Stainless Steel SUS317
Introduction to Stainless Steel SUS317: High-Corrosion-Resistant Austenitic Alloy
Stainless Steel SUS317 is a high-performance austenitic stainless steel alloy known for its excellent corrosion resistance, particularly in chloride-rich environments. With a composition that includes 18–20% chromium, 10–13% nickel, and 3–4% molybdenum, SUS317 provides enhanced resistance to pitting, crevice corrosion, and general corrosion, making it an ideal material for applications in chemical, petrochemical, and marine industries. Its addition of molybdenum significantly improves its corrosion resistance in highly acidic environments with high chloride content.
SUS317’s superior corrosion resistance makes it suitable for a wide range of applications, especially those exposed to harsh conditions. While it is not as strong as precipitation-hardened alloys, it is highly durable and resistant to corrosion, making it an excellent choice for industries requiring reliable performance in aggressive environments. CNC machining of SUS317 involves specialized techniques due to its higher resistance to corrosion but manageable machinability. At Neway, CNC-machined SUS317 parts are produced to meet the highest standards for durability and precision.
SUS317 Stainless Steel: Key Properties and Composition
SUS317 Stainless Steel Chemical Composition
Element | Composition (wt%) | Role/Impact |
|---|---|---|
Carbon (C) | ≤0.08% | Low carbon content reduces carbide precipitation and enhances weldability. |
Manganese (Mn) | 2.00% | Improves toughness, particularly at lower temperatures, and enhances overall strength. |
Chromium (Cr) | 18.0–20.0% | Provides resistance to corrosion and oxidation, particularly in acidic environments. |
Nickel (Ni) | 10.0–13.0% | Improves formability and resistance to corrosion, especially in marine environments. |
Molybdenum (Mo) | 3.0–4.0% | Enhances resistance to pitting and crevice corrosion, especially in chloride-rich environments. |
Phosphorus (P) | ≤0.045% | Improves machinability and helps reduce surface defects. |
SUS317 Stainless Steel Physical Properties
Property | Value | Notes |
|---|---|---|
Density | 8.03 g/cm³ | Typical for austenitic stainless steels, ensuring durability. |
Melting Point | 1,400–1,450°C | Suitable for high-temperature applications with excellent resistance to oxidation. |
Thermal Conductivity | 16.2 W/m·K | Moderate heat dissipation, suitable for applications with fluctuating temperatures. |
Electrical Resistivity | 7.4×10⁻⁷ Ω·m | Low electrical conductivity, ideal for non-electrical applications. |
SUS317 Stainless Steel Mechanical Properties
Property | Value | Testing Standard/Condition |
|---|---|---|
Tensile Strength | 520–720 MPa | ASTM A240/A240M standard |
Yield Strength | 205 MPa | Suitable for high-temperature and structural applications |
Elongation (50mm gauge) | 40% | Good ductility, allowing for easier forming and welding. |
Brinell Hardness | 150–190 HB | Achieved in a solution-treated state, offering moderate hardness. |
Machinability Rating | 55% (vs. 1212 steel at 100%) | Suitable for machining with carbide tools and low cutting speeds. |
Key Characteristics of SUS317 Stainless Steel: Benefits and Comparisons
SUS317 stainless steel offers excellent corrosion resistance, particularly in aggressive environments. Below is a technical comparison highlighting its unique advantages over similar materials like SUS304 Stainless Steel, SUS316 Stainless Steel, and SUS430 Stainless Steel.
1. Corrosion Resistance
Unique Trait: SUS317 offers superior resistance to pitting and crevice corrosion, especially in chloride environments, thanks to its molybdenum content.
Comparison:
vs. SUS304 Stainless Steel: SUS317 offers better corrosion resistance in acidic and chloride-rich environments than SUS304.
vs. SUS316 Stainless Steel: SUS316 and SUS317 offer similar corrosion resistance, but SUS317 performs better in environments with high chloride exposure.
vs. SUS430 Stainless Steel: SUS430 has significantly lower corrosion resistance than SUS317, particularly in acidic or chloride-rich conditions.
2. High-Temperature Performance
Unique Trait: SUS317 maintains its mechanical properties even at high temperatures, making it ideal for heat exposure applications.
Comparison:
vs. SUS304 Stainless Steel: SUS304 offers moderate resistance to heat but cannot match SUS317’s performance in extreme conditions.
vs. SUS316 Stainless Steel: SUS316 performs similarly to SUS317 in high-temperature environments but is less effective in chloride-rich applications.
vs. SUS430 Stainless Steel: SUS430 is not as resistant to high temperatures as SUS317 and offers inferior performance in thermal applications.
3. Machinability
Unique Trait: SUS317 is generally easy to machine, but its higher nickel and molybdenum content requires carbide tooling and slower machining speeds to avoid excessive tool wear.
