4140 / G42CrMo4 Steel Investment Casting

4140 (ASTM A732 IC 4140) and G42CrMo4 – 1.7231 (EN 10293) are chromium-molybdenum quench and temper steels. After hardening and tempering they reach high strength and good toughness, which makes them a standard choice for heavily loaded investment cast parts. BRK Metal casts 4140 / G42CrMo4 as a regular production alloy, for parts from 1 g to 25 kg.

Designations and equivalents

Standard	Designation	Note
ASTM A732	IC 4140 (class 8Q)	Investment casting grade, quenched and tempered
EN 10293	G42CrMo4 – 1.7231	European cast steel grade
AISI / SAE (wrought)	4140	Wrought equivalent; EN wrought grade 42CrMo4 – 1.7225

Chemical composition (wt. %, G42CrMo4 / EN 10293)

C	Si	Mn	Cr	Mo
0.38 – 0.45	≤ 0.60	0.60 – 1.00	0.80 – 1.20	0.15 – 0.30

Mechanical properties (quenched and tempered)

Property	IC 4140 – ASTM A732 8Q	G42CrMo4 – EN 10293 +QT2
Tensile strength Rm	≥ 1241 MPa	850 – 1000 MPa
Yield strength Rp0.2	≥ 1000 MPa	≥ 700 MPa
Elongation A	≥ 5 %	≥ 10 %

Values are minimums or ranges from the referenced standards for orientation; the current edition of the standard and your drawing requirements apply.

The two columns show different heat treatment levels: higher strength comes with lower elongation. State the required condition or minimum values on the drawing.

Typical applications

Firearm components, levers, links and brackets, gear and shaft parts, agricultural and construction machinery parts, and other components under high static or dynamic load. See our sector pages.

Design and production notes

Heat treatment: the specified properties are reached by quenching and tempering; the target hardness or strength should be defined on the drawing.
Section size: very thick and very thin sections in the same part respond differently to hardening; uniform walls give more consistent properties.
Corrosion: 4140 is not corrosion resistant; plan a coating such as galvanizing or cataphoresis (e-coating) where needed.
Finishing: machining and surface treatments on request.

More: steel investment casting, all material options, tolerances.

How to request a quote

Send a 2D drawing (PDF) and, if available, a 3D model (STEP), the alloy and condition you need, annual and per-order quantities, and any machining, coating or documentation requirements. Prices are calculated per part; the minimum order quantity depends on part size and geometry. Contact us to send your request.

FAQ

What is the difference between 4140 and 42CrMo4?

They are equivalent chromium-molybdenum steels from the American and European systems. For castings, the grades are IC 4140 (ASTM A732) and G42CrMo4 / 1.7231 (EN 10293).

Which strength can a 4140 investment casting reach?

It depends on heat treatment. ASTM A732 class 8Q requires at least 1241 MPa tensile strength, while EN 10293 G42CrMo4 +QT2 specifies 850–1000 MPa with higher elongation.

Is 4140 suitable for parts that need corrosion protection?

Yes, with a coating. 4140 itself rusts, so galvanizing, cataphoresis or another surface treatment is usually specified.

Contact

You can contact us either by phone or by email. Our team will get back to you as soon as possible.