Q1: Will 304 stainless steel rust near the ocean?
A: 304 stainless offers 1,500+ hours of salt spray resistance, making it suitable for inland applications. For direct coastal exposure (within 1 mile of saltwater), Sinsun recommends 316 stainless steel with 5,000+ hours resistance .
SS304/316 Stainless Steel Lag Screws
316 marine grade stops rust near saltwater
No rust streaks. No galvanic corrosion. No callbacks.
5,000+ hours salt spray test proven corrosion resistance.
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Sinsun Stainless Steel Lag Screws: Engineered for Coastal & Structural Applications
Material Science: Why Stainless Steel Grade Matters
The single biggest mistake in fastener selection is assuming all stainless steel performs equally in outdoor environments. Sinsun offers two distinct stainless steel grades, each engineered for specific exposure conditions.
| Material Grade | Tensile Strength | Salt Spray Resistance | Best Applications | Key Feature |
| 304 Stainless Steel | 515 MPa | 1,500+ hours | Freshwater decks, pergolas, fencing | Cost-effective corrosion resistance |
| 316 Stainless Steel | 515 MPa | 5,000+ hours | Coastal decks, marine docks, chemical plants | Molybdenum addition for chloride resistance |
| Carbon Steel (Competitor) | 400-700 MPa | 72 hours | Indoor use only | Will rust outdoors within months |
| Galvanized (Competitor) | 550 MPa | 500 hours | Inland decks only | Coating fails near saltwater |
Case Study: Florida beach houses using Sinsun 316 stainless lag screws show 0% corrosion after 15 years of continuous salt spray exposure . Standard 304 stainless shows pitting within 3-5 years in the same environment.
| Bolt Size | Max Load Capacity | Common Applications | Sinsun Recommendation |
| 1/4" | 800 lbs | Light railing blocks, trim work, furniture | Sinsun 304 for indoor/covered |
| 5/16" | 1,500 lbs | Railing posts, joist hangers, sheds | Sinsun 304 or 316 depending on exposure |
| 3/8" | 2,200 lbs | Deck railings, stair stringers, post bases | Sinsun 316 for coastal, 304 for inland |
| 1/2" | 4,500 lbs | Ledger boards, beam connections, timber framing | Sinsun 316 Marine Grade recommended |
| 5/8" | 6,500 lbs | Heavy structural ties, commercial decks | Sinsun 316 with full thread engagement |
Length Calculation Formula
Minimum Length = (Thickness of material being fastened) × 1.5 + Thread engagement
Example: Fastening a 2×4 ledger (1.5" thick) to a rim joist requires 1.5 × 1.5 = 2.25" + thread engagement → 3" minimum length
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Thread Design: Engineered for Wood Holding Power
Standard coarse thread: 4 to 7 threads per inch
Works best on softwoods like pine, cedar, and pressure-treated wood.
Deeper gullets for better wood fiber engagement.
Less torque means faster installation.
Fine Thread (Special Order): 8 to 10 threads per inch
Recommended for hardwoods like ipe, oak, and mahogany
To better grip dense materials, there are more threads
With the Sinsun Pro Series Double-Lead Thread, the same holding power can be achieved in 30% less time
Two separate thread starts
Less torque when driving
Perfect for building a production deck
| Lag Screw Diameter | Softwood Pilot Hole | Hardwood Pilot Hole | Why It Matters |
| 1/4" | 5/32" (4.0mm) | 11/64" (4.4mm) | Undersized holes cause 40% wood splitting risk |
| 3/8" | 15/64" (6.0mm) | 1/4" (6.4mm) | Proper hole size preserves thread grip |
| 1/2" | 5/16" (8.0mm) | 21/64" (8.3mm) | Oversized holes reduce pull-out strength by 50% |
2.How to Stop Stainless Steel from Rusting
The Myth: Stainless steel won't rust.
The Truth: When stainless steel comes into contact with metals that are different from it, it can corrode.
Sinsun Suggestions
Use only Sinsun stainless steel washers; never mix them with galvanized or carbon steel.
Use Duralac or Tef-Gel to coat the threads with anti-seize compound when using it near the coast.
