Q420R Steel Plate for Pressure Vessels (GB/T 713)

Q420R is a high-strength pressure vessel steel plate grade under the Chinese national standard. The manufacturing specification is GB/T 713.2-2023 (previous version: GB/T 713-2014), and the ultrasonic testing standard is NB/T 47013.3-2015.

This grade offers higher strength compared to Q370R. It is equivalent to P420NH or P420NL1 in the EN standard and similar to SA612 or SA737 in the ASME standard.

Q420R steel plates are impact tested at -20 C as standard, with minimum absorbed energy of 60 J (average).

Q420R designation explanation: Q stands for Yield Strength, 420 represents 420 MPa, R denotes Pressure Vessel Steel.

Yield Strength
>=420 MPa
Tensile Strength
590-720 MPa
Impact (-20 C)
>=60 J
Standard
GB/T 713.2-2023

Product Overview

Q420R Steel Plate is a high-strength carbon-manganese pressure vessel steel manufactured in accordance with GB/T 713.2-2023. It is specifically designed for high-pressure boilers, large pressure vessels, and heavy-duty equipment where superior strength and good weldability are critical.

Compared with Q370R, Q420R offers 50 MPa higher yield strength, enabling significant thickness reduction and weight savings in pressure vessel design while maintaining excellent reliability and safety under demanding service conditions.

Yield 420MPa Fine-grain Weldable -20 C Impact

Core Advantages

  • Higher strength than Q370R (420 MPa vs 370 MPa)
  • Standard -20 C impact testing (60 J)
  • Customizable: HIC/SSC, high-temp properties
  • Normalized + tempered (N+T) delivery condition

Professional Technical Support and Customization

Comprehensive Knowledge Base: Our sales team is proficient in mainstream domestic and international pressure vessel standards. Whether it's the Chinese national standard Q420R, the American ASME standard SA612/SA737, or the European standard P420NH/P420NL1, we can provide accurate technical communication.

Zero Communication Errors: With solid product knowledge, we can avoid all basic errors during the order technical condition confirmation stage, ensuring the accuracy of your order.

Flexible Customization Capabilities: The Q420R standard does not have mandatory requirements for hardness and high-temperature performance. If your design has special requirements (e.g., specific hardness, high-temperature mechanical properties, simulated post-weld heat treatment, HIC/SSC testing), we support customized production.

Hot-rolled ~15 days
Normalized ~30 days
Max thickness 100mm


 Applications

High-pressure boilers
Large pressure vessels
Heat exchangers
LPG storage tanks
Industrial gas storage
Pressure shells and heads


 Stock Resources

Normalized plates: 12-100mm (W:2000-2500, L:11000-12500)

Hot-rolled plates: 6-36mm (W:1800-2500, L:11000-12500)

Hot-rolled coils: 5-16mm (W:1500-2000)

Spot stock size range and supply conditions

Hot Rolled (AR)
Thickness (mm) Width (mm) Length (mm)
6-36 1800/2000/2200/2500 11000-12500
Normalized (N/N+T)
Thickness (mm) Width (mm) Length (mm)
12-100 2000/2200/2500 11000-12500
Hot-Rolled Coils
Thickness (mm) Width (mm)
5-16 1500/1800/2000

Supply Condition: CR, AR, N, N+T

Q420R Chemical Composition (max %)

C Si Mn Cu Ni Cr Mo Nb V Ti P S
<=0.20 <=0.55 1.20-1.60 <=0.30 0.20-0.50 <=0.30 <=0.08 0.015-0.050 <=0.1 <=0.030 <=0.020 <=0.010

Q420R - Alloying Elements and Roles

per GB/T 713.2-2023
C Carbon <=0.20%

Influences strength and hardness.

Si Silicon <=0.55%

Increases strength, deoxidizer.

Mn Manganese 1.20-1.60%

Enhances strength and toughness, desulfurizer.

P Phosphorus <=0.020%

Harmful element, reduces toughness.

S Sulfur <=0.010%

Harmful element, causes hot shortness.

Cu Copper <=0.30%

Improves corrosion resistance.

Cr Chromium <=0.30%

Improves corrosion resistance and hardness.

Ni Nickel 0.20%-0.50%

Enhances toughness and low-temperature properties.

Mo Molybdenum <=0.08%

Improves high-temperature strength and corrosion resistance.

Nb+V+Ti Microalloying Total <=0.220%

Combined addition refines grain structure and improves strength. Nb<=0.050%, V<=0.050%, Ti<=0.030%.

