# Tensile strength of Steel | Yield & Ultimate tensile strength

The tensile strength of steel refers to its ability to withstand axial loads or tension without breaking. Yield strength is the point at which deformation becomes permanent, and ultimate tensile strength is the maximum stress a material can endure before breaking. For example, common structural steel might have a yield strength around 250 MPa and an ultimate tensile strength of 400 MPa.

Hi guys in this article you know about tensile strength of Steel and its types and what is Yield and ultimate strength of Steel. Generally tensile strength is represented by Ft, Yield strength by fy and Ultimate strength by fu.

Steel have property of ductility,elongation, elasticity and plasticity. Ductility is stretching of Steel, when we stretch it increase in size that is elongation.

When tension pulling forces apply on steel,it can be stretch at that point where, it regain it original shape after removing stress is elastic limit or point (elasticity) that measured as Yield strength of steel.

When maximum tension pulling forces apply on steel,it can be stretch at that point where, it does not regain it original shape after removing stress is plastic limit or point (plasticity) that measured as Ultimate tensile strength of steel.

Fracture strength – The tension stress at which the steel breaks or fractures and failes is known as fracture strength or Tensile strength of steel.

But For design purposes, we should not allow the steel to be permanently deformed or fracture. So, we take the yield strength into consideration for design purposes of structure member column, beam,slab & other structure. This helps in ensuring that the steel is not allowed to be deformed at all permanently and fracture. Hence, yield strength is simply taken as tensile strength of reinforcement.

## What is tensile strength of steel? Yield strength & Ultimate strength

Tensile strength is resistance of steel to breaking under tension. When two equal and opposite pulling forces is applied over steel specimen, stress is develop known as tension stress which causes stretching or elongation in specimen, so tensile strength of steel is maximum strength of steel to resist or withstand against tension stress prior to failure at the end of plastic stage.

Now question is “What is the tensile strength of steel?” Their answer is: The tensile strength for structural steel is 400 N/mm2 and for carbon steel is 841N/mm2, it can be also measured in SI unit Mega Pascal as 400 – 841MPa in India and other country but in US customary region measured in psi and their value is 58000 – 121945psi.

Tensile strength of steel:- the tensile strength of structural steel is 400 N/mm2 and for carbon steel is 841N/mm2, it can be also measured in SI unit Mega Pascal as 400 – 841MPa in India and other country but in US customary region measured in psi and their value is 58000 – 121945psi.

The maximum load at which the specimen breaks is taken as tensile load and maximum stress at which specimen break is taken as tensile stress. The material which are under tension are increased in size stretch or elongate. In general words tensile strength of steel is define as resistance of steel to Breaking under tension stress.

There are three types of tensile strength of Steel:1) Yield strength, 2) Ultimate tensile strength and 3) Breaking strength or Tensile strength.

Tensile strength is maximum load that a material can support without fracture when being stretched. Tensile strengths is mathematically represented as force per unit area

F = P/A
Where F = tensile strength
P = maximum tensile load acting on specimen
A = cross sectional area of specimen

Tensile strength measured in psi in the English system of measurement are commonly expressed in units of pounds per square inch, often abbreviated to psi and MPa in SI used in India and other country,1MPa is equal to N/mm2.

stresses less than the tensile strength are removed, a material returns either completely or partially to its original shape and size. As the stress reaches the value of the tensile strength, however, a material, if ductile, that has already begun to flow plastically rapidly forms a constricted region called a neck, where it then fractures.

### Tensile strength of different grade types of Steel

There are different types of high yield strength Steel available in market are TMT bars, TMX bars, SD bars, HYSD bars, CRS bars, CTD steel bars,Tor steel bars and etc extensively used in construction line.

● 1) TMX steel: TMX stand for thermex powered bar,it is a High yield strength bar. It based on Thermax with German technology is used for this. It is New generation bar can we stand with 5000℃ temperature. Thermex bars, unlike CTD bars, have a proven record resisting loss of strength at high temperatures as experienced during fires.

Tensile strength of tmx steel (bar) is ranging between 450 – 550 N/mm2.

