Structural sections
Structural sections are I-beams, channels, angles and sheet piles: the profiles a building frame, a hangar, a pipe rack and a sheet-pile wall are assembled from.
6
items with size and weight tables
19
standards for rolling and acceptance
Items in this category
I-beams, channels, angles and sheet piles to GOST and GB from mills in China
What it is and how it is supplied
Structural sections are hot-rolled products whose cross-section is more complex than a round, a square or a flat: I-beam, channel, angle, sheet pile. They are rolled on section and beam mills from continuously cast feedstock, a bloom or a beam blank, in several passes through grooved rolls. The geometry of each profile is set by the standard's table: depth, flange width, web and flange thickness, corner radii and theoretical weight per metre.
Details
Projects in Uzbekistan are designed to GOST: I-beams to GOST 8239 and GOST R 57837, channels to GOST 8240, angles to GOST 8509 and GOST 8510, sheet piles to GOST 4781. Mills in China roll to GB/T 706 and GB/T 11263. A profile of the same number under GB and under GOST is not the same profile: GB/T 706 channels and I-beams have a wider flange and a higher weight per metre. This is why the bureau writes into the specification not only the number but the section dimensions h×b×s×t and the geometry standard, and the steel grade together with the standard it is certified to: St3sp5 and S245 versus Q235B, 09G2S and S345 versus Q355B.
The bureau inspects the batch at the mill before shipment: we measure depth and flange width with callipers, web and flange thickness with a micrometer, check camber and length, examine the surface, compare the mill test certificate (MTC), its heat number, chemical composition and mechanical properties, against the marking on the profile and the bundle tag, and record packing and loading with photographs in the inspection report. Rejects recorded in the report are replaced; the replacement is supplied by the mill under its contract with the bureau.
Grade equivalents
Equivalents are the nearest, not identical: the exact grade and standard are written into the contract.
| GOST | GB (China) | ASTM | EN | Note |
|---|---|---|---|---|
| St3sp5 / S245 | GB (China)Q235B | ASTMA36 | ENS235JR | NoteImpact toughness is specified at different temperatures: at −20 °C for St3sp5, at +20 °C for Q235B and S235JR. A cold-climate requirement is written into the specification separately. |
| S275 | GB (China)Q275B | ASTM— | ENS275JR | NoteNearest equivalent by yield strength; chemical composition and scope of testing differ between the three standards. |
| 09G2S / S345 | GB (China)Q355B | ASTMA572 Gr.50 | ENS355JR | NoteBefore GB/T 1591-2018 the grade was designated Q345B; certificates for earlier batches may still carry the old name. |
| S355 | GB (China)Q355C | ASTMA572 Gr.50 | ENS355J0 | NoteNearest equivalent by yield strength of 355 MPa; impact test temperature and method are specific to each of the three standards. |
| — | GB (China)Q355B | ASTMA992 Gr.50 | ENS355JR | NoteA992 is a grade for wide-flange beams with an upper limit on yield strength. Nearest equivalent, not an exact match. |
| — | GB (China)Q345P | ASTMA572 Gr.50 | ENS355GP | NoteSheet-pile grades. L4 and L5 to GOST 4781-85 are rolled from St3sp and St3ps; GOST has no dedicated sheet-pile grade. Nearest equivalent, not an exact match. |
Equivalents are the closest match, not identical: chemistry and tolerances differ between standards. The exact grade and standard are written into the contract.
Buyer questions
How to read a mill test certificate (MTC) for structural sections
Four blocks are checked in the certificate. Standard and grade: the same as written in the specification, not an equivalent. Heat number: matches the marking on the profile and the bundle tag. Heat chemistry: C, Si, Mn, P, S, and for Q355B also V, Nb, Ti, within the grade limits. Mechanical properties: yield strength, tensile strength, elongation and impact toughness at the temperature the grade requires. The bureau checks the certificate against the batch at the mill before shipment and attaches it to the inspection report.
How Q235B differs from St3sp5 and S245
All three have a yield strength of 235 MPa, which is why design calculations treat them as equivalents. The differences lie in test conditions and deoxidation: St3sp5 is impact-tested at −20 °C, Q235B at +20 °C; the suffix sp denotes killed steel, while Q235B to GB/T 700 is supplied rimmed (F) or killed (Z). If the project calls for St3sp5, the specification sets the degree of deoxidation and the test temperature; the mill performs the tests and enters the results in the certificate.
How the tonnage of a section order is calculated
From the theoretical weight per metre in the standard's table: weight per metre × length × number of pieces. The actual weight of a batch differs from the theoretical weight within the standard's weight tolerance, so the contract fixes which weight the batch is settled on: theoretical or actual by weighing. GB and GOST profiles of the same number have different theoretical weights; the specification is calculated to the standard written in it.
What is checked when structural sections are inspected at the mill
Section geometry: depth and flange width with callipers, web and flange thickness with a micrometer, at several points along the length. Shape: squareness of flanges, camber and twist along the length, length. Surface: laps, scabs, cracks, pits. Documents: the mill test certificate against the heat number on the marking and the tag. Packing, piece count and loading, with photographs in the inspection report.
What the minimum batch is and whether different profiles can be combined in one delivery
The batch is sized to your volume; send us the specification. A mill rolls each size to its rolling schedule, so the bureau matches the specification items against mill schedules, assembles the delivery from one or several mills and inspects every batch before shipment.
Price request
Send your specification and we will quote your batch
Price depends on grade, size, tonnage and delivery terms on the day of contract.
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