Metal Head at Top Section of Sprue Calculator

Metal Head Formula:

\[ h_t = h_c \times \left(\frac{A}{A_t}\right)^2 \]

Metal Head at Top Section (m):

1. What is Metal Head at Top Section of Sprue?

Definition: This is the length of molten metal that accumulates at the top of the sprue, which is the vertical passage through which molten metal is poured into a mold during casting.

Purpose: It's crucial for ensuring proper flow and filling of the mold cavity in metal casting processes.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ h_t = h_c \times \left(\frac{A}{A_t}\right)^2 \]

Where:

\( h_t \) — Metal head at top section (meters)
\( h_c \) — Head at choke section (meters)
\( A \) — Area of sprue in choke section (m²)
\( A_t \) — Area at top section (m²)

Explanation: The formula calculates the metal head at the top section based on the choke section head and the ratio of areas squared.

3. Importance of Metal Head Calculation

Details: Proper calculation ensures adequate metal pressure to completely fill the mold cavity and compensate for shrinkage during solidification.

4. Using the Calculator

Tips: Enter the head at choke section (in meters), area of sprue in choke section (in m²), and area at top section (in m²). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the area ratio squared in the formula?
A: The squared relationship comes from Bernoulli's equation and accounts for the velocity changes in the fluid flow through the sprue.

Q2: What's a typical value for head at choke section?
A: This varies by casting process but typically ranges from 0.05m to 0.2m depending on the mold size and metal being cast.

Q3: How precise should my area measurements be?
A: Measurements should be precise to at least 4 decimal places (in m²) as small changes can significantly affect the result.

Q4: What if my sprue isn't perfectly vertical?
A: This formula assumes a vertical sprue. For angled sprues, more complex calculations are needed.

Q5: Does this account for metal viscosity?
A: No, this is a simplified calculation assuming ideal fluid flow. For highly viscous metals, additional factors should be considered.