Stainless Steel: Types, Benefits and Applications

With global production exceeding 52.2 million tonnes in 2019, stainless steel (inox) remains one of the most widely used materials in the world.
From furniture to mechanical engineering, all the way to high-precision CNC machining, stainless steel has proven to be a reliable, durable and versatile resource ever since its invention by the Englishman Harry Brearley in 1913.

In the following 2025-updated article you will find:

• What stainless steel is

• The various types (austenitic, ferritic, martensitic, duplex, PH)

• Advantages of stainless steel

• Titanium vs Stainless Steel: what’s the difference?

• How to choose the right stainless steel

• Stainless-steel applications

• CNC machining of stainless steel

What is Stainless Steel?

Stainless steel is an alloy composed mainly of:

• iron

• carbon

• chromium (≥10.5%)

• nickel, molybdenum and other elements that modify its properties

Its distinctive feature is the spontaneous formation of a passive chromium-oxide layer, invisible and self-renewing, which protects the metal from:

• rust

• corrosion

• oxidation

Tip: If the surface layer is scratched, it automatically regenerates when exposed to oxygen – this is what makes stainless steel truly “stainless”.

CNC machining in progress for a stainless steel part

The Main Types of Stainless Steel

There are over 100 grades of stainless steel, classified into five major families.
Here are the most important for industrial production, mechanical engineering and CNC machining.

Austenitic (300 Series)

The most common and versatile family.

• excellent corrosion resistance

• wide thermal range

• non-magnetic

• highly formable

Used in: furniture, industrial piping, food industry, architecture, CNC machining.

Ferritic (400 Series)

Similar to mild steel but with better corrosion resistance.

• magnetic

• economical

• good ductility

Used in: appliances, interiors, boilers, decorative components.

Martensitic

High hardness and mechanical strength.

• magnetic

• lower corrosion resistance

Used in: cutlery, turbines, tools, high-stress components.

Duplex

A mix of austenitic + ferritic structures.

• exceptional corrosion resistance

• high mechanical strength

• good weldability

Used in: marine, chemical, pulp and paper industries.

Precipitation-Hardening (PH)

Also known as semi-austenitic.

• extremely high strength and hardness

• includes elements such as Al, Nb, Cu

Used in: aerospace, advanced mechanics, high-performance applications.

Parts CNC machined by Weerg with 5-axis Hermle c42u on steel 304

Advantages of Stainless Steel

Stainless steel is so widespread thanks to its unique mix of properties:

• Corrosion resistance: Ideal in humid, salty or chemical environments.
• High durability: Does not deform, does not rust, and lasts over time.
• Thermal stability: Excellent heat resistance.
• Hygienic and easy to clean: Perfect for food, medical and cosmetic applications.
• Non-porous surface: Does not retain water, bacteria or odours.
• Premium appearance: Available finishes: polished, satin, brushed, shot-peened.
• Recyclability: 100% sustainable.

Fun fact: stainless steel doesn’t heat up easily. Placing a hot object on a stainless-steel handrail hardly increases its temperature.

Titanium vs Stainless Steel: What’s the Difference?

One of the most common questions concerns the choice between titanium and stainless steel.

Stainless Steel

• metallic alloy

• heavier than titanium

• more affordable

• better weldability

• high strength

Titanium

• pure metal

• lightweight (40% lower density than stainless steel)

• extremely corrosion-resistant

• more expensive

• more difficult to machine

The choice depends on your project priorities: weight vs durability vs cost.

How to Choose the Right Stainless Steel

It depends on:

• operating environment

• presence of water or salinity

• need for formability

• budget

• mechanical requirements

• type of CNC machining

Applications of Stainless Steel

Stainless steel is ubiquitous across many sectors:

Food Industry

Counters, containers, equipment, utensils.

Medical

Surgical instruments, prosthetics, sterile devices.

Mechanical Engineering & Automation

Gears, shafts, brackets, supports, high-strength components.

Marine & Nautical

Bolts, hinges, fittings exposed to saltwater.

Design & Architecture

Furniture, handles, façades, decorative elements.

CNC Machining of Stainless Steel

Stainless steels in the 300 series, including 304 and 316L, are more difficult to machine than carbon steels but deliver excellent results when handled correctly.

• 400 series is easier to machine

• 303 is the easiest stainless steel to mill

• 304 and 316L require specific tools and optimised parameters

Weerg machines 304 and 316L using Hermle C42U 5-axis milling centres, ideal for difficult materials and for achieving tight tolerances and high-quality finishes.

Conclusions

Stainless steel is one of the most complete and reliable materials in modern industry.
Its corrosion resistance, durability, hygiene, aesthetic appeal and versatility make it ideal for:

• CNC machining

• metal 3D printing

• mechanical components

• structural applications

• design products

It is available in hundreds of variants, each designed for specific needs: from aggressive environments to high temperatures, from medical to precision engineering.

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