Sign in Start free
Steels & Irons · Low-alloy steel

AISI 4140 (42CrMo4)

Cr-Mo low-alloy steel with high hardenability and fatigue strength in the Q&T condition.

Typical properties

Published ranges for the usual condition. Heat treatment, section size and product form move these numbers — a starting point for a search, not design allowables.

Yield strength 655–1000 MPa (Q&T)
Tensile strength 900–1200 MPa
Density 7.85 g/cm³
Fracture toughness 60–100 MPa·√m

Bars show where this material sits against every other entry in the library that quotes the same property; strength scales are logarithmic.

Where it sits in the field

Strength against density for 25 engineering materials A logarithmic property chart. Density runs from 0.8 to 12 grams per cubic centimetre on the horizontal axis and strength from 10 to 3000 megapascals on the vertical axis. Each material is drawn as a vertical capsule spanning its published strength range, coloured by material class. 1 1.5 2 3 5 8 10 10 30 100 300 1000 3000 Density ρ (g/cm³) Strength σ (MPa) AISI 1045 carbon steel — ρ 7.85 g/cm³, tensile strength 565–850 MPa AISI 4140 (42CrMo4) — ρ 7.85 g/cm³, tensile strength 900–1200 MPa AISI 304 / 1.4301 stainless — ρ 7.9 g/cm³, tensile strength 515–720 MPa AISI 316L / 1.4404 stainless — ρ 8 g/cm³, tensile strength 485–620 MPa 17-4PH (1.4542) — ρ 7.75 g/cm³, tensile strength 930–1310 MPa Ductile iron EN-GJS-400-15 — ρ 7.1 g/cm³, tensile strength 400 MPa Aluminum 6061-T6 — ρ 2.7 g/cm³, tensile strength 310 MPa Aluminum 7075-T6 — ρ 2.81 g/cm³, tensile strength 572 MPa Ti-6Al-4V (Grade 5) — ρ 4.43 g/cm³, yield strength 830–1100 MPa Magnesium AZ31B — ρ 1.77 g/cm³, yield strength 150–220 MPa Copper Cu-ETP (C11000) — ρ 8.94 g/cm³, yield strength 70–330 MPa Cartridge brass C26000 (CuZn30) — ρ 8.53 g/cm³, tensile strength 300–900 MPa Bearing bronze C93200 (SAE 660) — ρ 8.9 g/cm³, tensile strength 240 MPa Monel 400 (NiCu30Fe) — ρ 8.8 g/cm³, yield strength 240–480 MPa Inconel 718 — ρ 8.19 g/cm³, yield strength 1030 MPa Hastelloy C-276 — ρ 8.89 g/cm³, yield strength 355 MPa Alumina Al₂O₃ (99.5 %) — ρ 3.9 g/cm³, compressive strength 2500 MPa Zirconia Y-TZP (3Y) — ρ 6.05 g/cm³, flexural strength 900–1200 MPa Silicon nitride Si₃N₄ — ρ 3.2 g/cm³, flexural strength 700–1000 MPa Polyamide PA66 (nylon) — ρ 1.14 g/cm³, tensile strength 80 MPa Polycarbonate (PC) — ρ 1.2 g/cm³, tensile strength 65 MPa PEEK — ρ 1.3 g/cm³, tensile strength 100 MPa PTFE (Teflon) — ρ 2.2 g/cm³, tensile strength 25 MPa CFRP (carbon/epoxy laminate) — ρ 1.55 g/cm³, tensile strength (0°) 1200–2000 MPa GFRP (glass/epoxy or polyester) — ρ 1.9 g/cm³, tensile strength 300–1100 MPa AISI 4140 · this material
Metals & Alloys (16) Ceramics & Glasses (3) Polymers & Elastomers (4) Composites (2) 25 of 37 library materials publish both a density and a strength. Bars span the published range; the dot is its midpoint.

Where it is used

Crankshafts, high-strength bolts, tooling, oil & gas components.

Processing and joining

Q&T heat treatment, nitriding; welding needs preheat + PWHT.

Class behaviour

AISI 4140 (42CrMo4) is a metals & alloys material: metallic bonding — delocalized electron gas; crystalline (mostly fcc, bcc, hcp).

That bonding is what produces the class-level trade-off you inherit here — high strength and stiffness with excellent toughness/ductility, set against prone to corrosion (except noble/passivated metals).

At a glance

Category
Steels & Irons
Subcategory
Low-alloy steel
Class
Metals & Alloys
Reference
steel-4140

Compare with

← All materials

Browse and filter the full library.

Is AISI 4140 (42CrMo4) the right call?

Give the selector your load case, environment and constraints, and it will rank this material against the alternatives — including the ones you had not considered.

Start free → See pricing