Terminology
Abbreviations, symbols, and glossary
Glossary of frequently used terminology, abbrevations and symbols used in the wire drawing industry.

Abbreviations

CCA Copper clad aluminum
CCS Copper clad steel
MCD Monocrystalline diamond (=SSCD)
ND Natural diamond
MD Monodie (=SSCD)
PCD Polycrystalline diamond
SCD Single crystal diamond (can be ND or SSCD)
SMCD Synthetic monocrystalline diamond (=SSCD)
SSCD Synthetic single crystal diamond
TC Tungsten carbide
WC Tungsten Carbide (=TC)

Symbols

A% wire area reduction percentage
c constant, derived from wire density
E% wire elongation percentage
L wire length
m wire mass
Ø diameter
Øin incoming wire diameter
Øout drawn wire diameter (= drawing die diameter)
V wire volume
α reduction cone angle (full angle)
Δ delta factor
ρ wire density
R electrical resistance
ρ electrical resistivity

Glossary

A

accuracy. (1) The agreement or correspondence between an experimentally determined value and an accepted reference value, or, in some cases, the average value obtained by applying the test method to all the sampling units in a lot or batch. (2) How close a calculation or reading of an instrument approaches the value of the calculated or measured quantity. Compare with precision.

angle. See preferred term reduction angle.

annealing.

B

back relief. The back relief enables the wire to exit freely from the bearing, avoiding contact with any sharp edge that could scratch the wire.

bearing. The bearing area determines the wire surface quality and the wire diameter. The length of the bearing (L) is usually about 20% to 50% of the nominal wire diameter (Ø). However, this percentage varies depending on the wire material, drawing process, and on the specifications of the wire to be drawn.

bearing length. See bearing.

bell cone. See prefferd term entrance cone.

blank. An ultra-hard material encased inside a stainless steel casing. The blank, with an interior geometry matched to the wire material being drawn, is the part of a wire drawing die that touches the wire. For that reason the blank material typically is diamond (natural, synthetic, or polycrystalline) or tungsten carbide. See PCD, SSCD, ND, TC.

brittle fracture. Separation of a wire accompanied by little or no macroscopic plastic deformation. Typically, brittle fracture can be prevented by annealing the wire before drawing.

C

carbide die. See preferred term TC die.

capstan. nnn

casing. The stainless steel outside (casing) of a drawing die holds an ultra-hard insert (also called blank or nib). The size of the die casing depends on the die holder size in the machine.

contact point. See wire contact point.

course wire. This wire diameter classification differs between ferrous and non-ferrous wires. Ferrous: 16 – 4.2mm (.630 - .16535”). Non-ferrous: 12/8 - 3.5/1.5mm (.472/.315 - .1378/.05906”). Compare to medium wire, fine wire, finest wire and super-fine wire.

cup-and-cone fracture (cup fracture). A mixed-mode fracture, of a ductile material, where the central portion undergoes plane-strain fracture and the surrounding region undergoes plane-stress fracture. One of the mating fracture surfaces looks like a miniature cup and the other fracture surface looks like a miniature  cone. Cup-and-cone fractures can be minimized by using wire drawing dies with optimal reduction angles, resulting in homogeneous deformation

D

DC die. DC dies are tungsten carbide dies with an inner diamond coating. The inner diamond coating consists of nano-sized diamond particles. These types of dies are usually used as a cost-effective alternative to PCD and TC dies in bunching and stranding applications where the wire forces are much lower than in wire drawing applications. In bunching and stranding applications DC dies typically maintain their diameter better than PCD and TC dies. The failure mode of DC dies is sudden when its coating wears off. Learn more about diamond coated stranding dies here>

deformation. A change in the form of a wire or rod. Measured in units of length. This applies to both round and shaped products.

delta factor. The delta factor is a value that is calculated from the wire area reduction and the reduction cone angle. According to the industry a delta factor should be between 1.5 and 3. A delta factor larger than 3 can increase the likelyhood of cup-cone fractures. See also homogeneous deformation.

die angle. See preferred term reduction angle.

die draft. See prefferred tem size sequence.

die set. Multiple ‘sets’ of size sequences used inside multi-wire drawing machines. All of the size sequences have the same wire drawing die sizes. Learn more about Esteves drawing die strings and sets here>

die wizard. See drawing die wizard.

drawing die. See wire drawing die.

draw ring. The wire begins its reduction and elongation in the reduction angle of the die. At that point the wire is in contact with the surface of the diamond and a wear ring is created over time. This drawing ring gets deeper and wider as more wire is drawn through the die. The appearance of the drawing ring may change due to the material drawn and the length of time that the die is used.

