China Professional manufacturer of PTFE Xylan Coated HEX BOLT SS316 A4-70 ISO4017
An A4 hex bolt also known as SS316 Hex bolt, refers to a hexagonal-headed bolt made from A4-grade stainless steel, which is highly resistant to corrosion, especially in marine and chemical environments
Material:
A4 stainless steel is equivalent to 316 stainless steel, containing molybdenum for enhanced corrosion resistance.
A4 Hex bolts as per ISO 3506, with strength grades as below
- A4-70: Standard tensile strength of 700 MPa.
- A4-80: Higher tensile strength of 800 MPa.
A4 SS316 Hex Bolt composition:
| Element | Percentage | Purpose |
|---|---|---|
| Chromium (Cr) | 16.0–18.0% | Provides corrosion resistance by forming a passive oxide layer. |
| Nickel (Ni) | 10.0–14.0% | Improves toughness, ductility, and resistance to acids and bases. |
| Molybdenum (Mo) | 2.0–3.0% | Enhances resistance to pitting and crevice corrosion, especially in chloride-rich environments. |
| Carbon (C) | ≤ 0.08% | Low content improves resistance to carbide precipitation during welding. |
| Manganese (Mn) | ≤ 2.0% | Contributes to strength and hardness. |
| Silicon (Si) | ≤ 1.0% | Improves oxidation resistance. |
| Phosphorus (P) | ≤ 0.045% | Impurities kept low to avoid affecting corrosion resistance. |
| Sulfur (S) | ≤ 0.015% | Kept minimal to maintain toughness and prevent brittleness. |
| Iron (Fe) | Balance | The primary component of stainless steel. |
A4 SS316 Hex bolt Dimensional Standards
- ISO 4014: Hex head bolts with metric coarse pitch thread.
- ISO 4017: Hex head screws with metric coarse pitch thread (similar to ISO 4014 but fully threaded).
- DIN 933: Fully threaded hex bolts (now superseded by ISO 4017 but still widely used).
- DIN 931: Partially threaded hex bolts (now superseded by ISO 4014).
A4 SS316 Hex bolt Thread Details
- ISO 261 / ISO 965-1: Metric thread profiles and tolerances.
- ASME B1.13M: Unified metric screw threads (for international compatibility)
Marking requirement
- ISO 3506-1: Requires marking of the bolt head with the steel grade (e.g., “A4-70” or “A4-80”).
PTFE (Polytetrafluoroethylene), commonly known as Teflon®,Xylan,is a specialized coating process used to enhance the performance of materials and components.We can provide the PTFE Xylan Coated HEX BOLT SS316 A4-70 ISO4017
Xylan coating is a type of fluoropolymer-based industrial coating often used for bolts, fasteners, and other components to improve performance in harsh environments
| Hex Bolt | |
| Standard: | ASME/ANSI B 18.2.1,IFI149,DIN931,DIN933,DIN558, DIN601,DIN960, DIN961, ISO4014,ISO4017 |
| Diameter: | 1/4″-2 1/2″,M4-M64 |
| Length: | ≤800mm or 30″ |