Ferry Cap Screws

Introduction to Surface Treatment

In order to ensure that the Ferry Cap Screws perform optimally in various environments, we offer a variety of surface treatment options:

（1）Black Oxide: Provides basic rust prevention capabilities and is suitable for indoor dry environments.

（2）Zinc Plated: Offers options such as blue-white zinc and colored zinc. It has a high cost-performance ratio and is suitable for general rust prevention needs.

（3）Hot Dip Galvanized: The coating is thick and has excellent corrosion resistance, and is often used in outdoor environments and for steel structures.

（4）Zinc-Nickel alloy: It has excellent corrosion resistance and is a modern and environmentally friendly alternative to cadmium plating.

（5）Dacromet: Free of hydrogen embrittlement risk, with extremely strong resistance to salt fog, it is an ideal choice for high-strength bolts (grade 10.9 and above).

（6）Geomet (Jumite): An environmentally friendly upgraded version of Dacromet, featuring no hydrogen embrittlement and excellent corrosion resistance.

（7）Electrophoretic (E-coat): Forms a dense organic coating with excellent corrosion resistance and coverage capability.

（8）Teflon (Teflon/PTFE): It offers extremely low friction coefficient and excellent chemical inertness, and is often used in anti-sticking and self-lubricating applications.

（9）Cleaning Passivation (Passivation): Specifically for stainless steel, it can remove surface iron contamination and enhance its inherent corrosion resistance.

How to choose the appropriate material?

When you are faced with the choice of various materials for Ferry Cap Screws, to assist you in making the most appropriate decision, you can refer to the following decision-making methods:

（1）Environment

If you are exposed to outdoor, humid or corrosive environments for a long time, stainless steel is the preferred choice.

If there is no special risk of corrosion, carbon steel or alloy steel offer better cost-effectiveness.

（2）Load

In high-load or high-vibration environments, alloy steel (of grade 10.9 or 12.9) must be selected.

For general fixation, carbon steel of grade 8.8 is sufficient.

（3）Cost

On the premise of meeting performance and lifespan requirements, choose the most economical solution.

The Ferry Cap Screws made of stainless steel and special alloys have a higher cost, while the cost of carbon steel is the lowest.

If the above methods still fail to provide you with the assistance you need, you can leave a message for me. Specifically, you can tell me the application scenario or your requirements. I can then conduct a more precise analysis for you.

Questions and Answers

（1）Does the stainless steel Ferry Cap Screws require surface treatment?

Usually, it is not necessary. Stainless steel achieves corrosion resistance through its inherent material properties. However, in some cases, cleaning and passivation are performed to remove iron contamination on the surface, thereby further enhancing its corrosion resistance.

（2）What is hydrogen embrittlement? Why should bolts above grade 10.9 avoid electro-galvanizing?

Hydrogen embrittlement is a dangerous phenomenon that occurs when hydrogen atoms from electroplating and other processes penetrate into the interior of high-strength steel, causing it to suddenly fracture in a brittle manner under stress. Therefore, for high-strength bolts above grade 10.9, processes without the risk of hydrogen embrittlement such as Dacromet and Jumet should be given priority.