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stainless steel cnc machining

Comprehensive Guide to Stainless Steel CNC Machining

Stainless steel is a versatile and common material in many industries. Durability, high strength, and corrosion resistance are just a few of its excellent attributes. CNC machining creates intricate and precise stainless steel components through computerized automation.

This article will delve into the different grades of stainless steel available, covering their advantages and applications. You'll also learn how to overcome various challenges associated with CNC machining of stainless steel material.

What is Stainless Steel CNC Machining?

Stainless steel CNC machining is an accurate and efficient machining process that uses CNC machines to shape, fabricate and cut stainless steel parts.

Numerous industries use stainless steel because it is durable and resistant to corrosion. However, CNC machining is a flexible and cutting-edge technique for producing intricate stainless steel machined parts with great precision.

The stainless steel CNC machining process starts with producing a compute-aided or digital design model of the desired parts. CAM (Computer-Aided Manufacturing) software then converts this design into code machines can read.

The CNC machine analyzes the code to activate the accurate movement of the cutting tool and extract material from the stainless workpiece. The CNC machine uses programmed instructions to carry out a variety of operations during the machining process. However, this is dependent on the specification and complexity of the parts.

Some of the operations are grinding, drilling, or turning. The computerized control of the CNC machine ensures repeatable, dependable operations that produce components with high accuracy and fewer mistakes.

Different Types of Stainless Steel for CNC Machining

cnc turned stainless steel part
CNC Turned Stainless Steel Part

This CNC machining material comes in various types. Each of them has unique qualities that suit different requirements. These are some of the common types of stainless steel for CNC machining:

Austenitic Stainless Steel

The most popular form of stainless steel is austenitic stainless steel. and are highly suitable for CNC machining due to their excellent formability, weldability, and corrosion resistance. This category’s two most common grades are 304 and 316 stainless steel.

Martensitic Stainless Steel

Martensitic stainless steel was named after Adolf Martens. These steels are renowned for their extraordinarily high toughness. These steels must undergo aging and heat treatments for high hardness and tempering.

It can have a low or high carbon quality. Examples of martensitic stainless steels are X12Cr13, X20Cr30, X50CrMoV15, and X17CrNi16-2.

Ferritic Stainless Steel

Ferritic stainless steel was discovered in 1912. However, it didn’t become known and considered for various applications until about 1980. They belong to the family of AISI 400.

Examples of ferritic stainless steel are Type 405, Type 409L, Type 410L, Type 430, Type 439, and Type 447.

Duplex Stainless Steel

cnc stainless steel part
CNC Stainless Steel Part

The structural design of duplex steel consists of two parts. It combines ferritic and austenitic stainless steel resulting in duplex alloys. These two essential structural components are enhanced by duplex steel alloy. This stainless steel is available in three grades: normal, super duplex, and lean duplex alloys.

Examples of duplex stainless steel are X2CrNiN22-2, X2CrCuNiN23-2-2, X2CrNiMoSi18-5-3, X2CrMnNiMoN21-5-3, X2CrNiMoCuN25-6-3, and X2CrNiCuN23-4.

Precipitation-Hardening Stainless Steel

Precipitation Hardening stainless steels can also be called PH stainless steel alloys. These alloys contain trace amounts of other substances, such as titanium, copper, phosphorus, or aluminum. These steels go through an age-hardening process after alloy production.

Stainless steels that precipitation harden can yield strengths 3–4 times greater than those of austenitic stainless steels. An example of PH stainless steel alloy is 17-4 PH Steel.

Understanding Different Grades of Stainless Steel

These are the various grades of high CNC machining for stainless steel:

Alloy 302

s316 swiss high precision machining
SS316_Swiss High Precision Machining

A higher grade of carbon is found in stainless steel alloy 302. Its good corrosion resistance properties make 302 a well-known material. Alloy 302 is, without a doubt, the most effective grade for CNC machining.

Alloy 303

The grade of stainless steel alloys that can be machined the easiest is 303. The significant preference for sulfur in steel composition accounts for grade 303’s high machineability. The choice of sulfur impacts the total corrosion resistance and hardness of grade 303.

Alloy 304

stainless steel 304 swiss lathe as machined
Stainless Steel 304_Swiss Lathe_As Machined

Because it has outstanding forming & welding qualities, grade 304 is the most adaptable and frequently used stainless steel grade in machining tools. 304L has less carbon than 304 and doesn’t require post-welding, and 304H has more carbon than 304. As a result, It offers adequate toughness for machining tools.

Alloy 316

After grade 304, grade 316 is the most widely used and standard. 316 contains molybdenum, which increases its capacity to resist corrosion above grade 304. Additionally, 316 has good forming and welding properties, contributing to its popularity as a machining grade.

Stainless steel, also 400 series, is utilized frequently in the production of machining tools due to its excellent toughness and outstanding corrosion resistance.

Benefits of Stainless Steel in CNC Machining

Stainless steel in CNC machining is ideal for creating durable and long-lasting custom stainless steel parts. These are some of the possible benefits:


stainless steel cnc turning
Stainless Steel CNC Turning

The stainless steel color is silver-white and does not tarnish or corrode with time. Chromium in large amounts is what gives it its look. Apart from strength, stainless steel also has other characteristics. Because of its lovely appearance, this metal is used in many different items. CNC-machined stainless steel parts have a clear, contemporary look without losing functionality.

High Tensile Strength

s316 cnc milling cnc turning as machined
Stainless Steel 316 CNC Milling Turning as Machined

Stainless steel has a greater tensile strength than mild steel, brass, and aluminum alloys. The tension required to stretch a material to its breaking point is known as tensile strength. This is an essential quality for many products throughout their useful lives, especially for parts that would undergo a lot of bending and rolling.