Q420R typical ranges (wt%): C <=0.20, Si <=0.55, Mn 1.20-1.60, P<=0.020, S<=0.010, Cu<=0.30, Cr<=0.30, Ni<=0.30, Mo<=0.08. Microalloying total (Nb+V+Ti) <=0.220%. Cu+Cr+Mo <=0.45.

Q420R Mechanical Properties and Impact Test

Thickness (mm) YS (MPa) TS (MPa) Elong (%) Impact -20 C (J)
>60-100 >=330 510-610 20 >=47
6-20 >=420 590-720 18 >=60

Q420R High-Temperature Mechanical Properties (Rp0.2 or RcL, MPa)

Thickness (mm) 100 ℃ 150 ℃ 200 ℃ 250 ℃ 300 ℃ 350 ℃ 400 ℃ 450 ℃
6-20 380 355 330 305 280 255 240 -
>20-30 365 340 315 290 270 245 230 -

Note: High-temperature tensile properties available upon request. Values for thickness >30mm can be negotiated.

Q420R vs SA612 vs P420NH

Item Q420R SA612 P420NH
Standard GB/T 713.2 ASME SA612 EN 10028-2
Yield Strength >=420 MPa >=345 MPa >=420 MPa
Tensile Strength 590-720 MPa 550-690 MPa 560-740 MPa
Impact mandatory Yes (-20 C, >=60J) Project dependent Yes (0 C, >=40J)
Specified temp -20 C Not specified 0 C

Scenario-Based Recommendation - GB Grade Comparison

Q345R

General pressure vessels, boilers
Yield >=345 MPa - Tensile 510-640 MPa
Charpy: 0 C
Standard grade, cost-effective
Q345R details

Q370R

High-pressure vessels, lightweight design
Yield >=370 MPa - Tensile 530-630 MPa
Charpy -20 C
Higher strength than Q345R
Q370R details

Q420R

High-pressure large vessels, heavy equipment
Yield >=420 MPa - Tensile 590-720 MPa
Charpy -20 C (60 J)
vs Q370R: 50 MPa higher yield
[Current Grade]

Q460R

Ultra-high pressure, critical equipment
Yield >=460 MPa - Tensile 630-750 MPa
Charpy -20 C (60 J)
vs Q420R: 40 MPa higher yield
Q460R details

16MnDR

Cryogenic tanks, cold regions
Yield >=315 MPa - Tensile 490-620 MPa
Charpy -40 C
Low-temperature application
16MnDR details
Quick selection path: Q245R (economy) -> Q345R (standard) -> Q370R (higher strength) -> Q420R (high strength) -> Q460R (ultra-high) ; Low-temp branch: 16MnDR (-40 C)

Quality Control and Inspection

Mill Test Certificate 3.1 Chemical analysis Mechanical testing Charpy V-notch -20 C High-temp tensile UT optional

Customizable Specification Range for Q420R

Thickness
6-100 mm
(custom rolling)
Width
1500-5200 mm
(adjustable per order)
Length
<= 18000 mm
(max. single length)

Delivery Condition

AR CR TMCP N+T N

AR as rolled - CR controlled rolled - TMCP thermo-mechanical - N+T normalized + tempered - N normalized

Additional Requirements

  • Simulated post-weld heat treatment (PWHT)
  • Brinell hardness requirements
  • HIC / SSC testing
  • High-temperature tensile properties

Other customized technical conditions are also negotiable.

The above ranges represent our standard customizing capability.

Frequently Asked Questions

What is Q420R steel plate used for?

Q420R steel plate is mainly used for high-pressure large boilers, pressure vessels, reactors, and heavy-duty equipment where high strength (420 MPa yield) is required.

What is the impact test temperature for Q420R?

Q420R steel plates are impact tested at -20 C as standard, with minimum average absorbed energy of 60 J (Charpy V-notch).

What is the difference between Q370R and Q420R?

Q420R offers 50 MPa higher yield strength (420 MPa vs 370 MPa) and higher tensile strength (590-720 MPa vs 530-630 MPa). Q420R also has higher impact energy requirement (60 J vs 47 J at -20 C).

What is the delivery condition for Q420R?

Q420R is typically delivered in normalized (N) or normalized + tempered (N+T) condition. Hot-rolled (AR) and controlled rolled (CR) are also available upon request.

Can you provide Q420R steel plates with custom sizes?

Yes. Custom rolling up to 100mm thick, 5200mm wide, 18000mm long. Delivery: 15-20 days hot-rolled, 30-35 days normalized.

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Emails go directly to customize@cehesteel.com - reply within 12h.

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