Building Steel

Athi Steel is proud to be a manufacturer of a full range of building steel, including Grade 500 TMT Bars, Twisted (CTD) Bars, Deformed Bars, as well as Round Bars.

What is TMT?What is Twisted?So what should I use?Technical TMTTechnical Twisted

TMT bars stands for “Thermo Mechanical Treatment” Bars. This means that the bars undergo a specialised process of hardening, by altering the grain structure of the bars on a microscopic level. The process involves the cooling of the surface of the bar, to create the correct level of surface hardness, while maintaining the core at a high temperature. The heat from the core of the bar then tempers the bar to produce the correct metallurgical properties and hence the correct balance of strength and ductility (bend ability) of the steel.

Athi Steel strives to meticulously control this process in order to maintain the Yield strength of its bars so that they are greater than 500 MPa. Athi Steel has also employed all the necessary procedures to ensure that its steel bars meet the standard set by Kenya Bureau of Standards (KeBS) KS 573, and also ensures that it follows the standards set out by BS 4449.

Athi Steel has been awarded the KeBS Diamond Mark of Quality for its TMT.

 

The full form of Twisted or “Y” bars is Cold Twisted Deformed (CTD) Bars. These bars, unlike the TMT bars are mechanically twisted after the rolling process, once they have cooled down from the high rolling temperatures. These bars are initially rolled as plain square bars, and then twisted in order to increase their strength. The mechanical twisting process induces torsional stresses within the bars, which is why it is the less preferred steel reinforcement bar in modern day construction. There is still however a large demand for these bars, as they are still the preferred bar in some regions.

These bars do not have as much strength as the TMT bars do, and also have less resistance to fires, earthquakes etc., as their Yield strength is lower than that of the TMT bars.

Athi Steel strives to ensure that the quality of these bars is maintained to the standards set out by Kenya Bureau of Standards (KeBS) KS 573 as well as British Standard, BS 4449.

 

The choice of bars that are used rests entirely on the type of structure one is building, and what the Project Engineer chooses to use.

However, TMT bars have the ability to resist earthquakes and fires much better than twisted bars do. The internal stresses within the TMT bar are also much less due to the fact that there are no stresses induced in them due to the requirement of additional twisting, therefore the TMT bar will also be able to absorb higher impact loads than a Twisted bar of the same size.

TMT bars also have superior other properties such as:

  • Better weld-ability
  • Higher strength
  • Better elongation
  • Higher ductility
  • Higher corrosion resistance
  • Higher fire resistance
  • Leads to a cost saving in terms of the quantity of steel used within a structure, transportation and handling.

 

 

THERMOMECHANICALLY TREATED (TMT) BARS
Nominal DiameterWeight (kg) per 12 Meter LengthCross-sectional area
84.7450.3
107.3978.5
1210.66113
1618.95201
2029.59314
2546.25491
3275.76804
Standards: Conforms to the BS 4449: 2005
Length:  12 Meters

 

 Special Length and Bending of Reinforcement Bars (Cut & Bend)
Athi steel offers a full steel solution with value addition coming from special length steel, cut and bend to customer specification. Cut and Bend can be done as per BS 4466:1989 and BS 8666:2005

 

THERMOMECHANICALLY TREATED (TMT) BARS
Bars of TMT Grade 500
PropertiesValues
Yield Strength (MPa)500 MPa min
Stress Ratio (Rm/Re)1.15 – 1.35
Elongation %14%

 

TWISTED, ROUND AND SQUARE BARS
Size (mm)Weight (kg) per 12 metre lengthCross Sectional Area (mm)
84.7450.3
107.3978.5
1210.66113
1618.95201
2029.59314
2546.25491
3275.76804

 

TWISTED BARS
Bars to Grade 460 or to KEBS Standard
PropertiesValues
Yield Strength (MPa)460 MPa min
Stress Ratio (Rm/Re)1.12 – 1.30
Elongation %12% min

 

Fill in the form below







captcha