Don't use carbon steel drill bits that can get particles stuck in the hole.
3. Control of torque
Over-tightening can strip threads in hardwood and lower shear strength by up to 25%.
Suggested Installation Torque:
75–100 ft-lbs for a 3/8" diameter
1/2" wide: 120–150 ft-lbs
5/8" in diameter: 180 to 220 ft-lbs
Solutions for Specific Industries
Abyc E-11 Compliant Marine And Coastal Construction
Sinsun 316 Stainless Steel Lag Screws are designed to work in the most extreme saltwater conditions.
316 stainless steel with molybdenum added
Installation: 45° alternating angle pattern to make it more resistant to waves.
Protection: Apply anti-seize compound on the threads
Regular Maintenance: Inspect the screws once a year with tools that designed to detect corrosion.
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Abyc E-11 Compliant Marine And Coastal Construction
Sinsun lag screws meet or exceed the International Residential Code's standards for building decks in homes.
Ledger Attachment: at least 1/2" in diameter and 2" from the edges of the ledger.
Post Connections: 3/8" or 1/2" wide with full thread engagement.
Based on the span of the joists, IRC Table R502.2.2.1 says how far apart they should be.
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Framing in timber (NDS 2018 compliant)
Precision engineering is required for heavy timber connections.
Minimum size: 1/2" diameter for primary connections.
Washers: Required under all heads to prevent wood crushing.
Pattern: Staggered spacing to avoid grain splitting.
Get a Quick Qoute| Specification | Sinsun 304 SS | Sinsun 316 SS |
| Material Grade | Stainless Steel 304 (18/8) | Stainless Steel 316 (Marine Grade) |
| Tensile Strength | 515 MPa (min) | 515 MPa (min) |
| Salt Spray Resistance | 1,500+ hours (ASTM B117) | 5,000+ hours (ASTM B117) |
| Thread Standard | ASME B18.2.1 | ASME B18.2.1 |
| Head Style | Heavy-Duty Hex | Heavy-Duty Hex |
| Washer Requirement | Required | Required |
| Available Diameters | 1/4" to 5/8" | 1/4" to 5/8" |
| Available Lengths | 1.5" to 10" | 1.5" to 10" |
| Certification | ASTM F1575, ISO 3506 | ASTM F1575, ISO 3506 |
Ryan from Canada
"I've been building coastal decks for 20 years. Sinsun 316 stainless lag screws are the only fasteners I trust within sight of the ocean. No rust, no callbacks, no complaints."
Alexander from America——
Helen was very responsive to all my emails, questions and very professional. Reasonable pricing compared to other coin companies I have used. I got a very good artwork before a sample. Production and shipping was fast. I am very happy and can recommend this partner!
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Common Questions About Stainless Steel Lag Screws
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We are committed to providing you with the best quality service and look forward to communicating with you to solve problems together and bring you a better experience.
our experts will solve them in no time.
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2014
HM POWER (Guangdong) Co., Ltd. was founded.
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2015
HM POWER atmospheric sealed air insulated ring main unit passed all the tests at Warsaw high-voltage test station and was allowed to be applied in Europe.
The first Atmospheric Pressure Sealed Nature-Air Insulated RMU/Switchgear was supplied in Europe.
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2017
The RMU passed the type tests at Xi’an high-voltage apparatus research institute of China, got a national standard number of XGN99 and went into the stage of mass production.
The RMU passed the new product and new technology authentication organized by Guangdong Provincial Machinery Industry Association and Guangdong Power Grid.
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2018
The Atmospheric Pressure Sealed Nature-Air Insulated RMU/Switchgear’s technological solutions were listed in a national building standard design portfolio, Electrical Design and Installation of Super High-rise Buildings.
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2023
The RMU was listed in the State Grid’s “Ring Main Unit (Cabinet) Standardized Customization Program”, Primary and Secondary Integrated and Complete Set of Ring Main Units and Standard Materials Catalog of Distribution Construction and Renovation (2019).
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2025
HM POWER was entitled National SRDI (Specialized, Refined, Differential, Innovative) Little Giant Enterprise of China.