A4-70 SS Pan Head Screws with Lock Washers 316 Stainless Spring + Flat Washer Salt Water Resistant Custom

Premium A4 stainless Phillips pan head screws with pre-assembled spring & flat washers. Passivated finish for marine, chemical & food processing. Vibration proof & corrosion resistant. M4-M12 sizes. Custom options.

Secure critical assemblies in corrosive environments with our **A4 Stainless Steel Phillips Pan Head Machine Screws with Pre-Assembled Spring and Flat Washers**. Crafted entirely from A4-70 (316) stainless steel, this complete set offers **superior resistance** to salt water, chemicals, acids, and humidity, combined with **vibration-resistant locking**. The pre-assembled flat washer distributes load, while the spring washer prevents loosening. Ideal for **marine hardware, chemical processing equipment, food machinery, coastal infrastructure, and outdoor applications** demanding maximum durability and reliability. Passivated finish standard.

Primary Uses & Applications:

* Marine deck hardware, hatches, and fittings.
* Offshore platforms & equipment.
* Chemical plant piping, valves, and instrumentation.
* Food & beverage processing machinery.
* Pharmaceutical equipment.
* Coastal structures (railings, signs, enclosures).
* Outdoor power generation equipment.
* High-humidity HVAC & ventilation.
* Any application requiring corrosion resistance *and* vibration proofing.

Surface Treatment/Finishes:
* **Passivation (Standard):** Mandatory chemical process removing free iron and enhancing the chromium oxide layer for maximum corrosion resistance. Applied to entire assembly.
* **Electropolishing (Optional):** Provides a smoother, brighter, more hygienic surface, further boosting corrosion resistance and cleanability. Ideal for food, pharma, and high-purity applications.

How to Use:

1. **Prevent Galling:** **Crucial!** Apply **stainless steel anti-seize compound** to the screw threads before installation, especially for stainless-on-stainless contact.
2. **Prepare:** Ensure female threads (nut/tapped hole) are clean, compatible (preferably A2/A4 SS), and deburred.
3. **Insert Assembly:** Place through clearance hole. Flat washer contacts bearing surface; spring washer between flat washer and head.
4. **Drive:** Use the **correct Phillips driver**. Apply **steady, moderate pressure and speed** (no high RPMs) to minimize heat/galling risk.
5. **Tighten:** Tighten until the spring washer is **slightly compressed** (provides locking force). **Avoid over-tightening.** Refer to A4 stainless torque specs.
6. **Function:** **Flat Washer** protects surfaces & distributes load. **Spring Washer** maintains tension against vibration/thermal cycling. **A4 Material** resists corrosion.
7. **Removal:** Anti-seize should aid removal. If galling occurs, do not force.