ASTM B777 Class 1 Tungsten Heavy Alloy

ASTM B777 Class 1 Tungsten Heavy Alloy

Elmet Technologies ASTM B777 Class 1 Tungsten Heavy Alloy specification overview. This guide will help you understand the properties, benefits, materials, and the common sizes of WHA Class 1 Elmet manufactures. Here at Elmet Technologies, we want our clients to understand every aspect of ASTM B777 Class 1 WHA to the fullest.

Overview

What is ASTM B777 Class 1 tungsten heavy alloy? Is all tungsten metal the same? These are questions we often hear from customers researching tungsten metals for industrial applications. Pure Tungsten is also known as Wolfram. It is an element that was first discovered in 1781. It is represented on the periodic table with symbol W and atomic number 74. Pure tungsten (W) is not the same thing as what is commonly referred to as tungsten alloys, tungsten heavy alloys or WHA. According to ASTM B777 there are four (4) classes of tungsten heavy alloy, namely class 1, class 2, class 3, and class 4.  In this section, we’ll discuss ASTM B777, Class 1. 

ASTM B777 Class 1 Properties

Class 1 WHA material contains nominally, 90 weight percent (wt.%) Tungsten (W). Elmet’s Class 1 products are designated as ET90 and ET90NM. Among the four designated classes of ASTM B777 WHA, Class 1 contains the least amount of W. However, it offers the highest ductility and ease of machining.

Class 1 material starts out as a blended metal powder (Pure W mixed with a binder of Ni and Iron). It is then pressed, sintered and in some cases machined into high quality tungsten heavy alloy (WHA) blocks, rods, and shaped parts. Although Class 1 has the lowest density, compared to Class 2, 3, & 4, it is still over twice the density of steels and most nickel-based super alloys. 

Elmet: Class 1 WHA Capabilities

Elmet can also further “work” Class 1 material through our unique processes such as high temperature rod swaging or hot plate rolling which enables us to make longer pieces and further increase yield strength. Class 1 tungsten alloy possesses the highest resistance to fracture for applications that involve service stress. Class 1 elongation can be further improved (additional fraction resistance) by specialized post-sintering heat treatment. 

All of Elmet Class 1 ET90 material is made in the USA at our fully integrated facility in Lewiston, Maine. 

Benefits of WHA Material

Class 1 WHA (ET90) is the most commonly specified tungsten alloy. Typically, it is used for aerospace balance weights, medical shielding and other applications that require high density material.  The advantages and benefits to utilizing WHA material include: 

• Environmental and density advantages over lead for radiation shielding
• Unique capabilities for vibration dampening and balance weight applications
• Ideal for applications requiring very high density
• Excellent ability to absorb gamma rays and x-rays
• Comparatively, it has improved machinability than pure tungsten
• Excellent mechanical properties

ASTM B777 Class 1: Specifications & Technical Data

The below table highlights the specifications of the Class 1 tungsten alloys (for both low mag and non mag), including mechanical properties. 

Sizes of WHA Class 1 Material

Elmet has a large and growing inventory of standard mold sizes which can help with shorter lead-times. All sizes can be sold “rough as sintered” or machined to provide tighter tolerances.  As mentioned above, sintered WHA blanks can also be further rolled or swaged by Elmet to produce plates, sheets, and rods.

Elmet also precision machines WHA parts for use as ballast weights, radiation shields, boring bars, ordnance components, and other components that require high density and good ductility.

To discuss your ASTM B777 Class 1 Tungsten Heavy Alloy (WHA) needs, or to learn more about the Elmet difference, please contact us at [email protected]