators of Q620D high-strength steel plate? +

The core performance indicators of Q620D are as follows: 1. Mechanical properties: yield strength ≥620MPa, tensile strength 720~880MPa, elongation ≥14%; 2. Low-temperature toughness: -20℃ impact test (KV2≥47J) to ensure toughness in cold environments; 3. Carbon equivalent: CEV ≤0.55% (for thickness ≤50mm) to guarantee weldability; 4. Delivery state: quenched + tempered (QT) to balance strength and toughness; 5. Chemical composition: strict control of C≤0.20%, Mn≤1.80%, Si≤0.60%, and microalloying with Nb/V/Ti to refine grains and improve strength-toughness matching.

What are the typical application scenarios of Q620D steel plates? +

Q620D is widely used in high-strength structural fields requiring low-temperature performance: 1. Engineering machinery: heavy crane booms, excavator chassis, load-bearing structures of mining machinery; 2. Construction machinery: high-rise building steel structures, large-span bridge bearing components, seismic-resistant structural parts; 3. Transportation equipment: heavy truck frames, special vehicle compartments (refrigerated trucks, engineering vehicles); 4. Energy equipment: wind power tower flanges, hydraulic support columns for coal mines, offshore platform auxiliary structures; 5. Special equipment: armored vehicle chassis, fire-fighting equipment frames, port hoisting machinery.

What are the key welding process requirements for Q620D steel plates? +

Key welding requirements for Q620D: 1. Preheating control: preheating temperature 100~150℃ (thickness ≥50mm needs 120~180℃) to prevent cold cracks; 2. Interpass temperature: ≤220℃ to avoid overheating and reduce toughness; 3. Welding materials: low-hydrogen electrodes (E9018-G) or solid wires (ER90S-G) matching strength grade; 4. Heat input: control within 15~25kJ/cm, adopt multi-layer multi-pass welding to reduce welding stress; 5. Post-weld treatment: stress relief annealing (580~620℃) is recommended for thick plates or complex structures, and avoid rapid cooling after welding.

What is the difference between Q620D and Q620C/Q620E grades? +

The core difference lies in low-temperature impact performance and impurity control: 1. Impact temperature: Q620C (0℃, KV2≥34J), Q620D (-20℃, KV2≥47J), Q620E (-40℃, KV2≥47J); 2. Impurity control: Q620D has stricter P (≤0.020%) and S (≤0.010%) limits than Q620C, and slightly looser than Q620E (P≤0.015%, S≤0.008%); 3. Application scenarios: Q620C for normal temperature, Q620D for cold regions (-20℃), Q620E for severe cold regions (-40℃); 4. Weldability: Q620D has a moderate carbon equivalent (CEV≤0.55%), balancing strength and welding processability better than Q620E.

What are the customization capabilities of Q620D steel plates? +

CEHE Steel provides full customization for Q620D: 1. Size customization: thickness 8~120mm, width 1500~4000mm, length 3000~18000mm (precision cutting to custom size); 2. Performance customization: Z-direction performance (Z15/Z25/Z35) for thickness ≥20mm, impact energy upgrade (KV2≥50J), surface finish grade (A/B/C); 3. Processing customization: flame/plasma cutting, beveling, shot blasting and painting, anti-corrosion coating; 4. Certification customization: mill test certificate (MTC) per EN 10204 3.1/3.2, third-party inspection (SGS/BV/CCS) reports; 5. Delivery cycle: stock for common sizes (3-7 days), customized production (20-30 days) with strict quality control.

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