Exera® 20AP free-cutting medical wire Wire

Datasheet updated

2022-05-10 07:47
(supersedes all previous editions)

Exera® 20AP is a hardenable, free-cutting carbon steel medical wire characterized by excellent machinability. The grade has high hardness, high wear resistance and exceptional dimensional stability after hardening.

Applications

Exera® 20AP is used for dental applications such as dental burrs and drills.

Chemical composition (nominal) %

C Si Mn P S Pb
1.0 0.2 0.4 ≤0.030 0.05 0.2

Forms of supply

Forms of supply/ finishes Diameter
Cu-Sn coating Standard tolerance Length
mm m
Wire in coils
Drawn 0.80-1.60 D4 -
1.60-2.50 D4 -
Straightened wire
Drawn 0.80-1.15 D4 2
1.15-2.00 D4 2
2.00-2.50 D3 2
Drawn/ground 2.00-3.00 h7 2
3.00-6.00 h7 3
6.00-12.00 h7 3

Other sizes on request.
Ovality: For D1 and D2, max. 50% of the tolerance width, for D3 max. 25% of the tolerance width.

Mechanical properties

Forms of supply/Finishes Diameter Tensile strength Proof strength Elongation
mm Rm1) Rp0.21) 2) A 1)3)
MPa MPa %
Wire in coils 0.80-1.60 770
Drawn 1.60-2.50 720 770 4
Straightened wire 0.80-1.15 >980 720 7
Drawn 1.15-2.00 >920 >910 3
Drawn/ground 2.00-2.50 >900 >850 5
2.00-3.00 >920 >830 7
3.00-6.00 810 >850 6
6.00-12.00 750 670 10
620
12

1) Nominal values. Other properties on request.
2) Rp0.2 and elongation values are given for information only.

Impact strength

Quenching time and temperature is dependent on material size, the specimens for impact strength are larger than standard wire.

Table of impact strength for Exera® 20AP, hardened and quenched condition (soaking temperature 800°C and soaking time 10 min, tempering time is 30 min)

Tempering temperature, °C Impact strength, J
200 1.3
300 2.0
400 7.3
500 10.0
600 17.0

Figure 1. Impact strength after recommended hardening procedures, valid for all dimensions.
Soaking time 30 minutes. Standard Charpy-V specimens at 20oC.

Physical properties

Density annealed 7.8 g/cm3, 0.28 lb/in3

Resistivity

Cold drawn, 0.18 µΩm
Heat treated, 0.21 µΩm

Thermal expansion 1)

Temperature, °C 20-100 20-200 20-300
Cold drawn 11.5 11.5 12.5
Heat treated 11.5 12.0 12.5

1) Mean values in temperature ranges (x10-6)

Exera® 20AP is a magnetic material.

Heat treatment

Soft-annealing

When required, soft-annealing should be conducted for a period of one hour at a temperature of 650 - 680oC.

Hardening

DiameterTemperatureSoaking timeQuenching
mmoCapprox. min.
≤5 800 - 820 3 - 6 in oil at 50oC
> 5 790 - 810 6 - 10 in water

The smaller the diameter, the shorter the soaking time. To avoid oxidation and decarburization, hardening should be conducted in a protective gas atmosphere using nitrogen, argon or a vacuum.

Contact Sandvik for further advice.

Prolonged service at elevated temperatures causes decreased hardness when used in the hardened and tempered condition. See also "Impact strength".

Tempering

Temperature, oC 100 - 600
Tempering time, min 30 - 60

The core of the material needs a tempering time of at least 30 minutes. To reduce the risk of cracking, tempering should be conducted immediately after hardening. The heating rate should not be too high, particularly in the case of intricately shaped components.

Hardness

Figure 2. Hardness after recommended hardening procedures, valid for all dimensions.
Soaking time 30 minutes.

Machining

The recommended values, based on Sandvik Coromant cemented carbide cutting tools or high speed steel tools from Sandvik, are to be regarded as starting data. To obtain the optimal combination of finishes, tolerances and productivity the values should be adjusted for each individual operation. The data assumes the use of a suitable cutting fluid. If machining without a cutting fluid, the values should be reduced by about 10%.

Detailed recommendations can be obtained from your nearest Sandvik Coromant or Sandvik office.

In the manufacture of sophisticated precision components, the material's highly uniform and very good machinability offers reliable production with high productivity. This is of major importance since component processing costs can be several hundred times greater than the cost of the raw material.

Material in the drawn condition up to Ø 3 mm has a Cu/Sn surface layer. The layer enables components to be machined by lathes equipped with guide bushing.

Turning

The charts below give guidance of how speed and feed affect diameter tolerances and surface roughness of turned components. The charts are based on longitudinal turning. The tolerances are given by using the ISO-system, i.e. IT7 could mean h7, k7 or js7.