drawing die wizard. Free Windows application to configure and visualize a drawing die in 2D and 3D. Learn more about Drawing Die Wizard here>

E

eddie. See eddie wire solutions.

eddie wire solutions. Free software application to calculate wire sizes, size sequences, and production volume. Learn more about Eddie Wire Solutions here>

elastic deformation. A change in wire diameter and length that is directly proportional to and in phase with an increase or decrease in applied force.

elongation. A term used to describe the amount of extension of a piece of wire when drawn. See also elongation percentage.

elongation set. See preferred term size sequence.

elongation control. Reffered to as dies that have been individually matched to ensure the elongation from one die to the next is within the speficied limits of a multi-wire drawing machine. This is typically done, when required, up to a size of 0.5mm (“). Learn more about Esteves matched sets here>

elongation percentage. (1) The extension of a wire when drawn through a wire die. (2) The extension of a uniform section of a specimen expressed as percentage of the original gage length: where Lo is original gage length, and Lx is final gage length.

engineering strain. The average linear strain or conventional strain. In tensile testing it is calculated by dividing the change in the wire length by the original wire length.

engineering stress. The conventional stress. In tensile testing, it is calculated by dividing the breaking load applied to the wire by the original cross-sectional area of the wire.

entrance cone. The entrance cone (bell) should be sufficiently open to allow wire drawing lubricant to enter the die and flush out any particles that have been generated. The entrance cone is typically well blended to the top of the reduction angle so that there is no sharp edge at the transition. The standard entrance cone angle for a drawing die is 60 degrees.

eWizard. Free paper or pdf handbook from Esteves Group. Basically an off-line version of this website. Download eWizard here (sign-in required)>

exit cone. The exit cone (back) is designed to strengthen the exit of the die. The exit cone keeps the metal forming area centered in the blank, improving heat transport away from the metal forming zone.

F

fine-wire. This wire diameter classification differs between ferrous and non-ferrous wires. Ferrous: 1.6 – 0.7mm (.0630 - .02756”). Non-ferrous: 2.1 - 0.15mm (.082677 - .0059055”). Compare to course wire, medium wire, finest wire and super-fine wire.

finest wire. This wire diameter classification differs between ferrous and non-ferrous wires. Ferrous: < 0.7mm (<.02756”). Non-ferrous: 1.0 - 0.05mm (.03937 - .0019685”). Compare to course wire, medium wire, fine wire and super-fine wire.

G

grain size. See PCD grain size.

H

homogenous deformation. Term that is referred to when the residual stresses are minimal when drawn with wire dies. Minimizing such stresses is mainly achieved by using optimal drawing die angles that are matched to the wire material alloy. Cup-cone breakage related issues are minimized when a wire is drawn homogeneously. Learn more about Esteves advanced engineering services here>

I

insert. See preferred term blank.

L

landing zone. See wire contact point.

M

matched set. Are several sequences of dies that are designed and manufactured to match the mechanical draft of a multi-wire machine. This ensures maximized die life and increased throughput and uptime. Learn more about Esteves matched sets here>

medium wire. This wire diameter classification differs between ferrous and non-ferrous wires. Ferrous: 4.2 – 1.6mm (.16535 - .0630”). Non-ferrous: 3.5 - 0.4mm (.1378 - .01575”). Compare to course wire, fine wire, finest wire and super-fine wire.

N

nano-die. See preferred term DC dies.

natural diamond die. See preffered term ND die.

ND die. ND dies are wire drawing dies with a natural diamond blank inside. Natural diamonds, abbreviated as ND, are naturally formed within the earth at high-pressure and high-temperature conditions. Because of its extremely rigid lattice, it can be contaminated by a few types of impurities such as boron and nitrogen. ND dies are typically avialabe up to a hole size of 2mm (.0787”). Compare with SSCD die, PCD die, and TC dieLearn more about natural diamond drawing dies here>

nib. See preferred term blank.

non-thermally stable PCD. Polycrystalline diamond (PCD) with a metallic binder. The binder is a required part of the PCD manufacturing process to bind the diamond powder while sintering with high pressure and high temperature. The thermal expansion difference between the diamond grains and the metallic binder limits the use of these blanks to a maximum operating temperature of  ~1202°F (650°C). Find non-thermally PCD blank specifications here>

O

orange peel. Surface roughening of a wire in the form of a pebble-grained pattern where a wire of unusually coarse grain is stressed beyond its elastic limit. Also known as alligator skin.