TMX bars are better than TMT bars as fire proof but from cost point of view, where you do not need fire proof structures like water tank, compound walls etc, TMT bars should be consider.

● 2) HYSD Bars: HYSD stand for high yield strength deformed bar are manufactured under heat treatment. There are different types of HYSD Steel bar 1) Tor steel bar & 2) CTD steel bar ( cold twisted deformed). During HYSD Bar manufacturing post heat treatment process, steel bars are either heat rolled or cold twisted for shaping.

Tensile strength of HYSD steel (high yield strength deformed bar) is about 410N/mm2 (4150 kg/cm2).

● 3) TMT bar:- TMT stands for thermomechanical treated bar,it is high yield strength bar made with outer surface is hard known as ferry perlite and inner surfaces soft known as core. Fe415,Fe415D, Fe500,Fe550,Fe550D, Fe600 grade of TMT Steel bar of different company Tata, Jindal are available in market and extensively used in construction work.

Tensile strength of TMT steel bar is ranging between 415 – 600N/mm2.

● 4) SD or D steel bar:- SD stand for super ductility and D Stand for ductile bar, it means it can be highly stretch or elongate.

Tensile strength of SD or D steel bar ranging between 415 – 600N/mm2.

### What are different types of tensile strength of steel?

There are three types of tensile strength 1) Yield strength,2) Ultimate strength and 3) Breaking or splitting strength.

● 1) Yield strength: the tensile stress of a material can withstand or resist without permanent deformation. In other words Yield strength is define as, the stress a material can withstand without permanent deformation.

When pulling forces is applied on steel specimen, it will elongate or strech upto elastic limit without deformation,it means Yield strength is stress of material at the point of end of Elastic stage and beginning of plastic property, when tensile stress is removed material regain its shape and size without deformation.

● 2) Ultimate Tensile strength:- the maximum tensile stress a material can withstand or resist without breaking, ultimate strength is maximum stress at the point of end of plastic stage in strain stress curve prior to break. In other word Ultimate tensile strength is define as, The maximum stress a material can with stand is known as ultimate tensile strength

When tensile stress is removed material do not regain its original shape and size because stretching beyond the elastic stage upto end of plastic stage. Material in plastic stage experience Irreversible and in elastic stage is a reversible. Due to ultimate stress material will deform but do not break.

● 3) Breaking or splitting tensile strength: the maximum tensile stress a material can not able to withstand or resist causing breaking. It is defined as resistance of a material to breaking under tensile stress. Breaking tensile stress is developed at the end of plastic stage of material in strain stress curve. In other words Fracture tensile strength is define as- The stress at which the material breaks or fractures and failes.

So it is clear that value of breaking tensile strength is higher than ultimate tensile strength and yield strength in respective manner such as breaking tensile strength > ultimate strength > Yield strength.

## Yield Strength & Ultimate tensile strength of Steel.

It is characteristics of Tensile strength of reinforcement used in construction of building and reinforcement designing.

the term yield strength of steel represented by fy and Ultimate tensile strength of Steel represented by fu. Ductility property of Steel that is ductility it has property of Steel to get stretch up to certain elongation point When it is applied with stress force.

### What is yield strength of Steel?

Yield strength define and refers to an indication of maximum stress that can be developed in Steel material without out changing plastic deformation.

According to yield strength steel is divided into two category

1) low/mild strength that is mild steel having yield strength is Fe250 which can resist the force of stress of 250N/mm2 when applied on it. tensile strength of mild steel is 410 mpa.

2) high yield strength that is reinforcement Steel used in building construction for example Fe415 and Fe500 that can resist the force of stress of 415N/mm2 and 500N/mm2 when applied on it.

Yield strength of structural steel is ranging between 415 – 600N/mm2 or 60000 – 90000 psi. It can be also measured in SI unit called Mega Pascal (MPa), and their value is 415 -600MPa.

And maximum stress that can be applied in steel before it begins to change shape permanently this is elastic limit of Steel and known as yield strength of Steel.

If stress force is added to the steel metal but does not reach the yield point It will return to its original shape after the when stress force is released and removed. and yield strength of steel is denoted by fy.

