Male NPT Counter Sunk Head Plug Internal Hex Socket

The surface treatment of the Male NPT Counter Sunk Head Plug Internal Hex Socket is a crucial factor that determines its corrosion resistance and durability.

（1）Zinc Plated

Core features and performance：High cost-performance ratio, moderate protection capability. The neutral salt spray test usually lasts for 72 to 100 hours. The colors are mostly white, yellow, blue, etc.

Advantages：Affordable price, good appearance.

Disadvantages：For Male NPT Counter Sunk Head Plug Internal Hex Socket with a grade higher than 10.9, caution is required when using them as they have a higher strength.

（2）Zinc-Nickel

Core features and performance：The anti-corrosion ability can last up to 720 hours and it is more environmentally friendly.

Advantages：High corrosion resistance and environmental friendliness.

The coating is uniform and has good lubrication properties (with a friction coefficient of approximately 0.09 - 0.14).

（3）Black Oxide

Core features and performance：The cost is very low, but the rust prevention performance is poor. It requires surface oil coating. It is commonly used for high-strength materials above grade 10.9.

Advantages：The cheapest and with a beautiful appearance.

Disadvantages：Poor rust resistance, prone to rusting

（4）Dacromet

Core features and performance：Extremely corrosion-resistant, with a salt spray test duration of 1000 - 2000 hours. The coating is thin (4 - 8 µm).

Advantages：The top-notch rust prevention performance is 7 to 10 times that of traditional galvanization.

Disadvantages：High cost and monotonous color.

（5）Hot Dip Galvanized

Core features and performance：The coating is thick and has strong adhesion. Long-term anti-corrosion is achieved through physical isolation.

Advantages：Outdoor anti-corrosion, wear-resistant and durable.

Disadvantages：The appearance is rough and it is mainly used for large-sized Male NPT Counter Sunk Head Plug Internal Hex Socket.

（6）Phosphating

Core features and performance：Not only can it prevent rust, but it can also improve lubrication, reduce thread engagement, and has a low cost. The performance depends on subsequent oil application. The salt spray test lasts from 10 to 96 hours.

Advantages：Improve lubrication, prevent sticking, and have no hydrogen embrittlement.

Disadvantages：The bare membrane has poor corrosion resistance.

（7）Chrome / Nickel Plated

Core features and performance：It offers excellent anti-corrosion properties, hardness and decorative features. The surface is shiny, easy to clean and resistant to chemical corrosion.

Advantages：The appearance of the Male NPT Counter Sunk Head Plug Internal Hex Socket will be attractive, with high hardness and easy to clean.

Disadvantages：The cost is relatively high.

（8）PVD / E-Coating

Core features and performance：Green and environmentally friendly, with a dense coating and strong decorative properties. The coating is formed through electrochemical deposition in the electrophoretic process.

Advantages：Environmental protection, excellent coating uniformity.

Disadvantages：High cost, complex process.