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About 13-8 PH Stainless Steel: Properties, Applications, Pros and Cons
- John
13-8 PH stainless steel is ideal for demanding applications in aerospace, automotive, and industrial sectors for its balanced properties.
This article explores the key characteristics of 13-8 PH stainless steel and covers its applications in various sectors.
What Is 13-8 PH Stainless Steel?
13-8 PH stainless steel is composed of about 13% chromium and 8% nickel, with the balance being iron and small amounts of other elements like molybdenum and aluminum. It is an advanced martensitic precipitation-hardening steel. It is known for its balanced combination of excellent strength and corrosion resistance. It is most used in industries such as aerospace, defense, and chemical processing.
13-8 PH Stainless Steel Equivalents
- UNS S13800
- EN 1.4534
- DIN X4CrNiMo13-8
13-8 PH Stainless Steel Standards
- AMS 5629
- ASTM A313
- ASTM A564
Chemical Composition of 13-8 PH Stainless Steel
| Element | C | Mn | Si | P | S | Cr | Ni | Mo | Al | Fe |
| wt% | 0.05 max | 0.10 max | 0.10 max | 0.010 max | 0.008 max | 12.25-13.25 | 7.5-8.5 | 2.00-2.50 | 0.90-1.35 | Balance |
13-8 PH Stainless Steel Properties
Physical Properties of 13-8 PH Stainless Steel
| Property | Metric Value | Imperial Value |
| Density | 7.75-7.85 g/cm³ | 0.280-0.2836 lbs/in³ |
| Melting Point | 1404 – 1471 °C | 2560 – 2680 °F |
| Thermal Conductivity | 14 W/m·K | 97.2 BTU·in/hr·ft²·°F |
| Thermal Expansion | 10.6 μm/m·°C | 5.89 μin/in·°F |
| Electrical Conductivity | 0.0001 ohm-cm at 25°C | – |
Is 13-8 Stainless Steel Magnetic?
It is lightly magnetic in the martensitic state. The magnetic characteristics of 13-8 stainless steel can vary depending on the heat treatment and mechanical processing it undergoes.
Mechanical Properties of 13-8 PH Stainless Steel
| Property | Typical Value |
| Tensile Strength | 1480 MPa (215,000 psi) |
| Yield Strength | 1415 MPa (205,000 psi) |
| Brinell Hardness | 363 HB |
| Rockwell Hardness | 45 HRC |
| Vickers Hardness | 450 HV |
| Elongation | 10-12% |
| Elastic Modulus | 195-200 GPa (28,300-29,000 ksi) |
Advantages of 13-8 PH Stainless Steel
Below, we explore these properties in detail, highlighting why 13-8 PH is favored in industries requiring both strength and durability.
High Strength
13-8 PH can be heat-treated to become extremely strong. It is perfect for parts that need to handle heavy loads, like airplanes and industrial machinery.
Heat Treatability
Its strength and hardness can be adjusted through heating treatment. It is very versatile for different uses, from small precision parts to large, strong structures.
Excellent Toughness
13-8 PH stainless steel can maintain good toughness in its hardened state. It resists cracking and breaking under impact or heavy pressure. It is used in applications such as pressure vessels and landing gear in aircraft.
Fatigue Resistance
13-8 PH stainless steel exhibits excellent fatigue resistance. It can endure multiple stress cycles without the formation of cracks. Because its martensitic structure combined with precipitation hardening, strengthens the material at the micro-level.
The alloy’s composition also helps distribute stress evenly, reducing the chance of crack formation from constant vibrations or load changes. This property is critical in applications like aircraft components and turbine blades.
Corrosion Resistance
13-8 PH stainless steel contains chromium, nickel, and molybdenum, which protect it from rust and corrosion. It performs well in environments with moisture, chemicals, or salt, like marine or chemical processing equipment.
Dimensional Stability
13-8 stainless steel has low thermal expansion. It undergoes very little expansion or contraction when exposed to temperature variations. This is important for precision parts like gears or shafts that need to stay exact in size even when heated.
Moderate Magnetic Properties
After hardening, 13-8 PH becomes slightly magnetic. It is useful in applications where both strength and some level of magnetic response are needed, such as in certain mechanical systems.
Disadvantages of 13-8 PH Stainless Steel
While 13-8 PH stainless steel has many excellent properties, it is not suitable for every application. Here are some limitations of 13-8 PH stainless steel.
Limited Corrosion Resistance
13-8 PH stainless steel performs well in many environments. However, it is not ideal for highly aggressive conditions, such as prolonged exposure to strong acids or chloride-rich environments like seawater.
Brittleness at Higher Hardness Levels
When 13-8 PH is heat-treated to achieve maximum hardness, it can become somewhat brittle. This happens because the martensitic structure becomes more rigid, which reduces its ability to absorb impact.
Complex Heat Treatment Process
The strength and hardness of 13-8 PH rely on precise heat treatment. Without careful control, it may not achieve its full strength or toughness.
High Cost
The alloying elements in 13-8 PH stainless steel, such as nickel, chromium, and molybdenum, make it more expensive to produce. Additionally, the advanced heat treatment process adds to the overall cost.
