IS 13321 covers structural hollow sections (CHS, SHS, RHS) — tubular steel used as structural columns, truss members, and architectural elements. YSt 310 and YSt 355 grades are most common for structural use per IS 800.
Specification for welded and seamless steel tubes used as structural members covering grades, dimensions, mechanical properties, and testing.
Key Values
YSt 310 yieldMin 310 MPa
YSt 310 tensileMin 450 MPa
YSt 355 yieldMin 355 MPa
Practical Notes
! YSt 310 is equivalent to IS 2062 E310 steel — compatible with IS 800 design provisions for hollow sections.
! Hollow sections have excellent axial compression capacity — up to 30% more efficient than open sections for columns.
! For exposed architectural steelwork, hollow sections provide cleaner aesthetics than I-beams.
! Welding of hollow section joints (CHS node connections) requires qualified welders per IS 817.