Mild Steel and Medium Tensile Steel Bars and Hard-Drawn Steel Wire for Concrete Reinforcement, Part 2: Hard-Drawn Steel Wire

IS 432 Part 1: Scope & Key Specifications

• Scope: Covers mild steel and medium tensile steel bars for general engineering and structural use.
• Rounding Off: Final test or analysis values must be rounded per IS 2-1960, maintaining significant figures equal to specified values.

Mechanical Properties of Bars (Clause 8.1, Table 1)

*Elongation measured on gauge length 5.65√S₀, where S₀ = cross-sectional area.

Notes:

• Bars can be tested after cutting to specified lengths.
• Standard aligns with international practices for steel bars.

flowchart TD
    A[Steel Bars] --> B{Type}
    B --> C[Mild Steel Grade I]
    B --> D[Mild Steel Grade II]
    B --> E[Medium Tensile Steel]
    C --> F[Size ≤ 20mm]
    C --> G[20mm < Size ≤ 50mm]
    D --> H[Size ≤ 20mm]
    D --> I[20mm < Size ≤ 50mm]
    E --> J[Size ≤ 16mm]
    E --> K[16mm < Size ≤ 32mm]
    E --> L[32mm <

IS 432 Part 1 – Definitions & Key Mechanical Properties

Definitions (Clause 2.0)

• The standard defines terms related to steel bars used in concrete reinforcement.
• SI units are adopted throughout.
• References updated Indian Standards for materials and testing.

Mechanical Properties of Steel Bars (Clause 8.1, Table 1)

Elongation is measured over a gauge length of 5.65√So, where So = cross-sectional area.

Notes:

• Yield stress is the minimum stress at which steel begins to deform plastically.
• Ultimate tensile stress is the maximum stress before failure.
• Elongation indicates ductility, important for seismic and structural performance.

flowchart LR
    A[Steel Bar] --> B{Type}
    B --> C[Mild Steel Grade I]
    B --> D[Mild Steel Grade II]
    B --> E[Medium Tensile Steel]
    C --> F[Size ≤ 20 mm]
    C --> G[20 mm < Size ≤ 50 mm]
    D --> H[Size ≤ 20 mm]
    D --> I[20 mm < Size ≤ 50 mm]
    E --> J[Size ≤ 16 mm]
    E --> K[16 mm < Size ≤

IS 432 Part 1: Types and Grades of Steel Bars

1. Types of Steel Bars (Clause 3.1)

• Mild Steel Bars
  • Grade I
  • Grade II
• Medium Tensile Steel Bars

2. Mechanical Properties (Clause 8.1, Table 1)

*Elongation measured on gauge length = 5.65√So (So = cross-sectional area).

3. Yield Stress Definition (Clause 2.8)

• Stress at which elongation begins without load increase.
• For steels without a clear yield point, yield stress corresponds to 0.5% permanent strain (increase in gauge length = 1/200 of gauge length).

Summary Diagram: Classification of Steel Bars

graph TD
    A[Steel Bars as per IS 432 Part 1] --> B[Mild Steel Bars]
    A --> C[Medium Tensile Steel Bars]
    B --> B1[Grade I]
    B --> B2[Grade II]

Use this table and definitions for selecting steel bars per IS 432 Part 1.

IS 432 Part 1: Manufacture and Chemical Composition of Steel Bars

1. Grades of Mild Steel Bars (Clause 3.1.1)

• Grade I and Grade II mild steel bars are specified.
• Medium tensile steel bars conform to IS 961-1975 (Fe 540 W-HT).

2. Mechanical Properties (Clause 8.1, Table 1)

Elongation is measured on a gauge length of 5.65√So, where So is the cross-sectional area.

3. Chemical Composition (Clause 4.3)

• Medium tensile steel bars must comply with IS 961-1975 for Fe 540 W-HT grade.
• Mild steel chemical composition varies by grade but generally includes low carbon content for weldability and ductility.

4. Manufacturer's Certification (Clause 10.4)

• Must provide a certificate stating:
  • Manufacturing process.
  • Mechanical test results.
  • Chemical composition (if required).
• Test sheets must identify the batch/cast number matching the material.

This ensures compliance with mechanical and chemical quality for reinforcement bars used in construction.

IS 432 Part 1: Mechanical Properties of Steel Bars

Key Mechanical Properties (Clause 8.1, Table 1)

Notes:

• Elongation measured on gauge length of 5.65√So, where So = cross-sectional area.
• Testing follows IS 1608 (equivalent to ISO 6892).

