How to read a TMT bar test report
A TMT test report, also called a mill test certificate, records the chemical and mechanical test results for one batch of bars. It has three parts: identification, chemical composition and mechanical properties.
Identification
- Manufacturer and brand.
- Grade, for example Fe 550.
- Diameter.
- Heat or batch number. This ties the report to the steel it was tested from.
Chemical composition
These are maximum limits. Lower carbon, sulphur and phosphorus make a bar more ductile and easier to weld.
| Element | Fe 550 limit under IS 1786 | Fe 550D limit under IS 1786 |
|---|---|---|
| Carbon | 0.30% max | 0.25% max |
| Sulphur | 0.055% max | 0.040% max |
| Phosphorus | 0.050% max | 0.040% max |
| Sulphur + Phosphorus | 0.100% max | 0.075% max |
Mechanical properties
| Property | What it means | Fe 550 requirement |
|---|---|---|
| Yield strength | The stress at which the bar starts to deform permanently | 550 N/mm² minimum |
| Tensile strength | The highest stress the bar takes before it breaks | 585 N/mm² minimum |
| Elongation | How far the bar stretches before it breaks | 10% minimum |
The report also records a bend test and a rebend test, each marked as passed.
Three things to match
- The brand and grade on the report match the marks on the bar.
- The diameter on the report matches the bars delivered.
- Every tested value is on the right side of its limit.
Test reports from Amrit Steels
All TMT material we supply is Fe 550 or Fe 550D grade and comes with test reports.
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WhatsApp us nowFrequently asked questions
What is a TMT test report?
A TMT test report, or mill test certificate, records the chemical composition and mechanical test results for one batch of TMT bars, identified by its heat or batch number.
What is the minimum yield strength of Fe 550 TMT?
Fe 550 TMT has a minimum yield strength of 550 N/mm² and a minimum tensile strength of 585 N/mm² under IS 1786.
What does the heat number on a test report mean?
The heat number identifies the batch of steel the bars were rolled from. It links the test results on the report to that batch.