Yield strength: the tensile stress of a material can withstand or resist without permanent deformation. In other words Yield strength is define as, the stress a material can withstand without permanent deformation.

When pulling forces is applied on steel specimen, it will elongate or strech upto elastic limit without deformation,it means Yield strength is stress of material at the point of end of Elastic stage and beginning of plastic property, when tensile stress is removed material regain its shape and size without deformation.

### What is Ultimate tensile strength of Steel?

Ultimate Tensile strength of steel:- the maximum tensile stress a material can withstand or resist without breaking, ultimate strength is maximum stress at the point of end of plastic stage in strain stress curve prior to break. In other word Ultimate tensile strength is define as, The maximum stress a material can with stand is known as ultimate tensile strength.

Ultimate Tensile strength of structural steel is ranging between 485 – 650N/mm2 or 70000 – 95000 psi. It can be also measured in SI unit called Mega Pascal (MPa), and their value is 485 -650MPa.

When tensile stress is removed material do not regain its original shape and size because stretching beyond the elastic stage upto end of plastic stage. Material in plastic stage experience Irreversible and in elastic stage is a reversible. Due to ultimate stress material will deform but do not break.

### Tensile ( Yield & Ultimate ) strength of mild steel

Mild steel is a type of carbon steel with a low amount of carbon – it is actually also known as “low carbon steel.” Although ranges vary depending on the source, the amount of carbon typically found in mild steel is 0.05% to 0.25% by weight.

Yield strength of structural mild steel is ranging between for 415 – 600N/mm2 or 60000 – 90000 psi. It can be also measured in SI unit called Mega Pascal (MPa), and their value is 415 -600MPa.

Yield strength of structural low mild steel is about 250N/mm2 or 36000psi. It can be also measured in SI unit called Mega Pascal (MPa), and their value is 250MPa.

Ultimate Tensile strength or simply tensile strength of structural mild steel is ranging between 485 – 650N/mm2 or 70000 – 95000 psi. It can be also measured in SI unit called Mega Pascal (MPa), and their value is 485 -650MPa.

Ultimate Tensile strength or simply tensile strength of low mild steel is 385N/mm2 or 56000psi. It can be also measured in SI unit called Mega Pascal (MPa), and their value is 385MPa.

Structural Mild steel and their strength is represented as Fe250,Fe415,Fe415D, Fe 450, Fe500, Fe 500D, Fe550, Fe550D and Fe600.

Fe415 grade of Steel : Yield strength of Fe415 is 415N/mm2, elongation is 14.5% and their ultimate tensile strength value is 485N/mm2.

Fe415D grade of Steel : Yield strength of Fe415D is 415N/mm2, elongation capacity is 18% due to ductility and their ultimate tensile strength value is 500N/mm2.

● Fe500 grade of Steel : Yield strength of Fe500 is 500N/mm2, elongation capacity is 18% and their ultimate tensile strength value is 545N/mm2.

● Fe500D grade of Steel : Yield strength of Fe500D is 500N/mm2, elongation capacity is 16% due to ductile nature and their ultimate tensile strength value is 565N/mm2.

● Fe550 grade of Steel : Yield strength of Fe550 is 550N/mm2, elongation capacity is 18% and their ultimate tensile strength value is 585N/mm2.

## Tensile strength test of steel

The term tensile strength refers to the amount of tensile (stretching) stress on material can withstand before breaking or failing. tensile strength of steel test is done most commonly measured by placing a test place in the jaw of tensile machine.

Tensile machine applies stretching stress by gradually separating the jaws. So tensile strength of steel test is done by jaw machine. Which choose steel for many application all rcc work based on number of properties, one of these property is also a tensile strength.

tensile strength of bar is about 841 mpa and tensile strength of mild reinforcement is 400 mpa. tensile strength of mild reinforcement in low because it has low carbon content and hence more ductility.

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### 1 thought on “Tensile strength of Steel | Yield & Ultimate tensile strength”

1. The knowledge here is super. Well explain in simple terms. And everything about yield, utimate… is well differentiate.

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