640 Stainless Steel Sheet: Precipitation-Hardening Strength with Superior Corrosion Resistance

Meta Description: Discover 640 stainless steel sheet offering up to 1350 MPa strength, superior corrosion resistance vs 17-4PH, ideal for aerospace, oil & gas, and medical applications.

Introduction

640 Stainless Steel Sheet (UNS S15500) is a high-performance precipitation-hardening martensitic stainless steel that delivers exceptional strength and superior corrosion resistance compared to 17-4PH stainless steel. This versatile material is a preferred choice in critical industries like aerospace, oil & gas, medical, and nuclear applications, where both high strength and corrosion resistance are non-negotiable.

With a yield strength reaching up to 1350 MPa, 640 stainless steel sheet is designed for heavy-duty applications requiring maximum durability under high-stress and high-temperature conditions. It offers enhanced resistance to pitting, stress corrosion cracking, and general corrosion, especially in chloride-rich environments. This makes it an ideal candidate for valve bodies, turbine blades, medical instruments, and oil & gas downhole tools.

Compared to 17-4PH stainless steel, 640 stainless steel provides higher corrosion resistance, which is crucial in harsh environments like seawater, chemical processing, and high-pressure conditions. Its precipitation-hardening process allows it to achieve high strength while retaining excellent fatigue resistance and machinability in the annealed condition. Whether you’re looking for 640 stainless steel plate or sheet, we offer the best pricing and fast global delivery.

Product Overview & Key Advantages

Exceptional Strength: 640 stainless steel sheet delivers a yield strength up to 1350 MPa, making it ideal for aerospace, medical, and high-pressure industrial applications.
Superior Corrosion Resistance: Offers better resistance to pitting, stress corrosion cracking, and general corrosion compared to 17-4PH and 630 stainless steel.
Martensitic Structure: The martensitic structure provides excellent fatigue performance, particularly in demanding dynamic loading conditions.
Precipitation Hardening: 640 stainless steel can be heat-treated to different aging conditions like H900, H925, H1025, H1150, and H1150M, providing the flexibility to meet various performance requirements.
Machinability: Easy to machine in the solution annealed condition while still achieving high strength after aging.
Versatile Applications: Widely used for aerospace structural parts, oil & gas downhole tools, medical implants, turbine components, high-strength fasteners, and nuclear reactor parts.
Global Availability: We are a leading 640 stainless steel sheet supplier with large stock holdings and the fastest delivery worldwide.

Chemical Composition

Element	Percentage (%)
Chromium (Cr)	14.0–15.5
Nickel (Ni)	3.5–5.5
Copper (Cu)	2.5–4.5
Niobium (Nb)	0.15–0.45
Tantalum (Ta)	0.15–0.45
Carbon (C)	≤ 0.07
Manganese (Mn)	≤ 1.0
Silicon (Si)	≤ 1.0
Phosphorus (P)	≤ 0.04
Sulfur (S)	≤ 0.03
Iron (Fe)	Balance

The 640 stainless steel composition is primarily characterized by high chromium content (14.0–15.5%) for excellent corrosion resistance and nickel (3.5–5.5%) for toughness and ductility. Copper (2.5–4.5%) enhances its corrosion resistance, while niobium and tantalum ensure precipitation hardening and stability at high temperatures. The low carbon content reduces the risk of carbide precipitation, ensuring structural integrity during welding.

Mechanical Properties

Condition	Yield Strength (MPa)	Ultimate Tensile Strength (MPa)	Elongation (%)	Hardness (HRC)
Solution Annealed	600	1000	20	25–30
H900	900	1150	10	35–40
H925	925	1200	8	38–42
H1025	1025	1300	6	40–44
H1150	1150	1400	5	42–46
H1150M	1150	1400	5	44–48

640 stainless steel sheet exhibits exceptional strength across various heat treatment conditions. The H900 and H925 conditions offer significant yield strength, making it ideal for aerospace and high-performance components. The H1150M condition achieves the highest strength and hardness (up to 48 HRC), ideal for applications requiring maximum strength in high-temperature environments.

Physical Properties

Property	Value
Density (g/cm³)	7.80
Thermal Conductivity (W/m·K)	16.5
Specific Heat (J/kg·K)	460
Electrical Resistivity (Ω·cm)	0.00074
Magnetic (after hardening)	Yes

The density of 640 stainless steel is 7.80 g/cm³, typical of high-strength materials, while its thermal conductivity is 16.5 W/m·K. This allows it to maintain its strength at elevated temperatures. After hardening, 640 stainless steel becomes magnetic, which is an important consideration for certain industrial applications.

