plain hard-drawn steel wire for prestressed concrete, Part 2: As the drawn wire

IS 1785 Part 2 - Scope & Key Specifications

Scope (Clause 2.0)

• Defines terms related to steel wire for concrete reinforcement.
• Applies to cold-drawn steel wire with specified chemical and mechanical properties.

Key Specifications:

1. Tolerance on Nominal Diameter (Clause 5.1)

2. Chemical Composition Limits (Clause 3.1.1)

• Sulphur ≤ 0.040%
• Phosphorus ≤ 0.040%

3. Quality Control Formula (Clause 8.3.2)

For chemical composition, diameter, tensile strength, proof stress:

[ \begin{cases} \text{Mean} + 0.6 \times \text{Range} \leq \text{Max Spec Limit} \ \text{Mean} - 0.6 \times \text{Range} \geq \text{Min Spec Limit} \end{cases} ]

• Range = Max test value - Min test value

4. Nominal Mass and Tolerance for As-Drawn Wire (Clause 5.1.2)

• Some diameters (7 mm, 8 mm) and their values have been deleted in Amendment No. 2.

This ensures wire quality and dimensional accuracy for reinforcement use.

IS 1785 Part 2: Key Definitions, Specifications & Tables

1. Definitions (Clause 2.0)

• Standard definitions apply for terms related to plain hard drawn steel wire used in prestressed concrete.
• These include wire diameter, tensile strength, proof stress, chemical composition, and tolerance.

2. Wire Diameter & Tensile Strength (Clause 6.1)

3. Tolerance on Nominal Diameter (Clause 5.1)

4. Quality Control Formula (Clause 8.3.2)

For chemical composition, diameter, tensile strength, proof stress:

[ \text{Mean} + 0.6 \times \text{Range} \leq \text{Max Spec Limit} ] [ \text{Mean} - 0.6 \times \text{Range} \geq \text{Min Spec Limit} ]

• Range = Max value - Min value from test results.

Summary Diagram: Quality Check for Wire Properties

flowchart TD
    A[Test Results] --> B{Calculate Mean & Range}
    B --> C[Check Mean + 0.6*Range ≤ Max Spec]
    B --> D[Check Mean - 0.6*Range ≥ Min Spec]
    C & D --> E{Pass/Fail}

This ensures wire properties meet strict standards for prestressed concrete applications.

IS 1785 Part 2 – Manufacture: Key Specifications & Formulas

1. Manufacturer's Certificate (Clause 9.4)

• Must state:
  • Process of manufacture (e.g., open hearth, electric duplex, acid Bessemer, basic oxygen).
  • Test sheet with:
    • Mechanical test results.
    • Chemical composition (if required).
  • Identification mark linking test sheet to specific cast/material.

2. Chemical & Mechanical Properties Control (Clause 8.3.2)

• For each property (chemical composition, diameter, tensile strength, proof stress):

[ \text{Mean} + 0.6 \times \text{Range} \leq \text{Max Spec Limit} ] [ \text{Mean} - 0.6 \times \text{Range} \geq \text{Min Spec Limit} ]

• Range = Max test value − Min test value.

3. Manufacturing Process (Clause 3.1)

• Steel must be cold-drawn from steel made by:
  • Open hearth, electric duplex, acid Bessemer, basic oxygen, or combination.
• Other processes require purchaser approval.

4. Traceability (Clause 7.1.2)

• Mill records must show:
  • Number of coils/bundles per cast.
  • Sizes and identification marks.
• Enables selection of test pieces and traceability.

Summary Table: Property Control Formula

This ensures consistent quality and traceability in wire manufacture per IS 1785 Part 2.

IS 1785 Part 2: Key Formulas, Tables & Specifications for Materials

1. Chemical Composition, Diameter, Tensile Strength & Proof Stress (Clause 8.3.2)

• For each property, test results must satisfy:

[ \text{Mean} + 0.6 \times \text{Range} \leq \text{Max Spec Limit} ]

[ \text{Mean} - 0.6 \times \text{Range} \geq \text{Min Spec Limit} ]

• Range = Max value - Min value from test results

2. Tensile Strength Requirements (Clause 6.1)

3. Ductility (Clause 8.3.3)

• Number of defective specimens must not exceed permissible limits based on the number tested (refer to IS 1785 Part 2 for exact permissible numbers).

