When selecting alloy steel materials for molds, machinery parts, or engineering applications, it’s common to see High Tensile Alloy Steel 4140QT and Plastic Mould Steel 2311 being compared — but are they truly interchangeable? Understanding the difference between 4140QT and 2311 steel grades can help ensure you choose the right material for your project’s performance and cost requirements.
At E Steel Sdn. Bhd., a trusted 4140 4140QT Steel Plate Supplier in Malaysia,
we go beyond selling materials — we help our customers make informed decisions.
With our in-house PMI (Positive Material Identification) Machine,
we guarantee that every plate and block supplied matches the correct chemical composition and grade as stated.
4140QT, also known as SCM440 or 709 steel, is a chromium-molybdenum (Cr-Mo) alloy steel widely used for high-strength applications.
The “QT” stands for “Quenched and Tempered,” a heat-treatment process that enhances its mechanical strength, toughness, and wear resistance.
Key Features of 4140QT Steel Plate:
Excellent strength-to-weight ratio
Good toughness and fatigue resistance
Suitable for heat treatment and machining
Common applications: shafts, gears, tool holders, and high-stress mechanical components
As a reliable SCM440 (also known as 709 Steel) Steel Plate Supplier, we supply this material in both annealed and QT conditions according to project requirements from minimum size of thk10mm.
2311, often known as P20 steel, is a pre-hardened mold steel used mainly in plastic injection molds, die casting molds, and tool frames. It offers good machinability and polishability but has lower strength compared to 4140QT.
Key Features of 2311 Steel:
Pre-hardened (~30–34 HRC) – ready for machining
Excellent polishability and uniform hardness
Suitable for plastic mold bases and dies
Cost-effective for tooling applications
|
Property |
4140QT (SCM440 / 709) |
2311 (P20) |
|---|---|---|
|
Type |
Cr-Mo Alloy Steel (Quenched & Tempered) |
Pre-Hardened Mold Steel |
|
Hardness |
28–32 HRC (adjustable by heat treatment) |
30–34 HRC (fixed) |
|
Tensile Strength |
Higher |
Moderate |
|
Machinability |
Moderate |
Excellent |
|
Toughness |
Excellent |
Good |
|
Main Use |
Shafts, gears, mechanical parts |
Plastic molds, mold bases |
|
Heat Treatment |
Can be hardened & tempered |
Usually not re-hardened |
In short,
2311 is better for mold tooling, while 4140QT excels in high-strength, load-bearing mechanical parts.
Ensuring the Correct Material is Supplied
At E Steel, our motto is ''Right Metals, Right Specifications to the Right Applications''.
We understand that using the wrong material can cause costly production issues.
To ensure accuracy, we utilize PMI testing on every batch — verifying that what you ordered is exactly what you receive.
Whether you are sourcing 4140QT steel plate, SCM440 plate, or 709 steel plate, our technical team provides mill certificates, full traceability, and professional material advice to help you choose the best option for your application.
Below is the PMI Report of the 4140 4140QT Steel Plate that we have performed.
Malaysia