Corrosion Resistance

Stainless steel alloy has good corrosion resistance and can resist rust and water stains. Stainless steel is perfect for indoor and outdoor applications because of its corrosion resistance. Due to the presence of chromium in the metal, which creates a thin layer to protect the steel when it comes into contact with oxygen, stainless steel possesses this feature.

 Cryogenic Resistance

stainless steel cnc milling
Stainless Steel CNC Milling

Some stainless steel grades remain stable at a range of temperatures. For instance, austenitic stainless steel alloy displays excellent toughness and enhanced tensile strength at temperatures below zero. Nevertheless, it’s crucial to remember that not all stainless steel grades have this characteristic.

Overcoming Challenges in Stainless Steel CNC Machining

There are various challenges when CNC machining stainless steel. However, there are ways to overcome such challenges, and they include:

Avoid Deformation of Your Workpiece

cnc milled stainless steel parts
CNC Milled Stainless Steel Parts

Numerous elements, including feed rate, speeds, and cutting tools, can cause a workpiece to deform. Increasing tool deflection while utilizing a worn cutting tool would make pieces out of tolerance and distorted. This is why it’s crucial to machine stainless steel at the proper speed and feed rate.

Select Special End Mills and Drills

It is advisable to use high-quality tools, such as drills and end mills made of tungsten or molybdenum HSS. They can resist the strain of the process when cutting stainless steel with little wear. These devices also enhance surface quality. Use durable tools sparingly because doing so could slow down machining and raise manufacturing expenses.

Use Pecking and Chip-breaking Cycles

ss 316 cnc machined parts
SS 316 CNC Machined Parts

One method of controlling chip formation in machining is pecking and chip-breaking cycles. This helps get rid of lengthy, stringy chips. Checking tools frequently is another technique to control chip formation because chip production is increased by worn cutting tools.

Manage Generated Heat

Heat is one of the causes of stainless steel CNC machining failures. It is advisable to keep the cutting speed moderate and use coolants to control the heat. Additionally, it is often advised to halt machining when the material begins to overheat.

Essential Tools and Equipment for Stainless Steel CNC Machining

Achieving optimal results and maximizing productivity in stainless steel CNC machining requires specialized tools and equipment tailored to handle this durable material. These are some of the essential tools and equipment needed for CNC machining for stainless steel:

  • CNC Machines: The CNC machine, which might be a CNC lathe, CNC milling machine, CNC machining center, or CNC turning center, is at the heart of CNC machining for stainless steel. A strong and sturdy design is essential to bear the demands of stainless steel machining while providing exact results.
  • Cutting Tools: Various cutting tools are employed for different CNC machining operations for stainless steel. Some of the tools include carbide end mills, carbide drills, carbide inserts, solid carbide readers, and taps.
  • Coolant System: A dependable system is crucial for effective CNC machining of stainless steel. The material’s low thermal conductivity requires efficient cooling to disperse heat during machining, preventing workpiece deformation and extending tool life. Water-based coolants or cutting fluids with high lubricity are commonly employed.
  • Tool Holders and Tooling Accessories: High-quality tool holders are essential for securely holding cutting tools in place during machining. Ensuring stability and reducing vibration improves machining accuracy and surface finish.
  • Workholding Fixtures: Securely holding stainless steel workpieces during CNC machining prevents movement and maintains dimensional accuracy. Workholding fixtures like vises, clamps, and chucks are commonly used.
  • Measurement Tools: Precise measurement is essential in CNC machining to ensure parts meet specified tolerances. Measurement tools, such as calipers, micrometers, depth gauges, and dial indicators, are indispensable for quality control.
  • Safety Equipment: Safety is paramount in CNC machining. Machine operators should wear proper personal protective equipment (PPE) such as safety glasses, gloves, and hearing protection to prevent accidents and injuries.
  • CNC Programming Software: Specialized programming software is essential for creating CNC programs. CAM software aids in generating tool paths and converting CAD designs into machine-readable code for CNC machines.

Role of Stainless Steel CNC Machining in Key Industries

ss304 5 axis cnc machined parts
SS304_5 Axis CNC Machined Parts

Stainless steel CNC machining roles in various key industries are:


Exhaust systems, fuel lines, and other automotive parts use stainless steel because they are durable and corrosion-resistant.


Due to its excellent corrosion resistance caused by seawater and other hostile environments, stainless steel is frequently utilized in marine applications.


Medical items such as implants, surgical instruments, and other devices frequently need the precision and accuracy that stainless steel CNC machining can offer.

Food and Beverage

Due to their sanitary qualities and corrosion resistance, free-machining stainless steel components are used in processing machinery, storage tanks, and other applications in the food and beverage sector.


Due to its strength, excellent corrosion resistance, and heat resistance, stainless steel components are employed in aviation engines, landing gear, and other crucial systems.


stainless steel cnc machining services
Stainless Steel CNC Machining Services

This article offers valuable insight into the challenges of stainless steel CNC machining. Many industries prefer stainless steel parts as their product of choice. CNC machining allows the price production of stainless steel art. It is also used to make machine parts, mainly since it is tough and corrosion-resistant. AT-Machining offers the most reliable metal CNC machining services for all applications requiring stainless steel materials. With extensive experience and highly skilled technicians, we will help bring your concept to life most effectively. Contact us today, and let’s discuss your project.

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From AT-Machining, I’m a CNC Machining Expert in this field for more than 20 years.  We offer cost-effective machining services from China. Ask for a quote for your ongoing or upcoming projects now!

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