TMT |
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Download Product Brochure (7.2mb)
Thermo Mechanical Treatment (TMT) is a combination of Plastic deformation of steel in austenitic stage followed by quenching and further tempering. In this process, the structure of hardened and tempered steel is formed under conditions of high dislocation density due to strain hardening. The Thermo Mechanical Treatment provides a large margin of ductility and better structural strength. It raises the impact strength at room and low temperature and lowers the cold shortness threshold, susceptibility to temper brittleness. The dislocation formed in austenite during mechanical working in its austenitic state is inherited after hardening in martensite.
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Process : TEMPCORE (CRM-Belgium)
Size : Round 6.0mm,Round 8.0mm, 10.0mm, 12.0mm, 16.0mm, 20.0mm, 25.0mm, 28.0mm, 32.0mm
Grade : 1786-2008
The Ladle Analysis of TMT billets are as per IS-228 and shall have maximum permissible percentage of constituents as follows:
| Constituent |
Percent Maximum |
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Fe41 |
Fe415D |
Fe500 |
Fe500D |
Fe550 |
Fe550D |
Fe600 |
| Carbon |
0.30 |
0.25 |
0.30 |
0.25 |
0.30 |
0.25 |
0.30 |
| Sulphur |
0.060 |
0.045 |
0.055 |
0.040 |
0.055 |
0.040 |
0.040 |
| Phosphorus |
0.060 |
0.045 |
0.055 |
0.040 |
0.055 |
0.040 |
0.040 |
| S+P |
0.110 |
0.085 |
0.105 |
0.075 |
0.100 |
0.075 |
0.075 |
For guaranteed weldability, the carbon equivalent, CE using the formula
CE=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 shall not be more than 0.53%, when micro alloys/ low alloys are used. When micro alloys/ low alloys are not used, carbon equivalent using the formula CE=C+Mn/6 Shall not be more than 0.42%
Nitrogen content of steel is restricted to a maximum percentage of 0.012and it is ensured regularly by check analysis.
In case of product analysis, the permissible variation from the limits specified in the above table shall be as follows:
| Constituent |
Variation over specified Maximum Limit, percent, Max. |
| Carbon |
0.02 |
| Sulphur |
0.005 |
Phosphorus |
0.005 |
| Sulphur and Phosphorus |
0.010 |
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