Comparison:
vs. SUS304 Stainless Steel: SUS304 is easier to machine than SUS317 due to its lower alloy content.
vs. SUS316 Stainless Steel: SUS316 is more challenging to machine than SUS317 but is more resistant to corrosion in certain environments.
vs. SUS430 Stainless Steel: SUS430 is easier to machine than SUS317 but does not provide the same level of corrosion resistance.
4. Cost-Effectiveness
Unique Trait: SUS317 offers a good balance of cost, corrosion resistance, and high-temperature performance, making it a cost-effective choice for critical applications.
Comparison:
vs. SUS304 Stainless Steel: SUS304 is more economical than SUS317 but lacks the corrosion resistance and high-temperature performance of SUS317.
vs. SUS316 Stainless Steel: SUS316 is more expensive than SUS317 due to its higher nickel content, but it offers superior corrosion resistance in some environments.
vs. SUS430 Stainless Steel: SUS430 is the least expensive but lacks the high-temperature and corrosion resistance of SUS317.
CNC Machining Challenges and Solutions for SUS317 Stainless Steel
Machining Challenges and Solutions
Challenge | Root Cause | Solution |
|---|---|---|
Work Hardening | High alloy content and hardness | Use carbide tools with TiN coatings for better cutting. |
Surface Roughness | Low carbon content and ductility | Optimize feed rates and use high-speed tools for smoother finishes. |
Tool Wear | High nickel and molybdenum content | Use high-performance tool coatings like TiAlN for reduced wear. |
Dimensional Inaccuracy | Stresses from machining | Perform stress-relief annealing to reduce dimensional variations and improve precision. |
Chip Control Issues | Long, stringy chips | Use high-pressure coolant and optimize tool geometry to break chips. |
Optimized Machining Strategies
Strategy | Implementation | Benefit |
|---|---|---|
High-Speed Machining | Spindle speed: 1,200–1,800 RPM | Increases productivity and reduces heat buildup. |
Climb Milling | Cutting in the direction of tool rotation | Improves surface finish (Ra 1.6–3.2 µm). |
Toolpath Optimization | Use trochoidal milling for deep pockets | Reduces cutting forces, minimizing part deflection. |
Stress-Relief Annealing | Preheat to 650°C for 1 hour per inch | Minimizes residual stress and improves machining accuracy. |
Cutting Parameters for SUS317 Stainless Steel
Operation | Tool Type | Spindle Speed (RPM) | Feed Rate (mm/rev) | Depth of Cut (mm) | Notes |
|---|---|---|---|---|---|
Rough Milling | 4-flute carbide end mill | 1,000–1,500 | 0.15–0.25 | 2.0–4.0 | Use coolant to prevent work hardening. |
Finish Milling | 2-flute carbide end mill | 1,500–2,000 | 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 | 500–700 | 0.20–0.30 | 1.5–3.0 | Dry machining is acceptable with air blast cooling. |
Surface Treatments for CNC Machined SUS317 Stainless Steel Parts
Electroplating: Adds a corrosion-resistant metallic layer, extending part life in humid environments and improving strength.
Polishing: Enhances the surface finish, providing a smooth, shiny appearance ideal for visible components.
Brushing: Creates a satin or matte finish, masking minor surface defects and improving aesthetic quality for architectural components.
PVD Coating: Boosts wear resistance, increasing tool life and part longevity in high-contact environments.
Passivation: Creates a protective oxide layer, enhancing corrosion resistance in mild environments without altering dimensions.
Powder Coating: Offers high durability, UV resistance, and a smooth finish, ideal for outdoor and automotive parts.
Teflon Coating: Provides non-stick and chemical-resistant properties, ideal for food processing and chemical handling components.
Chrome Plating: Adds a shiny, durable finish that enhances corrosion resistance, commonly used in automotive and tooling applications.
Black Oxide: Provides a corrosion-resistant black finish, ideal for parts in low-corrosion environments like gears and fasteners.
Industry Applications of CNC Machined SUS317 Stainless Steel Parts
Chemical Processing Industry
Pumps and Valves: SUS317 is ideal for components exposed to highly corrosive chemicals in industrial processing plants.
Marine Industry
Marine Equipment: SUS317 is commonly used for parts exposed to seawater and saline environments due to its excellent corrosion resistance.
Food and Beverage Industry
Processing Equipment: The material’s resistance to corrosion and high temperatures makes it perfect for food processing machinery and equipment.
Technical FAQs: CNC Machined SUS317 Stainless Steel Parts & Services
How does SUS317 compare to SUS316 in chloride environments?
What are the recommended machining techniques for SUS317?
Can SUS317 be used for high-temperature applications in the aerospace industry?
What welding techniques are suitable for SUS317 stainless steel?
How does SUS317 perform in harsh marine environments compared to other stainless steels?
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