Summary:

• Use Mean ± 0.6 × Range checks for quality control.
• Tensile strength decreases slightly with increasing wire diameter.
• Ductility tests ensure wire reliability with controlled defective specimen limits.

flowchart TD
    A[Material Test Results] --> B{Check Mean + 0.6 Range ≤ Max Limit}
    A --> C{Check Mean - 0.6 Range ≥ Min Limit}
    B --> D[Pass]
    C --> D
    D --> E[Tensile Strength meets Table Values?]
    E -->|Yes| F[Material Accepted]
    E -->|No| G[Material Rejected]

This ensures compliance with IS 1785 Part 2 specifications for prestressing steel wire.

IS 1785 Part 2 - Tolerances on Wire Diameter and Mass

1. Diameter Tolerance (Clause 5.1)

• Diameter measured by averaging six micrometer readings (two directions at right angles, three locations over ≥250 mm).

2. Ovality Check (Clause 5.1.2)

• Ovality ≤ ½ total diameter tolerance → No mass check needed.
• Ovality > ½ total diameter tolerance → Mass tolerance applies.

3. Nominal Mass and Tolerance (for wires with ovality > half tolerance)

Note: Values for 7.00 mm and 8.00 mm removed as per Amendment No. 2.

Measurement Method Summary:

• Diameter = Average of 6 measurements (2 directions × 3 locations).
• Use micrometer for precision.
• Check ovality and mass tolerance if required.

flowchart LR
    A[Measure Diameter at 3 locations] --> B[Take 2 measurements at right angles]
    B --> C[Calculate average diameter]
    C --> D{Ovality ≤ ½ tolerance?}
    D -- Yes --> E[No mass check needed]
    D -- No --> F[Check nominal mass tolerance]

This ensures wire quality per IS 1785 Part 2 standards.

IS 1785 Part 2 — Key Requirements Summary

1. Tensile Strength (Clause 6.1)

Tensile strength is based on nominal wire diameter (mm) and must meet minimum values (N/mm²):

2. Lot Conformity (Clause 8.3.1)

• A lot is accepted if all test characteristics meet the conditions in 8.3.2 and 8.3.3.

3. Statistical Acceptance Criteria (Clause 8.3.2)

For each characteristic (chemical composition, diameter, tensile strength, proof stress):

[ \text{Mean} + 0.6 \times \text{Range} \leq \text{Max Spec Limit} ] [ \text{Mean} - 0.6 \times \text{Range} \geq \text{Min Spec Limit} ]

• Range = Max test value - Min test value

Interpretation Diagram

flowchart LR
    A[Test Results] --> B[Calculate Mean & Range]
    B --> C{Check Conditions}
    C -->|Mean + 0.6*Range ≤ Max Limit| D[Pass Upper Limit]
    C -->|Mean - 0.6*Range ≥ Min Limit| E[Pass Lower Limit]
    D & E --> F{Lot Acceptance}
    F -->|All Pass| G[Lot Conforms]
    F -->|Any Fail| H[Lot Rejected]

This ensures consistent quality control and compliance with IS 1785 Part 2 standards.

IS 1785 Part 2 - Key Formulas, Tables & Specifications for Tests

1. Number of Tests (Clause 8.2 & 8.2.1.1)

• From each coil, select one test specimen per test.
• Test specimens must comply with relevant test methods.

2. Ductility Test (Clause 8.3.3)

• Permissible defective specimens depend on the number tested:

Note: Defective specimens are those failing to meet ductility requirements.

3. Reverse Bend Test (Clause 7.5.1 & Table 1)

• Wire must withstand three bends without fracture.
• Peg radius for reverse bend test depends on wire diameter:

4. Tensile Testing

• Follow the method for tensile testing of steel wire as per IS 1785 Part 2 (First Revision).

flowchart LR
    A[Select 1 Specimen per Coil] --> B{Perform Tests}
    B --> C[Tensile Test]
    B --> D[Ductility Test]
    B --> E[Reverse Bend Test]
    D --> F{Check Defects}
    F -->|Within Permissible Limits| G[Pass]
    F -->|Exceeds Limits| H[Fail]
    E --> I{3 Bends Without Fracture?}
    I -->|Yes| G
    I -->|No| H

Summary:

• One specimen per coil per test.
• Ductility defects limited as per clause 8.3.3.
• Reverse bend radius depends on wire diameter (3-5 mm wires).
• Wire must pass 3 bends without fracture.