P

PCD die. PCD dies are wire drawing dies with a polycrystalline diamond blank inside. Polycrystalline blanks consist of diamond grains sinteried at very high pressures , and temperatures. Three types of PCD dies exist: non-thermally stable, thermally-stable, and supported blanks. A range of grain sizes is available for each of these blanks. It is typically the wire die manufacturer that recommends the grainsize making it match the wire drawing process. PCD dies are typically avialabe up to a hole size of 35mm (1.378”). Compare with SSCD die, ND die, and TC die. Learn more about polycrystalline diamond dies here>

PCD grain size. Maximum size of the diamond particles within a PCD blank. These particle sizes typically are 1, 3, 5, 10, 12, or 25 micron. Learn more about PCD blank specifications here>

plastic deformation. The permanent (inelastic) amount of elongation or reduction of  a wire when it is drawn beyond its elastic limit.

plastic strain. Wire size or elongation change that does not disappear after the wire is drawn. Usually accompanied by some elastic deformation.

polycrystalline diamond die. See preffered term PCD die.

precision. The closeness of agreement between the results of measurements. Standard deviation is used to describe the measurement error or amount  of “imprecision”.

pressure die. Pressure dies are dies that have a pressurizing insert located in front of a drawing die. This additional insert pressurizes the lubricant between the wire and drawing die with the aim of reducing frictional forces and enabling faster wire drawing. Pressure dies are typically used in dry drawing (soap) applications where the wire surface finish is of a lower importance.

R

recutting. Recutting or sometimes called refurbishing or reboring of the die, removes all the defects generated by the passing of the wire through the die’s geometry. This operation gives the die a bigger diameter. The amount of the required increase in diameter depends on the wear and general condition of the die. Recutting is a complete reprocessing of the die, rebuilding a proper geometry. Learn more about Esteves refurbishing services here>

reduction percentage. (1) The difference between the original cross-sectional area of the incoming wire to the exiting wire when drawn through a wire die . Also known as reduction of area. (2) The difference between the original cross-sectional area of a tensile specimen and the smallest area at or after fracture as specified for the material undergoing testing. Also known as reduction of area.

reduction angle. The reduction cone is the area where the incoming wire is reduced. If requested, Esteves Group can optimize the reduction angle (2α) for different wire materials to ensure that the deformation takes place in a smooth, homogeneous, and controlled way. Typically, the harder the material being drawn, the narrower the reduction angle of the die. The softer the material being drawn, the wider the angle of the die. Also, the greater the reduction or elongation of the wire being drawn, the wider the angle required. As the elongation of the wire being drawn is reduced, the required reduction angle will be narrower.

repolishing. Repolishing of a die consists of removing the defects caused by wire being drawn through the reduction angle. Repolishing is possible when the drawing ring is not too deep and the bearing area is not damaged. In other words, repolishing is possible on dies with slight wear. Learn more about Esteves refurbishing services here>

resizing. Resizing a wire drawing die consists of enlarging the hole size. depending on the required increase in diameter this can be done through either repolishing or recutting. Learn more about Esteves refurbishing services here>

rod breakdown machine. Terminolgy used to refer to a machine that is used to draw rod down to wire sizes. Several types of these machines exist amongst others are…..

roller die. Roller dies are typically used to reduce large-size rods. They can be an alternative to drawing dies, although wire drawing dies offers much better dimensional control of the wire diameter as the wear of a drawing die only changes its cross-sectional area. Wire rolling forces can cause the gap between the rolls to change resulting in the rod or wire to change its shape. Wire forming using drawing dies allows for diameters all the way down to 7 μm (.00027”) and a requires lower capital equipment cost than using roller dies.

S

shape back. See preferred term exit cone.

size sequence. A size sequence is a set of wire drawing dies that are matched to a wire drawing machine (and wire material alloy) and take the incoming wire in several steps down to the required final diameter of a wire drawing machine. Learn more about Esteves drawing die strings and sets here>

SSCD die. SSCD dies are wire drawing dies with a synthetic single crystal diamond blank inside. Also called synthetic mono crystal diamond, and also abbreviated as SMCD or MCD. SSCD blanks are man-made diamonds manufactured under controlled conditions and are free from inclusions and cracks. These tightly controlled quality aspects lead to predictable and constant die performance. SSCD dies are typically avialabe up to a hole size of 2.15mm (.0840”). Compare with ND die, PCD die, and TC dieLearn more about synthetic single crystal diamond dies here>

strain. The unit of change in wire size due to force. Also known as nominal strain.

