Hexagonal Head Jack Screw

QS Fastener: Hexagonal Head Jack Screw

Name: Hexagonal Head Jack Screw
Standard: ANSI B18.2.1
Material: ASTM A320 B8M CL.2, 316SS
Size: 1-1/2 Inch
Length: 95mm
Thread: Unified National Coarse 8UN 2A

Quantity

Contact Now

add to cart

Hexagonal Head Jack Screw — High-Strength Corrosion-Resistant Fastening Solution for Demanding Environments
Manufactured from 316 stainless steel (ASTM A320 B8M CL.2), the Hexagonal Head Jack Screw fully complies with ANSI B18.2.1 standards, offering exceptional corrosion resistance and high strength. With a standard size of 1-1/2 inches, its hexagonal head design is compatible with conventional tools, making it ideal for rigorous applications such as mold positioning, machinery leveling, and heavy equipment installation.

316 stainless steel (UNS S31600, European standard 1.4401) is the preferred material for Hexagonal Head Jack Screw due to its outstanding corrosion resistance, widely used in marine engineering, chemical processing, food equipment, and medical devices in corrosive environments. Its performance advantages stem from optimized alloy composition and stable passive film protection mechanisms.

1. Alloy Composition and Corrosion Resistance Mechanism of Hexagonal Head Jack Screw
(1) Impact of Key Alloying Elements on Performance
The corrosion resistance of 316 stainless steel relies on the following alloy components (typical values):
- Chromium (Cr: 16–18%):
- Forms a dense Cr₂O₃ passive film, ensuring Hexagonal Head Jack Screw stability in oxidizing environments (e.g., atmosphere, nitric acid) with corrosion rates <0.1 mm/year.

- Nickel (Ni: 10–14%):
- Enhances austenite stability, improving Hexagonal Head Jack Screw resistance to stress corrosion cracking (SCC).

- Molybdenum (Mo: 2–3%):
- Significantly boosts pitting resistance, raising the critical pitting temperature (CPT) in Cl⁻ environments (e.g., seawater) by 15–20°C compared to 304-grade material.

(2) Corrosion Performance Comparison: Hexagonal Head Jack Screw vs. 304 Fasteners

Corrosion Type	316 Performance	304 Performance	Test Standard
Pitting (Cl⁻ environment)	CPT: 25–30°C (3.5% NaCl)	CPT: 10–15°C (3.5% NaCl)	ASTM G48 Method A
Stress Corrosion Cracking	SCC-resistant (≤80°C, Cl⁻<1000 ppm)	Prone to cracking (≥60°C, Cl⁻>100 ppm)	ASTM G36 (boiling MgCl₂)

2. Performance Validation in Typical Environments
(1) Marine Applications
- Salt Spray Test: Hexagonal Head Jack Screw shows no red rust after 1000 hours per ASTM B117 (304 typically fails at 500 hours).

- Case Study:
- Offshore oil platform Hexagonal Head Jack Screw (Cl⁻ ~19,000 ppm) exhibits no pitting after 10 years, outperforming zinc-plated carbon steel (3-year lifespan).

(2) Chemical Environment Adaptability
- Sulfuric Acid Resistance: At 10% concentration and 20°C, corrosion rate <0.1 mm/year (304: 0.5 mm/year).
- H₂S Environments: Complies with NACE MR0175 for sulfur-rich oil/gas fields.

3. Surface Treatment Enhancements for Hexagonal Head Jack Screw
For extreme conditions, additional treatments further improve performance:

Treatment	Advantage	Application
Electropolishing (EP)	Reduces surface Cl⁻ adsorption sites	Semiconductor, high-purity chemical equipment
PTFE Coating	Resists pH 0–14 acids/alkalis	Chemical piping, reactor fastening

4. Engineering Selection Guidelines
(1) Prioritize Hexagonal Head Jack Screw for:
- Cl⁻ concentration >200 ppm (e.g., seawater cooling systems).
- FDA-compliant medical/food equipment.

(2) Material Upgrade for Extreme Conditions:
- Cl⁻ >10,000 ppm + temperature >80°C → Switch to duplex steel 2205.
- Hot concentrated sulfuric acid (>40%, 60°C) → Hastelloy C276.

5. Technological Trends
Emerging advancements for Hexagonal Head Jack Screw include:
- Nano-passivation coatings: Extend salt spray test lifespan to 3000+ hours.
- Smart preload design: Integrated sensors for real-time fastening monitoring.

Send Message