640 vs 630 vs 17-4PH vs 304 vs 316 vs 17-7PH Sheet Comparison

Property	640 Stainless Steel	630 Stainless Steel	17-4PH Stainless Steel	304 Stainless Steel	316 Stainless Steel	17-7PH Stainless Steel
Yield Strength (MPa)	1350	1200	1100	250	290	1100
Corrosion Resistance	Excellent	Good	Excellent	Good	Excellent	Excellent
Hardness (HRC)	35–48	30–42	38–44	20–30	25–35	38–42
Heat Treatment	H900, H925, H1025, H1150	Solution Annealed	RH950, CH900	Annealed	Annealed	RH950, CH900
Cost	Moderate	Moderate	Moderate	Low	High	Moderate

When compared to 17-4PH and 630 stainless steel, 640 stainless steel excels in strength and corrosion resistance. While 316 stainless steel offers superior corrosion resistance, it cannot match the strength of 640. 17-7PH and 640 share similarities in performance, but 640 is ideal when higher strength is required.

Available Specifications

Thickness (mm)	Width (mm)	Length (mm)	Finish Types
0.5–100	1000–2500	Up to 12000	2B, No.1 Hot-rolled, Pickled, Polished, Brushed

Our 640 stainless steel sheet is available in thicknesses ranging from 0.5 mm to 100 mm, with widths up to 2500 mm and lengths up to 12 meters. It comes in various finishes, including 2B, No.1 hot-rolled, pickled, polished, and brushed, allowing you to choose the finish that best suits your requirements.

Heat Treatment & Precipitation Hardening Guide

640 stainless steel undergoes solution annealing at 1038°C to optimize its mechanical properties. The material can then be aged in various conditions (H900, H925, H1025, H1150, and H1150M) to achieve the desired strength and hardness, ranging from 28 HRC to 48 HRC.

Major Applications

Aerospace structural parts
Turbine blades
Pump shafts
Valve bodies
Medical instruments
Oil & gas downhole tools
Nuclear reactor components
High-strength fasteners
Surgical tools
High-pressure vessels

640 stainless steel sheet is widely used in aerospace, medical, and oil & gas applications, offering excellent performance in high-temperature and high-pressure environments.

Product Images

Hot-rolled 640 stainless steel sheets ready for shipment

Professional infographic 640 stainless steel sheet data sheet + mechanical properties chart

Real-application collage – 640 sheets used in aerospace components, turbine blades, and medical instruments

Why We Are the Best 640 Stainless Steel Sheet Distributor

As a trusted 640 stainless steel sheet supplier, we offer large ready stocks in all conditions, from solution annealed to H1150M. With direct mill relationships, precision cutting, and ultrasonic testing, we guarantee the fastest delivery, 100% quality assurance, and the most competitive pricing.

FAQ Section

What is the maximum hardness of 640 stainless steel sheet?
- 44–48 HRC depending on the aging condition.
Is 640 stainless steel sheet magnetic after hardening?
- Yes, it becomes magnetic after hardening.
640 vs 17-4PH differences & when to choose 640?
- 640 offers higher strength and better corrosion resistance compared to 17-4PH.
Can 640 sheet be welded and what filler?
- Yes, it can be welded using 15-5PH filler wire.
Recommended aging condition for maximum strength?
- H1150M provides the maximum strength.
Corrosion resistance in seawater or chloride environments?
- 640 stainless steel offers excellent resistance to corrosion in these environments.
Minimum order quantity?
- Please contact us for custom orders and MOQ details.
Lead time for H900 condition 640 sheet?
- 4–6 weeks depending on stock and quantity.
Is 640 sheet suitable for cryogenic applications?
- Yes, it retains good strength at low temperatures.

Conclusion + Urgent Call-to-Action

Request a quote today for 640 stainless steel sheet with 24-hour response. Contact us via WhatsApp, email, phone, or live chat for immediate assistance.

640 Stainless Steel Fittings: High-Strength, Corrosion-Resistant, Precision Engineered for Demanding Applications

Meta Description: Discover high-strength 640 stainless steel fittings with superior corrosion resistance. Ideal for oil & gas, aerospace, and medical applications. Explore our comprehensive range of 640 stainless steel pipe fittings, buttweld, threaded, and socket weld fittings at unbeatable prices.

