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ASTM A516 Grade 70(A516GR70) Boiler and Pressure Vessel Steel Plate

Q: Does A516Gr70 steel plate require post-weld heat treatment?

Thickness ≤50 mm: Not mandatory, but recommended for critical welds.Thickness >50 mm or for use in hydrogen sulphide or wet corrosion environments: Post-weld heat treatment is mandatory to eliminate residual welding stresses and prevent hydrogen-induced cracking.

Q: What is the applicable temperature range for ASTM A516 Grade 70 boiler and pressure vessel steel plates?

Standard Safe Temperature Range: -29°C to 343°CThis is the range recommended for long-term stable operation in engineering design. Within this temperature range, the mechanical properties of the material (such as strength and toughness) can be reliably guaranteed.Extreme Temperature Limits: -46°C to 538°CLower Temperature Limit (-46°C): By using steel plates supplied in the normalised condition (commonly referred to as Gr.70N), the material can meet impact toughness requirements down to -46°C.Upper Temperature Limit (538°C): According to ASME codes, the maximum permissible service temperature for this material in non-corrosive environments is 538°C.

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ASTM A516 Grade 70(A516GR70) Boiler and Pressure Vessel Steel Plate have high strength, good toughness, and weldability, and can withstand working conditions under high temperature and pressure.

Standard :
ASTM A516/A516M
Grade :
A516 Grade 70 (A516GR70)
Thickness :
6.0-300 mm
Width :
1500-4050 mm
Length :
3000-15000 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

What is ASTM A516 Grade 70?

ASTM A516 Grade 70 is a standard specification established by the American Society for Testing and Materials (ASTM International) for pressure vessel plates, carbon steel, for moderate and lower-temperature service. It is one of the most commonly used carbon steels for constructing pressure vessels, boilers, and other critical equipment in the power generation, oil and gas, and petrochemical industries. Its key characteristics are excellent notch toughness and weldability.

ASTM: American Society for Testing and Materials (ASTM International). The organization that sets the standard.

A516: The specific designation for "Pressure Vessel Plates, Carbon Steel, for Moderate- and Lower-Temperature Service."

Grade 70: Indicates the minimum yield strength of the material is 70 ksi (kilo-pounds per square inch). Other common grades in the A516 standard are 55, 60, and 65.

Characteristics of ASTM A516 Grade 70(A516GR70) Boiler and Pressure Vessel Steel Plate

1.High strength: Have high strength and can withstand working conditions under high temperature and pressure.

2.Good Weldability: The relatively low carbon content makes it easy to weld using all common methods without pre-heating (for thinner sections) or requiring complex post-weld heat treatment procedures.

3.Excellent Notch Toughness: It performs well at lower temperatures, resisting brittle fracture. This is often verified by Charpy V-Notch (CVN) impact testing at specified temperatures (e.g., -50°F / -45°C for normalized plates).

4.Cost-Effective: It is a widely produced and available grade, making it more economical than low-temperature alloys or stainless steels.

Specifications and dimensions of the ASTM A516 Grade 70 steel supplied

Grade	A516 Grade 70
Standard	ASTM A516/A516M-25: Standard Specification for Pressure Vessel Plates, Carbon Steel, for Moderate and Lower-Temperature Service
Dimension range	Thickness: 6.0 - 300 mm, Width: 1500 - 4050 mm, Length: 3000 - 15000 mm
Surface Conditions	Natural, Sandblasting, Pickling, Oiling, Painting, etc.
Delivery Conditions	Normalized
Quality Control	All products undergo rigorous inspection and testing before leaving the factory, and factory test certificates are provided. Non-destructive testing (ultrasonic testing), Charpy V-notch impact testing, Z-axis performance testing (Z15/Z25/Z35 grade), and third-party testing (e.g., SGS) can be added according to the order.
Weldability	Excellent weldability. Care must be taken regarding preheating, selection of welding materials, interpass temperature control, and post-weld heat treatment to prevent cold cracking during welding and ensure low-temperature toughness.
Place of Origin	China

Chemical Composition

Chemical composition of ASTM A516 Grade 70 steel

Grade	A516 Grade 70
Element	C	Mn	Si	P	S
Content (%)	≤ 0.27	0.85-1.20	0.15-0.40	≤ 0.025	≤ 0.025

Carbon Equivalent (CEV)

Thickness (mm)	≤ 50	> 50
Typical CEV (wt %)	≤ 0.43	≤ 0.45

A516 Grade 70(A516GR70) is commonly used in welded structures, and its carbon equivalent is a very important indicator that directly affects the material's weldability.

Formula for calculating carbon equivalent (IIW): CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15

Mechanical Properties

Property	Standard Value	Practical Significance
Tensile Strength (MPa)	485–620	Resistance to fracture; higher values may reduce ductility.
Yield Strength (MPa)	≥260 (thickness ≤50mm)	Critical stress for plastic deformation; affects vessel wall thickness design.
Elongation (%)	≥17 (50mm gauge length)	Measures ductility; higher values indicate better deformation capacity.
Charpy V-Notch Impact	≥20J @ -46°C	Low-temperature toughness; essential for cryogenic applications.

