Stainless steel 301 is an austenitic grade known for its high strength and excellent corrosion resistance. It is often used in applications requiring a combination of toughness and formability. The grade numbers 1/2 hard, 1/4 hard and full hard typically refer to different tempers or conditions of the steel, which affect its mechanical properties.
Grades of Stainless Steel 301
- 301 (Annealed):
- Properties: Good ductility and formability.
- Applications: Used in applications where bending and forming are required, like automotive parts and kitchen equipment.
- 301 (1/4 Hard):
- Properties: Increased strength and hardness compared to the annealed version, but still retains some ductility.
- Applications: Suitable for parts that need moderate strength and formability, like clips and fasteners.
- 301 (1/2 Hard):
- Properties: Higher strength than 1/4 hard and significantly reduced ductility.
- Applications: Commonly used in springs and other applications where high strength is essential.
- 301 (Full Hard):
- Properties: Maximum strength and hardness, with minimal ductility.
- Applications: Ideal for applications requiring high tensile strength, such as structural components and heavy-duty springs.
Summary
- Annealed (Soft): Best for forming and shaping.
- 1/4 Hard: Moderate strength; some ductility.
- 1/2 Hard: High strength; lower ductility.
- Full Hard: Maximum strength; minimal ductility.
Each temper is tailored for specific applications, balancing strength and formability as needed.
Here’s a summary of the mechanical properties, specifically yield strength and tensile strength, for stainless steel 301 in different temper conditions:
Stainless Steel 301 Mechanical Properties
| Condition | Yield Strength (ksi) | Yield Strength (MPa) | Tensile Strength (ksi) | Tensile Strength (MPa) |
|---|---|---|---|---|
| 1/4 Hard | 30-40 | 205-275 | 90-100 | 620-690 |
| 1/2 Hard | 40-50 | 275-345 | 95-105 | 655-725 |
| Full Hard | 50-60 | 345-415 | 100-120 | 690-825 |
Notes
- Yield Strength: The stress at which the material begins to deform plastically. Higher yield strength indicates greater resistance to permanent deformation.
- Tensile Strength: The maximum stress that a material can withstand while being stretched or pulled before necking occurs.
- Variability: The values can vary based on specific processing methods and the thickness of the material.
These properties highlight how the temper affects the strength characteristics of stainless steel 301, with higher hardness leading to increased yield and tensile strength.
Here’s a summary of the suitability of stainless steel 301 in different hardness conditions for deep draw stamping parts:
Suitability for Deep Draw Stamping
- SS301 (Full Hard):
- Suitability: Not suitable
- Reason: Very low ductility and high strength make it prone to cracking during deep drawing processes. It is generally too rigid for complex shapes.
- SS301 (1/2 Hard):
- Suitability: Moderately suitable
- Reason: Offers a good balance of strength and ductility. It can be used for some deep draw applications, but care must be taken with complex shapes and forming processes to avoid failure.
- SS301 (1/4 Hard):
- Suitability: Suitable
- Reason: Better ductility compared to 1/2 Hard and Full Hard, making it more capable of handling the deformation required in deep drawing. It provides a good balance of formability and strength.
Conclusion
- SS301 Full Hard: Not recommended for deep drawing due to low ductility.
- SS301 1/2 Hard: Can be used with caution for moderate complexity.
- SS301 1/4 Hard: Most suitable for deep draw stamping parts, providing good formability and strength.