Buying tungsten heavy alloy without verifying what you’re actually getting is a costly mistake. Suppliers don’t always deliver what they promise, and substandard material has a way of showing up exactly when it matters most, mid-project, with no easy fix.
Measure Density with a Water Displacement Kit
This is one of the most practical checks available, and it costs very little to do. Water displacement lets you calculate actual density by comparing the weight of your sample in air against its weight submerged. The math is straightforward once you’ve done it once.
Most tungsten heavy alloy grades sit between 17.0 and 18.5 g/cm³. A reading that falls short of the published spec for that grade is a clear sign something is off. When sourcing tungsten heavy alloy for sale from a new supplier, running this test on the first delivery takes about ten minutes and removes a lot of uncertainty from the equation.
Check for Magnetic Properties to Spot Low-Grade Substitutes
Pure tungsten is not magnetic. Tungsten heavy alloy, however, contains nickel-iron or nickel-copper binders, which can produce a weak magnetic response depending on the binder composition. What you’re actually testing for here are substitutes, cheaper metals sometimes mixed in to bulk up weight without matching the density or performance of genuine alloy.
A basic rare-earth magnet is enough to run this check. Strong magnetic attraction in a sample that’s supposed to be a nickel-copper alloy is worth questioning. Strong attraction in a grade that should use a nickel-iron binder is less alarming but still worth comparing against spec sheets.
X-Ray Fluorescence Detects Binder Composition Accurately
Handheld XRF scanners measure elemental composition without damaging the sample. That matters because the binder, whether it’s nickel-iron or nickel-copper, affects corrosion resistance, machinability, and performance under load.
Some suppliers mislabel alloy grades or substitute one binder type for another because the price difference is meaningful. An XRF reading gives you actual percentages, not a supplier’s word. Rental options for these scanners exist if purchasing one isn’t practical for your operation.
Weigh a Small Sample against Published Density Charts
Every recognized tungsten heavy alloy grade has a published density range. W-Ni-Fe alloys typically fall around 17.0 to 18.5 g/cm³, while W-Ni-Cu alloys run slightly lower depending on tungsten content.
Weigh a precisely measured sample and compare the result to the chart for the grade you ordered. A deviation of more than 0.3 g/cm³ from the stated spec is worth raising with the supplier before accepting the shipment. Small deviations sometimes reflect measurement error; larger ones usually don’t.
Surface Oxidation Often Signals Improper Processing
Tungsten heavy alloy should have a consistent, smooth surface after sintering. Visible oxidation, a dull, discolored, or mottled surface, suggests the material was either sintered at the wrong temperature or exposed to oxygen during cooling.
This matters because improper sintering affects internal density, not just surface appearance. A sample can look mostly fine and still have internal voids or inconsistent grain structure that weakens the final part. Surface condition won’t catch every processing flaw, but it’s an easy visual screen that takes seconds to run.
