| Product name |
Carriage Bolt |
| Size |
M3-100 |
| Length |
10-3000mm or as required |
| Grade |
4.8/8.8/10.9/12.9 |
| Material |
Steel/35k/45/40Cr/35Crmo |
| Surface treatment |
Plain/Black/Zinc/HDG |
| Standard |
DIN/ISO |
| Certificate |
ISO 9001 |
| Sample |
Free Samples |
Definition and Basic Structure
Definition: Galvanized screw is a transmission component that is coated with a zinc layer (electroplated zinc or hot-dip zinc) on the surface of the screw. It is mainly used to convert rotational motion into linear motion and has anti-corrosion ability.
Base material: Usually carbon steel (such as 45 # steel, 40Cr) or stainless steel, with a zinc layer covering the surface after galvanizing.
Thread type: Commonly trapezoidal thread (Tr type) or ball screw, the latter is mostly used in high-precision scenarios.
Galvanizing process: Divided into electroplated zinc (thin and uniform coating) and hot-dip zinc (thick coating, strong corrosion resistance).
Characteristics of Galvanizing Process
The corrosion prevention mechanism works through two main ways:
Sacrificial anode protection: The zinc layer preferentially oxidizes, delaying the corrosion of the substrate steel.
Physical barrier: A dense zinc layer isolates water vapor, oxygen, and substrate from contact.
| Process Type |
Coating Thickness |
Corrosion Resistance |
Applicable Scenarios |
| Galvanized (Electro) |
5-20 μm |
General |
Indoor equipment, low corrosion environments |
| Hot Dip Galvanizing |
50-150 μm |
Excellent |
Outdoor, chemical, and marine environments |
Core Advantages
Corrosion resistance: Suitable for humid, salt spray, acidic and alkaline environments (such as ships and chemical equipment).
Economy: The cost of galvanizing is lower than that of stainless steel lead screws, and the lifespan is significantly extended.
Low maintenance: The self-healing properties of the zinc layer reduce the need for frequent maintenance.
Adaptability: Can be matched with various transmission systems, such as stepper motors and servo motors.
Application Scenarios
Outdoor machinery: Construction machinery, agricultural equipment (exposed to rainwater and soil environments).
Ship and ocean engineering: Deck lifting mechanism, valve control (resistant to salt spray corrosion).
Chemical equipment: Reaction kettle transmission system, pipeline regulating device (acid and alkali resistant medium).
Construction industry: Automatic doors and windows, lifting platforms (low-cost rust prevention requirements).
Food processing: Meets hygiene standards (requires smooth surface and no risk of rust).
Frequently Asked Questions
What is the difference between electro-galvanized and hot-dip galvanized?
Electro-galvanizing provides a thinner, smoother finish ideal for indoor use, while hot-dip galvanizing offers a much thicker coating for superior corrosion resistance in harsh outdoor or marine environments.
Can I request a specific size or length for the carriage bolts?
Yes, we provide sizes ranging from M3 to M100 and lengths from 10mm to 3000mm, or they can be customized according to your specific requirements.
Are the samples really free?
Yes, we offer free samples so you can verify the quality and specifications of our products before placing a bulk order.
What materials are available for these galvanized screws?
Our products are typically made from high-quality carbon steel (45#, 40Cr, 35k) or alloy steel (35Crmo) to ensure strength and durability.
What quality standards do your products follow?
All our products are manufactured according to DIN and ISO international standards and are backed by ISO 9001 certification.
How does the zinc layer protect the screw?
The zinc layer acts as a physical barrier against oxygen and moisture and also provides sacrificial protection, where the zinc corrodes instead of the underlying steel.
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