When it comes to pressure vessel fabrication, selecting the right material directly determines the safety, longevity, and performance of your equipment. Engineers and procurement professionals in the oil & gas, petrochemical, and power generation industries often find themselves comparing A-515 Gr 70 killed with A516 Gr 70 - two of the most widely specified carbon steel plates under ASTM and ASME standards.
At GNEE Steel, we have been manufacturing, stocking, and exporting these pressure vessel quality (PVQ) plates for over a decade. With a factory warehouse spanning 5000+ tons of inventory and a global logistics network, we help clients in over 60 countries secure certified steel plates with short lead times. In this comprehensive article, we break down the essential differences between these two grades to help you make an informed purchasing decision.
GNEE Steel factory workshop - pressure vessel steel plate
What Is the Difference Between A-515 Gr 70 Killed and A516 Gr 70? A Quick Overview
Before diving into technical details, here is a quick overview of the primary differences:
| Comparison Dimension | A-515 Gr 70 Killed | A516 Gr 70 |
|---|---|---|
| Standard Designation | ASTM A515/A515M | ASTM A516/A516M, ASME SA516 |
| Steel Type | Carbon-silicon killed steel | Carbon-manganese-silicon steel |
| Primary Temperature Service | Intermediate to high temperature | Moderate to lower temperature |
| Deoxidation Practice | Fully killed, coarse austenitic grain size | Fully killed, fine austenitic grain size practice |
| Notch Toughness | Lower; not suitable for low-temperature applications | High; excellent at low temperatures down to -46°C |
| Weldability | Good | Excellent (lower carbon equivalent) |
| Max Thickness | Typically up to 200 mm (8 in.) | Up to 204 mm (8 in.+) |
| Heat Treatment | Normalized (typical for high-temp service) | Normalized mandatory for thickness > 40 mm |
| European Equivalent | DIN 17155 19Mn6, JIS G3103 SB480 | EN 10028-2 P355GH |
Let us now explore each key area in detail.
ASTM A-515 Gr 70 Killed: Chemical Composition and Material Definition
What Is A-515 Gr 70 Killed Steel?
ASTM A515 Grade 70 is a carbon-silicon, fully killed steel plate specified under ASTM A515/A515M for welded boilers and other pressure vessels operating in intermediate to high-temperature service environments. The term "killed" indicates that the steel has been fully deoxidized during the steelmaking process through the addition of silicon, manganese, and aluminum, resulting in no gas evolution during solidification and a more uniform composition and property profile throughout the plate.
Chemical Composition of A-515 Gr 70 Killed (Product Analysis Max %)
| Thickness (mm) | C | Mn | Si | P max | S max |
|---|---|---|---|---|---|
| t ≤ 25 | 0.31 | 1.20 | 0.15–0.40 | 0.035 | 0.035 |
| 25 < t ≤ 50 | 0.33 | 1.20 | 0.15–0.40 | 0.035 | 0.035 |
| 50 < t ≤ 100 | 0.35 | 1.20 | 0.15–0.40 | 0.035 | 0.035 |
| 100 < t ≤ 200 | 0.35 | 1.20 | 0.15–0.40 | 0.035 | 0.035 |
| t > 200 | 0.35 | 1.20 | 0.15–0.40 | 0.035 | 0.035 |
Key observation: A515 Gr 70 contains higher carbon content (0.31–0.35%) compared to A516 Gr 70, which contributes to its superior performance at elevated temperatures but limits its low-temperature toughness.
Mechanical Properties of ASTM A-515 Gr 70 Killed
| Property | Value (SI) | Value (Imperial) |
|---|---|---|
| Tensile Strength | 485–620 MPa | 70–90 ksi |
| Yield Strength (min) | 260 MPa | 38 ksi |
| Elongation in 50 mm (min) | 21% | 21% |
| Elongation in 200 mm (min) | 17% | 17% |
A515 Gr 70's combination of high tensile strength and high-temperature resistance makes it suitable for boiler drums, superheater headers, and steam drums in thermal power plants.
ASTM A516 Gr 70: Chemical Composition, Properties, and Key Advantages
What Is A516 Gr 70 Steel?
ASTM A516 Grade 70 is a carbon-manganese-silicon pressure vessel quality steel plate designed for moderate and lower-temperature service. Unlike A515 Gr 70, A516 Gr 70 is specifically engineered to deliver improved notch toughness at low operating temperatures, making it the preferred choice for applications where brittle fracture resistance is critical. The steel is produced to a fine austenitic grain size practice, which enhances its fracture toughness at low temperatures.
