CNC Machining Services in china for Alloy Steel 4140

We offer a wide range of alloy steel 4140 CNC machining services. As a leading company in this field, we will provide you with highly accurate and good quality alloy steel 4140 CNC machining parts that meet even your most stringent requirements.

Alloy Steel 4140 CNC Machining services

Listed below are the two main services for machining Alloy Steel 4140.


CNC Milling for Alloy Steel 4140

EJCNC has a wide range of CNC milling capabilities, and we specialize in the machining of Alloy Steel 4140. Our CNC milling capabilities include high-precision surface grinding, drilling, turning, boring, slotting, and cut-off operations. We have a talented team of machinists with years of experience in CNC milling Alloy Steel 4140. Our advanced technology ensures that each component is manufactured to precise specifications for consistent quality and performance.

CNC turning for Alloy Steel

CNC Turning for Alloy Steel 4140

Our company is proud to offer CNC turning capability for Alloy Steel 4140. Our CNC Turning machines are equipped with advanced digital control systems that can perform precise and intricate operations on Alloy Steel 4140 with a high level of accuracy. We also have the ability to produce high-volume parts in a short amount of time, making our CNC Turning services highly efficient. With our reliable services, you can be assured that your Alloy Steel 4140 parts will be delivered on time and with quality results.

What is Alloy Steel 4140?

AISI 4140 alloy steel is a chromium-, molybdenum-, and manganese-containing low alloy steel. It has high fatigue strength, corrosion resistance, abrasion and impact resistance, toughness, and torsional strength. The following datasheet gives an overview of AISI 4140 alloy steel.

chemical components

AISI 4140 is made by placing iron, carbon, and other alloying elements into an electric furnace or oxygen furnace. 
The following table shows the chemical composition of AISI 4140 alloy steel.
4140 chemical components

mechanical properties

 The following table outlines the mechanical properties of AISI 4140 alloy steel.

4140 mechanical properties

Steel 4140 Alternative names / Designation

4140 Alternative names

Heat treatments for alloy steel 4140

AISI 4140 alloy steel is heated at 845°C (1550°F) followed by quenching in oil. Before hardening, it can be normalized by heating it at 913°C (1675°F) for a long period of time, followed by air cooling.
Heat treating 4140 steel can be done in several ways, depending on the desired results. Here are some common heat treatments for 4140 steel:


Annealing is a process of slowly heating 4140 steel and then cooling it at a controlled rate. This process makes the steel more ductile and less brittle and is often used before machining or cold working the material.


Normalizing is similar to annealing, but the steel is heated to a higher temperature and cooled more quickly. This process also makes the steel more ductile and less brittle, but can also help relieve stress from prior heat treating or machining processes.


Hardening is a process of quickly heating 4140 steel and then cooling it in oil or water. This process makes the steel harder and stronger, but also more brittle. It is often used in preparation for machining or other processes that require a hard, strong material.


Tempering is the process of heating 4140 steel to a specific temperature and then cooling it at a controlled rate. This process is often used after hardening to help reduce the brittleness of the steel. It can also be used to adjust the hardness of the steel to meet the needs of a specific application.

Why choose our services

Why choose our CNC machining for Alloy Steel 4140 parts?

We have over 10 years of experience in CNC machining, and our state-of-the-art facilities allow us to produce high-quality 4140 parts, which are able to meet the most demanding tolerances and specifications. 
Here are some details about us:

Customized design is available:

We can produce according to your design or samples.

Competitive price:

With our own factory, we can offer you the best price for high-quality products.

Fast delivery:

We have large stock for common sizes and we can deliver the goods within 7 days after you place the order.

Good after-sales service:

We will be responsible for any quality problem with our products. If you have any questions, please feel free to contact us. We will try our best to solve the problem for you.

Surface Finishing Options for Alloy Steel 4140

There are several common surface finishing options for alloy steel 4140. These include:


Plating is a process in which a metal is coated with another metal. This can be done for many reasons, including preventing corrosion, strengthening the metal, or changing its appearance.

powder coating:

Powder Coating: This is a process where the powder is applied to the 4140 steel and then heated, creating a durable and long-lasting finish.

black coating

The black coating is an option for 4140 steel. This finish is often used in the automotive industry because it provides a sleek, finished look.


Polishing is often used to create a high-quality, mirror-like finish. It can also improve the functionality of the 4140 part by reducing friction or making it easier to clean.


When using CNC milling for machining steel 4140, there are a few things to keep in mind in order to get the best results. 
1. First, it is important to use sharp tools for machining steel 4140. This will help to ensure that the cuts are clean and precise.
2. Second, it is necessary to use coolant when milling alloy steel 4140. This will help to prevent the material from overheating and becoming damaged. 
3. Finally, it is important to take care when handling the finished parts. Alloy steel 4140 is strong and durable, but it can be brittle and should be handled with care.

The cutting speed of 4140 is an important factor to consider when machining this material. It is typically referred to as surface feet per minute (SFM) and depends on a few different factors, such as the type of tool being used, the feed rate, and the depth of cut. Generally speaking, for a high-speed steel tool, the cutting speed for 4140 ranges from 40 SFM for roughing operations to 80 SFM for finishing cuts. This number can be adjusted depending on the specific needs, but should not exceed 100 SFM. 

It is possible to bend 4140 steel, but it requires special care and caution. 4140 steel is an alloy steel that contains chromium, molybdenum, and manganese. Due to its strength and hardness, it is often used in applications such as automotive parts and farm equipment. In order to bend 4140 steel successfully without damaging it, you will need a press brake capable of exerting enough force to form the metal into the desired shape. 

Our company specializes in machining materials such as alloy steel 4340, alloy steel 1.7225, and alloy steel 1.7131. We have the capability to provide high-quality machining services for all these materials. Our staff is highly experienced in machining these particular steels and will ensure that the final product meets all of your requirements. We use advanced machinery and inspect our products regularly to ensure the highest quality products are delivered to our customers. 

Need Alloy Steel 4140 CNC machining China services For Your Projects?

Our CNC Machining Services for Alloy Steel 4140 offers a great opportunity for any business or individual who needs to process materials quickly and accurately. Don’t hesitate to get in touch with us!