Structural Steel Sections

Products of structural steel

A variety of structural steel products are manufactured by steel plants for construction of steel structures. The products are in various shapes and size depending upon the requirements of design. Depending upon the manufacturing process, these sections are classified as hot-rolled sections and cold-rolled sections

A.      Hot rolled sections

They are produced in steel plants from steel billets by passing them through series of rollers. They are classified by Bureau of Indian Standards as follows:

1.       Beams

a)      Indian Standard Junior Beams (ISJB) abbreviated as JB.

b)      Indian Standard Light Weight Beams (ISLB) abbreviated as LB.

c)       Indian Standard Medium Weight Beams (ISMB) abbreviated as MB.

d)      Indian Standard Wide Flange Beams (ISWB) abbreviated as WB.

These are designated as JB150, LB150, MB150, and WB150 where 150 is the depth of the section in mm.

2.       Columns/ Heavy Weight Beams

a)      Indian Standard Column Section (ISSC) abbreviated as SC.

b)      Indian Standard Heavy Weight Beams (ISHB) abbreviated as HB.

These are designated as, for example, SC150, HB200 where 200 is the depth of section in mm.

3.       Parallel Flange Beams and Column Sections

a)      Indian Standard Narrow Parallel Flange Beams (ISNPB) abbreviated as NPB.

b)      Indian Standard Wide Parallel Flange Beams (ISWPB) abbreviated as WPB.

They are designated as NPB 200*100*18.42 where 200 is the depth in mm, 100 is nominal flange width in mm and 18.42 is the mass in kg/m or WPB 500*300*107.5 where 500 is the depth, 300 is the nominal flange and 107.5 is the mass in kg/m.

4.       Channels

a)      Indian Standard Light Weight Channels (ISLC) abbreviated as LC.

b)      Indian Standard Junior Channels (ISJC) abbreviated as JC.

c)       Indian Standard Medium Weight Channels (ISMC) abbreviated as MC.

d)      Indian Standard Medium Weight Parallel flange Channels (ISMCP) abbreviated as MCP.

These are designated as, for example, JC150,LC150, MC150, MCP150 where 150 is the depth of section in mm.

5.       Angles

Indian Standard equal/unequal (ISA) abbreviated as <.

These are designated as, for example, <200 100*10 where 200 and 100 are lengths of legs in mm and 10 is the thickness in mm.

6.       T-Sections

a)      Indian Standard rolled Deep legged Tee bars (ISDT) abbreviated as DT.

b)      Indian Standard rolled Normal Tee bars (ISNT) abbreviated as NT.

c)       Indian Standard silt Light weight Tee bars (ISLT) abbreviated as LT.

d)      Indian Standard silt medium weight Tee bars (ISMT) abbreviated as MT.

e)      Indian Standard silt Tee bars from H sections (ISHT) abbreviated as HT.

These are designated as, for example, DT100, NT50, LT200, MT100 and HT100 where the numerical value indicate depth in mm.

7.       Tubular sections

These are designated by their nominal bore and classified as ight, medium and heavy depending upon the wall thickness. They are further graded as YSt210, YSt240 and YSt310 for yield strength of 210,240 and 310 MPa respectively.

8.       Rectangular/Square Hollow Sections.

These are designated by their outside dimensions and thickness. For example, 60*40*2.9 HF RHS means 60mm is thickness, 40mm is the breadth and 2.9mm is the thickness. HF stands for Hot Formed and RHS for Rectangular Hollow Section. Similarly SHS stands for Square Hollow Section. The material is graded similar to the tubular sections.

9.       Plate, Sheet, Strip and Flats

a)      Plates are designated as ISPC followed by figures denoting length*width*thickness in mm.

b)      Sheets are designated as IISH followed by figures denoting length*width*thickness in mm.

c)       Strips are designated as ISST followed by figures denoting width*thickness in mm.

d)      Flats are designated as width followed by letters ISF and thickness in mm.

B.      Cold rolled light-gauge sections

Cold formed light-gauge sections are used where thicker hot –rolled sections become uneconomical especially in small builsings subjected to lighter loads. These are produced by cold rolling whereas smaller number of special shapes are produced onpress brakes. They are available in the form of equal angles, unequal angles, hat sections and 2 sections. They are designated by numbers denoting depth*width*thickness (all in mm).

Rectangular/Square Hollow Cold Formed Sections are also available. They are designated as 60*40*2.9 CF SHS, where 60mm is depth, 40 mm is breadth and 2.9 mm is thickness.CF stands for Cold Formed and SHS stands for Square Hollow Section.

                                                     figure: Various structural steel sections