Chemical Composition of A516 Gr 70 (Product Analysis)
| Thickness (mm) | C max | Mn | Si | P max | S max |
|---|---|---|---|---|---|
| 6.0–12.5 | 0.27 | 0.85–1.20 | 0.13–0.45 | 0.035 | 0.035 |
| 12.5–25 | 0.28 | 0.85–1.20 | 0.13–0.45 | 0.035 | 0.035 |
| 25–50 | 0.28 | 0.85–1.20 | 0.13–0.45 | 0.035 | 0.035 |
| > 50 | 0.30 | 0.85–1.20 | 0.13–0.45 | 0.035 | 0.035 |
Key observation: A516 Gr 70 has significantly lower maximum carbon content (0.27–0.30%) compared to A515 Gr 70, contributing to its excellent weldability and superior low-temperature notch toughness.
Mechanical Properties of ASTM A516 Gr 70
| Property | Value (SI) | Value (Imperial) |
|---|---|---|
| Tensile Strength | 485–620 MPa | 70–90 ksi |
| Yield Strength (min) | 260 MPa | 38 ksi |
| Elongation in 50 mm (min) | 21% | 21% |
| Elongation in 200 mm (min) | 17% | 17% |
While the tensile and yield strength ranges overlap with A515 Gr 70, the critical differentiator lies in impact toughness - A516 Gr 70 can undergo Charpy V-notch testing at temperatures as low as -46°C, a capability A515 Gr 70 does not reliably deliver.
A516 Gr 70 steel plate MTC
Key Difference 1: Temperature Service Range - The Most Critical Factor
The single most significant difference between A-515 Gr 70 killed and A516 Gr 70 lies in their designed operating temperature ranges.
A515 Gr 70: Primarily engineered for intermediate and higher-temperature service in welded boilers and other pressure vessels. It is designed to maintain structural integrity and resist creep and graphitization at elevated temperatures. This is achieved through its higher carbon and silicon content, combined with a coarse austenitic grain size practice that enhances high-temperature stability. Typical applications operate at temperatures up to 427–538°C (800–1000°F).
A516 Gr 70: Specifically optimized for moderate and lower-temperature service. The fine austenitic grain size practice provides superior notch toughness and impact resistance at temperatures down to -46°C (-50°F), making it suitable for cryogenic and sub-zero applications.
Bottom line: If your project involves high-temperature steam drums or boilers, choose A515 Gr 70. If your vessel operates in refrigerated or potentially sub-zero environments, A516 Gr 70 is the correct specification.
Key Difference 2: Grain Size Control - Coarse vs Fine Austenitic Grain Practice
A fundamental metallurgical distinction between the two grades lies in their grain structure control:
Coarse Grain Practice (A515 Gr 70 Killed)
A515 Gr 70 is manufactured to a coarse austenitic grain size practice (typically ASTM grain size 1–5). This intentional coarsening of the grain structure provides enhanced resistance to creep deformation and graphitization at high service temperatures. Larger grains mean fewer grain boundaries, which reduces the paths for dislocation movement - a critical advantage when the steel operates in high-temperature, long-duration service environments.
Fine Grain Practice (A516 Gr 70)
A516 Gr 70 is produced to a fine austenitic grain size practice (typically ASTM grain size 5 or finer). The finer grain structure dramatically improves low-temperature notch toughness and impact resistance. More grain boundaries act as barriers to crack propagation, which is why A516 Gr 70 excels in applications where the risk of brittle fracture at lower temperatures must be minimized.
This grain size difference is not merely technical - it has real-world consequences for material selection and ASME pressure vessel code compliance.
Key Difference 3: Carbon Content and Its Impact on Weldability
Carbon Content Comparison
| Grade | Carbon Content (max %) | Implication |
|---|---|---|
| A515 Gr 70 | 0.31–0.35 | Higher carbon → reduced weldability, higher preheat requirements |
| A516 Gr 70 | 0.27–0.30 | Lower carbon → excellent weldability, lower preheat requirements |
The higher carbon content in A515 Gr 70 contributes to its high-temperature strength but makes it more susceptible to hydrogen-induced cracking (cold cracking) during welding. Welding A515 Gr 70 typically requires controlled preheating and interpass temperature management, while A516 Gr 70's lower carbon equivalent allows for smoother fabrication with less stringent welding procedures.
