Hexagonal carbon steel galvanized through nut precision chemical screws and accessories

Application Scenarios and Characteristics of Hexagon Carbon Steel Galvanized Screws in Chemical Equipment

(With Higher Precision Achieved by Machining)

1. Core Application Scenarios in Chemical Equipment

1.1 General Equipment Casings and Frames

• Application: Equipment casings, supports, panels, access doors in dry, non‑corrosive environments
• Service conditions: Normal temperature and pressure, neutral/weakly alkaline atmosphere, no acid or alkali spray
• Advantages: High strength, low cost, easy installation, meeting structural fastening and anti‑rust requirements

1.2 Pipeline and Valve Accessories

• Application: Flanges, valves, filters, instrument connections for pipelines conveying water, steam, neutral gas/oil
• Service conditions: C2–C3 corrosive environment (low–medium pollution, low salt spray)
• Restriction: Prohibited in strong acid, strong alkali, high chloride ion (Cl⁻), hydrogen sulfide (H₂S) media

1.3 Rotating Equipment (Pumps, Fans, Stirrers, etc.)

• Application: Bases, bearing housings, coupling guards, cooling systems and other non‑sealed, non‑pressure parts
• Service conditions: Vibration environment, circulating water/cooling air, slight condensation
• Advantages: High strength (mainly Grade 8.8), anti‑vibration, easy maintenance

1.4 Instruments and Control Systems

• Application: Fixing and installation of transmitters, flow meters, control cabinets, junction boxes
• Service conditions: Clean, low humidity, no direct contact with process media
• Key point: High machining precision ensures instrument positioning and long‑term stability

1.5 Auxiliary Systems and Non‑Critical Components

• Application: Ladders, platforms, guardrails, ventilation ducts, cable trays, etc.
• Service conditions: Outdoor/semi‑outdoor, industrial atmosphere, small amount of dust and moisture
• Recommendation: Prioritize hot‑dip galvanizing (thick coating, long corrosion resistance)

2. Core Characteristics of Material and Process

2.1 Material and Strength (Carbon Steel)

• Common grades: Grade 4.8 (low carbon steel, unquenched), Grade 8.8 (medium carbon steel, quenched and tempered)
• Performance: Grade 8.8 tensile strength ≥ 800 MPa, balancing strength and toughness for medium‑low load in chemical equipment
• Limitation: Bare carbon steel is not corrosion‑resistant and requires surface treatment

2.2 Galvanizing for Corrosion Protection (Core Advantage)

• Principle: Zinc acts as sacrificial anode, corroding preferentially to protect the steel substrate
• Process comparison:

• Environmental taboos: Not resistant to strong acid, strong alkali, high Cl⁻, H₂S, high temperature and high humidity organic acids

2.3 Precision Advantages of Machining (vs. Cold Heading)

• Dimensional accuracy: Smaller tolerances for hexagon width across flats, thickness, shank diameter, thread pitch diameter (up to Grade 6g/6h)
• Thread quality: Complete profile, no burrs, smooth fitting, better sealing surface fit
• Consistency: Stable precision per piece/batch, suitable for precision assembly and repeated disassembly
• Customization: Capable of machining non‑standard lengths, special threads, stepped shanks, chamfers and other complex structures

3. Selection and Application Guidelines

1. Environment matching
    
   • Dry & clean (C1): Electro‑galvanized Grade 4.8/8.8
   • Industrial atmosphere/humid (C2–C3): Hot‑dip galvanized Grade 8.8
   • Strong corrosion / high Cl⁻: Forbidden, use 316 stainless steel, Hastelloy, etc.
    
2. Strength and load
    
   • Static load / non‑critical: Grade 4.8
   • Dynamic load / vibration / critical structure: Grade 8.8 or higher
    
3. Sealing and assembly
    
   • Sealing surfaces: High machining precision + gaskets/sealant to prevent media leakage
   • Preload: Tighten strictly according to torque values to avoid loosening and galling
    
4. Maintenance and service life
    
   • Regularly inspect coating integrity; repair or replace if damaged
   • Service life of hot‑dip galvanizing in C3 environment: approx. 15–20 years
    

We have introduced advanced equipment and technology from Japan and Germany (CNC 5-axis and 6-axis machines) to better serve our customers' needs.

Our maximum processing outer diameter is 60, and the minimum control tolerance is 0.001. We have Japanese CNC Tsugami, CNC Citizen, multi-station cold extrusion forming machines, 500T press machines, casting equipment, and various process equipment, which can effectively provide customers with the best technical solutions.

Our company has a total of 300 employees, including 20 technicians, 10 engineers, and 15 quality control personnel. We have over 300 pieces of equipment.

Our company implements 8S management and has passed ISO9001 and TS16949 automotive certifications.

Our customers include Siemens, bo-sch, Foxconn, Panasonic Motors, Husqvarna, Shimano, NVIDIA, DJI Drones, Siegenia, and Cater-pillar.