Editorial Technical Reference

Extension Spring

This page explains how Extension Spring is classified within Fabricated Metal Product Manufacturing. Technical values and manufacturer relationships are research references; confirm the current specification and supplier evidence for each order.

Technical Definition & Core Assembly

An extension spring is a helical coil spring designed to absorb and store energy by resisting axial tension, with hooks or loops at each end for attachment.

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Product Specifications

Technical details and manufacturing context for Extension Spring

Definition

Extension springs are widely used in applications requiring a pulling force, such as in automotive mechanisms, industrial machinery, agricultural equipment, and consumer products like garage doors and trampolines. They are specified by dimensions (wire diameter, coil diameter, free length), spring rate, initial tension, and end types (e.g., full loop, extended hook). Grades are distinguished by material quality (e.g., music wire vs. stainless steel), precision of tolerances, and surface treatment, which affect durability and performance in different environments.

Working Principle

An extension spring operates on Hooke's law, where the force required to extend the spring is proportional to the extension distance, within its elastic limit. The spring stores mechanical energy when stretched and returns to its original length when the load is removed. The initial tension, built into the spring during coiling, ensures that the coils remain closed at rest and provides a pre-load force before extension begins.

Common Materials

Music wire (ASTM A228), Oil-tempered wire (ASTM A229), Stainless steel 302/304 (ASTM A313), Chrome silicon (ASTM A401), Galvanized carbon steel

Technical Parameters

Parameter	Typical range	Notes & selection driver
Wire Diameter	0.1–12 mm	Range for typical extension springs; smaller for precision, larger for heavy-duty.ISO 10243
Free Length	5–500 mm	Length without load; depends on application.DIN 2098
Spring Rate	0.1–100 N/mm	Force per unit extension; varies widely.EN 13906-2
Initial Tension	0–20 N	Force to start extension; depends on coil index and material.EN 13906-2
Maximum Extension	50–80% of free length %	Safe extension range to avoid permanent set.
Operating Temperature	-40 to 250 °C	Depends on material; stainless steel higher, music wire lower.
Surface Finish	Plain, oiled, zinc plated, powder coated	Corrosion protection options.ASTM B633
End Type	Full loop, extended hook, cross-over loop	Configuration for attachment.
Tensile Strength	1500–2500 MPa	For music wire; varies with wire diameter.ASTM A228
Tolerance Class	Grade 1, 2, 3	Precision of dimensions and load.DIN 2098
Fatigue Life	10^5–10^6 cycles cycles	Under normal operating conditions.
Coil Direction	Right or left hand	Specified for assembly.

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Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Extension Spring.

Published Manufacturer Relationships

Source-reviewed profile relationships currently associated with Extension Spring

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