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    Founded in the 1990s, it is a large hardware and fastener manufacturer integrating R&D, production and sales. It is equipped with advanced production equipment and automated assembly lines with strong annual output capacity, holds a full range of honors and a sound quality inspection system, specializing in various self-drilling screws, bolts and customized special-shaped fasteners.

Zinc Plated Hex Self-Drilling Screws with Composite Washers

Zinc Plated Hex Self-Drilling Screws with Composite Washers
Brand: Hengzuan
Product Name: Hex Head Self-Drilling Screws with Bonded Composite Washers
Surface Finish: Blue-white electro-galvanized; color zinc coating available upon request
Specifications: Main wire diameters 4.2/4.8/5.5/6.3mm in stock; full range of shank lengths from 20mm to 165mm. Custom non-standard shank lengths and drill point sizes are supported, suitable for drilling steel plates of 2–6mm thickness.
Packaging: Separately packed in 25kg export cartons; full shipments loaded on wooden pallets wrapped with stretch film. Neutral export packaging and customer private labeling customization are available.

Product Details

I. Application Fields & Product Positioning

This product is a dedicated fastener for outdoor roofing projects, widely applied to color steel tile workshops, photovoltaic roofs, boundary fences, steel structure canopies, exterior curtain walls and other exposed construction projects. Large volumes are exported year-round to building material markets across the Middle East, Southeast Asia, Africa and other overseas regions.

It fundamentally solves the water seepage issue at roof screw holes and serves as the flagship waterproof self-drilling fastener. Ideal for assembly and fixation of single-layer color steel sheets, rock wool sandwich panels and multi-layer thermal insulation boards. Pre-drilling is not required during construction, which drastically cuts labor hours.

II. Raw Materials & Production Processes

Premium carbon steel is adopted as raw material and subject to overall quenching heat treatment. The drill tip meets standard hardness with sharp cutting performance, resisting tip chipping and tail breakage.

The complete production workflow consists of eleven procedures: raw material rough drawing, annealing, phosphating, fine drawing, cold heading, drill tip forming, thread rolling, thermal refining treatment, galvanizing, washer assembly and packaging.

Uniform and regular thread profiles create tight engagement with steel plates to prevent thread stripping during screwing. The EPDM rubber gasket and steel washer are pre-compounded by machinery and pre-installed on the flange surface before delivery. The gasket will not fall off or shift after compression during installation, delivering stable sealing performance.

III. Core Product Advantages

Integrated All-in-One Self-Drilling Function

The dedicated drill tip structure completes three operations (drilling, tapping and fastening) in one single pass. Compatible with various galvanized steel sheets and color steel profiles of 2–6mm thickness. Short-length variants fit single-layer thin panels, while extended versions are designed for sandwich insulation boards.

Long-Lasting Waterproof Sealing Performance

EPDM rubber withstands extreme high and low temperatures, aging and long-term UV exposure without cracking or shrinkage. After tightening, it fully seals gaps around screw holes to eliminate rainwater infiltration risks at the source.

IV. Quality Control & Supporting Services

All specifications are permanently stocked. Standard orders can be dispatched within 48 hours. We accept small-batch trial orders and large full-container export orders.

Every batch undergoes pre-delivery sampling inspection covering drill tip hardness, thread precision and washer bonding strength to eliminate defective products.

We provide one-stop bundled supply with matching waterproof plugs and sealing accessories manufactured in our factory. Custom self-drilling screws with special thread profiles and non-standard extended shanks can be produced against customer drawings. Stable production capacity guarantees long-term repeat orders for overseas clients.


OUR STRENGTHS

Production Capacity

The company covers an area of 40,000 square meters with over 300 employees, achieving an annual output of more than 20,000 tons each for self-drilling screws and hot-dip galvanized bolts, capable of standard supply and customized special-shaped fastener production.

Production Equipment

It is equipped with over 200 sets of advanced Taiwan-origin self-drilling screw production equipment and 6 numerical control production lines, featuring advanced hardware configuration and high automated production level.

Quality Control

Following the ISO9001:2015 quality management system, the company has built a complete quality inspection laboratory and implements strict full-process quality control and testing from raw materials to finished products.

Certifications

The enterprise has obtained a number of industry honors and national 3A-level quality and integrity brand certification, holding industry status as the Vice Chairman Unit of Hebei Fastener Association and Executive Director Unit of relevant national chambers of commerce.

Production Capacity Production Equipment Quality Control Certifications

OUR STRENGTHS

Production Capacity

Production Capacity

The company covers an area of 40,000 square meters with over 300 employees, achieving an annual output of more than 20,000 tons each for self-drilling screws and hot-dip galvanized bolts, capable of standard supply and customized special-shaped fastener production.

Production Equipment

Production Equipment

It is equipped with over 200 sets of advanced Taiwan-origin self-drilling screw production equipment and 6 numerical control production lines, featuring advanced hardware configuration and high automated production level.

Quality Control

Quality Control

Following the ISO9001:2015 quality management system, the company has built a complete quality inspection laboratory and implements strict full-process quality control and testing from raw materials to finished products.

Certifications

Certifications

The enterprise has obtained a number of industry honors and national 3A-level quality and integrity brand certification, holding industry status as the Vice Chairman Unit of Hebei Fastener Association and Executive Director Unit of relevant national chambers of commerce.

 

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