Summary of Testing Standards:

• Tensile Testing: IS 1608 / ISO 6892
• Bend Test: IS 1599 / ISO 10065

flowchart TD
    A[Steel Bar] --> B[Tensile Test (IS 1608)]
    B --> C{Measure}
    C -->|Ultimate Tensile Stress| D[Min values per Table 1]
    C -->|Yield Stress| E[Min values per Table 1]
    C -->|Elongation| F[Min % per Table 1]

This ensures steel bars meet minimum mechanical requirements for structural safety and ductility.

IS 432 Part 1: Sizes of Mild and Medium Tensile Steel Bars

Key Specifications (Clause 6.1 & 2.5)

• Nominal Sizes (Diameter for round bars / Side for square bars):

  • 5, 6, 8, 10, 12, 16, 20, 22, 25, 28, 32, 36, 40, 45, 50 mm

• Nominal Size Definition (Clause 2.5):

  • Dimension corresponds to diameter (round bars) or side length (square bars).

Quality Requirements (Clause 5.1)

• Bars must be cleanly rolled to specified dimensions and weights.
• Free from cracks, surface flaws, laminations, and rough edges.

Typical Mass per Meter (approximate)

Mass calculated as:

[ \text{Mass (kg/m)} = \frac{\pi}{4} \times d^2 \times \rho ]

where ( d ) = diameter in meters, ( \rho = 7850 , kg/m^3 ).

flowchart LR
    A[Nominal Size] --> B[Round Bars: Diameter]
    A --> C[Square Bars: Side Length]
    B & C --> D[Dimensions per IS 432 Part 1]
    D --> E[Quality Checks: No defects]
    D --> F[Mass per meter calculated]

This summary covers the essential sizes and quality requirements for steel bars per IS 432 Part 1.

IS 432 Part 1: Testing Methods for Mild and Medium Tensile Steel Bars

Equivalent Test Standards

Mechanical Properties (Clause 8.1, Table 1)

• Elongation measured on gauge length = 5.65√(So), where So = cross-sectional area of test piece.
• Test samples can be taken from any part of the bar or coil after cutting to specified length.

Summary

• Use IS 1608 for tensile tests and IS 1599 for bend tests.
• Mechanical properties vary by grade and bar diameter.
• Elongation is a key ductility parameter.
• ISO test methods are allowed for conformity assessment.

flowchart LR
    A[Steel Bar Sample] --> B{Testing Method}
    B -->|Tensile Test| C[IS 1608 / ISO 6892]
    B -->|Bend Test| D[IS 1599 / ISO 10065]
    C --> E{Evaluate Mechanical Properties}
    E --> F[Ultimate Tensile Stress

IS 432 Part 1: Marking and Identification Key Points

Marking Requirements (Clause 11.3)

• Each bundle/coil of bars may be marked with the BIS Standard Mark.
• The test certificate must bear the Standard Mark if marking is used.
• The Standard Mark ensures compliance with the Indian Standard under BIS inspection and quality control.
• Use of the Standard Mark is regulated by the Bureau of Indian Standards Act, 1986.

Identification (Clause 11.2)

• Medium tensile steel bars must be distinctly marked to differentiate from mild steel bars.
• Mild steel bars (Grades I & II) have distinctive identification tags.

Manufacturer's Certificate (Clause 10.4)

• For bars not inspected at the manufacturer's works, a certificate with manufacturing process, mechanical test results, and chemical composition (if required) must be supplied.
• Test sheets must show the identification number corresponding to the cast.

Summary Table: Identification & Marking

Additional Notes:

• The Standard Mark is a guarantee of product quality and conformity.
• For detailed licensing conditions, contact BIS offices (addresses provided in the code).

flowchart TD
    A[Steel Bars] --> B{Type of Steel}
    B -->|Medium Tensile| C[Distinctive Marking]
    B -->|Mild Steel (Grade I & II)| D[Identification Tags]
    A --> E[Bundled/Coiled Bars]
    E --> F{Marking with BIS Standard Mark?}
    F -->|Yes| G[Test Certificate with Standard Mark]
    F -->|No| H[No Marking Required]
    A --> I[Manufacturer's Certificate]
    I --> J[Manufacturing Process + Test Results + Chemical Composition]

For mechanical and bend testing methods, IS 1608 and IS 1599 correspond to ISO 6892 and ISO 10065 respectively, ensuring international equivalence in testing.

IS 432 Part 1: Sampling and Test Pieces Summary

Sampling and Test Piece Preparation

• Sampling for tensile and bend tests must follow IS 226:1975 (Clause 9.5, 9.1).
• For bars with non-uniform size, use the maximum thickness of the test piece for limits (Clause 9.2.1).
• Test pieces can be taken from any part of the bar or coil after cutting to specified length.