Applications

Applications of ASTM A516 Grade 70(A516GR70) Boiler and Pressure Vessel Steel Plate:

It is widely used in the manufacture of various boilers, pressure vessels, and other equipment, mainly including the following aspects:

1. Power generation industry

Be used to manufacture various power station boilers, such as coal-fired boilers, gas-fired boilers, circulating fluidized bed boilers, etc.

2. Chemical industry

Be used to manufacture various chemical equipment, such as reaction kettles, evaporators, separators, etc.

3. Oil and natural gas industry

Be used to manufacture various oil and gas transmission pipelines, oil and gas storage tanks, and other equipment.

Other Information

Manufacturing Process Characteristics

The performance of ASTM A516 Grade 70 relies on a strict manufacturing process, with key steps including:

Smelting:

Typically carried out using a Basic Oxygen Furnace (BOF) or Electric Arc Furnace (EAF) to ensure uniform chemical composition and low levels of harmful elements.

Rolling:

Hot rolling is employed, with controlled rolling temperatures (such as through Thermo-Mechanical Controlled Process, TMCP) to refine the grain structure, enhancing toughness and strength.

Heat Treatment:

Normalizing is required by the standard: The steel plate is heated above the critical point (approximately 870-910°C), held at temperature, and then air-cooled. This refines the grain structure, homogenizes the microstructure, and ensures stable mechanical properties.

For thick plates (usually >50mm), additional tempering may be necessary to reduce internal stresses.

Non-Destructive Testing (NDT):

Testing must comply with ASTM A609 standards. Common methods include:

1) Ultrasonic Testing (UT) for detecting internal defects.

2) Magnetic Particle Testing (MT) or Liquid Penetrant Testing (PT) for detecting surface defects.

3) The extent of testing (e.g., 100% UT or sampling UT) must be determined based on design requirements.

Considerations for Using ASTM A516GR70 Boiler and Pressure Vessel Steel Plate

Cleaning:

Before use, the steel plate needs to be cleaned to remove surface oil stains and impurities to avoid affecting the service life of the steel plate.

Welding:

When welding the steel plate, pay attention to the welding temperature and welding time to avoid problems such as cracks in the weld.

Processing:

When processing the steel plate, use appropriate processing technology and equipment to avoid damaging the steel plate.

Storage:

When storing the steel plate, avoid moisture, direct sunlight, etc., to avoid affecting the quality of the steel plate.

Comparison with Other Grades

The key grades of ASTM A516 (55/60/65/70) are primarily distinguished by their tensile strength:

Grade	Tensile Strength (MPa)	Yield Strength (MPa)	Key Use Case
A516 Grade 55(A516GR55)	380-515	≥ 205	Low-pressure applications
A516 Grade 60(A516GR60)	415-550	≥ 220	Intermediate pressure
A516 Grade 65(A516GR65)	450-585	≥ 240	Higher pressure
A516 Grade 70(A516GR70)	485-620	≥ 260	High-pressure & low-temp

Summary

ASTM A516 Grade 70 is a benchmark carbon-manganese steel plate for medium to low-temperature pressure vessels. Its core advantages include "moderate strength, excellent weldability, and reliable low-temperature toughness," while being more cost-effective than alloy steel plates. During selection, it is essential to specify supplementary requirements based on actual working conditions (pressure, temperature, medium) and procure the material through official channels to ensure the authenticity of quality certifications.

Attachment

Mill Test Certificate & Certificate of Origin-A516GR70.pdf

FAQ

Q1:

Can A516Gr70 pressure vessel steel plates be used in hydrogen sulphide (H₂S) environments?

Yes, provided that HIC/SCC (hydrogen-induced cracking/stress corrosion cracking) testing is carried out.

Q2:

Does A516Gr70 steel plate require post-weld heat treatment?

Thickness ≤50 mm: Not mandatory, but recommended for critical welds.

Thickness >50 mm or for use in hydrogen sulphide or wet corrosion environments: Post-weld heat treatment is mandatory to eliminate residual welding stresses and prevent hydrogen-induced cracking.

Q3:

Can A516Gr70 steel plates be used for cryogenic tanks?

Yes, A516Gr70 steel plates are suitable for the manufacture of LNG, LPG and liquid nitrogen storage tanks, but must undergo impact testing at -40°C/-46°C as required.

Q4:

Must A516Gr70 boiler and pressure vessel steel plates be supplied in a normalised condition?

Yes, the standard mandates that they be supplied in a normalised condition.

Normalising: Heating to 30–50°C above Ac3, followed by air cooling, to refine the grain structure, relieve internal stresses and significantly improve low-temperature toughness.

Hot-rolled or controlled-rolled conditions cannot consistently meet impact requirements and are not a substitute for normalisation.

Q5:

What is the applicable temperature range for ASTM A516 Grade 70 boiler and pressure vessel steel plates?

Standard Safe Temperature Range: -29°C to 343°C

This is the range recommended for long-term stable operation in engineering design. Within this temperature range, the mechanical properties of the material (such as strength and toughness) can be reliably guaranteed.

Extreme Temperature Limits: -46°C to 538°C

Lower Temperature Limit (-46°C): By using steel plates supplied in the normalised condition (commonly referred to as Gr.70N), the material can meet impact toughness requirements down to -46°C.

Upper Temperature Limit (538°C): According to ASME codes, the maximum permissible service temperature for this material in non-corrosive environments is 538°C.