1. What is Grain Fineness Number?

Grain Fineness Number (GFN) is a quantitative indication of the grain distribution in foundry sand. It represents the average grain size and distribution pattern of sand particles used in molding processes.

2. How Does the Calculator Work?

The calculator uses the Grain Fineness Number formula:

Where:

• \( GFN \) — Grain Fineness Number
• \( \sum FM \) — Sum of Product of Factor And Grams (kg)
• \( \sum F_i \) — Total Mass of Sand (kg)

Explanation: The formula calculates the average fineness of sand grains by dividing the sum of the products of multiplication factors and corresponding gram weights by the total mass of the sand sample.

3. Importance of GFN Calculation

Details: Accurate GFN calculation is crucial for determining the quality and suitability of foundry sand for specific casting applications. It affects mold strength, surface finish, and casting quality.

4. Using the Calculator

Tips: Enter the sum of product of factor and grams in kg, and the total mass of sand in kg. Both values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for Grain Fineness Number?
A: GFN typically ranges from 40 to 120, with higher numbers indicating finer sand grains.

Q2: How does GFN affect casting quality?
A: Proper GFN ensures good mold strength, adequate permeability, and smooth surface finish on castings.

Q3: When should GFN testing be performed?
A: GFN testing should be done regularly as part of quality control in foundry operations, especially when receiving new sand shipments or after sand reclamation.

Q4: Are there limitations to GFN measurement?
A: GFN provides an average value and doesn't show the complete distribution curve. Additional sieve analysis may be needed for comprehensive sand characterization.

Q5: How often should foundry sand be tested for GFN?
A: Regular testing is recommended - typically daily in production environments or whenever sand properties are suspected to have changed.