Q370R Steel Plate for Pressure Vessels (GB/T 713.2-2023)

Q370R is a grade designation for pressure vessel steel plate 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 is approximately equivalent to P355NH / P355N / P355NL1 in the EN 10028 standard and P355NH in ISO 9328. There is no direct ASME equivalent; substitution requires design approval.

Q370R steel plates are delivered in normalized or normalized + tempered condition, with mandatory impact testing at -20°C (≥47 J).

Q370R designation explanation: Q stands for Yield Strength, 370 represents 370 MPa, R denotes Pressure Vessel Steel.

Yield Strength

≥370 MPa

Tensile Strength

530–630 MPa

Impact (-20°C)

≥47 J

Standard

GB/T 713.2-2023

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Product Overview

Q370R Steel Plate is a low–alloy pressure vessel steel manufactured in accordance with GB/T 713.2. With a minimum yield strength of 370 MPa, it is designed for higher-pressure boilers, pressure vessels, and pressure-retaining equipment where higher strength and low-temperature toughness are required.

Compared with Q245R and Q345R, Q370R provides higher strength, allowing reduced wall thickness and weight savings in pressure equipment design, while maintaining good weldability and low-temperature impact toughness at -20°C.

Yield 370MPa Low-alloy Weldable -20°C impact

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Core Advantages

Higher strength (370 MPa yield) enables weight reduction
Guaranteed -20°C impact toughness (≥47 J)
Professional technical support (GB/EN/ISO)
Customizable: HIC/SSC, high-temp properties
Simulated PWHT · Third-party inspection

Professional Technical Support & Customization

Comprehensive Knowledge Base: Our sales team is proficient in mainstream domestic and international pressure vessel standards. Whether it's the Chinese national standard Q370R, the European standard P355NH/P355N, or other equivalents, 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: If your design has special requirements (e.g., specific hardness, high-temperature mechanical properties, simulated post-weld heat treatment, HIC/SSC testing, restricted carbon equivalent), we support customized production.

Normalized ≈30 days

N+T ≈35 days

Max thickness 100mm

📋 Applications

High-pressure boilers

High-pressure vessels & reactors

Heat exchangers & condensers

Spherical tanks

Large storage tanks

Pressure shells & heads

📦 Stock Resources

Normalized plates: 6–60mm (W:2000–2500, L:11000–12500)

N+T plates: 12–100mm (W:2000–2500, L:11000–12500)

Custom rolling: up to 100mm

Click to check Q370R inventory

Spot stock size range and supply conditions

Normalized (N)

Thickness (mm)	Width (mm)	Length (mm)
6–60	2000/2200/2500	11000–12500

Normalized + Tempered (N+T)

Thickness (mm)	Width (mm)	Length (mm)
12–100	2000/2200/2500	11000–12500

Supply Condition: N, N+T (per GB/T 713.2-2023)

Q370R Chemical Composition (max %)

C	Si	Mn	Cu	Ni	Cr	Mo	Nb	V	Ti	P	S
≤0.18	≤0.55	1.20–1.70	≤0.30	≤0.30	≤0.30	≤0.08	≤0.050	≤0.050	≤0.030	≤0.020	≤0.010

Additional limits: Nb+V+Ti ≤ 0.22%; Cu+Cr+Mo ≤ 0.45%. Thickness >60mm: carbon upper limit may be raised to 0.20% by agreement. Nb+V+Ti total for Q245R/Q345R/Q370R shall not exceed 0.050 / 0.120 / 0.150% respectively when added.

Q370R · alloying elements & roles

per GB/T 713.2

C Carbon ≤0.18%

Influences strength and hardness; kept low for weldability.

Si Silicon ≤0.55%

Increases strength, deoxidizer.

Mn Manganese 1.20–1.70%

Enhances strength and toughness, desulfurizer.

P Phosphorus ≤0.020%

Harmful element, reduces toughness; tighter limit than Q345R.

S Sulfur ≤0.010%

Harmful element, causes hot shortness.

Cu Copper ≤0.30%

Residual element; Cu+Cr+Mo ≤ 0.45%.

Cr Chromium ≤0.30%

Residual element; improves hardenability slightly.

Ni Nickel ≤0.30%

Residual element; enhances toughness.

Nb Niobium ≤0.050%

Microalloying; refines grain, improves strength. Nb+V+Ti ≤0.22%.

V Vanadium ≤0.050%

Microalloying; refines grain, improves toughness.

Ti Titanium ≤0.030%

Microalloying; refines grain, fixes carbon and nitrogen.

Mo Molybdenum ≤0.08%

Residual element; improves high-temperature strength.

Alt Aluminum (total) ≥0.015%

Deoxidizer, refines grain structure.

N Nitrogen controlled by process

Controlled by production process; affects aging and grain refinement.

Q370R typical ranges (wt%): C ≤0.18, Si ≤0.55, Mn 1.20–1.70, P≤0.020, S≤0.010, Cu≤0.30, Cr≤0.30, Ni≤0.30, Mo≤0.08, Alt≥0.015. Nb+V+Ti ≤0.22, Cu+Cr+Mo ≤0.45. N controlled per process.

