Stainless Steel CNC Machining Services

Stainless Steel (SS) is an iron alloy containing at least 11% chromium. The stainless steel alloys may include a combination of carbon, nickel, nitrogen, aluminum, silicon, and manganese. The stainless steel alloy is a large family of SS products. The alloys are strong and hard, with a high creep resistance and melting point. SS is one of the hardest materials on Earth.

There are several stainless steel alloys, each having different performance characteristics. These may include strength, corrosion resistance, improved workability, machineability, weldability, ductility, brittleness, and price.

There are two principal identifiers for stainless steel; 1) families and 2) grades.

Stainless Steel Families

Stainless steel alloys are divided into five distinct families, which are listed below:  

• Austenitic Stainless Steel

This is the most widely used SS Alloy, 70% of production. It is excellent for machining, welding, and corrosion resistance. The 300 series of austenitic SS alloys have 18% chromium and 8% nickel. Some grades may include manganese and molybdenum.

The alloys are non-magnetic but gain magnetic properties when cold-worked. Heat-based hardening does not work with austenitic SS alloys. 

The most popular austenitic SS alloy grades include 303, 304, and 316 SS. These alloys are used for nuts, bolts, fasteners, gas turbines, and food processing equipment.

• Ferritic Stainless Steel

Ferritic SS is the most cost-effective family of SS alloys. A popular choice for chloride environments, this alloy family is tough, has moderate corrosion resistance, and is weldable. Most grades are magnetic. These alloys include chromium (12% -18%), molybdenum, niobium, nickel, and titanium. Carbon content is low. The most commonly used alloy grades are 409 & 430.

•  Duplex Stainless Steel

Sometimes known as austenitic-ferritic stainless steel, this alloy combines the best of those two families. Duplex SS has high strength and corrosion resistance for off-shore applications. The alloy is weldable, magnetic, and has excellent mechanical properties. Duplex-grade alloys have lower percentages of molybdenum and nickel.

Duplex SS is the most recent SS alloy developed, and new alloys a tailored for specific applications. The most popular duplex alloys grades are 318L, LDX 2101, LDX 2304, 2507, and 4501. Heavy industrial applications are typical for duplex SS alloys.

• Martensitic Stainless Steel

This family was the first developed and had 12% - 18% chromium and 0.1 – 1.2% carbon. It is challenging and can be further treated and hardened. This SS is easy to form, has good ductility, and has moderate corrosion resistance. This alloy is used to manufacture car parts, surgical instruments, valves, turbine blades, and cutlery. Common grades are 410, 420, and 440A.

• Precipitation Hardening Stainless Steel

 This is the least popular alloy, although it can be used for hardened edge applications such as knives and scalpels. Carbon is added for high strength and hardness and is also used for firearms, aerospace components, hand tools, nuclear components, and the oil and gas industry. The materials have moderate corrosion resistance and weldability and are magnetic. The most common material grades include 410 and 420.

• 18%-20% Chromium
• 0.8%-10.5% Nickel
• 2% Manganese
• 0.1% Nitrogen
• 0.08% Carbon
• 0.75% Silicon
• 0.045% Phosphorus
• 0.03% Sulphur

Stainless steel is one of the hardest metals known, and with various stainless steel alloys available, there is one for almost every application.

• Strength and Durability

SS has a remarkable strength-to-weight ratio, exceptional impact resistance, low susceptibility to brittleness, and the ability to withstand extreme thermal conditions.

• Extensive Applications

The materials can be formed into virtually any shape, size, and type of metal fabrication, including forming, machining, welding, punching, drilling, and cutting. This makes SS suitable for the broadest range of applications.

• Fire and Heat Resistance

Due to the oxidation resistance, SS does well in temperature extremes.

• Corrosion Resistance/Hygiene

SS offers the highest degree of cleanliness on any surface. It has a smooth, non-porous, non-absorbent surface that is non-toxic and can be sanitized with aggressive disinfectants and without material degradation. SS is used extensively in the medical and food service industries.

• Magnetism (Certain Grades Only)

While not all SS alloys have magnetic properties, several grades of SS do. The alloy must contain iron and have a martensitic or ferritic crystalline structure.

• Self-Healing

SS alloys have a large amount of chromium content which allows the formation of a tough, invisible corrosion-resisting chromium oxide film on the steel surface. If the surface of the steel is damaged mechanically or chemically, this film will cover the steel in oxygen environments.

• Appearance

SS has an attractive satin finish that is smooth and shiny. It is resistant to dents, scratches, stains, and fingerprints, even after heavy usage.

• Value

Stainless steel has an extremely long life and is easy to maintain.

• Sustainability

When considering product longevity, SS becomes a value option for material selection. SS requires little maintenance and doesn’t leach toxic chemicals. Today, 95% of the milled scrap comes from reclaimed SS and is 100% recyclable.