Types of I-Beams: Sizes, Grades and Applications
In this blog, we’ll break down the properties, applications, and advantages of oxygen-free copper, helping you understand why it’s preferred over standard copper in various industries.
Types of I-Beams: Sizes, Grades and Applications
“I-beam” is a family, not a single product. Indian standards alone define several I-section types, each with a different weight-to-depth balance suited to a particular job. Knowing the types makes specifying — and buying — far easier.
The main I-beam types
In the Indian system, I-sections are grouped by weight class for a given depth:
- ISMB (Indian Standard Medium Weight Beam): the most widely used general-purpose I-beam, balancing strength and weight for typical construction.
- ISLB (Indian Standard Light Weight Beam): lighter for the same depth, used where loads are modest and weight savings matter.
- ISJB (Indian Standard Junior Beam): the lightest class, for light framing and secondary members.
- ISWB (Indian Standard Wide Flange Beam): wider flanges and higher capacity, bridging toward H-beam territory.
If you’re weighing a wide-flange section against a standard I-beam, our I-beam vs H-beam guide explains the trade-off.
Sizes
I-beams are designated by their nominal depth in millimetres — for example, ISMB 200 is 200 mm deep. Common depths run from 100 mm up to 600 mm, with weight per metre rising as depth and section class increase. The full set of standard sizes and weights is laid out in our ISMB weight chart.
Steel grades
I-beams are typically rolled in structural grades such as IS 2062 E250 (Fe 410) for general construction, with higher grades like E350 available for heavier-duty or weight-critical designs. The grade sets the yield strength your engineer designs against, so it should always be specified alongside the section size.
Applications by type
- ISMB: floor beams, roof beams, lintels, general structural framing.
- ISLB / ISJB: light roofing, secondary supports, low-load framing.
- ISWB: heavier beams and members approaching column-like duty.
For open-section alternatives in supporting roles, compare with C-channel vs I-beam.
FAQ
What does ISMB 300 mean? An Indian Standard Medium Weight Beam, 300 mm deep.
Which grade is standard for I-beams? IS 2062 E250 (Fe 410) for most construction; higher grades for demanding designs.
How do I pick a type? Match the section class and depth to the span and load — confirm with a structural engineer.
Need a specific I-section and grade? See our structural steel beams or request a quote. Start with the structural steel beams guide for the big picture.
FAQ's
Need Help?
We're Here for You!
Feel free to contact us any time. we will get back to you as soon as we can!
Ask Anything
Do you have any questions?
A: Carbon steel relies on carbon content alone for its properties. Alloy steel adds elements like chromium, nickel, molybdenum, and vanadium to achieve specific improvements — higher strength, better low-temperature toughness, creep resistance, or corrosion resistance — giving it a far broader performance range than carbon steel.
A: For ambient to 400°C service, ASTM A516 Grade 70 is the standard choice. For high-temperature refinery or power plant use (up to 600°C), ASTM A387 Grade 11 or 22 (chrome-moly) applies. For cryogenic service down to -196°C, 9% nickel steel (ASTM A553) is required.
A: Wear-resistant grades like AR400/AR500 are quenched to martensitic hardness of 370–500 HB — 3–4× harder than structural grades like A572-50. They resist abrasive wear in mining and construction equipment but have limited weldability and are not suitable as primary structural members.
A: CE (= C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15) predicts susceptibility to hydrogen-induced cold cracking during welding. Sheets with CE above ~0.40 require preheating to slow cooling and allow hydrogen diffusion, preventing weld cracking. Always develop a qualified WPS based on the specific CE value.
