One Element Family, Yield Strengths From 250 to 1,900 MPa

Few material families on this site span as wide a mechanical range from essentially one base element as steel does, and the tool engineers use to predict how a given composition will actually behave is a single, real equation.

A36 structural

250 MPa yield

AISI 1018

370 MPa yield

AISI 1045

530 MPa yield

AISI 4140 (alloy)

655 MPa yield

AISI D2 (tool steel)

1500 MPa yield

Maraging 300

1900 MPa yield

Yield strength across representative grades. Maraging 300 yields at nearly 8 times A36's strength, from the same base element.

Carbon equivalent: predicting hardenability from composition

CE = C + \frac{Mn}{6} + \frac{Cr+Mo+V}{5} + \frac{Ni+Cu}{15}

Carbon equivalent, a standard welding and hardenability formula. It expresses how much the various alloying elements, not just carbon itself, contribute to how readily a steel forms hard, brittle martensite on cooling, covered on this material's materials science page. A higher CE means more preheating and slower cooling are needed to weld the steel without cracking.

A higher carbon equivalent predicts both greater hardenability (useful for tool steels like D2) and greater difficulty welding without cracking, the same underlying martensite-formation tendency cutting both ways depending on whether you want it.

Why stainless grades sit apart

The stainless grades covered on this material’s country-wise and application-wise pages (304, 316, 430, 410) add chromium specifically for corrosion resistance rather than pure strength, and their mechanical behaviour (austenitic 304 and 316 stay tough and ductile, ferritic 430 and martensitic 410 behave more like the carbon steels above) depends on which iron phase, covered on the materials science page, the added chromium and nickel stabilise.

Sources: grade properties and carbon equivalent formula are standard published specifications (ASM Handbook, AWS welding standards).