The Applications of 13-8 PH Stainless Steel
Here’s an overview of the key applications of 13-8 PH stainless steel:
- Aerospace
Landing gear, structural components, actuators.
- Oil and Gas
Valves, drilling equipment, and downhole tools.
- Marine
Submarine components, and propulsion systems.
- Chemical Processing
Pumps, valves, high-pressure reactors.
- Medical Devices
Surgical instruments, implants.
- Power Generation
Turbine components, hydropower equipment.
- Automotive
High-performance parts, gears, drive shafts.
Heat Treatment of 13-8 PH Stainless Steel
The heat treatment of 13-8 PH stainless steel is a highly versatile and critical process. These can further enhance the material’s performance depending on the different requirements. Below are additional heat treatment processes that can be applied:
Solution Annealing
- Heat to 927°C to 940°C (1700°F to 1725°F) and hold for about 1 hour per inch of thickness.
- The material is in a softer state (Condition A), with a martensitic structure ready for further hardening.
Cryogenic Treatment(Optional)
- Cool the material to -73°C (-100°F) or lower after solution annealing, then proceed with aging.
- Enhances hardness, toughness, and dimensional stability, particularly useful for cryogenic or low-temperature applications.
Aging (Precipitation Hardening)
After solution annealing, precipitation hardening increases the material’s strength and hardness. Various aging temperatures offer different balances of strength, hardness, and toughness.
Here is the table of common aging conditions.
| Condition | Aging Temperature | Hold Time | Resulting Properties |
| H950 | 510°C (950°F) | 4 hours | Maximum strength, high hardness |
| H1000 | 538°C (1000°F) | 4 hours | High strength, improved toughness |
| H1050 | 565°C (1050°F) | 4 hours | Balanced strength and toughness |
| H1100 | 593°C (1100°F) | 4 hours | Lower strength, higher toughness |
| H1150 | 621°C (1150°F) | 4 hours | Lowest strength, maximum toughness |
| H1150M | Double Aging | Varies | Maximum toughness, reduced strength |
Overaging
- Overaging is a specific condition of aging. It occurs when the material has been aged beyond the point of maximum strength
- Overaging is done by holding the material at a higher temperature (like H1150M) or for a longer time and sometimes involves double aging (e.g., first aging at 621°C (1150°F), then at 593°C (1100°F)).
- Maximizes toughness and reduces hardness.
Post-Weld Heat Treatment
- After welding, the material is solution-annealed and then aged.
- Ensures the welded area has the same mechanical properties as the rest of the material, preventing weakness in the heat-affected zone (HAZ).
Other Processing Methods of 13-8 PH Stainless Steel
The mechanical processing of 13-8 PH stainless steel can involve various steps. Hot working, cold working, forging, forming, and welding are optional. Machining is a common step to achieve precision dimensions.
After each mechanical process, the material typically undergoes further heat treatment to restore or enhance its mechanical properties.
Hot Working
- Deforme the material at high temperatures (1038°C to 1149°C or 1900°F to 2100°F). Includes hot rolling, forging, or extrusion.
- Used to shape large or complex parts with minimal risk of cracking.
Cold Working
- Deforming 13-8 PH stainless steel at room temperature through processes like rolling, drawing, or pressing.
- Increase the material’s strength and hardness.
Forming
- Shaping processes like bending, stamping, or stretching to form specific shapes without removing material.
- Deforms the material into a required shape for structural or functional purposes.
Machining
- Cutting, drilling, turning, or milling to achieve precise dimensions and geometries.
- Used to create precise, finished components after forming processes.
Welding
- Joining two pieces of material using heat and sometimes filler metal. After welding, the material can undergo heat treatment to regain its full strength and toughness.
- Used for assembling complex structures.
Furthermore About 13-8 PH Stainless Steel
Will 13-8 Stainless Steel Rust?
13-8 stainless steel is resistant to rust and corrosion.
Under certain extreme conditions, such as prolonged exposure to seawater or harsh chemicals, it may still experience some corrosion.
What Is The Difference Between 13-8 PH and 17-4 PH?
13-8 PH has a higher nickel content and includes aluminum. It is known for higher toughness and performs better at stress-corrosion cracking.
17-4 PH contains more chromium. It offers better general corrosion resistance, especially in marine environments.
What is PH 13-8 Mo Stainless Steel?
PH 13-8 Mo stainless steel is a precipitation-hardening alloy with chromium, nickel, and molybdenum. This alloy offers improved strength, corrosion resistance, and toughness It is used in aerospace and oil and gas industries.
13-8 PH VS PH 13-8 Mo Stainless Steel
PH 13-8 Mo contains molybdenum. It has better corrosion resistance. PH 13-8 Mo typically has higher strength after heat treatment.
While both are strong, PH 13-8 Mo is preferred for applications requiring superior corrosion resistance.
Summary
13-8 PH offers excellent fatigue resistance, weldability, and flexibility through heat treatment processes. It is a versatile material for demanding environments.
At Steel Pro Group, we are committed to providing top-quality materials for high-performance industrial needs. If you are looking for reliable solutions for your projects, please visit our website or contact us for a personalized consultation and quote. We’re here to help you make the best material choice for your specific requirements!
