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IS 1730:1989 Part 1 is the Indian Standard (BIS) for dimensions for steel flats - part 1: rolled steel flats. This standard specifies the standard dimensions and sectional mass of hot-rolled steel plates, sheets, strips, and flats used for structural and general engineering purposes. It guides engineers and fabricators in selecting standardized sizes to optimize production and minimize waste.
Specifies the dimensions of hot rolled steel flats for general engineering purposes.
EN 10058:2018CEN (European Committee for Standardization)
HighCurrent
Hot rolled flat steel bars and steel wide flats for general purposes - Dimensions, and tolerances on shape and dimensions
Direct equivalent specifying dimensions and tolerances for hot-rolled steel flats.
ASTM A6/A6M-22ASTM International (US)
MediumCurrent
Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling
Covers dimensional tolerances for flat bars within a broader specification for all structural steel shapes.
JIS G 3194:2014JSA (Japanese Standards Association)
HighCurrent
Hot-rolled steel sections for structures
Specifies dimensions, mass, and tolerances for various hot-rolled sections, including flat steel.
BS 4360BSI (British Standards Institution)
LowWithdrawn
Specification for weldable structural steels
This was a material standard that referenced dimensional standards, but was commonly associated with UK flat bar supply.
Key Differences
≠IS 1730:1989 provides a single set of tolerances, whereas EN 10058:2018 offers different tolerance classes for thickness, allowing for more specific product selection.
≠EN 10058 explicitly defines and quantifies tolerance for 'out-of-squareness' of the bar's cross-section, a parameter not specifically defined in IS 1730.
≠The range of preferred nominal dimensions (width and thickness combinations) listed in IS 1730 differs from the ranges specified in EN 10058 and JIS G 3194.
≠IS 1730 specifies a tighter tolerance for exact length cutting (+50mm, -0mm) compared to the standard tolerance in EN 10058 (+100mm, -0mm).
Key Similarities
≈All standards cover the fundamental dimensional and shape tolerances for hot-rolled steel flat bars, including width, thickness, and straightness (camber).
≈The manufacturing process considered, hot rolling, is the common basis for all the compared standards, leading to similar product characteristics like rolled edges.
≈All standards provide tables that correlate the size of the flat bar (width and thickness) with its permissible dimensional deviations.
≈They all specify a tolerance on straightness, typically expressed as a maximum deviation over a defined length (e.g., per meter).
Parameter Comparison
Parameter
IS Value
International
Source
Thickness Tolerance (for 50mm wide x 10mm thick flat)
±0.40 mm
±0.5 mm (Normal class)
EN 10058:2018
Width Tolerance (for 50mm wide x 10mm thick flat)
±1.0 mm
±1.0 mm
EN 10058:2018
Straightness Tolerance (Camber)
Shall not exceed 0.20% of the length (e.g., 2mm in 1m)
Shall not exceed 3mm in any 1m length (for width < 150mm)
EN 10058:2018
Corner Radius (for 10mm thick flat)
Max 0.5t = 5.0 mm
Max 2.5 mm (for thickness 5 to 15mm)
EN 10058:2018
Length Tolerance (Exact Lengths)
+50 mm / -0 mm
+100 mm / -0 mm (unless otherwise agreed)
EN 10058:2018
Out-of-Squareness (for 10mm thick flat)
Not explicitly defined; corner radius is specified instead.
Max deviation 'u' shall not exceed 0.5 mm
EN 10058:2018
Width Tolerance (for 4 inch wide flat; approx 101.6mm)
±1.5 mm (for width > 65 to 110 mm)
±0.063 in [±1.6 mm] (for width > 2.5 to 4 in)
ASTM A6/A6M-22
⚠ Verify details from original standards before use
Key Values3
Quick Reference Values
Density of steel for mass calculation7.85 kg/dm³ (7850 kg/m³)
Standard thickness range for flats3 mm to 40 mm
Standard width range for flats10 mm to 250 mm
Key Formulas
Mass per meter of flat (kg/m) = Width (mm) × Thickness (mm) × 0.00785