Why Measuring Hydrogen in Aluminium Melts Is Essential to avoid Porosity in Castings

Porosity is one of the most persistent challenges in aluminium casting—and hydrogen is the primary gas-related contributor to porosity in aluminium castings. Aluminium alloys have a natural tendency to absorb hydrogen in their liquid state, and if that hydrogen isn’t removed before casting, defects are inevitable.

In fact, hydrogen absorption in molten aluminium stems primarily from a simple but unavoidable chemical reaction:

2Al + 3H₂O → Al₂O₃ + 3H₂

Where does all this water come from? The answer: almost everywhere. Moisture is present in the atmosphere, in the combustion products of gas‑ or oil‑fired furnaces, in hygroscopic fluxes, in contaminants within the melt, and even as hydrated corrosion on feedstock. As these moisture sources interact with molten aluminium, hydrogen is formed and readily absorbed. Once absorbed, hydrogen becomes trapped during solidification—resulting in porosity, reduced mechanical properties, and ultimately, rejected castings.

Accurate Hydrogen Measurement: A Critical Step in Casting Quality

To prevent porosity in aluminium casting, degassing treatments must remove the majority of dissolved hydrogen from the melt. But how can a foundry know whether those degassing operations have been effective?

The answer is simple: measure the hydrogen before casting.

Accurate, rapid hydrogen measurement is vital for confirming melt quality, optimising degassing processes, and maintaining consistent casting standards.

Introducing the Hyscan II Hydrogen in Aluminium Analyser

On foundry shop floors around the world, this essential measurement is delivered by the Hyscan II Hydrogen in Aluminium Analyser, developed and manufactured in the UK by MechaTech Systems Ltd.

Hyscan II provides accurate, rapid, hydrogen measurement within 5 minutes of sampling

The Hyscan II uses a quantitative reduced pressure test to monitor hydrogen levels during aluminium alloy processing, providing operators with a precise hydrogen value within just five minutes of sampling.

Why Foundries Trust the Hyscan II

• Built for the Foundry Environment: Rugged, mobile, and easy to operate.

• Fast, Quantitative Results: Enables informed decisions before casting begins.

• Supports Process Improvement: Ideal for evaluating melt treatments and identifying process-related issues.

• Cost Savings: Lower scrap rates, reduced energy consumption, and improved labour efficiency often enables full capital cost recovery within the first year.
  

The Hyscan II has established itself as a global leader in hydrogen measurement technology, relied upon by production foundries across the world to ensure consistent casting quality.

Want to Learn More?

Contact Us for more information and a quotation:

enquiries@mechatechsystems.co.uk  / +44 (0)1454 414723

or read more about Hyscan II online.