640 Stainless Steel Coil: High-Strength, Corrosion-Resistant Precipitation-Hardening Steel
Meta Description: Discover 640 stainless steel coil for aerospace, medical, and high-performance applications. Offering superior corrosion resistance and strength (up to 1350 MPa), it outperforms 17-4PH and 630 stainless steel coil.
Introduction
640 Stainless Steel Coil (UNS S15500) is a precipitation-hardening stainless steel that provides outstanding strength, reaching up to 1350 MPa, and superior corrosion resistance compared to other martensitic grades like 17-4PH and 630 stainless steel coil. This high-performance material is designed for industries where high strength, durability, and fatigue resistance are critical, such as aerospace, medical devices, and high-performance fasteners.
The 640 stainless steel coil offers excellent fatigue performance, machinability in the annealed condition, and resistance to both general and localized corrosion, making it ideal for manufacturing parts subjected to extreme mechanical stresses, such as aerospace springs, aircraft fasteners, and medical implants.
With a combination of high tensile strength and outstanding resistance to corrosion, 640 stainless steel coil is a versatile material that meets the demanding standards of industries where reliability is crucial. It is an ideal alternative to grades like 15-5PH stainless steel coil, offering similar strength with enhanced corrosion resistance in harsh environments.
Whether you need material for high-strength springs, pump shafts, or valve trim, 640 stainless steel coil is the perfect solution. As one of the best 640 stainless steel coil suppliers, we offer high-quality material, available in a wide range of conditions and sizes, and backed by extensive testing and certification processes.
Product Overview & Key Advantages
- Superior Strength: Offers up to 1350 MPa yield strength, making it ideal for aerospace structural parts, high-strength fasteners, and medical device components.
- Corrosion Resistance: Exceptional performance in chloride environments, seawater, and other harsh conditions.
- High Fatigue Resistance: Designed to withstand cyclic loading and maintain performance under demanding conditions.
- Machinability in Annealed Condition: Easily processed and machined in its annealed state, reducing manufacturing costs and lead times.
- Versatile Applications: Ideal for critical aerospace, medical, and high-performance applications.
- Precipitation Hardening: Ability to adjust mechanical properties by controlling aging conditions such as H900, H925, H1025, H1150, and H1150M.
Detailed Advantages:
- Precipitation Hardening: By adjusting aging conditions, the 640 stainless steel coil can achieve different mechanical properties to suit a wide variety of applications. Whether you need a softer material for ease of machining or a hardened material for maximum strength, 640 stainless steel coil offers the flexibility you need.
- Corrosion Resistance: The addition of chromium and copper ensures that 640 stainless steel coil provides excellent corrosion resistance. It is highly resistant to pitting and crevice corrosion in environments with high chloride content, which makes it ideal for marine and chemical processing environments.
Chemical Composition
| Element | Percentage (%) |
|---|---|
| Chromium (Cr) | 14–15.5 |
| Nickel (Ni) | 3.5–5.5 |
| Copper (Cu) | 2.5–4.5 |
| Niobium (Nb) + Tantalum (Ta) | 0.15–0.45 |
| Iron (Fe) | Balance |
| Carbon (C) | ≤ 0.07 |
| Manganese (Mn) | ≤ 1.0 |
| Silicon (Si) | ≤ 1.0 |
| Phosphorus (P) | ≤ 0.04 |
| Sulfur (S) | ≤ 0.03 |
The 640 stainless steel coil is composed primarily of chromium (14-15.5%) and nickel (3.5-5.5%), which provide it with its excellent strength and corrosion resistance. The addition of copper (2.5-4.5%) and niobium (Nb) or tantalum (Ta) enhances the precipitation-hardening capabilities, allowing for high strength after aging.
Mechanical Properties
| Condition | Yield Strength (MPa) | Ultimate Tensile Strength (MPa) | Elongation (%) | Hardness (HRC) |
|---|---|---|---|---|
| Solution Annealed | 550 | 850 | 20 | 25–30 |
| H900 | 900 | 1100 | 10 | 38–42 |
| H925 | 925 | 1150 | 8 | 39–43 |
| H1025 | 1025 | 1200 | 6 | 40–44 |
| H1150 | 1150 | 1250 | 4 | 42–46 |
| H1150M | 1150 | 1300 | 3 | 44–48 |
640 stainless steel coil demonstrates remarkable mechanical properties across a wide range of heat treatments. In the H900 condition, it achieves a yield strength of 900 MPa, which is ideal for applications that require good strength and ductility. For maximum hardness, the H1150M condition offers a yield strength of 1150 MPa, with hardness levels up to 48 HRC.