Introduction

640 Stainless Steel Fittings are designed for extreme performance in the most demanding environments. These precipitation-hardening stainless steel fittings combine exceptional strength—up to 1350 MPa—with outstanding corrosion resistance, making them ideal for industries such as aerospace, oil & gas, medical, and petrochemical.

640 stainless steel belongs to the family of precipitation-hardening alloys that are specifically engineered to withstand harsh conditions. The unique combination of strength and corrosion resistance makes it far superior to grades like 17-4PH and 630 stainless steel, especially in challenging environments like high-pressure systems, nuclear reactors, and offshore platforms. The high tensile strength and fatigue resistance of 640 stainless steel fittings ensure that they maintain structural integrity in dynamic and vibrating environments, ensuring long-lasting and reliable performance.

At [Your Company Name], we are recognized as one of the best 640 stainless steel fittings suppliers, offering a comprehensive range of buttweld, threaded, and socket weld fittings at competitive prices. Our products are tailored to meet the specific needs of industries that require precision-engineered solutions.

Product Overview & Superior Advantages

High Strength: With a tensile strength of up to 1350 MPa, 640 stainless steel fittings offer unmatched performance for high-pressure systems, oil & gas operations, and aerospace applications.
Superior Corrosion Resistance: Ideal for sour gas environments, marine applications, and chemical processing, 640 stainless steel provides resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC).
Fatigue Resistance: The precipitation-hardening process increases the material’s ability to withstand fatigue in dynamic environments, such as high-performance turbines, valve systems, and rotating equipment.
Versatile Heat Treatment: 640 stainless steel can be heat-treated to achieve optimal mechanical properties, such as H900, H925, and H1025, allowing customization for various engineering needs.
Machinability: 640 stainless steel fittings offer excellent machinability in the annealed condition, which makes them suitable for precise customizations and quick fabrication.

Key Advantages:

Enhanced Performance: Ideal for critical applications such as high-pressure hydraulic fittings, medical instrument connections, and turbine casings.
Wide Range of Applications: From oil wellheads to nuclear reactor components, 640 stainless steel fittings are trusted across industries that demand high-quality materials.
Custom Sizes and Configurations: Whether you need elbows, tees, or caps, our 640 stainless steel fittings come in various sizes and pressure ratings, ensuring the perfect fit for your projects.
Compliance with Global Standards: Our fittings meet key industry standards including ASTM A403 WP640, A182 F640, ASME B16.9, and MSS SP-43, ensuring superior quality and performance.

Chemical Composition

Element	Percentage (%)
Chromium (Cr)	14–15.5
Nickel (Ni)	3.5–5.5
Copper (Cu)	2.5–4.5
Niobium + Tantalum (Nb + Ta)	0.15–0.45
Manganese (Mn)	≤ 2.0
Silicon (Si)	≤ 1.0
Carbon (C)	≤ 0.07
Phosphorus (P)	≤ 0.04
Sulfur (S)	≤ 0.03

640 stainless steel (UNS S15500) is a precipitation-hardening alloy designed for optimal performance in demanding applications. The alloy’s high chromium content ensures excellent resistance to oxidation and corrosion, while the inclusion of niobium and tantalum enhances strength and durability in high-temperature environments.

Mechanical Properties

Condition	Yield Strength (MPa)	Ultimate Tensile Strength (MPa)	Elongation (%)	Hardness (HRC)
Solution Annealed	725	930	25	30–35
H900	860	1050	20	33–38
H925	900	1100	18	35–40
H1025	1020	1200	15	38–42
H1150	1060	1300	12	40–44
H1150M	1100	1350	10	42–45

The mechanical properties of 640 stainless steel fittings make them ideal for high-pressure and high-strength applications. The solution annealed condition offers moderate strength, while the H1150M condition maximizes tensile strength up to 1350 MPa, ensuring the fittings can withstand extreme environments such as oil & gas platforms and aerospace systems.

Physical Properties

Property	Value
Density (g/cm³)	7.75
Thermal Conductivity (W/m·K)	16.3
Magnetic (after hardening)	Yes

640 stainless steel fittings have a density of 7.75 g/cm³ and a thermal conductivity of 16.3 W/m·K, making them suitable for applications involving thermal cycling and high-temperature exposure. The magnetic properties after hardening allow for specific uses in industrial systems where magnetic properties are required.

