Everyone knows about this material but here in this blog, I will explain to you in detail by sharing my knowledge regarding it which will help you when you are using or purchasing it.
Steel is essentially an alloy of iron and carbon in which carbon content is not more than 1.5% and it is completely in the combined form.
The topic is elaborate in details as below
- Introduction
- Different Things Made From Steel In The Construction Sector
- Various Steel Products
- How Steel Is Made?
- Types Of Bars
- Properties Of Steel
- Different Grade
- Famous Steel Plants In India
- Importance Of Use Of Reinforcement Steel In Construction
- FAQ
Introduction
It creates an intervening platform between cast iron and wrought iron with 0.25 to 1.5% carbon content
Cast iron can take compressive stress and wrought iron can take tensile stress but it is suitable for all construction purposes in general. It is strong equally in both tension and compression.
| Types | % Carbon Content |
| (1) Mild steel (M.S.) (2) Medium carbon steel (3) High carbon steel | 0.10 to 0.25 0.25 to 0.60 0.60 to 1.10 |
Different Things Made From Steel In The Construction Sector
- Angle sections (i) equal legs (ii) unequal legs
- Channel sections
- Corrugated sheets
- Expanded metal
- Flat bars
- I-sections (Rolled joints/beams)
- Plates (thickness varies from 5 to 50 mm.)
- Tor steel bars (size varies from 6 to S0 mm.)
- Round bars (diameters from 5 to 250 mm.)
- Square bars (cross-section with sides from 5-250 mm.)
- T-sections
Various Steel Products
| Uses of Steel | To make |
| (1) Mild type | Motor body, sheet metal, tin plates, etc. |
| (2) Medium carbon type | Boilerplates, rails, tires, hammers, large stamping and pressing dies, etc. |
| (3) High carbon type (Hard steel) | Sledge hammers, springs, stamping dies, drills, smith’s tools, stone mason’s tools, chisels, hammers, saws, wood working tools, axes, cutlery, knives, punches, etc. |
How Steel Is Made?
Iron ore is heated and melted in a furnace where impurities are removed and carbon is added.There are two processes:
- Blast furnace
- Electric arc Furnace
Blast Furnace Method
Blast furnace was invented by Henry Bessemer in mid of 1850. Even today it is made by this process in which air is blown through molten pig iron to oxidize the material and separate impurities.
Firstly iron ore, limestone, and coke are added to the furnace from top and started sinking to the bottom which is called stack and where temperature getting hotter as it moves to the bottom of furnaces. The gases created removed from the upper half. In the bottom half where limestone starts reacting with impurities in iron core and coke forming the slag where the temperature reaches 3000 degrees Celsius. Molten iron formed is removed from the bottom and slag is major factors carrying other materials that float top of the molten iron from the slag notch provided at a height above the molten iron notch.
Types Of Bars
- Main bars
- Distribution bars
- Bent up bars
- Corner
- Tie up bars
The bars are of two types as per material
(i) Mild bars (ii) Tor bars
They are available in two types of section
(i) Circular (ii) Square
Circular mild type bars are popularly used in RCC work of buildings. Nowadays pale green-colored powder-coated type bars are in demand, for corrosion resistance and long life of bonding with concrete.
Properties Of Steel
Different Grades
To RCC, mainly three grades of it are used
- Fe 250 (Mild )
Characteristic strength, fy = 250 N/mm2
Mild bars are denoted by symbol ‘Ф’.
- Fe 415 (Tor ) or High Yield Strength Deformed bars = HYSD bars.
Characteristic strength, fy = 415 N/mm2.
Tor bars are denoted by symbol ‘Ф’.
- TMT bars: TMT = Thermo Mechanically Treated bars
The yield strength of the bar is increased without losing its yielding property.
In addition, the bond strength is also increased due to this treatment.TMT bars have excessive power blended with excessive elongation. This increases the ductility and weldability of the bars.
Due to higher ductility and toughness, TMT bars are used in earthquake-prone areas. These bars have better corrosion resistance. These bars are available in grades Fe 400, Fe 500, and Fe 550.
Types of reinforcements available in the market are shown in Table:
| Type | Conforming to I.S. Code | Yield stress/0.2% Proof stress |
| Mild (Plain bars) | IS: 432 – 1966 | 250 N/mm2 |
| High yield strength Deformed bars (HYSD | IS 1786 1979 | 415 N/mm2 500 N/mm2 |
| Hard drawn steel wire fabric | IS 1566 1967 | 480 N/mm2 |
| Thermo mechanically Treated bars (TMT) | _ | 400 N/mm2 500 N/mm2 550 N/mm2 |
The characteristic strength of this material is its tensile strength determined on standard specimen below which not more than 5% specimen gives the results. However, code permits the use of minimum yield stress or 0.5% proof stress as a characteristic strength of it.
The reinforcing bars are generally available in the market in the following sizes.
| Mild (plain bars) | 6, 10, 12, 16, 20, 25, 32 mm |
| Deformed bars | 8, 10, 12, 16, 20, 22, 25, 28, 32 mm |
| TMT bars | 8, 10, 12, 16, 20, 25 mm |
Famous Steel Plants In India
Following are the list of famous of famous companies and plants in India:
| Steel Plant Name | Owned By | Area |
| TISCO | TATA | Jamshedpur |
| Durgapur Plant | SAIL | Durgapur |
| Jindal Steel and Power | Jindal Group | Raigarh |
| Bokaro Plant | SAIL | Bokaro |
| Visvesvaraya Iron and Steel Plant | SAIL | Bhadravathi |
| Bhilai Plant | SAIL | Chhattisgarh |
| IISCO | SAIL | Asansol |
| Visakhapatnam Plant | Rashtriya Ispat Nigam Limited | Visakhapatnam |
| Essar Plant | Essar Steel Limited | Hazira |
| Vijayanagar Plant | JSW Limited | Hospet |
| Salem Plant | SAIL | Salem |
| Rourkela Plant | SAIL | Rourkela |
| Bhushan Plant | Bhushan Steel | Dhenkanal |
Source: bizvibe.com
Importance Of Use Of Reinforcement Steel In Concrete
The importance of reinforcement in concrete can be stated as follows
(1) It has very good tensile strength while concrete is very poor. Therefore, it is used in the tension zone.
For mild , Fe 250, fy = 250 N/mm2
For Tor , Fe 415, fy = 415 N/mm2
Generally for concrete, Flexural strength = tensile strength = fcr
fcr =0.7 √fck N/mm2
(IS: 456 200, P. 16, cl. 6.2.2)
For M 20 grade concrete,
fcr = 0.7 √20
= 3.13 N/mm2
(2) As the temperature coefficients of this material and concrete are nearly equal, temperature stresses are reduced when it is used in concrete.
(3) The concrete shrinks on the setting. It provides a proper bond between this material and concrete.
(4) The modulus of elasticity of it is very high.
Es = 2×105N/mm2.
If you also want to more about timber the complete guide is provided here.
FAQ
Yes, whenever it is in direct contact with oxygen and moisture for a long period as iron in it reacts with oxygen which results in iron oxide which is rust.
Due to the presence of various alloys materials such as carbon, sulfur, manganese, etc.
Generally mild types (Fe 250) is used as it is durable and strong.
In terms of metal, Tungsten is the strongest and in terms of alloy Steel is the strongest