The tools used in Figure 3 - 6 were brazed cemented carbide tools and in Figure 7 indexable cemented carbide inserts. Brazed tools used: Sandvik Coromant tool 310 L197-1212-200 grade H10F, rake angle 0°, clearance angle 6° and entering angle 90°. Indexable tools used: Sandvik Coromant insert TCMT 110202-UF GC415 and tool holder STGCL 1212F 11.

Figure 3. Wire diameter 1.20 mm, high tensile strength, drawn condition, depth of cut between 0.2-0.3 mm. Brazed cemented carbide

Figure 4. Wire diameter 1.20 mm, medium tensile strength, drawn condition depth of cut between 0.2-03 mm. Brazed cemented carbide.

Figure 5. Wire diameter 3.00 mm, drawn condition, depth of cut between 0.4-0.6 mm. Brazed cemented carbide.

Figure 6. Wire diameter 3.50 mm, ground condition, depth of cut between 0.5-0.9 mm. Brazed cemented carbide.

Figure 7. Wire diameter 6.0 mm, ground condition, depth of cut between 0.2-0.5 mm. Indexable cemented carbide inserts.

CNC lathes and similar

Indexable insert tools. For diameters d < approx. 20 mm lower cutting speeds should be used.

FeedCutting speed
mm/rev.m/min.
GC 4015CT525GC 235
CT 5015GC 4025GC 4035
0.05 310 225 -
0.15 200 190 180
0.5 - - 150

Bar automatics

Diameter > approx. 2 mm

ToolCutting speed
m/min.
CC 45-55
HSS 25-35

Single and multiple spindle automatic lathes

Diameter > approx. 10 mm

OperationFinish turningRough turning
Feed, mm/rev.
Single point 0.05-0.10 0.10-0.25
Forming 0.01-0.03 0.03-0.08
Plunge cutting and parting off 0.02-0.05 0.05-0.10

Longitudinal turning automatics, plunging automatics and similar machines

Diameter < approx. 10 mmCutting depthFinish turning1)MediumRough turning2)
OperationmmFeed, mm/rev.
Single point turning <1 0.005-0.01 0.01-0.015 0.025
Forming 1-3 0.02
0.01
0.03
0.02
0.05
0.03
Plunge cutting and parting off >3 0.005
0.01
0.015
0.02
0.03
0.04

1) For parts requiring high precision.
2) For parts with moderate tolerance requirements and parts that subsequently must be finish machined.

Parting off and grooving

Parting off in CNC lathes and similar

ToolFeedCutting speed
mm/rev.m/min.
GC 235, 4025 0.05-0.15 55-110
HSS 0.02-0.05 25-35

Threading

ToolGradeCutting speed
m/mm.
Threading dies HSS 3-6
Self-opening die heads HSS 5-10
Thread chasers HSS
CC
20-35
80-135
Thread rolling HSS
CC
10-15
15-20
Thread turning GC1020 80-100

Drilling

Drill diameterFeedSpeed
mmmm/rev.rpm
0.5 0.005 2650
1 0.01 2500
31) 0.03 1500
51) 0.05 1200
81) 0.07 900
101) 0.09 700

1)Cemented carbide drills of Delta type with the following data can also be used:
Grade GC1020, speed 60-100 m/min.

Milling

OperationGradeFeedCutting speed
mm/toothm/mm.
Finish milling with high cutting speed under
favorable working conditions
530 or
1025
0.1
0.2
140-180
110-150
Finish and medium-rough milling under normal to
difficult working conditions
4030 or
4040
0.1
0.2
130-160
100-125
Medium-rough to rough milling under difficult conditions
SM30 or
4040
0.1
0.2
90-110
80-90

End milling

Tool typeGradeCutting speed
CCm/mm.
Indexable-insert tools 530 190
Solid carbide end mills 4030
4040
165
135
Brazed helical fluted end mills
GC1020
P40
120
40

Hobbing

ToolCutting speed
m/min.
CC 30-60
HSS
25-50

Reaming

Cutting speed for diameters > about 2 mm

ReamerGradeCutting speed
m/min.
Straight/helical fluted HSS
CC
10
25
Gun drill geometry
HSS
15

Feed

DiameterFeedAllowance
mmmm/rev.mm
1-5 0.05-0.10 0.05-0.10
6-10 0.10-0.20 0.10-0.20
11-20
0.15-0.30
0.20-0.30

All data is nominal. Values refer to 20°C unless otherwise stated.

For other requirements and further information please contact Sandvik.

Further information

Material datasheets and in-depth technical information about Sandvik Bioline grades and products are available on the Sandvik website, www.sandvik.com/medical.

Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Alleima materials.