TMT and TMX steel bars, Definitions and Differences

TMT bars or thermo mechanically treated bars have a tough outer core and a soft inner core which provides high strength when compared with other reinforcements for concrete. Thermomechanical processing usually combines mechanical or plastic deformation processes like forging, rolling, etc with thermal processes like water quenching, heat treatment, heating and cooling at a variable rate into a singular process. 

During the manufacturing process, the steel TMT bars draw a short, intense cooling as they cross through the Tempcore process for TMT. The Tempcore process is designed to provide reinforcing bars with high yield strength and durability. In this process, the steel TMT bars receive a short, intensive cooling as they pass through the especially resigned Tempcore Water Cooling System after the last Rolling Mill Stand. The sudden quenching transforms the surface layer of the steel bar to a hardened formation. 

After the Thermomechanical processing, TMT Bars can be covered in the following grades; Fe: 415 /500 /550/ 600. These graded steel are much more potent compared with common CTD Bars and give up to 20% more durability to concrete construction with the same quantity of steel. Because of its high strength and durability, TMT bars are widely used in constructing general purpose concrete reinforcement structures, bridges, and flyovers, dams, thermal and hydel power plants, industrial constructions, high-rise buildings, transportation structures, rapid transport systems, etc.

THERMEX, from HSE GERMANY and TEMPCORE from CRM BELGIUM, are the two licensed technologies to fabricate thermally processed bars globally. The THERMEX bars are having 80% market in India and a 60% of market share globally. HSE Germany developed the mentioned method after years of research, experimentation, and field trials. 

The THERMEX process comprises a unique Quenching and Self-tempering (QST) method that allows rolling mills to produce economical high strength deformed bars which fully meet the demands of various engineering perspectives. The process doesn’t involve the usage of costly alloys and hence is much cheaper and cost-effective than the existing ones. 

This basic process and succeeding amendments from the research were patented worldwide and was accepted widely without hesitation. The global acceptance of the THERMEX bars is owed to its simplicity and ease of operation. Today this technology is accessible to rolling mills on a license basis. Since THERMEX is a brand name referring to the quenching & self-tempering process which was registered in the mid-1980s, TMX rebar is a specific brand of rebar and TMT is NOT a particular brand and this explains the most widely discussed query about connections of TMT and TMX.

TMT or TMX steel bars for construction?

TMT is commonly used in civil construction purposes while TMX bars are much more strengthened ones and are used for constructing commercial and high raised edifices. TMX bars are the modified and better version of TMT and it meets the highest quality standards exist around the globe hence they are always the better option.  The following are some of the advantages of TMX bars over TMT bars. 

Thermal Stability: High thermal stability is the major factor to consider TMX over TMT. TMX bars are capable to confront even the higher temperatures of 4000-600° Celsius. 

Corrosion Resistance: The thermomechanical process helps to avoid the residual stress in the bar, making them corrosion-resistant than CTD bars. They work perfectly to resist corrosion in all climatic conditions. 

Flexibility: With greater elongation comes greater flexibility. TMX bars also possess higher bending capacity because of this.

High Weldability: TMX bars are balanced in chemical composition and are free of chemical impurities. The weldability of TMX bars is exceptional because of this. It can be welded easily without preheating or post-heating. 

Elongation properties: TMX bars have excellent elongation properties compared to thermo mechanically treated bars. In fact, the elongation of TMX bars ranges from 16-23% whereas the industry standard norms range within 14.5%.

Earthquake resistance: The greater elongation properties and flexibility of TMX bars aids in increasing the resistance for buildings against Earthquakes and such natural calamities.  

Better ribs: TMX Bars have better ribs than TMT bars which gives them enhanced adhesiveness, and helps the structure with higher robustness and durability. 

New generation high strength steel

TMX steel is a high-quality version of TMT steel bar so they certainly have inevitable advantages over TMT Bars in terms of excellent characteristics, such as weldability, durability, thermal stability, ductility, and tensility, etc. They not only meet international standards but also are economical and cost-efficient. TMX bars are widely praised as the new generation high strength steel which actually makes a lot more sense. The ease of usability of TMX bars over any others aids in quicker construction and hence saving a lot more money with labor. Consistent quality and accuracy being the strength pillars on TMX’s side, it holds the edge amongst all other bars used in the industry.  


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