CNC Machining stainless steel (CNC stainless steel) is one kind of steel. It’s best known for its excellent strength and durability, machinability and uniformity. Widely used in CNC steel machining projects. Even in wet or corrosive environments. This makes it a very popular metal for both industrial applications and consumer products.
advantages and benefits of choosing CNC Machining stainless steel
Cryogenic Resistance:
Some stainless steel grades, like austenitic steels, exhibit excellent toughness and improved tensile strength at temperatures below zero. But, not all stainless steel grades have this feature.
Corrosion Resistance:
Chromium inclusion in stainless steel forms a thin layer to shield the steel when in contact with oxygen. This corrosion resistance makes stainless steel ideal for various outdoor and interior applications. Including extremes of temperature and pressure.
Appearance:
Stainless steel has a silver-white color that does not discolor or rust over time, due to its high chromium content. Its attractive appearance, along with its strength, makes it popular for various products.
Heat Treatment:
Heat treatment is an option to consider for specific hardness requirements. But it may affect other mechanical properties. But Austenitic stainless steels cannot be heat-treated.
Magnetism:
Consider the magnetic properties of the chosen material. Austenitic steel is non-magnetic due to its microstructure.
Challenges in CNC Machining Stainless Steel
Although CNC stainless steel has advantages in Machining project. But it still has some Challenges For Custom Stainless Steel Machined Parts.
1. Overheating
Stainless steel stands out as a poor heat conductor compared to other steel and metal types. the rapid heating up of stainless steel during work can pose risks to the material itself. as well in the tools and CNC machines utilized in the process. Careful management of heat is crucial to maintain the integrity of the stainless steel and the machining equipment.
2. Difficult Surface Finishing
Selecting the appropriate surface finish for stainless steel CNC machined parts can indeed be challenging. Because the surface finish of stainless steel not only impacts its aesthetics. Also affects other qualities. Such as corrosion resistance, electrical properties, impact resistance, and weldability. So, careful consideration and expertise are required to achieve the desired functional and aesthetic qualities in stainless steel CNC machined parts.
3. Technical Expertise
When handling stainless steel, technical expertise is essential. Because machining it can damage the material. Using the wrong cutting tools or speed makes machining stainless steel laborious and slow, requiring precision and care due to its challenging nature.
4. Poor Machinability
Machining stainless steel can indeed be more challenging compared to other metals. Its rapid hardening presents difficulties, contributing to its low machinability grade. As a result, specialized equipment is often necessary for machining stainless steel effectively.
5. Tooling costs
Tooling costs are a critical factor in the economics of machining stainless steel parts. The abrasive nature and high hardness of stainless steel can lead to accelerated tool wear, necessitating more frequent tool changes. It in turn increases production costs and downtime. Careful consideration of tooling expenses is essential for the economics of machining stainless steel.
Best Stainless Steel Alloys for Machining
CNC machining material has different types. Each of them has its unique qualities that suit different requirements. Below are the best 4 types of stainless steel for CNC machining.
| Description | Pros | Cons | Usages | |
| SS303 | Highly machinable and readily available. | Excellent machinability,Good corrosion resistance,Moderately priced | Not ideal for marine applications Does not harden during heat treatment | Nuts, bolts, and screws,Electronic Hardware,Aircraft fittings,Bushings |
| SS304 | The most common stainless steel grade with good weldability | Good weldability,machinability,corrosion resistance,Excellent cost | Highly susceptible to cracking and corrosion | Architectural applications,Heat exchanger,Food Handling,Automotive parts |
| SS316 | Higher corrosion resistance marine grade | Higher corrosion resistance than 304 | harsh chemical environments, surgical instruments. | |
| SS416 | The most machinable stainless steel. | Moderate corrosion resistance,Excellent machinability,Outstanding strength | Not ideal for marine environments,chlorine-saturated environments,Not widely available,Poor weldability | Nuts and bolts,Shafts and gears,Valves,Pumps |
| PH17-4 | Chromium content reaches up to 30% . It is a grade of precipitation-hardened martensitic stainless steel. | Corrosion resistance,High toughness,High strength | Prone to heat damage | Aircraft turbines,Oil and gas,Nuclear reactions |
CNC machining stainless steel Applications
CNC machining stainless steel is used for any industry that requires high-strength applications. Stainless steel is an ideal material for applications. For example：
- Automotive
- Food and Beverage
- Aerospace
- Medical instruments
- Machine parts
- Gears
- Parts for tractors
- Heavy construction equipment
- Vacuum and pressure vessels
CNC Stainless Steel Processing
Stainless steel can undergo different machining processes. Some of these processes are:
Milling
In stainless steel CNC machining, milling is indeed one of the most common primary processes. This process involves the use of high-speed rotating cutting tools on a stationary workpiece. But, selecting the appropriate tool for milling stainless steel alloys is crucial. The wrong choice of tools or high speeds can lead to rapid tool wear. Milling stainless steel offers the advantages of very high accuracy and the production of smooth cutting edges.
Turning
The turning process necessitates the use of a stationary cutting tool and a rotating workpiece. The tool makes direct contact with the rotating workpiece to cut material. This method is used for machining austenitic stainless steel. Emphasizing the significance of minimizing tool overhang for this particular machining process.
Drilling
Drilling, as a secondary metalworking process, is combined with other techniques to create holes in metal workpieces. Stainless steels undergo drilling for purposes. Such as forming screw holes, enabling secondary assembly, or enhancing aesthetics.
Threading
Threading is usually on steel parts to accommodate the mounting of screws and fasteners. The threads can be found either inside a hole or on the exterior of the workpiece. Stainless steel threading is applied to pipes and tubes.
Laser Cutting
Laser cutting processing is using amplified light beam to melt and drop stainless steel. This technique is suitable only for thin sheets of stainless steel. Unlike cemented carbide tools, laser cutting avoids tool wear. But, it is a costly method and demands highly skilled labor.
Grinding
Grinding is used to improve the surface finishing. It also increases the workpiece accuracy by removing minute volumes of material. This technique involves the use of abrasive wheels rubbed against stainless steel workpieces. And it eliminates burrs resulting from welding. Besides, grinding contributes to the creation of smooth cutting edges on stainless steel parts.
Waterjet Cutting
Waterjet cutting uses high-pressure water force for cutting. This method is capable of cutting thick sheets of stainless steel. But, if the stainless steel grade exhibits low corrosion resistance, waterjet cutting may lead to detrimental effects.
Surface finishing
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