Physical Properties
| Property | Value |
|---|---|
| Density (g/cm³) | 7.80 |
| Thermal Conductivity (W/m·K) | 16.0 |
| Specific Heat (J/kg·K) | 460 |
| Electrical Resistivity (Ω·cm) | 0.00074 |
| Magnetic (after hardening) | Yes |
640 stainless steel coil has a density of 7.80 g/cm³, which is consistent with other high-strength stainless steels. It offers moderate thermal conductivity (16.0 W/m·K), ensuring stable performance across a wide range of temperatures. After hardening, it becomes magnetic, which may be relevant for certain applications.
640 vs 630 vs 17-4PH vs 304 vs 316 Coil Comparison
| Property | 640 Stainless Steel | 630 Stainless Steel | 17-4PH Stainless Steel | 304 Stainless Steel | 316 Stainless Steel |
|---|---|---|---|---|---|
| Yield Strength (MPa) | 1350 | 1300 | 1100 | 250 | 290 |
| Corrosion Resistance | Excellent | Good | Excellent | Good | Excellent |
| Hardness (HRC) | 38–48 | 35–45 | 38–44 | 20–30 | 25–35 |
| Heat Treatment | H900, H925, H1150 | H900, H925 | H950, H900 | Annealed | Annealed |
| Cost | High | Moderate | Moderate | Low | High |
640 stainless steel coil offers higher strength and better corrosion resistance than 630 and 17-4PH stainless steel coils. Compared to 304 and 316, 640 provides better strength without sacrificing corrosion resistance.
Available Specifications
| Thickness (mm) | Width (mm) | ID (mm) | Finish Types |
|---|---|---|---|
| 0.3–8.0 | 20–1500 | 300/400/508/610 | 2B, 2D, Bright Annealed, No.4, Polished |
Our 640 stainless steel coil is available in thicknesses ranging from 0.3 mm to 8.0 mm, widths up to 1500 mm, and inner diameters of 300 mm, 400 mm, 508 mm, and 610 mm. We offer a variety of finishes, including 2B, No.4, bright annealed, and polished to meet your specific needs.
Heat Treatment & Precipitation Hardening Guide
To achieve the desired mechanical properties, 640 stainless steel coil is subjected to solution annealing at 1038 °C, followed by aging treatments such as H900, H925, H1025, and H1150. The aging process allows for a range of hardness levels from 28–44 HRC, providing flexibility for different applications.
Major Applications
- Aerospace structural springs
- Aircraft fasteners
- Medical instrument components
- High-strength bellows
- Pump shafts
- Valve trim
- Turbine parts
- Nuclear reactor components
- Surgical tools
- High-performance springs
- Chemical processing coil tubing
640 stainless steel coil is widely used in aerospace, medical, and high-performance applications where both high strength and corrosion resistance are essential. From aircraft springs to medical tools, this material excels in demanding environments.
Product Images
Hot-rolled 640 stainless steel coils ready for shipment
Professional infographic 640 stainless steel coil data sheet + mechanical properties chart
Real-application collage – 640 coils used in aerospace springs, turbine parts, and medical instruments
Why We Are the Best 640 Stainless Steel Coil Distributor
With our direct mill relationships, large ready stock, and custom slitting capabilities, we are the most reliable supplier of 640 stainless steel coil. We offer competitive pricing, fast global delivery, and certified material (EN 10204 3.1/3.2). Our team ensures precision cutting and quality testing, including ultrasonic testing and PMI testing.
Packaging & Delivery Standards
We deliver all orders securely using export-standard packaging, including VCI paper for corrosion protection, wooden saddles, and steel edge protection to ensure safe delivery.
FAQ Section
-
What is the maximum hardness of 640 stainless steel coil?
- The maximum hardness is 48 HRC in H1150M condition.
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Is 640 stainless steel coil magnetic after hardening?
- Yes, it becomes magnetic after hardening.
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640 vs 17-4PH differences?
- 640 offers superior corrosion resistance and higher strength compared to 17-4PH.
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Can 640 coil be welded and what filler?
- Yes, it can be welded with 17-4PH filler.
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Recommended condition for maximum strength?
- H900 is recommended for maximum strength.
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Corrosion resistance in chloride environments?
- 640 offers excellent resistance in chloride-rich environments.
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Minimum order quantity?
- Contact us for MOQ details.
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Lead time for H900 condition 640 coil?
- Lead time is typically 4–6 weeks.
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Is 640 coil suitable for cryogenic applications?
- Yes, 640 is suitable for cryogenic environments.
Conclusion + Urgent Call-to-Action
Request a quote today for 640 stainless steel coil. Contact us via WhatsApp, email, phone, or live chat for a 24-hour response.