Post Overview

Base Material:

Steel is the primary base material for hot-dip galvanizing. Therefore, the melting point of the coating metal must be significantly lower than that of steel.

Generally, low-silicon rimmed steel is considered most suitable for hot-dip galvanizing. The ASM Handbook specifies that the silicon content (wSi) should be less than 0.05%. In China, research indicates that Q235-B steel is optimal for hot-dip galvanizing, as it forms a dense, continuous, and uniform intermetallic compound layer after coating.

However, the widespread adoption of continuous casting technology has introduced challenges for galvanizing. These newer steel grades often contain silicon levels exceeding 0.05%. If the workpiece is not low-carbon steel or has insufficient or excessive silicon content, hot-dip galvanizing becomes difficult. Nevertheless, alternative process methods can still achieve successful galvanization.

Coating Materials:

Common coating metals include:

Zinc (melting point: 419.5°C)

Aluminum (melting point: 658.7°C)

Tin (melting point: 231.9°C)

Lead (melting point: 327.4°C)

Among these, zinc is relatively inexpensive and easy to apply, making it a low-cost anti-corrosion coating. It is widely used to protect steel components—particularly against atmospheric corrosion—and for decorative purposes.

(Note: wSi = weight percentage of silicon in the steel composition.)