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IS 1864:1979 is the Indian Standard (BIS) for hot-rolled steel l-sections for shipbuilding. This standard specifies the dimensions, mass, and sectional properties of hot-rolled steel L-sections intended primarily for structural use in shipbuilding.
Hot-rolled steel L-sections for shipbuilding
Overview
Status
Current
Usage level
Specialized
Domain
Structural Engineering — Structural Engineering and Structural Sections
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! L-sections covered here are optimized for use as stiffeners in ship hulls and decks, offering a better weight-to-stiffness ratio for marine applications compared to standard equal angles.
! Material compliance must strictly follow marine grades (e.g., IS 3039) and classification society rules, as this code only dictates geometric properties.
! When modeling in BIM (like Tekla or AVEVA Marine), ensure you select the 'ISL' library rather than standard 'ISA' (Indian Standard Angle) to get the correct center of gravity and root radii.
Standard Specification for Structural Steel for Ships
Specifies requirements for structural steel plates, shapes (including L-sections), and bars for ship construction.
JIS G 3128:2018JSA (Japanese Standards Association), Japan
HighCurrent
Hot-rolled steels for shipbuilding
Covers hot-rolled steel plates, sections, and flat bars intended for hull structures.
IACS UR W11IACS (International Association of Classification Societies), International
MediumCurrent
Normal and Higher Strength Hull Structural Steels
Defines the unified material and testing requirements that national standards and classification society rules are based on.
EN 10025-2:2019CEN (European Committee for Standardization), European Union
MediumCurrent
Hot rolled products of structural steels - Part 2: Technical delivery conditions for non-alloy structural steels
General structural steel standard, whose grades (e.g., S235, S275) are often approved for shipbuilding with additional classification society requirements.
Key Differences
≠IS 1864:1979 references a withdrawn material standard (IS 226) or defers to the purchaser, whereas modern standards like ASTM A131 define a full range of specific shipbuilding grades (A, B, D, AH32, DH36, etc.).
≠Modern international standards provide detailed specifications for various high-strength and thermo-mechanically controlled processed (TMCP) steels, which are absent in the 1979 version of the Indian standard.
≠IS 1864:1979 does not mandate Charpy V-notch impact testing, which is a critical requirement in standards like ASTM A131 and IACS UR W11 for ensuring fracture toughness, especially for grades intended for low-temperature service.
≠The dimensional and rolling tolerances in IS 1864:1979 are generally less comprehensive and may be less stringent than those in harmonized international standards, which often reference specifications like ISO 657 for L-sections.
Key Similarities
≈All standards share the primary objective of specifying requirements for hot-rolled steel L-sections intended for structural applications in shipbuilding.
≈The scope of product form is similar, as IS 1864, ASTM A131, and JIS G 3128 all explicitly cover L-sections (angles) along with other structural shapes used in ship construction.
≈The fundamental manufacturing method specified across all standards is hot-rolling for the final product shape.
≈All standards mandate basic mechanical property verification through tensile testing to determine tensile strength and elongation, and typically require bend tests to ensure sufficient ductility.
Parameter Comparison
Parameter
IS Value
International
Source
Tensile Strength (Normal Strength Grade)
410 - 540 MPa (based on referenced IS 226)
400 - 520 MPa
ASTM A131/A131M (Grade A)
Yield Strength (Normal Strength Grade)
~250 MPa (Typical for referenced IS 226)
235 MPa minimum
ASTM A131/A131M (Grade A)
Elongation (Normal Strength Grade)
23% minimum (on gauge length 5.65√S₀)
22% minimum (on gauge length 200 mm)
ASTM A131/A131M (Grade A)
High-Strength Steel Provision
Not specified; refers to 'as specified by purchaser'
Yes, specified (e.g., Grade AH36 with 355 MPa min yield)
ASTM A131/A131M
Charpy Impact Test (Grade D)
Not specified / Not applicable
Required: Average 27 Joules at -20 °C
IACS UR W11
Chemical Composition (Carbon, max)
0.25% (based on referenced IS 226 for sections ≤ 20mm)
0.21% (for Grade A)
ASTM A131/A131M (Grade A)
Weldability Control
Controlled via general limits on C, S, and P.
Controlled via Carbon Equivalent (CE) formula for higher grades.
IACS UR W11
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
designation prefixISL (Indian Standard L-Section)
standard supply length6 to 15 m
mass tolerance per piece± 4.0%
mass tolerance per lot± 2.5%
Tables & Referenced Sections
Key Tables
Table 1 - Dimensions, Mass and Sectional Properties of Hot-Rolled Steel L-Sections
They are designated by the prefix 'ISL' followed by the longer leg dimension, shorter leg dimension, and thickness (e.g., ISL 150 x 90 x 10).
Are the material properties covered in IS 1864?+
No, IS 1864 only covers dimensions and sectional properties. Material properties for shipbuilding steel are covered by IS 3039.
Can ISL sections be substituted with ISA (Standard Angles)?+
Not directly without redesign, as L-sections (ISL) have distinct leg proportions and properties specifically designed to act as efficient hull stiffeners.