Key Difference 4: Heat Treatment Requirements
Normalizing for A515 Gr 70
A515 Gr 70 is typically supplied in the normalized condition to optimize its high-temperature properties. Normalizing involves heating the plate to an austenitizing temperature range of 900–950°C and air-cooling to refine grain structure, reduce internal stresses, and improve creep resistance at elevated service temperatures.
Normalizing for A516 Gr 70
For A516 Gr 70, normalization is mandatory for plates exceeding 40 mm (1.5 in.) in thickness, as specified in ASTM A516/A516M. The normalized plate is heated to 1,650–1,750°F (900–950°C) and air-cooled to refine grain size, enhance low-temperature toughness, and homogenize the microstructure. This mandatory requirement ensures that even thick-section A516 Gr 70 plates maintain adequate notch toughness for safety-critical pressure vessel applications.
Application Comparison: Where Each Grade Excels
Typical Applications for A-515 Gr 70 Killed
- Industrial boilers and steam drums requiring sustained high-temperature performance
- Superheater headers in thermal power plants
- High-temperature heat exchangers in refineries
- Petrochemical pressure vessels operating at elevated temperatures
- Power generation equipment where creep resistance is critical
Typical Applications for A516 Gr 70
- Low to moderate-temperature pressure vessels in chemical processing
- Liquefied petroleum gas (LPG) storage tanks requiring low-temperature toughness
- Cryogenic storage vessels (with supplementary Charpy V-notch testing)
- Oil & gas separators and distillation columns
- Sour service pressure vessels (with optional HIC and NACE MR0175 compliance)
- API 650 and API 620 storage tanks
Conclusion: Making the Right Choice - A-515 Gr 70 Killed or A516 Gr 70?
Choosing between A-515 Gr 70 killed and A516 Gr 70 ultimately depends on your project's operating temperature range, fabrication requirements, and mechanical property priorities. If your pressure vessel operates in intermediate to high-temperature environments - think steam drums, superheaters, or refinery boilers - A-515 Gr 70 killed with its coarse grain practice and higher carbon content is the correct specification. However, if your application demands superior low-temperature notch toughness, excellent weldability, and flexibility for sour service or cryogenic environments, A516 Gr 70 is the industry-preferred choice backed by decades of safe service history.
Unsure which grade fits your project? Our technical team at GNEE Steel is ready to help you evaluate your specifications and recommend the right material. Contact us today for a personalized quote, free material advice, and guaranteed certification support.
Frequently Asked Questions (FAQ)
Is A515 Gr 70 always killed?
Yes. ASTM A515/A515M specifies that the steel shall be killed and produced to a coarse austenitic grain size practice. Killed steel ensures no gas evolution during solidification, resulting in uniform composition and properties throughout the plate.
Can A516 Gr 70 be used at high temperatures?
While A516 Gr 70 can withstand moderately elevated temperatures, it is not designed for sustained high-temperature service where creep and graphitization become limiting factors. For continuous operation above approximately 400°C, A515 Gr 70 or alloy steel grades such as SA387 are more appropriate.
What is the European equivalent of A516 Gr 70?
The direct European equivalent is EN 10028-2 P355GH, which shares similar tensile strength and application characteristics for pressure vessel service at moderate and lower temperatures.
Does GNEE Steel offer cut-to-size services for A515 and A516 plates?
Yes. We provide precision cutting services (oxy-fuel, plasma, laser, and waterjet) as well as edge preparation and beveling to your exact specifications. Contact our sales team with your required dimensions.
What is ASTM A515 material?
ASTM A515 Plate Steel
Carbon-silicon steel plates primarily for intermediate- and higher-temperature service in welded boilers and other pressure vessels.
What is the equivalent material of ASTM A515?
Equivalent material of ASTM A515 Grade 70 steel plate have JIS G3103 SB480, DIN 1715 1.0844, A48 CP,AP,FP; Fe 460-2-KW, SS21,02,01; Gr 360,400; ASTM A414 Grade F.
What is the difference between A515 GR 60 and A516 GR 60?
A515 Grade 60 steel plate is primarily for intermediate- and higher-temperature service in welded boilers and other pressure vessels. A516 Grade 60 carbon steel plate grade is mainly utilized primarily in welded pressure vessels for moderate to lower temperature service.
What is A516 GR 60 material equivalent to?
P265GH
ASTM A516 Grade 60 is a boiler / pressure vessel quality of steel plate for use in low to moderate services. It has improved notch toughness. A516 GD 60 steel plate is comparable to the P265GH and 430A/B grades.