For detailed permissible defect numbers, refer to the full IS 1785 Part 2 table in

IS 1785 Part 2: Sampling and Criteria for Conformity

1. Sampling (Clause 8.1.2 & Table 2)

The number of coils to be randomly selected from a lot depends on the lot size:

2. Criteria for Conformity (Clause 8.3)

• The entire lot is conforming if all characteristics satisfy:
  • Conditions in 8.3.2 (likely acceptance limits for tests)
  • Conditions in 8.3.3 (possibly related to individual test results or averages)

Summary:

• Sampling size is based on lot size per Table 2.
• Acceptance requires all sampled coils to meet specified test criteria.

This ensures quality control by statistically validating the lot through representative samples.

flowchart LR
    A[Lot of Coils] --> B{Lot Size}
    B -->|<=25| C[Select 3 Coils]
    B -->|26-65| D[Select 4 Coils]
    B -->|66-180| E[Select 5 Coils]
    B -->|181-300| F[Select 7 Coils]
    B -->|>300| G[Select 10 Coils]
    C & D & E & F & G --> H[Test Samples]
    H --> I{All Characteristics Meet Criteria?}
    I -->|Yes| J[Lot Accepted]
    I -->|No| K[Lot Rejected]

For detailed acceptance criteria, refer to clauses 8.3.2 and 8.3.3 in IS 1785 Part 2.

IS 1785 Part 2: Delivery, Inspection and Testing Facilities

Key Specifications & References:

• Clause 9.1:
  Delivery, inspection, and testing shall conform to IS 1387-1967 unless otherwise specified.

• Clause 7.1.2:
  Manufacturer/supplier must provide mill records including:

  • Number of coils/bundles per cast
  • Sizes and identification marks for traceability

• Ductility Testing (Clause 8.3.3):
  Permissible defective specimens allowed per number tested (example):

  No. of Specimens Tested	Permissible Defective Specimens
  9	1

• Marking & Identification (Clause 10.1.2):
  Use of Standard Mark governed by BIS Act, 1986. License conditions available from BIS.

Additional Notes:

• Heat treatment of wire rods before cold drawing is mandatory for suitability (Clause 3.2).
• For wires subject to further drawing (e.g., prestressed concrete pipes), tensile strength may be reduced by 10% by mutual agreement (Clause 6.1 note).

Summary Table: Inspection & Testing Reference

flowchart TD
    A[Manufacturer] --> B[Provide Mill Records]
    B --> C[Delivery of Wire Coils/Bundles]
    C --> D[Inspection as per IS 1387-1967]
    D --> E[Testing: Ductility, Tensile Strength]
    E --> F{Pass/Fail?}
    F -- Pass --> G[Marking & Dispatch]
    F -- Fail --> H[Reject or Reprocess]

IS 1785 Part 2 (1983) — Identification and Marking

Clause 10.2 specifies the marking requirements for wire rods/coils:

• Tag Information Must Include:
  • Manufacturer's identification
  • Length or mass of the coil
  • Nominal diameter of the wire
  • Batch or coil number

This ensures traceability and quality control.

Summary Table for Marking Tag Content

Additional Notes:

• Tags must be securely attached to each bundle or coil.
• Marking helps in quality assurance and inventory management.
• No specific formulas apply here; this is a specification for labeling.

flowchart TD
    A[Start: Coil Production] --> B[Attach Tag]
    B --> C{Tag Content}
    C -->|Manufacturer| D[Manufacturer ID]
    C -->|Length/Mass| E[Length or Mass]
    C -->|Diameter| F[Nominal Wire Diameter]
    C -->|Batch Number| G[Batch/Coil Number]
    D & E & F & G --> H[Secure Attachment]
    H --> I[Coil Ready for Dispatch]