Stainless Steel SUS201

Affordable austenitic stainless steel offers a balance of corrosion resistance, strength, and formability for various industrial applications.

Introduction to Stainless Steel SUS201: A Versatile Material for Corrosion Resistance

Stainless Steel SUS201 is a cost-effective austenitic stainless steel alloy with good corrosion resistance, formability, and strength. It contains higher levels of manganese and nitrogen compared to SUS304, which enhances its mechanical properties. With its low nickel content, SUS201 is an affordable alternative to 304 stainless steel, making it ideal for various industrial applications where both performance and cost-efficiency are essential.

SUS201 is particularly known for its ability to resist corrosion in mildly corrosive environments. It is commonly used in kitchen equipment, architectural elements, and general industrial machinery applications. In CNC machining, SUS201 is often processed to produce high-quality parts and excellent surface finishes. CNC-machined SUS201 stainless steel parts are widely used in the automotive, food processing, and construction industries, offering both durability and aesthetics.

SUS201 Stainless Steel: Key Properties and Composition

SUS201 Stainless Steel Chemical Composition

Element

Composition (wt%)

Role/Impact

Carbon (C)

≤0.15%

Low carbon content enhances weldability and reduces carbide precipitation.

Manganese (Mn)

5.5–7.5%

Increases strength and enhances corrosion resistance compared to standard 304.

Chromium (Cr)

16.0–18.0%

Provides corrosion resistance and contributes to the alloy’s strength.

Nickel (Ni)

≤5.0%

Reduced nickel content compared to SUS304, making it a more cost-effective option.

Nitrogen (N)

0.25–0.75%

Enhances strength and corrosion resistance, especially in acidic environments.

SUS201 Stainless Steel Physical Properties

Property

Value

Notes

Density

7.93 g/cm³

Standard for austenitic stainless steels, providing reasonable weight.

Melting Point

1,400–1,450°C

Suitable for both cold working and high-temperature applications.

Thermal Conductivity

16.2 W/m·K

Moderate heat dissipation, suitable for general-use applications.

Electrical Resistivity

7.4×10⁻⁶ Ω·m

Low resistivity, ideal for structural and non-electrical applications.

SUS201 Stainless Steel Mechanical Properties

Property

Value

Testing Standard/Condition

Tensile Strength

520–720 MPa

ASTM A240/A240M standard

Yield Strength

240 MPa

Suitable for structural applications requiring moderate strength.

Elongation (50mm gauge)

40%

High ductility for forming and welding applications.

Brinell Hardness

160 HB

Soft state, easy to machine and weld.

Machinability Rating

55% (vs. 1212 steel at 100%)

Optimized for turning, milling, and drilling in CNC machining.

Key Characteristics of SUS201 Stainless Steel: Benefits and Comparisons

SUS201 stainless steel is often compared to other alloys such as SUS304 Stainless Steel and SUS316 Stainless Steel, as these materials are commonly used in similar applications. Below is a comparison that highlights the unique advantages of SUS201.

1. Optimized Corrosion Resistance

  • Unique Trait: While not as resistant as SUS304, SUS201 provides good corrosion resistance in mildly corrosive environments.

  • Comparison:

    • vs. SUS304: SUS304 offers superior corrosion resistance, but SUS201 is a more affordable option with acceptable performance in many applications.

    • vs. SUS316: SUS316 offers excellent resistance to chlorides and acidic environments, making it ideal for marine applications, while SUS201 is better for cost-sensitive projects.

2. Cost Efficiency

  • Unique Trait: SUS201 is more affordable than SUS304, making it ideal for applications that do not require the higher corrosion resistance of 304.

  • Comparison:

    • vs. SUS304: SUS201 can be up to 30% cheaper, making it a more cost-effective choice for structural and general-purpose uses.

    • vs. SUS316: SUS201 is more economical, providing sufficient corrosion resistance for less aggressive environments.

3. Superior Formability and Weldability

  • Unique Trait: The low carbon content in SUS201 enhances weldability and reduces carbide precipitation, ensuring strong welds without the need for preheating.

  • Comparison:

    • vs. SUS304: Both alloys have good weldability, but SUS201’s lower nickel content makes it slightly easier to weld.

    • vs. SUS316: SUS316’s higher nickel content enhances resistance to welding issues like cracking, but SUS201 remains easier to process for simpler applications.

4. Dimensional Stability

  • Unique Trait: SUS201 has good dimensional stability under machining processes, providing tolerances of ±0.05 mm in CNC operations.

  • Comparison:

    • vs. SUS304: SUS304’s higher cost is justified by its superior dimensional stability, particularly in extreme conditions.

