When specifying steel for storage tanks, bridges, or pressure vessels, the choice often comes down to one question: strength or toughness? With ASTM
A573 grade 70, you don't have to choose.
This carbon steel plate grade delivers both — and the numbers prove it.
1. Superior Strength-to-Toughness Ratio
Standard structural steels like
A36 offer a yield strength of 36 ksi. ASTM A573 Grade 70 provides 42 ksi minimum yield strength and a tensile range of 70–90 ksi. That's nearly 17% higher yield strength than A36 — without sacrificing ductility.
2. Verified Impact Performance (Charpy Test Data)
What truly sets Grade 70 apart is its improved notch toughness. While specific Charpy values vary by thickness and testing temperature, the specification mandates fully-killed, fine-grain practice specifically for applications requiring enhanced impact resistance. Independent testing confirms consistent performance down to -20°F, where conventional carbon steels become brittle.
3. Reliable Elongation Numbers for Fabrication
Elongation indicates formability. Grade 70 maintains 21% minimum elongation in 2 inches and 18% in 8 inches for plates wider than 24 inches. These figures mean you can roll, bend, and form the plate into tank shells and penstocks without edge cracking — a critical factor for fabricators tracking scrap rates.
4. Weldability Without Preheating (Shop-Proven)
Carbon content is the enemy of weldability. With a maximum carbon of 0.27%, ASTM A573 Grade 70 welds reliably using standard procedures. Most thicknesses require no preheating, reducing shop labor costs by an estimated 15–20% compared to higher-carbon grades.
5. Real-World Applications Backed by Standards
From liquefied gas storage tanks to crane runway beams, Grade 70 is the specified material where both strength and impact resistance matter. The 1.50-inch maximum thickness covers the majority of structural and pressure vessel applications.
Bottom Line: If your project demands certified mechanical properties and verified low-temperature performance, ASTM A573 Grade 70 isn't just an option — it's the data-backed choice.
