Date Published:May. 07. 2024 Date Updated:Oct. 07. 2024
What is Specific Strength? A new index for weight reduction of equipment 【Smaller and Lighter】
Advantages of Weight Reduction
In recent years, there has been a growing demand to reduce the weight of metal parts in industrial machinery, automotive, and aircraft industries.
For instance, the benefit of lighter equipment not only enhances work efficiency and safety due to easier transportability and installation but also reduces transportation costs and time.
There are several ways to achieve weight reduction, but it's also crucial to review the materials used in metal parts.
Materials with high specific strength play an important role in material selection and design for weight reduction purposes.
In addition, lightweight devices consume less power and generate less heat, which contributes to energy conservation and environmental protection, as well as the achievement of the SDGs.
What is Specific Strength?
Specific strength is the ratio of tensile strength to density, also known as the strength-to-weight ratio.
The formula for specific strength is:
Specific strength (kN·m/kg) = Tensile strength (N/mm²) ÷ Density (specific gravity) (g/cm³)
In other words, specific strength measures the strength of a material relative to its mass.
A higher specific strength value indicates that the material is lighter and stronger.
The Difference between Strength and Specific Strength
Both strength and specific strength are indicators of a material's mechanical properties.
Strength means the maximum stress a material can withstand before it fails.
Specific strength, also called strength-to-weight ratio, is the strength of a material divided by its density.
Different Installation Benefits for High Strength Screws and High Specific Strength Screws
High Strength Screws
Using screws made of high strength (high tensile strength) material allows the screw diameter to be reduced in size in relation to the required fastening force, thus enabling equipment and devices to be downsized.High Specific Strength Screw
In places where screw diameters cannot be changed, using screws with high specific strength can reduce the weight of equipment and devices without changing the screw diameter.
NBK offers a wide variety of high strength (high tensile strength) and high specific strength screws.
Browse our full lineup of high strength screws here
Browse our full lineup of high specific strength screws here
Differences between High Strength Screws and High Specific Strength Screws
NBK Standard Products Specific Strength by Material
| Material |
High Strength Titanium (Ti-6AI-4V) |
RENYTM |
Steel (SCM435)＊1 |
High Strength Stainless Steel (SUS316L) |
VESPEL |
PPS |
Aluminum Alloys (A5056) |
Stainless Steel (SUSMX7)＊2 |
||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tensile Strength (N/mm2) |
895 | 285 | 1220 | 1000 | 160 | 185 | 294 | 700 | ||||
| Density (specific gravity) (g/cm3) |
4.43 | 1.65 | 7.81 | 7.98 | 1.43 | 1.66 | 2.64 | 7.93 | ||||
| Specific Strength (kN・ｍ/kg) |
202.03 | 172.72 | 156.2 | 125.31 | 111.88 | 111.44 | 111.36 | 88.27 | ||||
| Representative part number |
SNSTG | SPA-C | SNS-EL | SNSLG | SPDC-C | SPS-C | SNSA | SNSS | ||||
＊1：The values assumed for steel bolts classified as strength grade 12.9.
＊2：The values assumed for stainless steel bolts classified as strength grade A2-70.
※These are reference values, not guaranteed values (calculated based on tensile strength).
● RENYTM is a trademark or registered trademark of Mitsubishi Gas Chemical Company, Inc.
● VESPEL is a registered trademark of DuPont.
Recommended Products
