Yield Stress and Ultimate Stress for Structural Steel
Table 1 of IS 800:2007 lists the mechanical properties of structural steel conforming to IS 2062. It provides the yield stress (fy) and ultimate tensile stress (fu) for standard grades used in Indian steel construction. These values are the basis for all capacity calculations in IS 800.
Key Requirements
•Steel shall conform to IS 2062 or other relevant IS standards listed in Table 1
•Yield stress (fy) values decrease with increasing plate thickness — use the value corresponding to actual thickness
•For thickness ≤ 20 mm, use the standard fy values in the table
•For thickness 20–40 mm, fy reduces by approximately 10 MPa for most grades
•Mill test certificates must confirm that actual fy and fu meet or exceed the specified values
Reference Tables
Table 1 — Yield Stress and Ultimate Stress (IS 800:2007)
Steel Grade (IS 2062)
fy (MPa) — t ≤ 20 mm
fy (MPa) — 20 < t ≤ 40 mm
fu (MPa)
E250 (Fe 410W A)
250
240
410
E300 (Fe 440)
300
290
440
E350 (Fe 490)
350
330
490
E410 (Fe 540)
410
390
540
E450 (Fe 570) Grade D
450
430
570
E450 (Fe 570) Grade E
450
430
570
fy values depend on plate thickness. For t > 40 mm, refer IS 2062 directly. E250 (Fe 410W A) is the most commonly used grade in India.
Practical Notes
✓E250 (Fe 410W A) is the workhorse grade for Indian construction — hot-rolled sections (ISMB, ISMC, ISA) from SAIL/RINL/JSW are typically this grade. Always confirm with mill TC.
✓E350 is increasingly used for high-rise and industrial structures where weight savings matter. ISLB/ISMB sections are now available in E350 from major producers.
✓The 'E' in E250 stands for the yield stress value in MPa. The older Fe 410 designation refers to the ultimate tensile stress (fu = 410 MPa).
Common Mistakes
⚠Using fy = 250 MPa for thick plates (> 20 mm) without reduction — IS 2062 and Table 1 require reduced fy for thicker plates.
⚠Confusing Fe 410 (old designation, fu = 410) with E410 (new designation, fy = 410) — these are completely different grades.
⚠Not verifying the actual grade from mill test certificates — sections delivered as 'E250' may actually have higher yield stress, but design must use the specified minimum.