Q370R Mechanical Properties & Impact Test

Thickness (mm)	YS (MPa)	TS (MPa)	Elong (%)	Impact -20°C (J)
6–16	≥370	530–630	20	≥47
>16–36	≥360	530–630	20	≥47
>36–60	≥340	520–620	20	≥47

Note: Q370R is delivered in normalized or normalized + tempered condition. Impact test at -20°C is mandatory per GB/T 713.2-2023. Bending test: D=2a.

Q370R High-Temperature Mechanical Properties (Rp0.2 / MPa, min)

Thickness (mm)	100°C	150°C	200°C	250°C	300°C	350°C	400°C
>20–36	330	310	290	275	260	245	230
>36–60	310	290	275	260	250	235	220
>60–100	290	270	265	250	245	230	215

Note: High-temperature tensile test is performed upon customer request for thickness >20mm, test temperature to be specified in the contract. Values shown are Rp0.2 (or Rcl) minimum in MPa.

Q370R vs P355NH vs P355N

Item	Q370R	P355NH	P355N
Standard	GB/T 713.2	EN 10028-2	EN 10028-2
Delivery condition	N / N+T	N	N
Min yield (MPa)	370 (≤16mm)	355 (≤16mm)	355 (≤16mm)
Impact mandatory	Yes (-20°C, ≥47J)	Yes (-20°C, ≥40J)	Yes (0°C, ≥40J)
Specified temp	-20°C	-20°C	0°C

Scenario-Based Recommendation · GB Grade Comparison

Q245R

Low‑pressure vessels, boilers, economical choice

Yield ≥245 MPa · Tensile 400-520 MPa
Charpy: 0°C ( -20°C optional )

vs Q370R: much lower strength, low‑cost for low‑stress designs

Q245R details

Q345R

Standard pressure vessels, most widely used

Yield ≥345 MPa · Tensile 510-640 MPa
Charpy 0°C

vs Q370R: 25 MPa lower yield, -20°C impact not mandatory

Q345R details

Q370R

High‑pressure vessels, lightweight design, -20°C

Yield ≥370 MPa · Tensile 530-630 MPa
Charpy -20°C ≥47J

vs Q345R: 25 MPa higher yield, mandatory -20°C impact

Current Grade

16MnDR

Cryogenic tanks, cold regions, LPG

Yield ≥315 MPa · Tensile 490-620 MPa
Charpy -40°C guaranteed

vs Q370R: lower strength but -40°C capability; purpose‑built for cryogenic

16MnDR details

09MnNiDR

Ethylene, chemical, extreme‑cold equipment

Yield ≥280 MPa · Tensile 430-570 MPa
Charpy -70°C (Ni alloyed)

vs Q370R: much lower strength but -70°C capability

09MnNiDR details

Quick selection path: Q245R (economy) → Q345R (standard) → Q370R (higher strength, -20°C) ; Low‑temp branch: 16MnDR (-40°C) → 09MnNiDR (-70°C)

Quality Control & Inspection

Mill Test Certificate 3.1 Chemical analysis Mechanical testing Charpy V-notch -20°C UT optional Third-party inspection

📐 Customizable Specification Range for Q370R

Thickness

6–100 mm

(custom rolling)

Width

1500–5200 mm

(adjustable per order)

Length

≤ 18000 mm

(max. single length)

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Delivery Condition

N N+T

N normalized · N+T normalized + tempered. Per GB/T 713.2-2023, Q370R is delivered in normalized or normalized + tempered condition.

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Additional Requirements

Simulated post‑weld heat treatment (PWHT)
Brinell hardness requirements (specify range)
HIC / SSC testing on request
High‑temperature tensile properties
Restricted carbon equivalent (CEV)

📋 Other customized technical conditions (impact temperature, UT grade, etc.) are also negotiable.

✅ The above ranges represent our standard customizing capability — dimensions, delivery conditions, and supplementary tests can be further adjusted to meet your project specifications.

Frequently Asked Questions

What is Q370R steel plate used for?

Q370R steel plate is mainly used for high-pressure boilers, pressure vessels, heat exchangers, spherical tanks, and other pressure-retaining equipment that requires higher strength and -20°C impact toughness, manufactured according to GB/T 713.2.

What is the difference between Q345R and Q370R?

Q370R has a higher minimum yield strength (370 MPa vs 345 MPa) and a mandatory -20°C impact test (≥47J). Q345R typically requires 0°C impact. Q370R also has tighter limits on P and S.

Is Q370R equivalent to P355NH?

Q370R is approximately equivalent to P355NH in EN 10028-2, with similar yield strength and -20°C impact requirements. However, they are not officially interchangeable; substitution requires design approval.

Does Q370R require impact testing?

Yes. Impact testing at -20°C with a minimum average energy of 47 J is mandatory under GB/T 713.2-2023 for Q370R.

Can you provide Q370R steel plates with custom sizes?

Yes. Custom rolling up to 100mm thick, 5200mm wide, 18000mm long. Delivery: approximately 30 days normalized, 35 days N+T.

Request a Quote

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