Dimensions and dimensional tolerances for hot rolled steel plates for the ship’s hull structure

IS 5488: Scope - Key Specifications & Table Summary

Scope (Clause 3.2)

• Defines nominal sizes of steel plates by width, length, and thickness.
• Plates are specified in millimeters.
• Thickness must be less than or equal to the maximum thickness in Table 1 for given width x length.

Table 1: Nominal Sizes of Plates (Width x Length) & Max Thickness (mm)

Important Notes:

• Thickness values are maximum permissible for each width-length combo.
• Thickness less than max is allowed.
• Rounding off test/analysis results per IS 2:1960.

Summary Diagram: Plate Size Specification Flow

flowchart TD
    A[Select Plate Width & Length] --> B[Check Table 1]
    B --> C{Is Thickness ≤ Max Thickness?}
    C -- Yes --> D[Plate Size Acceptable]
    C -- No --> E[Plate Size Not Allowed]

This ensures plates conform to standardized dimensions for structural use as per IS 5488.

IS 5488 Key References: Nominal Sizes & Mass of Steel Plates

1. Nominal Sizes of Plates (Clause 3.2, Table 1)

• Widths range from 900 mm to 3500 mm
• Lengths from 5000 mm to 15000 mm
• Maximum thickness varies by width and length, e.g., for 5000 mm length and widths up to 3500 mm, max thickness is 63 mm.
• Thickness decreases with increasing length and width.

2. Mass Calculation (Clause 3.4)

• Mass (kg) = 7.85 × thickness (mm) × area (m²)
• Steel density assumed as 7.85 kg/dm³

3. Notes

• Thickness less than max in Table 1 is available for given width × length.
• Nominal sizes correspond to thickness per Clause 3.1.

Summary Formula for Mass:

[ \text{Mass (kg)} = 7.85 \times \text{thickness (mm)} \times \text{length (m)} \times \text{width (m)} ]

Visual Summary (Mermaid):

flowchart TD
    A[Plate Dimensions] --> B[Width (900-3500 mm)]
    A --> C[Length (5000-15000 mm)]
    B & C --> D[Max Thickness (varies)]
    D --> E[Mass Calculation]
    E --> F[Mass = 7.85 × thickness × area]

For detailed thickness limits, refer to Table 1 in Clause 3.2 of IS 5488.

IS 5488: Dimensions and Tolerances for Hot-Rolled Steel Plates

1. Tolerance on Thickness (Clause 3.1.2)

Note: More stringent tolerances can be negotiated with the supplier.

2. Tolerance on Width of Sheared Plates (Clause 3.3.1)

Notes:

• Plates >32 mm thickness may have as-rolled or gas-cut edges; tolerances to be agreed.
• Plates ≤32 mm thickness are as-rolled; tolerances mutually agreed.

Summary Diagram:

graph TD
  A[Thickness] --> B[Up to 12 mm: ±7% / -0.4 mm]
  A --> C[12-15 mm: ±5% / -0.4 mm]
  A --> D[15-45 mm: ±4% / -(0.02×t+

IS 5488: Thickness Specifications and Tolerances

1. Maximum Thickness (Clause 3.1 & Note 1)

• Maximum thickness depends on the width x length combination.
• Any thickness less than the maximum specified in the table is permissible for that size.

2. Tolerance on Thickness (Clause 3.1.2)

• More stringent tolerances can be negotiated with the supplier.

3. Nominal Thickness & Size (Clause 3.1 & 3.2)

• Nominal thickness values are standardized.
• Corresponding nominal length and width sizes are provided in Table 1 (not included here).

Summary:

• Use the maximum thickness table (Clause 3.1 Note 1) for size limits.
• Apply the tolerance table above for manufacturing variations.
• Confirm nominal thickness and size from Table 1 per Clause 3.2.

flowchart TD
    A[Plate Dimensions] --> B[Check Max Thickness (Table)]
    B --> C{Thickness < Max?}
    C -- Yes --> D[Apply Thickness Tolerance]
    C -- No --> E[Reject or Modify Size]
    D --> F[Confirm Nominal Size (Table 1)]

This ensures compliance with IS 5488 thickness requirements.

IS 5488 Key Specifications for Length & Width of Plates

1. Maximum Thickness vs. Length & Width (Clause 3.1, Note 1)

• Thickness ≤ max thickness from Table 1 for given length × width.
• Any thickness less than max is available.

2. Nominal Sizes of Plates (Clause 3.2, Table 1)

(Refer full Table 1 for all length-width-thickness combos)

3. Tolerances on Width (Clause 3.3.1)

IS 5488: Tolerance on Width and Length of Sheared Plates

1. Tolerance on Width (Clause 3.3.1)

• Note: Plates >32 mm thickness may have as-rolled or gas-cut edges; tolerances subject to purchaser-supplier agreement.

2. Tolerance on Length

a) Non-continuous Mill (Clause 3.3.2.1)

b) Continuous Mill (Clause 3.3.2.2)

• Thickness 5 to 10 mm:
  +1% length (max 70 mm) / 0 (minus)

Summary Notes

• Minus tolerance is always zero for both width and length.
• For plates thicker than 32 mm, tolerances are subject to agreement.
• Width tolerance depends on length, width, and thickness.
• Length tolerance varies by mill type and thickness.

flowchart TD
    A[Plate Thickness] -->|≤ 20 mm| B[Use Table Values for Width & Length]
    A -->|> 20 mm| C[Use Higher

IS 5488 - Tolerance on Width of Sheared Plates (Clause 3.3.1)

Notes:

• Plates > 32 mm thick: Width tolerance as per agreement (as-rolled or gas-cut edges).
• Plates < 32 mm thick: Supplied as-rolled; tolerances mutually agreed.

