In order for one to understand the difference between tensile strength vs yield strength, we must first define each of these properties in regard to steel materials.
- Tensile = Stretching
- Yield = Stress
What is tensile strength?
Tensile strength refers to the amount of load or stress that the steel can handle until it stretches or breaks; it is measured by testing the steel's resistance to tension caused by applying mechanical loads to it. Tensile strength is used to identify the point at which steel goes from elastic (temporary) to plastic (permanent) deformation..
It is worth noting that the tests done on materials to determine tensile strength vs. yield strength are similar. At the beginning stages of failure, the steel will undergo what is called a ductile failure. This type of failure refers to the point at which the steel surpasses its yield point and results in permeant deformation of the material. The final stage of failure is referred to as brittle failure, and this is also the point at which the tensile strength measurement is taken.
In summary, tensile strength is the maximum point at which steel can be stretched or pulled apart before it breaks.
Tensile Strength of Steel
Tensile strength of steel refers to the maximum amount of tensile (stretching) stress that a steel material can withstand before failure. This property is crucial in various applications, from construction and engineering to manufacturing and automotive industries. Tensile strength is determined through standardized tests where a steel specimen is subjected to controlled tension until it breaks. The result is usually expressed in megapascals (MPa) or pounds per square inch (psi). Different types of steel, including carbon steel, alloy steel, and stainless steel, exhibit varying tensile strengths due to their distinct compositions and treatments. For instance, carbon steel typically ranges from 400 to 700 MPa, while certain high-strength alloy steels can exceed 1,000 MPa.
The tensile strength of steel is influenced by several factors, including its chemical composition, heat treatment processes, and microstructure. Alloying elements such as chromium, nickel, and vanadium enhance tensile strength by altering the steel's crystalline structure and improving its resistance to deformation and fracture. Heat treatments like quenching and tempering can significantly increase tensile strength by refining the grain structure and eliminating internal stresses. Moreover, modern advancements in metallurgy and material science continue to push the boundaries of steel's tensile strength, making it an even more versatile and indispensable material in modern engineering and technology.
What is yield strength?
Yield strength refers to the amount of stress a material, in this case, steel, can withstand before it undergoes plastic deformation (the permanent alteration of shape, form or texture of a material due to the action of stress)
Like tensile strength, yield strength is also measured by applying a given amount of stress on a material. Yield strength can be described as the point at which the material reaches its limit of elasticity. If the amount of stress applied to the steel remains under the yield point, then the steel will return to its original shape once that stress is removed. Yield strength represents upper load limit that is safe to apply to a given material, so this is an important parameter for a wide variety of applications.
Yield Strength of Steel
Yield strength of steel is the stress at which a steel material begins to deform plastically. Prior to reaching this point, the material will deform elastically, meaning it will return to its original shape once the applied stress is removed. Yield strength is a critical parameter in engineering and construction because it defines the maximum stress that can be applied without causing permanent deformation. Typically measured in megapascals (MPa) or pounds per square inch (psi), yield strength varies widely among different types of steel. For example, mild steel generally has a yield strength of around 250 MPa, whereas high-strength, low-alloy steels can have yield strengths exceeding 600 MPa.
The yield strength of steel is influenced by its chemical composition, manufacturing processes, and heat treatments. Elements such as carbon, manganese, and silicon can increase yield strength by enhancing the steel's hardness and reducing its ductility. Heat treatment processes, like annealing, normalizing, and tempering, modify the internal structure of the steel to optimize its mechanical properties, including yield strength. Cold working processes, such as rolling and drawing, can also increase yield strength by introducing dislocations and defects into the steel's crystal lattice. Understanding and controlling yield strength is essential for ensuring the safety and durability of steel structures, as it helps engineers design components that can withstand specific loads and stresses without undergoing irreversible deformation.
Comparing yield strength vs. tensile strength
Each of these properties deal with the amount of stress a steel material can withstand. The main difference is that yield strength is measured at the point of plastic (permanent) deformation, whereas tensile strength is measured at the point at which the steel fractures.
Tensile strength is used primarily for brittle materials, so this means that this measurement is rarely used in applications such as building structures made from ductile materials due to the amount of deformation they sustain.
The tensile strength of steel can be calculated at 100% accuracy, as compared to yield strength which is estimated for most materials, including steel. It is important to know both properties for your steel materials, but it is equally important to be able to distinguish tensile strength vs. yield strength.
Custom steel products from ECONSTEEL
ECONSTEEL leverages longstanding relationships in the steel industry to supply steel products with the mechanical properties your application demands.