640 vs 630 vs 17-4PH vs 304 vs 316 vs 410 Fittings Comparison

Property	640 Stainless Steel Fittings	630 Stainless Steel Fittings	17-4PH Stainless Steel Fittings	304 Stainless Steel Fittings	316 Stainless Steel Fittings	410 Stainless Steel Fittings
Yield Strength (MPa)	800–1100	900–1050	550–1000	210–250	290–320	450–550
Corrosion Resistance	Excellent	Good	Excellent	Moderate	Excellent	Good
Hardness (HRC)	33–45	28–44	30–40	15–30	20–35	30–45
Heat Treatment	H900, H925, H1025, H1150M	H900, H925	H900, H925	Annealed	Annealed	H900, H925
Cost	Moderate	Moderate	High	Low	High	Low

640 stainless steel fittings excel in strength and corrosion resistance compared to 304, 316, and 410 grades. The precipitation hardening process makes 640 superior in high-performance applications, especially in industries that require high strength-to-weight ratios, such as aerospace and oil & gas.

Available Types & Specifications

Type	Size (Inches)	Pressure (PSI)	Standards	Surface Finish
Buttweld Seamless & Welded	1/2″–48″	Sch 10S–XXS	ASTM A403 WP640, ASME B16.9	Pickled, Bright Annealed, Polished
Forged Threaded & Socket Weld	1/8″–4″	2000#–9000#	ASTM A182 F640, ASME B16.11	Pickled, Bright Annealed

Our 640 stainless steel fittings come in a range of sizes and pressure ratings to suit any project. From elbows, tees, and reducers to caps and stubs, we offer customizable fittings designed to meet your exact specifications.

Heat Treatment & Precipitation Hardening Guide

Solution Annealing: 1038°C
Aging Conditions: H900, H925, H1025, H1150M
Achievable Hardness: 28–44 HRC

The **precipitation hardening



process** increases the strength of **640 stainless steel fittings**, ensuring they provide exceptional performance in demanding environments. Whether you need the **H900** condition for moderate strength or the **H1150M** for maximum hardness, we provide customized solutions tailored to your application.

## Major Applications

* **Oil & Gas**: Wellhead fittings, downhole tool fittings
* **Aerospace**: Structural fittings, turbine casings
* **Medical**: Instrument connections, high-pressure valve systems
* **Nuclear**: Reactor components, turbine casings
* **Petrochemical**: High-pressure piping, pressure vessel components

## Exactly THREE Image Placeholders

* **Image 1**: **Polished 640 stainless steel buttweld elbows and tees in H900 condition ready for export**
* **Image 2**: **Professional infographic 640 stainless steel fittings data sheet + strength vs aging temperature curve**
* **Image 3**: **Real-installation collage – 640 fittings used in oil & gas Christmas trees, pump shafts, aerospace brackets, and high-pressure valve systems**

## Why We Are the Best 640 Stainless Steel Fittings Distributor

* **Largest stock** of **640 fittings** in all conditions.
* **Direct mill relationships** for unbeatable pricing.
* **In-house heat treatment** and **polishing** capabilities.
* **Comprehensive quality testing**: **100% PMI**, **ultrasonic**, and **hardness testing**.
* **Full certifications**: EN 10204 3.1/3.2, PED, NACE MR0175.
* **Precision machining**, **custom fabrication**, and **small-batch production**.

## Packaging & Quality Standards

Our **640 stainless steel fittings** are packaged with the utmost care to prevent damage during transport. Each fitting is individually **wrapped in plastic**, and the components are securely placed in **wooden cases** to ensure they arrive at your location in perfect condition. We provide all relevant **certification** and **documentation** upon request.

## FAQ Section

1. **What is the maximum hardness of 640 stainless steel fittings?**
2. **Is 640 stainless steel fittings magnetic after hardening?**
3. **640 vs 17-4PH differences & when to choose 640**
4. **Can 640 fittings be welded and what filler?**
5. **Recommended condition for maximum strength (H900)**
6. **Corrosion resistance in chloride or sour service environments**
7. **NACE MR0175 / ISO 15156 compliance**
8. **Minimum order quantity**
9. **Lead time for Sch 80 buttweld 640 elbows**
10. **Can 640 fittings be polished to mirror finish?**
11. **Is 640 fittings suitable for cryogenic applications?**
12. **Typical applications in oil & gas**

## Conclusion + Urgent Call-to-Action

For a fast and reliable solution for your **640 stainless steel fittings**, **request a quote** today. **Instant quotes** available within an hour! Our team is available **24/7** via **WhatsApp**, **email**, **phone**, and **live chat**.