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DISCOVER THE AESTHETIC OF METAL
Ultimate Tensile Strength of Metals: What It Is and How to Calculate It
Ultimate tensile strength (UTS) is one of the essential characteristics that engineers and designers depend on when choosing the type of metal to use in construction, as well as in the automobile and aerospace industries, or any manufacturing industry. It is a property of a material that determines how much stress a metal can sustain before breaking over time. Tensile strength is measured using a tensile testing machine, which applies tensile load to the specimen until the material breaks. The ultimate tensile strength of the material can be calculated by dividing the force required to break the material by its original cross-sectional area. This blog will explore what ultimate tensile strength is, why it matters, how to calculate ultimate tensile strength, and how it compares with other mechanical properties like yield strength.
Table of Contents
What is ultimate tensile strength
Ultimate tensile strength (UTS) refers to the maximum tensile stress that a material can bear before fracturing. It is also called a failure point of the material. Another term for UTS is tensile strength (TS). Strength in UTS is a measure of a material’s ability to resist the applied force. In this process, the material will undergo elastic deformation, plastic deformation, and break lastly. Ultimate tensile strength is an essential indicator of the behaviour of a material when stretched, and it is measured in megapascals (MPa) or pounds per square inch (psi).
UTS is a point at the top of the stress-strain curve. As a material is stretched, eventually the stress becomes so great that it can no longer increase on the stretch; it will reach a maximum value, UTS, which the material will not exceed, beyond which the material will start to neck or permanently deform until it eventually fractures.
Simply Explained Tensile Strength:
● When you suspend a heavy burden on a piece of metal, a rod, then it is going to stretch some.
● The point at which it stretches the most before snapping is where ultimate tensile strength is observed.
● This property is critical when it comes to structural metal, which is employed in building, bridges, tools, transportation and manufacturing sectors.
Why is ultimate tensile strength important for metals?
Ultimate tensile strength is not just a lab value—it’s a real-world design benchmark. In numerous sectors of industry, such as architecture, industrial metal fabrication, marine construction, etc., the determination of the UTS of a metal resolves the question of the probability of failure of a structure or a product under anticipated load.
The importance of it is as follows:
a. Structural Safety and Integrity of Design
Engineers apply UTS to select materials that can not break under pressure. The use of metals with high UTS is needed in buildings, aeroplanes, and machinery to promote the safety of operation both under normal circumstances and extreme situations.
b. Quality Control and Quality Standards
Materials undergo examination of their UTS to achieve industry requirements such as ASTM certification or ISO certification. This ensures consistent manufacturing and performance for the end user.
c. Metals Comparative Analysis
Various metals react differently under stress. Typically, an example may be stainless steel being preferred over aluminium in high-stress systems due to its strength.
Ultimate Tensile Strength Formula
Now that we have defined what ultimate tensile strength is and why it is important, let us talk about how to calculate ultimate tensile strength.
The “dumbbell” -shaped parts are placed in the tensile testing machine, and a load is applied until the part breaks. Then, the cross-sectional area of the part is measured and recorded. Most tensile testing machines can record the applied force and display the tensile strength based on the cross-sectional area after the test is completed. If not, the force and cross-section can be substituted into the following formula:
UTS is straightforward when it comes to the formula of the latter:
UTS = F / A (Strength = Force / Area)
Where:
UTS = Ultimate Tensile Strength (MPa or psi)
F = Maximum load (force), before fracture (N or lb)
A = The original area of the cross-sectional area of the specimen (mm²)
Example Calculation:
Consider that a steel pipe breaks at a maximum of 30,000 N, and that previously the cross-sectional area was 50 mm².
UTS =30000 N /50 mm² =600 MPa
This means the steel rod had an ultimate tensile strength of 600 MPa, which is a relatively strong material suitable for structural use.
There is also the possibility of computing UTS via the information obtained from a universal testing machine (UTM) when a tensile test is running.
Ultimate Tensile Strength for Alloy Metal
Different metals have different ultimate tensile strengths depending on their composition, processing, and treatment.
1. Steel
Steels have a tensile strength in the range of 200–2000 MPa, depending on composition and treatment. Stainless steel (304, 316) ranges from 520–860 MPa. Low carbon steel is from 370 to 700 MPa. Maraging steel ranges from 1,400 to 2,400 MPa.
2. Aluminum
Aluminum can achieve a strength of around 90–400 MPa, depending on the alloy. Ultimate tensile strength of 6061 aluminum alloy typically ranges from 310 to 340 MPa.
3. Brass
The ultimate tensile strength of brass ranges from 200 to 550 MPa.
4. Titanium
Titanium is a naturally found silver metal, having a tensile strength of 275–1100 MPa.
Observations:
● Titanium and Inconel have very high values on UTS, which make them most suitable for aerospace and medical equipment.
● Stainless steel combines strength, corrosion resistance and ease of work, hence the popularity with architects and fabricators.
Are you looking for powerful and visually appealing metals to enhance your projects? Topson Stainless Steel is a manufacturer that focuses on high-strength stainless steel plates, profiles and custom metal products for the manufacturing industries around the world.
Ultimate Tensile Strength vs Yield Strength
While ultimate tensile strength shows the maximum load a material can withstand before breaking, yield strength refers to the point at which a material begins to deform permanently. The two are very similar, but are used in engineering in different ways.
Key Differences:
The yield strength contributes to the aspect that a structure is likely to revert to its original state once the load is removed. The ultimate tensile strength ensures the structure can survive the most intense conditions without catastrophic failure. Both values should be taken into account in a design in most applications since a balance should exist between flexibility and durability.
As an example, duplex stainless steels offered by Topson Stainless Steel have a high yield strength and a high UTS, which is why those grades cannot be overestimated in marine and architectural applications where both the load-bearing capacity and formability are vital.
FAQ
1. What is ultimate tensile strength used for?
Ultimate tensile strength is used to determine the ability of a material to withstand pulling forces before failure. It plays a crucial role in design, selection of materials, and safety considerations.
2. How is ultimate tensile strength measured?
A tensile testing machine is used to measure UTS where the specimen is stretched into a crack. UTS = the maximum force of the initial cross-sectional area.
3. How do I purchase metals of a given UTS?
At Topson Stainless Steel, it is possible to see a large number of metals with detailed mechanical properties such as UTS, yield strength and many others.
Conclusion
The knowledge of what ultimate tensile strength is and how to find it enables an engineer, an architect or a manufacturer to construct safer and efficient structures. Considering the yield strength vs. ultimate tensile strength or assessing the performance of metals, UTS is one of the fundamental measurements used in material science and engineering design.
David Tan
Stainless Steel Materials & Products Expert. With 20+ years of experience in stainless steel, specialize in various stainless steel surface treatments and stainless steel fabricating. Familiar with multiple stainless steel characteristics and applications.
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