Additional: Tolerance on Thickness (Clause 3.1.2)

Summary:

• Width tolerance depends on plate length, width, and thickness.
• For thin plates (≤20 mm), fixed plus tolerance and zero minus tolerance.
• For thicker plates (>20 mm), larger plus tolerances apply.
• Thickness tolerance varies with thickness range, with asymmetric plus/minus limits.

This ensures dimensional accuracy for fabrication and fit-up in structural applications.

IS 5488 - Tolerance on Length of Steel Plates

1. Tolerance on Length for Plates from Non-Continuous Mill (Clause 3.3.2.1)

2. Tolerance on Length for Plates from Continuous Mill (Thickness 5 to 10 mm) (Clause 3.3.2.2)

• Plus tolerance: +1% of length, max 70 mm
• Minus tolerance: 0 mm

3. Notes

• Plates > 32 mm thickness: Length tolerance as agreed between purchaser and supplier.
• Minus tolerance is always zero (no shortening allowed).

Summary Formula for Non-Continuous Mill Plates

[ \text{Tolerance}_{+} = \begin{cases} 0.5% \times L & \text{if } L \leq 6000 \text{ mm} \ 35 \text{ mm} & \text{if } 6000 < L \leq 8000 \text{ mm (≤20 mm thick)} \ 0.5% \times L \text{ or } 40 \text{ mm} & \text{depending on thickness and length} \end{cases} ]

[ \text{Tolerance}_{-} = 0 \text{ mm} ]

flowchart TD
    A[Plate Length L] --> B{Thickness ≤ 20 mm?}
    B -- Yes --> C{L ≤ 6000 mm?}
    B -- No --> D{L ≤ 8000 mm?}
    C -- Yes --> E[+0.5% of L / -0 mm]
    C -- No --> F{L ≤ 

IS 5488 - Key Formula and Specifications for Mass of Steel Plates

Mass Calculation (Clause 3.4)

• Nominal mass of plates is calculated based on:

  [ \text{Mass} = 7.85 \times \text{thickness (mm)} \quad \text{kg/m}^2 ]

• Here, 7.85 kg/m³ is the density of steel.

Plate Dimensions & Thickness (Clause 3.2 & Table 1)

• Plates are available in nominal sizes with widths ranging from 900 mm to 3500 mm.
• Lengths range from 5000 mm to 15000 mm.
• Maximum thickness varies by width and length (see partial table below):

Thickness less than max allowed for each width-length combo is available.

Summary:

• Calculate mass per m² using thickness × 7.85 kg.
• Select plate size and thickness per Table 1 limits.
• Use nominal sizes for ship hull steel plates.

flowchart TD
    A[Select Plate Dimensions] --> B[Check Max Thickness from Table 1]
    B --> C[Choose Thickness ≤ Max Thickness]
    C --> D[Calculate Mass: Mass = 7.85 × Thickness (kg/m²)]
    D --> E[Use for Structural Design & Procurement]

This ensures correct mass estimation and compliance with IS 5488 for shipbuilding steel plates.

IS 5488: Measurement and Testing Procedures - Key Specifications

1. Rounding Off Test Results (Clause 0.4)

• Final test values must be rounded as per IS 2:1960.
• Retain the same number of significant digits as specified in the standard.

2. Nominal Sizes of Plates (Clause 3.2 & Table 3.3.2)

• Plate dimensions in mm: Width ranges from 900 to 3500 mm, Length from 5000 to 15000 mm.
• Maximum thickness varies with width and length, e.g., for 5000 mm length and 900 mm width, max thickness = 63 mm.
• Thickness decreases as length and width increase.

3. Tolerance on Length (Clause 3.3.2.1)

Notes:

• Thickness less than max specified for given width × length is permissible.
• Applies to plates from non-continuous mills.

Summary Table: Max Thickness Example

This ensures dimensional accuracy and quality control during plate manufacturing and testing.

Rounding Off of Test Results (IS 5488)

• Clause 0.4:
  Final test or analysis values must be rounded off as per IS 2:1960 (Rules for rounding off numerical values).
• The number of significant figures retained in the rounded value should match the specified value's precision in the standard.

Key Tolerances (Tables from IS 5488)

Important Notes:

• Plates >32 mm thickness may have as-rolled or gas-cut edges; tolerances subject to purchaser-supplier agreement.
• Plates <32 mm thickness supplied as-rolled

IS 5488: Supply Conditions and Agreements - Key Specifications & Tables

1. Nominal Sizes of Plates (Clause 3.2, Table 1)

• Widths range from 900 mm to 3500 mm
• Lengths from 5000 mm to 15000 mm
• Maximum thickness varies with width and length, e.g., for 5000 mm length and widths up to 3500 mm, max thickness is 63 mm.
• Thickness decreases with increasing length and width.

2. Mass Calculation (Clause 3.4)

• Nominal mass (kg) = 7.85 × thickness (mm) × area (m²)
• Steel density = 7.85 kg/dm³ (or 7850 kg/m³)

3. Tolerance on Width (Clause 3.3.1)

• Plates > 32 mm thickness may have as-rolled or gas-cut edges; tolerances by agreement.
• Plates < 32 mm thickness supplied as-rolled; tolerances by mutual agreement.

Summary Table: Max Thickness Example (Excerpt)

This ensures clear supply conditions, dimensional tolerances, and mass calculations for shipbuilding steel plates per IS 5488.