Grade 660 Stainless Steel Round Bar Hot Rolled and Forged Bar ASTM EN DIN JIS GB Standard

Grade 660 Stainless Steel Round Bar Hot Rolled and Forged Bar ASTM EN DIN JIS GB Standard

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Grade 660 Stainless Steel Round Bar Hot Rolled and Forged Bar ASTM EN DIN JIS GB Standard

Introduction to Grade 660 Stainless Steel

Grade 660 stainless steel is a high-performance, precipitation-hardening stainless steel that offers a combination of high strength, excellent corrosion resistance, and good fabricability. It is specifically engineered to meet the most demanding engineering and industrial requirements. Due to its superior mechanical properties and ability to withstand high-temperature environments, Grade 660 is widely used in aerospace, nuclear, chemical processing, and other high-stress, high-temperature applications.

This stainless steel grade is available in various forms, with the round bar being one of the most commonly used formats. It is available in both hot-rolled and forged forms, making it suitable for a variety of industrial processes and applications. Grade 660 stainless steel round bars meet the requirements of ASTM, EN, DIN, JIS, and GB standards, ensuring their reliability and conformity to international specifications.

Chemical Composition of Grade 660 Stainless Steel

The chemical composition of Grade 660 stainless steel includes the following elements:

• Chromium (Cr): 15.0–17.0%

• Nickel (Ni): 6.0–8.0%

• Molybdenum (Mo): 2.0–3.0%

• Copper (Cu): 0.5–1.5%

• Carbon (C): 0.15–0.45%

• Manganese (Mn): 0.30–2.00%

• Silicon (Si): 0.50% max

• Phosphorus (P): 0.04% max

• Sulfur (S): 0.03% max

• Iron (Fe): Balance

This composition results in a material with exceptional strength, excellent resistance to oxidation, and a high level of resistance to both pitting and crevice corrosion. The high chromium content provides excellent corrosion resistance, while nickel and molybdenum further enhance the material's strength and durability in extreme conditions.

Mechanical Properties of Grade 660 Stainless Steel

Grade 660 stainless steel round bar possesses the following mechanical properties:

• Tensile Strength: 125-155 ksi (860–1070 MPa)

• Yield Strength: 85-115 ksi (590–790 MPa)

• Elongation: 12-20% (depending on the temper)

• Hardness (Rockwell B): 85–95 HRB

• Modulus of Elasticity: 28,000–30,000 ksi (193–207 GPa)

These properties make it an ideal material for applications requiring high strength and resistance to mechanical stress. The material also maintains its integrity in environments with varying temperature conditions, making it suitable for both high-temperature and cryogenic applications.

Applications of Grade 660 Stainless Steel Round Bar

Grade 660 stainless steel round bars are used in a wide range of industries and applications, including:

1. Aerospace Industry:

   • Used in the manufacture of aircraft engine components such as shafts, turbine blades, and other high-stress parts that require exceptional strength and fatigue resistance.

   • Suitable for parts exposed to high temperatures and oxidative environments.

2. Chemical Processing:

   • Employed in the construction of equipment that needs resistance to corrosion and high-pressure environments, such as pumps, valves, and reactors.

   • Excellent for handling aggressive chemicals and environments that involve high temperatures and high pressures.

3. Nuclear Industry:

   • Due to its resistance to corrosion and ability to withstand high temperatures, it is used in the nuclear industry for reactor components and other critical parts exposed to radiation.

4. Oil and Gas:

   • Used for equipment subjected to extreme pressure and corrosion conditions, such as drilling equipment, valves, and casings in oil exploration and production.

5. Food Processing:

   • Grade 660 stainless steel round bars are also used in the food processing industry due to their resistance to corrosion and ease of cleaning.

6. Medical Devices:

   • Used in the manufacture of surgical instruments and medical devices that require sterilization and high mechanical strength.

Manufacturing Process of Grade 660 Stainless Steel Round Bar

The production of Grade 660 stainless steel round bars involves several key steps to ensure the material meets the required mechanical properties and standards.

1. Hot Rolling:

   • The first stage of production typically involves hot rolling, where billets of Grade 660 stainless steel are heated to a high temperature (typically above 1000°C) and passed through rollers to form the round bar shape.

   • This process ensures that the material is homogeneous and has a uniform microstructure, which is essential for achieving the desired mechanical properties.

2. Forging:

   • In some cases, Grade 660 stainless steel round bars are produced through forging, which involves heating the steel and then shaping it using a die or hammer. Forging enhances the material's strength and toughness by improving the grain structure.

   • Forged bars have superior mechanical properties and are preferred for high-performance applications.

3. Heat Treatment:

   • After rolling or forging, the stainless steel may undergo a heat treatment process to further enhance its strength and hardness. This may include solution annealing, where the steel is heated and rapidly cooled, or aging, where the material is heated to a specific temperature to allow for the precipitation of strengthening phases.

4. Cold Working (Optional):

   • Cold working may be employed to achieve specific properties, such as increased hardness and strength. However, cold working is not always required for Grade 660 stainless steel, as the material already possesses high strength after heat treatment.

5. Surface Finish:

   • The final step involves surface finishing, which can include processes such as pickling, grinding, or polishing to remove surface defects and enhance the aesthetic appearance of the round bar.

Standards and Certifications

Grade 660 stainless steel round bars are manufactured in accordance with international standards, including ASTM, EN, DIN, JIS, and GB. These standards ensure the material’s compliance with safety, quality, and performance requirements.

1. ASTM A313 (USA):

   • This standard specifies the requirements for stainless steel wire, including grades such as 660. It covers mechanical properties, dimensions, and tolerances.

2. EN 10088-3 (Europe):

   • This European standard provides specifications for stainless steel products, including round bars, and covers both chemical composition and mechanical properties.

3. DIN 17440 (Germany):

   • This standard specifies the technical delivery conditions for stainless steel round bars, ensuring they meet the necessary requirements for mechanical performance and surface finish.

4. JIS G4303 (Japan):

   • The Japanese Industrial Standard provides guidelines for stainless steel products, ensuring that they meet the mechanical and chemical properties required for various industrial applications.

5. GB/T 1220 (China):

   • This Chinese standard provides specifications for stainless steel bars and rods, ensuring compliance with international quality and performance requirements.

Advantages of Grade 660 Stainless Steel Round Bar

• High Strength: Grade 660 stainless steel round bars offer superior tensile and yield strength, making them ideal for high-load applications.

• Corrosion Resistance: The high chromium content provides exceptional resistance to corrosion, pitting, and crevice corrosion.

• Excellent Wear Resistance: The material exhibits excellent wear resistance, making it suitable for applications subjected to mechanical abrasion.

• High-Temperature Resistance: Grade 660 stainless steel maintains its strength and dimensional stability at high temperatures, making it suitable for aerospace and other high-heat applications.

• Versatility: Available in both hot-rolled and forged forms, this material can be used in a wide range of applications across multiple industries.

• Ease of Fabrication: Despite its high strength, Grade 660 stainless steel is still capable of being machined and welded with the proper equipment and techniques.

Conclusion

Grade 660 stainless steel round bars offer an exceptional balance of strength, corrosion resistance, and heat resistance, making them an ideal choice for a wide range of high-performance applications. Available in both hot-rolled and forged forms, these bars meet the highest standards and are manufactured to comply with international specifications such as ASTM, EN, DIN, JIS, and GB. Whether for aerospace, chemical processing, or oil and gas applications, Grade 660 stainless steel round bars deliver outstanding durability and reliability in even the most demanding environments