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Astro 91 Hardfacing Alloy

Rugged Overlay Alloy with Tungsten Carbide Particles

Astro 91 is the super alloy for drilling through cement, rock and all refractory materials.  Maximum wear and abrasion resistance.

From: $1,094.80 (includes shipping across Australia)



Astro 91 consists of select, sintered tungsten carbide particles, held in a tough, ductile nickel-silver matrix.  This matrix, with good tinning qualities, high tensile and shear strengths, provides shock absorbing characteristics.  The tungsten carbide particles, held in the matrix, give multiple cutting edges, with hardness approaching that of a diamond.  In use, the matrix gradually wears away and, as it does so, exposes the cutting edges of the tungsten carbide particles.  This same sort of action continues until full and complete usage of the tungsten carbide particles has been realised.  Astro 91 is manufactured in furnaces, under precisely controlled conditions, assuring a uniformly fabricated hardfacing rod.



Astro 91 is widely used in the oil tool industry, primarily as an effective cutting agent on rotary shoes, mills and reamers, drag bits, tipping of pointers and augers used in cleaning operations.  Also, Astro 91 has been broadly used in economically devising masonry drilling tools and core drills from steel pipe, bolts, shafts etc.

The unique properties of Astro 91 will allow you to make your own tools at a fraction of the cost of diamonds or carbide tools.



  • Cuts through all refractory materials
  • Utmost abrasion resistance and cutting action
  • Low temperature application preserves carbides
  • Easy to use – apply to the end of a pipe to make a core drill!



Clean the surface to be over-layed.

‘Tin’ the cleaned surface by applying Astro 210FC, using a neutral flame.

Astro 210FC has an affinity for Astro 91, providing an excellent base.

Continuing to use a neutral flame, heat the tinned surface to the point of remelt.

At this time, melt off Astro 91, holding the rod end inside the flame cone to prevent oxidation of the tungsten carbide particles.

Continue to add Astro 91 as required.

Depending on job requirements, use flux.

Flux residue can be removed after the job has cooled.

Additional information




2.5Kg, 5Kg, 10Kg, 15Kg


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