strain aging. The changes in yield point, tensile strength, ductility, and hardness that occur when a cold worked wire is stored for some time.

strain hardening. See work hardening.

stress. The forces that resist a change in the volume of a material that is or has been subjected to external forces. Stress is expressed in force per unit area and is calculated on the basis of the original dimensions of the cross section of the wire. Stress can be either direct (tension) or shear.

stress-strain curve. A graph in which values of stress and strain are plotted. Stress is usually plotted vertically and strain horizontally. 

super-fine wire. Non-ferrous wire of a size between  0.4 - 0.01mm (.015748 - .0003937”). Compare to course wire, medium wire, fine wire, and finest wire.

supported PCD. These are non-thermally stable polycrystalline blanks with a tungsten carbide support ring. This ring is usually used as an extra support when drawing larger wire (rod) sizes. Find supported PCD blank specifications here>

T

tapered set. A tapered set is a die string that is designed and manufactured to make a bull block machine run optimally by homogenizing the temperatures in each soap box. Learn more about Esteves tapered sets here>

tensile strength. In tensile testing, the ratio of maximum load to original cross-sectional area. Also known as ultimate strength.

tensile test. Test to determine the behavior of a wire subjected to uniaxial loading, which tends to stretch the metal. A piece of wire of known length and diameter is gripped at both ends and stretched at a slow, controlled rate until rupture occurs. Also known as tension testing.

TC die. TC dies are wire drawing dies with a tungsten carbide blank inside. Tungsten carbide, abbreviated as WC or TC, also called cemented carbide, hardmetal or widia, is a metal matrix composite. Tungsten carbide particles are the aggregate, and metallic cobalt serves as the matrix. It is a non-oxidizing ceramic that can withstand high temperatures while maintaining hardness comparable to corundum or sapphire. TC dies are typically avialabe from 0.127mm (.005”) and larger. Compare with PCD die, SSCD die, and ND dieLearn more about carbide dies here>

thermally stable PCD. Polycrystalline diamond (PCD) where its metallic binder has been leached out. The binder is a required part of the PCD manufacturing process to bind the diamond powder while sintering with high pressure and high temperature. Removing the binder increases the PCD blanks maximum operating temperature to 562°F (850°C). Compare with non-thermally stable and supported PCD. Find thermally-table PCD blank specifications here>

tungsten carbide die. See preferred term TC die.

U

ultimate tensile strength (UTS). The maximum tensile stress a wire can sustain without fracture, determined by dividing the maximum load by the original cross-sectional area of the wire. Also known as nominal strength or maximum strength.

ultra-hard insert. See preferred term blank.

W

wire back. See preferred term back relief.

wire contact point. The point where the wire contacts the reduction angle is very important for a successful drawing process. For most wire types the contact should take place between 1/3 to 2/3 of the reduction angle height to ensure good metal deformation. The contact point is influenced by the reduction angle, the total thickness of the diamond insert, and the diameter of the incoming wire. Taking into account these parameters, a customized die can be designed in our Drawing Die Wizard software to help you improve your drawing process. If the angle is too wide for the elongation of the wire, causing the contact point of the wire to be too close to the bearing, the die can wear out very quickly. A wear-ring first forms at the point of wire contact in the reduction angle. As the die is used, wear will slowly extend from the wear-ring to the bearing. Once the wear reaches the bearing, wire surface quality will deteriorate and the die as well as the wire will become oversized.

wire drawing die. Wire drawing dies are precision tools used to produce round or shaped wire to very tight tolerances. The deformation and elongation of wire material takes place within the profile of the wire drawing die as the wire is drawn through it. The stainless steel outside (casing) of a drawing die holds an ultra-hard insert (also called blank or nib). The inner profile of a die has five parts. The transitions between the different parts of the profile are blended to ensure a smooth connection of the different areas, reducing the generation of metallic particles during the wire drawing process. Compare wire drawing die blank types here>

work hardening. An increase in hardness and strength when drawing wire caused by plastic deformation at temperatures below the recrystallization range. Also known as strain hardening.

Y

yield point. The first stress in a material, usually less than the ultimate stress, at which a wire will deform plastically..

yield strength. The stress at which a wire exhibits a specified deviation from proportionality of stress and strain. An offset of 0.2% is used for many metals.

yield stress. The stress level of highly ductile materials, such as structural steels, at which large strains take place without further increase in stress.

Young’s modulus. Synonymous to modulus of elasticity. It is the ratio of tensile or compressive stresses to the resulting strain.

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