Stainless steel hardness is a critical factor in determining its mechanical performance, machinability, and application suitability. For engineers, manufacturers, and buyers, understanding the differences between HB (Brinell Hardness), HR (Rockwell Hardness), and HV (Vickers Hardness) is essential when selecting the right stainless steel grade for their projects.
Introduction to Hardness:
Hardness refers to the ability of a material to resist the pressing of hard objects into its surface. It is one of the important performance indicators of metal materials. Generally, the higher the hardness, the better the wear resistance. Commonly used hardness indicators are Brinell hardness, Rockwell hardness, and Vickers hardness.
1. Brinell hardness (HB) Press a hardened steel ball of a certain size (usually 10mm in diameter) into the surface of the material with a certain load (usually 3000kg), keep it for a period of time, after removing the load, the ratio of the load to the indentation area, Is the Brinell hardness value (HB), the unit is kilogram-force/mm2 (N/mm2).
2. Rockwell hardness (HR) When HB>450 or the sample is too small, the Brinell hardness test cannot be used and the Rockwell hardness measurement can be used instead. It uses a diamond cone with an apex angle of 120° or a steel ball with a diameter of 1.59 and 3.18mm, which is pressed into the surface of the material to be tested under a certain load, and the hardness of the material is obtained from the depth of the indentation.
According to the hardness of the test material, it can be expressed in three different scales:
HRA: It is the hardness obtained with a 60kg load and a diamond cone indenter. It is used for extremely hard materials (such as cemented carbide, etc.).
HRB: It is the hardness obtained by using a 100kg load and a hardened steel ball with a diameter of 1.58mm, which is used for materials with lower hardness (such as annealed steel, cast iron, etc.).
HRC: It is the hardness obtained with a load of 150kg and a diamond cone indenter. It is used for materials with high hardness (such as hardened steel, etc.).
3 Vickers hardness (HV) A diamond square cone indenter with a load of 120kg or less and an apex angle of 136° is pressed into the surface of the material. The surface area of the material indentation pit is divided by the load value to obtain the Vickers hardness HV value. (kgf/mm2).
Key Hardness Testing Methods: HB, HR, and HV
| Method | Full Name | Test Principle | Suitable For | Units |
|---|---|---|---|---|
| HB | Brinell Hardness | Presses a hardened steel or tungsten ball into the surface | Soft to medium-hard metals | HBW |
| HR | Rockwell Hardness | Uses a steel ball or a cone-shaped diamond under load | Quick, general testing | HRC, HRB, etc. |
| HV | Vickers Hardness | Uses a diamond pyramid-shaped indenter | Very hard/thin materials | HV |
Differences Between HB, HR, and HV
1. Brinell Hardness (HB)
Large indentation area, suitable for coarse materials.
Common in structural applications (e.g., stainless steel plates).
Slower test, but more accurate for rough surfaces.
Applications: Stainless steel bars, forged components, heavy equipment.
2. Rockwell Hardness (HR)
Fastest method, often used in manufacturing lines.
Several Rockwell scales (A, B, C) exist based on the indenter and load.
Less destructive than Brinell.
Applications: Stainless steel sheets, coils, and precision parts.
3. Vickers Hardness (HV)
Microhardness testing, suitable for very thin materials and surface coatings.
High accuracy, used in labs or R&D.
Applications: Stainless steel foil, thin strip, high-precision parts.
How to Choose the Right Hardness Test?
| Scenario | Recommended Test |
|---|---|
| Thick and heavy components | Brinell (HB) |
| Fast factory testing | Rockwell (HR) |
| Thin materials or microstructure analysis | Vickers (HV) |
Still unsure? Contact Huaxiao Metal for expert guidance on the right stainless steel grade and hardness test method for your project.
Why Hardness Matters in Stainless Steel Procurement
Machinability: Harder grades are more difficult to machine.
Wear Resistance: Higher hardness means longer life in abrasive environments.
Forming & Bending: Softer materials are easier to form.
At Huaxiao Metal, our stainless steel products come with certified hardness reports so you can trust what you’re buying. We supply a full range of stainless grades like 304, 316, 430, and duplex stainless steels with reliable mechanical properties.
Stainless Steel Hardness in Real Applications
Food industry: 304 SS with moderate HRB values for corrosion and shaping.
Automotive: 430 SS with higher HRC for wear resistance.
Chemical industry: 316L SS with HV data for pressure handling.
Request Stainless Steel with Specific Hardness Requirements
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Conclusion
Understanding the differences between HB, HR, and HV hardness is key when evaluating stainless steel materials. Each method serves different testing needs and offers unique advantages.
At Huaxiao Metal, we not only supply high-quality stainless steel materials but also provide technical support to help you choose the right product.