Thread inserts (also known as screw thread inserts, wire thread inserts, thread bushes, thread sleeves, or stainless steel thread inserts) are helical coils precision-formed from high-precision rhombic stainless steel wire. They are a new type of internal thread fastener featuring concentric high-precision internal and external threads.
They can be screwed into threaded holes in metallic or non-metallic materials to form national standard-compliant internal threads with high strength, wear resistance, superior connection rigidity, vibration resistance, impact resistance, high-temperature resistance, corrosion resistance and interchangeability. They can also be used to repair worn or damaged internal threaded holes.
As a type of thread insert fastener, the internal threads formed after installation offer distinct advantages over standard threads. These advantages are mainly reflected in the following nine aspects:
1.Extended Service Life
Made of stainless steel with high hardness, thread inserts can increase the service life of threads in softer base materials by tens to hundreds of times. They also enhance thread strength and prevent thread stripping and cross-threading.
2.Enhanced Thread Connection Strength
When applied to soft, low-strength alloys such as aluminum and magnesium, thread inserts effectively boost thread connection strength. For example, the maximum tensile strength of standard internal threads in aluminum profiles is only 1394N, while that of internal threads fitted with thread inserts can reach a minimum of 2100N.
3.Increased Stress-Bearing Area
They are suitable for thin-walled components that require robust connections but cannot accommodate an enlarged tapped hole diameter.
4.Improved Connection Conditions & Boosted Load Capacity and Fatigue Resistance
As elastic fasteners, thread inserts can eliminate pitch and thread profile deviations between screws and tapped holes, enabling uniform load distribution. This, in turn, enhances the load-bearing capacity and fatigue resistance of the threaded connection.
5.Prevention of Thread Seizure
Thanks to the inherent material properties and ultra-smooth surface of thread inserts, they will not cause seizure with the mating base material even in harsh environments such as humidity and corrosion. This avoids the loss of replacing expensive base components due to seized, unremovable threaded holes. They are ideal for high-safety applications including chemical engineering, aerospace, and military equipment.
6.Wear, Heat & Corrosion Resistance
The ultra-high surface finish of thread inserts effectively reduces friction between internal and external threads. Additionally, the material itself boasts excellent high-temperature and corrosion resistance. They are suitable for frequently disassembled/assembled components and rotating tapped holes to extend their service life.
7.Vibration Resistance & Anti-Loosening Performance
The special structure of locking-type thread inserts can lock screws firmly in tapped holes even under intense vibration and impact, delivering superior anti-loosening performance compared to other locking devices. They are widely used in high-reliability applications such as instruments and meters, precision and valuable power equipment, as well as aerospace and military hardware.
8.Facilitated Maintenance
Thread inserts can salvage base components with incorrectly processed or damaged internal threads, allowing the original screws to be reused in a fast and cost-effective manner. For instance, components like diesel engine blocks, textile parts, aluminum components, and lathe tool holders that would otherwise be scrapped due to a single damaged tapped hole can be restored to service by re-tapping the hole and installing a thread insert.
9.Thread Conversion Capability
Thread inserts enable convenient, efficient, cost-effective, and practical conversion between metric, imperial, and international standard threaded holes, making them suitable for all import and export products.
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