Method for determination of resistance to wear by abrasion of natural building stones

IS 1706: Scope Summary

• Scope: This standard specifies requirements for cast iron grinding paths used in grinding machines.
• Material: Cast iron with a Shore's scaleroscope hardness between 30 and 50.
• Hardness Testing: Hardness must be checked at least 10 times on the rim and at several points along the grinding path using a Shore's scaleroscope with diamond hammer.
• Rounding Off: Test or calculated values must be rounded as per IS 2:1960, retaining significant figures equal to those specified in the standard.
• International Coordination: The standard aligns with international practices and local field requirements.

Key Specification Table

flowchart LR
    A[Cast Iron Grinding Path] --> B[Hardness 30-50 (Shore's scaleroscope)]
    B --> C[Hardness Testing]
    C --> D[At least 10 times on rim]
    C --> E[Several points on grinding path]
    A --> F[Rounding of Values]
    F --> G[As per IS 2:1960]

This concise scope ensures material quality and testing rigor for grinding paths in machinery.

IS 1706: Dimensions and Preparation of Test Specimens

Key Specifications (Clause 2.1)

• Specimen shape: Cube
• Size: 7.06 cm ± 2% (each face area = 50 cm²)
• Preparation:
  • Saw cutting followed by grinding wheels
  • Avoid chisel and hammer
  • All faces must be true and parallel

Grinding Apparatus (Clause 1.1 & Fig. 2)

• Grinding disc diameter: ~750 mm
• Orientation: Horizontal, rotating about vertical axis
• Features: Replaceable grinding path, square frame for clamping, counter-weight

Measurement (Clause 4.2)

• Use a measuring instrument with 0.01 mm accuracy to measure thickness change after abrasion.

Rounding Off Results (Clause 0.4)

• Round off test results per IS 2-1960.
• Retain the same number of significant digits as specified values.

Summary Table: Specimen Dimensions

flowchart LR
    A[Sample] --> B[Saw Cutting]
    B --> C[Grinding Wheels]
    C --> D[Cube Specimen 7.06 cm ±2%]
    D --> E[Clamp in Grinding Machine]
    E --> F[Grinding Disc (750 mm)]
    F --> G[Measure Thickness Change (±0.01 mm)]

This ensures consistent specimen preparation and measurement for abrasion testing as per IS 1706.

IS 1706: Abrasion Testing Machine Key Specifications

• Machine Type: Horizontally fixed smooth grinding disc
• Disc Diameter: ~750 mm (Clause A-1.1)
• Axis: Vertical rotation
• Grinding Path: Replaceable, smooth surface on the disc (Clause A-2)
• Specimen Clamping: Square frame to hold specimen firmly (Fig. 2)
• Counter-weight: Provided for balanced clamping pressure

Measurement Accuracy

• Thickness change measured with an instrument accurate to 0.01 mm (Clause 4.2)

Summary Table

flowchart LR
    A[Grinding Disc ~750 mm] --> B[Rotates Vertically]
    B --> C[Specimen Clamped on Square Frame]
    C --> D[Counter-weight for Pressure]
    D --> E[Thickness Measured (0.01 mm accuracy)]

This setup ensures consistent abrasion testing per IS 1706 requirements.

IS 1706: Holding Device for Test Specimen – Key Specifications

• Holding Device: Open square frame made of cast iron or steel.
• Height: Lower edge positioned about 5 mm above the grinding disc surface.
• Positioning: Centre of specimen at 220 mm from the centre of the disc.
• Function: Holds the specimen loosely but necessarily to allow free movement during grinding.

Grinding Disc & Specimen Setup (Fig. 2 Summary)

• Disc diameter: ~750 mm
• Disc rotation speed: 30 ± 1 rev/min (Clause 3.1)
• Revolution counting: Automatic stop after every 22 revolutions.

Key Details for Holding Device:

Additional Notes:

• The holding frame must allow loose holding to avoid restraining specimen movement.
• The loading lever should be frictionless and maintain parallelism with the disc surface.
• The pressure stamp connects via a self-aligning joint for uniform load application.

flowchart LR
    Disc[Grinding Disc (750 mm)]
    Specimen[Specimen]
    Frame[Holding Frame]
    CentreDisc((Centre of Disc))
    CentreSpecimen((Centre of Specimen))

    CentreDisc -->|220 mm| CentreSpecimen
    Specimen --> Frame
    Frame -->|5 mm above| Disc

This setup ensures consistent abrasion testing as per IS 1706.

IS 1706: Test Procedure Key Points

1. Measuring Instrument (Clause 4.2)

• Use an instrument with accuracy of 0.01 mm to measure thickness change after abrasion.

2. Test Conditions (Clause 3.1)

• Abrasion disc speed: 30 ± 1 rpm
• Automatic revolution counter stops disc every 22 revolutions.
• Check counter reliability before testing.

3. Rounding Off Results (Clause 0.4)

• Round final test values per IS 2-1960.
• Retain the same number of significant digits as specified in the standard.

4. Abrasion Testing Machine (Clause A-1.1)

• Grinding disc diameter: approx. 750 mm
• Horizontally fixed, rotating about a vertical axis.
• Equipped with replaceable grinding path.
• Specimen clamped in a square frame with counter-weight.

