When extreme high temperature stability & strength are required
- Maintains strength at elevated temperatures
- Low distortion at high temperature
- Molybdenum must be used in vacuum or inert gas at high temperatures
- Common molybdenum grades and specifications
- Molybdenum shoulder bolt features and benefits
Molybdenum shoulder bolts possesses a very high melting point of 2620°C, a low coefficient of thermal expansion and a high level of thermal conductivity. Because molybdenum bolts have the ability to withstand extremely high temperatures without changing shape, expanding or softening significantly, they are ideal for high strength / high temperature applications that are shielded from oxygen. Exposing molybdenum fasteners to oxygen above 600°C will cause them to readily oxidize.
As a result, molybdenum shoulder bolts find their way into high temperature vacuum furnaces, glass production, military and space applications where oxygen is not present.
Resources: Molybdenum Torque Spec
Molybdenum shoulder bolts, also called stripper bolts are a unique fastener with three main parts: head, shoulder, and thread. The head has the largest diameter and is where the torque is applied, typically with a socket driver. The shoulder is smooth and unthreaded, and has a set diameter and length. The shoulder’s role is to act as a shaft or dowel for rotating parts, axles for rolling parts, guides for sliding elements, and pivot points. The final part of a molybdenum shoulder bolt is the threaded shaft. The threaded portion of a shoulder bolt has a major diameter slightly smaller than the shoulder diameter.
Molybdenum (Commercially Pure)
Because of its high melting point of 2620C and its good strength, pure molybdenum finds it niche in high temperature vacuum or inert environments without oxygen.
Molybdenum Specifications: ASTM B386, ASTM B387, Type 361
TZM - Titanium / Zirconium / Molybdenum Alloy
This alloyed version of molybdenum provides enhanced strenght at elevated temperatures and is excellent for support structures in vacuum furnaces or other high temperatuer and oxygen free environments.
TZM Specifications: UNS R03630, ASTM B384, ASTM B385, ASTM B386, ASTM B387