Knowing how to identify steel grade and quality protects your building and your budget. Grade 40 and Grade 60 bars look almost the same, and underweight or substandard bars can pass a quick glance. This guide shows the checks anyone can do on site, and when to rely on paperwork and lab tests.
1. Read the Rolled-In Marks
Bars made to ASTM A615 carry marks rolled onto the surface, usually in this order:
- Manufacturer’s mark: letters or a symbol identifying the mill.
- Size mark: the bar number or size.
- Type mark: for example, “S” for carbon-steel bars under A615.
- Grade mark: Grade 60 bars show the number 60 (or 4 on metric-marked bars) or one continuous longitudinal line. Grade 40 bars have no grade mark.
If bars have no marks at all, you cannot trace who made them or what grade they are.
2. Check the Size and Weight
Weight is the most reliable simple check. A bar’s weight in kg per metre should be close to D² ÷ 162, where D is the diameter in mm.
| Size | kg per metre | kg per 12 m bar |
| 10 mm | 0.617 | 7.41 |
| 12 mm | 0.889 | 10.67 |
| 16 mm | 1.580 | 18.96 |
| 20 mm | 2.469 | 29.63 |
| 25 mm | 3.858 | 46.30 |
Under ASTM A615, a bar may not weigh less than 94% of its nominal weight. For all sizes, see how to calculate the weight of steel bars.
3. Look at the Ribs and Surface
- Ribs should be clear, even and continuous along the bar.
- There should be no cracks, laps or flakes.
- Light surface rust is normal, but deep pits are not.
See common defects in steel bars.
4. Do a Simple Bend Check
On site, bend a spare offcut around a pipe or bar bender to a tight hook. A good bar bends smoothly without cracks on the outside of the bend. However, this is only a rough check; the proper bend test is done in a lab.
5. Check the Paperwork
- An invoice showing brand, grade, size and weight.
- A mill test certificate with yield strength, tensile strength and elongation.
- Matching batch or heat numbers on bundle tags and the certificate.
6. Test When It Matters
For multi-storey buildings or public projects, send samples to a lab for tensile, bend and chemical tests. See how to test steel bar quality.
Quick Checklist
| Check | Good sign | Warning sign |
| Marks | Maker, size and grade marks | No marks |
| Weight | Close to the table | Clearly lighter |
| Ribs | Even and sharp | Worn, broken or uneven |
| Paperwork | Invoice and test certificate | Cash deal, no documents |
Buy Quality Steel Bars
Kamran Steel has manufactured deformed steel bars in Lahore since 1984. We supply Grade 40, Grade 60 and Grade 75 bars to ASTM A615 in sizes from 10 mm to 36 mm, with mill test certificates on request. Check today’s steel rate in Pakistan or contact our sales team.
Read how Kamran Steel marks and tests its bars on our quality assurance page. You can estimate the cost of your order in seconds with our steel rate calculator.
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