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Core Expanding Rivet

Updated: 2026-07-15

Overview

Core expanding rivets, known as 击芯胀丝 in Chinese, are specialized mechanical fasteners designed for applications where only one side of the material is accessible. These rivets feature a unique design that allows them to expand radially when installed, creating a secure, permanent joint. Primarily used in construction, automotive, and manufacturing industries, core expanding rivets are particularly effective for fastening hollow materials like tubes or panels. Their ability to create strong joints without requiring access to both sides makes them invaluable for many assembly applications.

Structure and Working Principle

锤击壁虎 敲击膨胀栓镀彩锌击芯胀丝 富奥源头工厂河北富奥紧固件制造有限公司

A core expanding rivet consists of two main components: a hollow outer sleeve and an internal mandrel. The sleeve has a flared end and is typically slotted to facilitate expansion. The mandrel features a head that remains outside the material and a break-off stem. During installation, the rivet is inserted into a pre-drilled hole. As the mandrel is pulled (usually with a special tool), it causes the sleeve to expand radially, creating a tight fit against the material walls. The mandrel stem breaks off at a predetermined point, leaving a clean finished appearance.

Key Features

Core expanding rivets offer several advantages over conventional fasteners. Their expansion capability provides excellent vibration resistance, making them ideal for applications subject to movement or stress. They distribute load evenly around the hole circumference, reducing material fatigue. The blind-side installation feature allows for assembly in confined spaces where traditional fasteners can't be used. These rivets also create a seal around the hole, offering some protection against moisture and contaminants. Different materials (steel, aluminum, stainless steel) allow for use in various environments and applications.

Application Areas

Core expanding rivets are widely used in industries requiring strong, reliable fastening solutions. In construction, they're employed for joining metal framing, HVAC systems, and curtain walls. The automotive industry uses them for assembling body panels and interior components. Manufacturing applications include assembly of furniture, electronics enclosures, and machinery. Their ability to join dissimilar materials makes them particularly useful in composite material applications. They're also common in aerospace and transportation equipment manufacturing.

Maintenance and Precautions

镀彩锤击壁虎 一钉得膨胀螺栓击芯胀丝 富奥源头厂家批发河北富奥紧固件制造有限公司

While core expanding rivets are generally maintenance-free once installed, proper installation is crucial for optimal performance. The correct hole size must be drilled - typically 0.1-0.2mm larger than the rivet diameter. Using undersized holes can prevent proper expansion, while oversized holes reduce holding strength. Installation tools should be properly maintained and calibrated to ensure consistent mandrel breakage. For critical applications, periodic inspection of riveted joints is recommended to check for any loosening or corrosion, especially in harsh environments.

B2B Procurement Guide

When procuring core expanding rivets in bulk, consider material compatibility with your application. Aluminum rivets are lightweight and corrosion-resistant but have lower strength than steel options. Stainless steel offers the best corrosion resistance for harsh environments. Specify the required diameter range (commonly 3mm to 12mm) and grip range (material thickness the rivet can accommodate). Lead times for custom orders can vary from 2-6 weeks, so plan accordingly. For reference, bulk pricing typically decreases by 15-30% for orders over 10,000 units.

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