Diagram: Abrasion Testing Machine Setup

graph TD
    A[Grinding Disc (750 mm dia)]
    B[Vertical Axis Rotation]
    C[Replaceable Grinding Path]
    D[Square Frame Clamping Specimen]
    E[Counter-weight]
    F[Automatic Revolution Counter]

    A --> B
    A --> C
    D --> A
    E --> D
    F --> B

This setup ensures consistent abrasion testing under controlled speed and measurement accuracy.

IS 1706: Calculation and Reporting of Wear

Key Formula for Average Loss in Thickness (Clause 5.2)

[ t = \frac{10 (W_1 - W_2) V_1}{W_1 \times A} ]

Where:

• t = Average loss in thickness (mm)
• W₁ = Initial weight of specimen (g)
• W₂ = Final weight after abrasion (g)
• V₁ = Initial volume of specimen (cm³)
• A = Surface area of specimen (cm²)

Testing Procedure Highlights (Clause 5)

• Dry specimen at 110°C for 24 h and weigh to 0.1 g accuracy.
• Measure initial thickness with an instrument accurate to 0.01 mm (Clause 4.2).
• Abrade specimen using emery abrasive powder (20 g per 22 revolutions).
• Grinding disc speed: 30 rev/min, load: 30 kg.
• Total revolutions: 220, with specimen rotated 90° after 110 revolutions.
• Keep specimen, disc, and abrasive dry.
• After abrasion, reweigh and re-measure thickness.

Reporting (Clause 6.1)

• Report the average abrasion values obtained from multiple specimens/tests.

Summary Table

flowchart TD
    A[Dry specimen at 110°C for 24h] --> B[Weigh specimen (W₁)]
    B --> C[Measure initial thickness]
    C --> D[Place specimen on abrasion machine]
    D --> E[Abrade with 20g emery powder every 22 revs]
    E --> F[Total 220 revolutions

IS 1706: Abrasion Testing Machine - Key Specifications & Details

Abrasion Testing Machine (Clause A-1.1 & 4.1)

• Grinding Disc: Smooth, horizontal, fixed, diameter ≈ 750 mm.
• Axis: Vertical rotation.
• Grinding Path: Replaceable, as per Fig. 2 (square frame clamps specimen).
• Counter-weight: Provided for balance.
• Dimensions: All in millimeters.

Measuring Instrument (Clause 4.2)

• Accuracy: 0.01 mm for thickness change measurement post-abrasion.

Test Procedure (Clause 5)

• Specimens clamped on frame.
• Disc rotates, abrading specimen on grinding path.
• Thickness measured before and after test.

Summary Table: Abrasion Testing Machine Specs

flowchart LR
    A[Specimen Clamped] --> B[Grinding Disc Rotates]
    B --> C[Abrasion Occurs on Specimen]
    C --> D[Measure Thickness Change (±0.01 mm)]

This setup ensures standardized abrasion testing per IS 1706 requirements.

IS 1706: Specification for Abrasive Material (Emery Grain) & Abrasion Test

Key Specifications & Procedure:

• Specimen Preparation:

  • Dry at 110°C for 24 hours
  • Weigh to nearest 0.1 g

• Abrasion Test Setup:

  • Grinding disc diameter: ~750 mm (horizontal, smooth, rotating vertically)
  • Disc speed: 30 revolutions/minute
  • Load on specimen: 30 kg at center
  • Abrasive powder: 20 g emery grain spread evenly on grinding path
  • After every 22 revolutions, remove abraded powder and add fresh 20 g abrasive
  • Total revolutions: 220 (turn specimen 90° after 110 revolutions)
  • Keep disc, abrasive, and specimen dry throughout test

• Measurements:

  • Thickness measured before and after abrasion using thickness measuring apparatus (see Fig.1 in IS 1706)
  • Weight measured before and after abrasion to nearest 0.1 g

Summary Table of Abrasion Test Parameters

flowchart LR
    A[Dry specimen at 110°C for 24h] --> B[Weigh specimen]
    B --> C[Place specimen in thickness gauge]
    C --> D[Fix specimen on abrasion machine]
    D --> E[Apply 20g abrasive powder]
    E --> F[Rotate disc at 30 rpm, load 30kg]
    F --> G[After 22 rev, replace abrasive powder]
    G --> H[Repeat until 110 rev]
    H --> I[Rotate specimen 90°]
    I --> J[Continue to 

Rounding Off Numerical Values as per IS 1706

• IS 1706 refers to IS 2-1960 for rounding off rules.
• The number of significant digits in the rounded value must match that of the specified value in the standard.
• Final test or calculated results should be rounded accordingly before compliance checks.

Key Formula for Wear Thickness Loss (Clause 5.2)

[ t = \frac{10 \times (W_1 - W_2) \times V_1}{W_1 \times A} ]

Where:

Summary:

• Round final values per IS 2-1960.
• Maintain the same significant figures as specified.
• Use the formula above to calculate average thickness loss from weight and dimensions.

flowchart TD
    A[Initial Specimen] -->|Measure W1, V1, A| B[Calculate Wear]
    B --> C[Perform Abrasion]
    C -->|Measure W2| D[Calculate t]
    D --> E[Round off t as per IS 2-1960]
    E --> F[Check compliance with IS 1706]