316 - Stainless steel - Cross recess pan head screw

Why Upgrade to Grade 316?

While Grade 304 is excellent for general use, it has limitations in harsh environments. Grade 316 was specifically developed to overcome these limitations. The addition of molybdenum creates a more stable passive layer that resists breakdown from chloride ions—the primary cause of "pitting" corrosion in coastal and chemical environments. For pan head screws used on boats, in swimming pools, or in chemical plants, 316 is not just an upgrade—it is a necessity.

Material Specifications: A4-70

Our 316 pan head screws are manufactured to the A4-70 strength class with the following characteristics:

Molybdenum Content (2-3%)

This is the defining element that separates 316 from 304. Molybdenum significantly improves resistance to chloride-induced pitting and crevice corrosion, making 316 essential for marine and chemical applications.

Enhanced Nickel Content (10-14%)

Grade 316 contains more nickel than 304, which further stabilizes the austenitic structure and improves overall toughness and corrosion resistance.

Mechanical Strength (Class 70)

A4-70 indicates a minimum tensile strength of 700 N/mm² and yield strength of 450 N/mm². This provides reliable structural performance equivalent to standard 304 screws.

Non-Magnetic Properties

Grade 316 exhibits lower magnetic permeability than 304, making it preferred for sensitive electronic and medical instrumentation.

Quality Assurance

Material verification is critical for marine-grade products. An EN 10204 3.1 Material Certificate confirming the molybdenum content is available upon request. Please note that third-party inspection services require an additional fee.

Critical Applications

Grade 316 pan head screws are the standard specification for:

• Marine Electronics: Instrument panels and navigation equipment on boats and offshore platforms.
• Swimming Pools & Spas: Equipment housings exposed to chlorinated water.
• Chemical Processing: Control panels and enclosures in plants handling corrosive substances.
• Pharmaceutical Manufacturing: Clean-room equipment requiring frequent sterilization with aggressive chemicals.

Frequently Asked Questions

Is 316 necessary for swimming pool applications?

Yes, highly recommended. Swimming pools contain chlorine, which is a chloride compound. Standard 304 stainless steel will eventually develop pitting corrosion when exposed to chlorinated water over time. Grade 316, with its molybdenum content, is specifically designed to resist chloride attack and is the industry standard for pool equipment, ladders, and fittings.

Is the price premium of 316 over 304 worth it?

It depends entirely on your environment. For indoor or dry outdoor applications, 304 is perfectly adequate and more economical. However, if your screws will be exposed to salt air (within 5km of the coast), chlorinated water, or industrial chemicals, the cost of replacing corroded 304 screws—plus potential damage to the equipment—will far exceed the initial premium for 316. In harsh environments, 316 is an investment, not an expense.

Can 316 screws be used in pharmaceutical clean rooms?

Yes, Grade 316 is widely used in pharmaceutical and biotechnology facilities. It withstands repeated exposure to aggressive cleaning and sterilization agents (including bleach and hydrogen peroxide) that would damage lesser materials. Its smooth surface is also easy to clean and does not harbor bacteria, making it ideal for hygienic environments.