Mechanical Properties of Bars (Clause 8.1, Table)

Notes:

• Elongation is measured on a gauge length of 5.65√So, where So = cross-sectional area of the test piece.
• Sampling and preparation should strictly follow IS 226:1975 for consistency.

flowchart LR
    A[Bar/Coil] --> B[Cut to Specified Length]
    B --> C[Select Test Piece]
    C --> D[Measure Max Thickness if Non-uniform]
    D --> E[Perform Tensile & Bend Tests per IS 226]
    E --> F[Check Mechanical Properties vs Table]

This ensures representative sampling and reliable mechanical property verification per IS 432 Part 1.

IS 432 Part 1: Inspection and Quality Control - Key Points

Sampling for Tests (Clause 9.5)

• Sampling for tensile and bend tests must follow IS 226:1975.
• Ensures representative testing of mild and medium tensile steel bars.

Delivery, Inspection, and Testing Facilities (Clause 10)

• General inspection and testing requirements conform to IS 1387:1967.
• No material dispatch without purchaser’s certification or ISI Certification Mark on bundles/coils.

Equivalent Test Standards

Summary of Quality Control Process

flowchart TD
    A[Material Manufacture] --> B[Sampling per IS 226]
    B --> C[Tensile & Bend Tests (IS 1608 & IS 1599)]
    C --> D[Inspection per IS 1387]
    D --> E{Pass Tests?}
    E -- Yes --> F[Certification & ISI Mark]
    E -- No --> G[Reject / Reprocess]
    F --> H[Dispatch to Purchaser]

Key Takeaways:

• Follow IS 226 for sampling.
• Use IS 1608 & IS 1599 for tensile and bend testing.
• Inspection per IS 1387 ensures material quality.
• Certification or ISI mark mandatory before dispatch.

This ensures steel bars meet mechanical and quality standards before delivery.

Packaging and Delivery - IS 432 Part 1 Key Points

Clause References:

• Clause 9.5 (Sampling):
  Sampling for tensile and bend tests must follow IS 226:1975 (Method for tensile testing of steel products).

• Clause 2.6 (Parcel Definition):
  A parcel is any quantity of bars (coils or bundles) presented for examination and testing at one time.

• Clause 7.1 (Tolerances):
  Rolling and cutting tolerances must comply with IS 1852:1973.

• Clause 10.2 (Delivery):
  No material should be dispatched before certification by the purchaser or authorized representative unless marked with the ISI Certification Mark.

Summary Table: Packaging & Delivery Requirements

Important Notes

• Certification mark (ISI) on bundles/coils allows dispatch without prior purchaser approval.
• Testing must be conducted per referenced IS codes for quality assurance.
• Packaging should ensure bars are bundled/coiled as per standard parcel definitions for easy inspection.

flowchart LR
    A[Manufacture Bars] --> B[Sampling as per IS 226]
    B --> C{Tests Passed?}
    C -- Yes --> D[Certification by Purchaser or ISI Mark]
    D --> E[Dispatch Material]
    C -- No --> F[Reject or Re-test]

This ensures quality compliance and traceability during packaging and delivery.

IS 432 Part 1: Standard Mark and Certification Key Points

Clause 11.3: Identification and Marking

• Each bundle/coil of bars may be marked with the BIS Standard Mark (ISI Mark).
• The test certificate must also bear the Standard Mark if the bars are marked.
• The Standard Mark assures compliance with IS standards under BIS supervision.
• Continuous BIS surveillance ensures ongoing conformity.
• Licence conditions for use of the Standard Mark are governed by BIS rules.

Clause 10.4: Manufacturer's Certificate

• For bars not inspected at the manufacturer's works, a Manufacturer's Certificate must be supplied.
• Certificate must include:
  • Manufacturing process details.
  • Mechanical test results (tensile, bend, etc.).
  • Chemical composition if required.
  • Identification number matching the material.

Relevant Testing Standards (Equivalent ISO)

Summary Diagram: Certification Flow

flowchart TD
    A[Manufacture of Bars] --> B{Inspection at Manufacturer's Works?}
    B -->|Yes| C[Certification by Purchaser's Representative]
    B -->|No| D[Manufacturer's Certificate with Test Results]
    C --> E[Mark Bundle/Coil with Standard Mark]
    D --> E
    E --> F[Dispatch Material with Test Certificate & Standard Mark]

Contact BIS for Licensing & Details:
Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002
Phone: 3310131 (Common to all offices)

This ensures traceability and quality assurance as per IS 432 Part 1.