Wire Drawing Die Materials Compared

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Five materials are used for wire drawing dies, and no single one is best for every wire. This page sets them side by side — what each one is, which wire it suits, how it wears and what it costs — and then gives our recommendation for the common cases. If you would rather just tell us the wire and let us choose, go straight to the technical quote page.

Die materials at a glance

	Tungsten carbide (TC)	Nano-coated	PCD	SSCD	Natural diamond (ND)
What it is	Tungsten carbide grains in a cobalt binder	Carbide die with a nano-crystalline diamond layer grown onto the bore by CVD	Diamond grains sintered into a solid blank; self-supported or in a carbide ring	Synthetic single-crystal diamond, free of inclusions	Natural single-crystal diamond
Typical wire	Steel wire, large sizes, short runs, trials	Steel and non-ferrous wire, medium to large sizes	Copper and aluminium conductors; non-ferrous alloys; steel in small sizes	Fine and ultra-fine wire: copper, stainless, precious metals, bonding and medical wire	Fine and ultra-fine non-ferrous and precious-metal wire
Size range	Confirmed per enquiry	From under 1 mm up to large sizes	From fine sizes up to about 30 mm	Fine sizes, confirmed per enquiry	Fine sizes, confirmed per enquiry
Wear life	The baseline	Typically 10× or more TC	Tens of times TC	Long, in fine sizes	Long, in fine sizes
Surface finish on the wire	Good	Very good — low-friction diamond surface	Very good	Excellent	Excellent
Toughness / shock resistance	Highest	High — carbide body	Good; higher in a carbide ring	Lower — single crystal	Lower — single crystal
Friction	Highest of the five	Low	Low	Lowest	Lowest
Can it be recut to a larger size?	Yes	No — replaced when worn	Yes, usually more than once	Yes	Yes
Relative price per die	Low	High	Medium to high	Highest	Highest
Exposure to tungsten prices	High	Low	Low (carbide ring) to very low (self-supported)	Very low	Very low

All five are supplied in a steel casing sized to your die holder. Bore geometry is made to your specification and confirmed per order.

Tungsten carbide (TC)

Tungsten carbide grains in a cobalt binder. The toughest of the five and the cheapest to buy, with the shortest life. It stays the sensible choice for short runs, trials, very large sizes and plants that recut their own dies — and its price moves with the tungsten market. What separates a good carbide die from a cheap one is the powder and the machining: how the tungsten powder is washed and graded sets the microstructure, and the machining accuracy sets how the insert sits in its casing and takes the load. Tungsten carbide dies

Nano-coated

A carbide die with a nano-crystalline diamond layer grown onto the bore. The carbide carries the load; the diamond does the wearing, so the bore stays close to size 10 times or more as long as plain carbide, with low friction and a smoother wire. Available in large sizes. The one limitation: the coating cannot be recut, so a worn die is replaced. Our first choice for most lines. Nano-coated dies

PCD

Diamond grains sintered into a solid blank, self-supported or bonded in a tungsten carbide ring. The standard die for copper and aluminium conductors, and used for steel wire in small sizes. Tens of times the life of carbide, and the diamond goes right through the working depth, so a worn PCD die is re-polished to the next size and used again. The economical choice below about 2 mm. PCD dies

SSCD

Synthetic single-crystal diamond, grown under controlled conditions and free of the inclusions and cracks found in natural stones, so die-to-die performance and recut behaviour are more predictable. Used for fine and ultra-fine wire — copper, stainless, precious metals, bonding and medical wire — where surface finish and roundness matter most. Supplied on request; sizes confirmed per enquiry.

Natural diamond (ND)

The original drawing-die material for fine wire, and still used for fine and ultra-fine non-ferrous and precious-metal wire where the finest finish is wanted. Each stone is individual, so performance varies more than with SSCD. Supplied on request; sizes confirmed per enquiry.

Shaped profiles

Square, hexagonal, rectangular, flat and other non-round wire is drawn through shaped dies. We supply them in nano-coated, PCD and tungsten carbide, to your drawing. Shaped dies

How to choose

Our recommendation, by the wire you draw. It follows the same rule throughout: start with nano-coated, and go to PCD below about 2 mm or if you recut your dies.

Your wire	Start with	Also consider
Low-carbon steel — nail wire, mesh wire, welding wire	Nano-coated	PCD below about 2 mm; TC for short runs
High-carbon, spring and rope wire	Nano-coated	PCD (self-supported) for tyre cord and fine sizes; TC for trials
Stainless steel	Nano-coated	SSCD for fine sizes
Copper and aluminium conductors	PCD below about 2 mm; nano-coated above	—
Stranded and bunched conductors (compacting dies)	Nano-coated	—
Ultra-fine non-ferrous, bonding and precious-metal wire	SSCD or natural diamond	—
Square, hexagonal, flat and other profiles	Shaped dies in nano-coated, PCD or TC	—
Short runs, trials, very large sizes	Tungsten carbide	Nano-coated once the size is proven

Two more questions decide the rest:

Do you recut worn dies? If yes, PCD, carbide, SSCD or ND — anything but nano-coated, whose coating cannot be recut.
Dry or wet drawing? All five work with both. For dry drawing the lubricant matters as much as the die — see wire drawing powder.

Not sure? Tell us the wire, the sizes and the speed on the technical quote page and we will recommend one.

Why bore geometry matters as much as material

The material sets how slowly a die wears; the bore geometry sets how hard it has to work. Two parts of the bore do most of it:

The approach angle. Each pass has a best range, and it moves with the reduction in that pass and the friction between wire and die — it is not one fixed number. As a rule, the harder the wire, the smaller the angle. Too steep, and the deformation is abrupt and the die runs hot; too shallow, and the wire rubs over a long contact length, the lubricant film suffers and the wire can neck or break.
The bearing length. Too long adds friction and heat; too short, and the size will not hold, so the die goes out of tolerance early.

On steel wire the same two settings show up in the wire itself — tensile strength, torsion and bend results — not just in die life. That is why we ask for the wire grade and the reduction per pass, not only the sizes.

FAQ

Which die material is best for high-carbon steel wire?

Nano-coated for most sizes: the carbide body takes the load and the diamond surface takes the wear, and the gain over plain carbide is largest on hard wire at speed. For tyre cord and other fine high-carbon sizes, self-supported PCD. Tungsten carbide for trials and short runs.

Is SSCD better than natural diamond?

For most fine-wire work, yes. SSCD is free of the inclusions and cracks found in natural stones, so one die behaves like the next and recuts are more predictable. Natural diamond is still used where its finish is wanted and the stone is suitable.

Nano-coated or PCD — which one?

PCD below about 2 mm, or if you recut worn dies. Otherwise nano-coated: it comes in large sizes and gives long life on steel and non-ferrous wire alike. Compare them on die cost per tonne of wire, not on the price of one die.

When is tungsten carbide still the right choice?

Short runs, trials, very large sizes, and anywhere purchase price matters more than die life. A good carbide die is also the baseline that the others are measured against.

What approach angle should a wire drawing die have?

It depends on the wire and the reduction in that pass. Harder wire takes a smaller angle, and the best angle moves with the reduction and the friction. Tell us the wire grade and your pass schedule, and we will set the approach angle and bearing length for each die, or make them to your specification.

Can you supply all five materials?

Yes. Tungsten carbide, nano-coated and PCD are the volume items; SSCD and natural diamond are supplied on request for fine-wire work. All come in a steel casing to fit your machine.