Aluminium Alloys – Titanium Boron Aluminium Alloy for Efficient Grain Refinement of Hypoeutectic Aluminium

Topics Covered

Background

Titanium Boron Aluminium

Titanium Boron Aluminium in Foundries

Titanium Boron Aluminum Chemistry

Benefits of Using Titanium Boron Aluminium Alloy

Addition Rate

Background

Using grain refiners in aluminium castings helps improve die filling and mass feeding, to counteract solidification shrinkage. This results in an improved distribution of porosity, and so better mechanical properties and increased leak tightness. These effects can lead to a net reduction in scrap rates, and improved consistency and reliability of castings, delivering improved profitability in the foundry.

Titanium Boron Aluminium Alloy

Titanium Boron Aluminium Alloy is optimally adapted to hypoeutectic Al-Si foundry alloys. The extremely small mixed borides (Al, Ti)B₂ in TiB Alloy have proven to have a high grain-refining efficiency in Al-Si alloys.

Titanium Boron Aluminium Alloy in Foundries

Foundries across the world, especially aluminium alloy wheel producers, are finding Titanium boron aluminium alloys offers a unique range of benefits not found with any other foundry grain refiner.

The relatively low density mixed borides are ideal to counteract settling effects in furnaces, crucibles or ladles.

Foundry ingot producers have seen lower complaints when using Titanium boron alloy. End users, particularly wheel casters, have achieved reduced scrap levels on machining and after X-ray inspection.

Titanium Boron Aluminum Chemistry

(nominal composition by weight)

Titanium . . . . . . . . . 1.5 - 1.7%

Boron . . . . . . . . . . . 1.3 - 1.5%

Silicon . . . . . . . maximum 0.3%

Iron . . . . . . . . . maximum 0.3%

Vanadium . . . . . maximum 0.2%

Benefits of Using Titanium Boron Aluminium Alloy

The advantages of using titanium boron aluminium alloy are:

•        Fast acting: two minutes residence time.

•        Ideal for long holding times and ingot remelting.

•        Highly efficient grain refining.

•        Improved mould filling.

•        Improved distribution of porosity gives less scrap after machining.

•        Fewer shrinkage defects.

•        Reduced reject levels on x-ray inspection.

Addition Rate

Typical addition rate for TiBAlloy of 1-2 kg/MT (for Al-Si alloys containing approximately 0.1%Ti) can be adjusted to achieve the precise foundry grain refining properties desired for your application. TiBAlloy addition rates are similar to conventional grain refiners such as 5/1 TiBAl.

The product’s lower-density mixed borides (Al, Ti)B2 provide benefits for long holding times and also for ingot remelts.

Original material sourced from Metallurg Aluminium