    • vs. SUS316: SUS316 offers better dimensional stability at high temperatures but comes at a higher price point than SUS201.

5. Post-Processing Flexibility

  • Unique Trait: SUS201 can undergo a wide range of post-processing treatments, including polishing, PVD coating, and passivation, providing a good combination of durability and aesthetics.

  • Comparison:

    • vs. SUS304: SUS304 offers more extensive options for surface treatments, particularly in highly corrosive environments.

    • vs. SUS316: SUS316 is typically preferred for its corrosion resistance, but SUS201 is a more affordable choice for general industrial uses.

CNC Machining Challenges and Solutions for SUS201 Stainless Steel

Machining Challenges and Solutions

Challenge

Root Cause

Solution

Work Hardening

High manganese and nitrogen content

Use carbide tools with TiN coatings and optimize feed rates to reduce tool wear.

Surface Roughness

Slight "tearing" due to high ductility

Use climb milling techniques and adjust cutting speeds for smoother finishes.

Burr Formation

Softer material properties

Increase spindle speed and reduce feed rates during finishing operations.

Dimensional Inaccuracy

Residual stresses from cold rolling

Perform stress-relief annealing at 650°C for dimensional stability.

Chip Control Issues

Stringy, continuous chips

Use high-pressure coolant (7–10 bar) and implement chip breakers for better control.

Optimized Machining Strategies

Strategy

Implementation

Benefit

High-Speed Machining

Spindle speed: 900–1,200 RPM

Reduces heat buildup and improves tool life by 15%.

Climb Milling

Directional cutting path for optimal surface finish

Achieves surface finishes of Ra 1.6–3.2 µm, improving part aesthetics.

Toolpath Optimization

Use trochoidal milling for deep pockets

Reduces cutting forces by 30%, minimizing part deflection.

Stress-Relief Annealing

Preheat to 650°C for 1 hour per inch

Minimizes dimensional variation to ±0.03 mm.

Cutting Parameters for SUS201 Stainless Steel

Operation

Tool Type

Spindle Speed (RPM)

Feed Rate (mm/rev)

Depth of Cut (mm)

Notes

Rough Milling

4-flute carbide end mill

900–1,200

0.15–0.25

2.0–4.0

Use flood coolant to prevent work hardening.

Finish Milling

2-flute carbide end mill

1,200–1,500

0.05–0.10

0.5–1.0

Climb milling for smoother finishes (Ra 1.6–3.2 µm).

Drilling

135° split-point HSS drill

600–800

0.10–0.15

Full hole depth

Peck drilling for precise hole formation.

Turning

CBN or coated carbide insert

300–500

0.20–0.30

1.5–3.0

Dry machining is acceptable with air blast cooling.

Surface Treatments for CNC Machined SUS201 Stainless Steel Parts

  1. Electroplating: Adds a corrosion-resistant metallic layer, extending part life in humid environments and improving strength.

  2. Polishing: Enhances the surface finish, providing a smooth, shiny appearance ideal for visible components.

  3. Brushing: Creates a satin or matte finish, masking minor surface defects and improving aesthetic quality for architectural components.

  4. PVD Coating: Boosts wear resistance, increasing tool life and part longevity in high-contact environments.

  5. Passivation: Creates a protective oxide layer, enhancing corrosion resistance in mild environments without altering dimensions.

  6. Powder Coating: Offers high durability, UV resistance, and a smooth finish, ideal for outdoor and automotive parts.

  7. Teflon Coating: Provides non-stick and chemical-resistant properties, ideal for food processing and chemical handling components.

  8. Chrome Plating: Adds a shiny, durable finish that enhances corrosion resistance, commonly used in automotive and tooling applications.

  9. Black Oxide: Provides a corrosion-resistant black finish, ideal for parts in low-corrosion environments like gears and fasteners.

Industry Applications of CNC Machined SUS201 Stainless Steel Parts

Automotive Industry

  • Engine Mounting Brackets: Cold-rolled SUS201 steel is ideal for automotive components that require high tensile strength and durability.

Industrial Machinery

  • Hydraulic Cylinders: Stress-relieved SUS201 steel maintains precise tolerances under high-pressure environments.

Construction and Structural

  • Building Frames: SUS201’s cost-effectiveness and strength make it the go-to material for construction beams and frames.

Technical FAQs: CNC Machined SUS201 Stainless Steel Parts & Services

  1. How does SUS201 steel compare to SUS304 in terms of corrosion resistance?

  2. What are the key benefits of choosing SUS201 steel for high-volume production?

  3. Can SUS201 steel be used for food processing applications?

  4. How does CNC machining affect the surface finish of SUS201 stainless steel?

  5. What post-processing treatments are most effective for enhancing the durability of SUS201 steel?

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