(supersedes all previous editions)
Exera® 4C27A is a hardenable stainless chromium steel alloyed with molybdenum. This grade is supplied in wire form.
It is characterized by:
Exera® 4C27A is used for the manufacture of precision components such as watch parts, measuring points, dental tools, precision instruments and drilled surgical needles.
Exera® 4C27A is a hardenable grade used for medical and dental tools as dental burrs, dental drills, bone drills, dental taps, reamers, screw drivers and drilled surgical needles.
|Forms of supply/ finishes||Diameter||Tensile strength||Proof strength||Elongation|
|Rm1)||Rp0.21) 2) 3)||A1) 3)|
|Wire in coils:|
1) Nominal values. Other properties on request.
2) Corresponds to 0.2 % proof strength.
3) Rp0.2 and elongation values are given for information only.
Density (annealed) : 7.8 g/cm3, 0.28 lb/in3
Resistivity Cold drawn : 670 µΩm
Heat treated : 740 µΩm
1) Mean values in temperature ranges (x10-6)
Exera® 4C27A is a magnetic material.
When required, soft-annealing should be conducted for a period of one hour at a temperature of 650-680°C.
|Diameter||Temperature||Soaking time||Quenching 1)|
|<6||1030-1050||3-6||in oil at 50 °C|
|>6||1030-1050||6-10||in oil at 50 °C|
1) Diameter <2 mm may also be cooled in air or, to prevent oxidation, in a protective gas.
The smaller the dimensions, the shorter the soaking time. To prevent oxidation and decarburization, hardening should be carried out in a protective gas atmosphere using nitrogen, argon or vacuum.
Temperatures below 350°C are recommended for the retention of favorable corrosion resistance.
Tempering time 30-60 min.
The core of the material should have a tempering time of at least 30 min. 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.
Figure 1. Hardness after recommended hardening procedures, valid for all dimensions.
Soaking time 30 minutes.
Figure 2. Hardness after recommended hardening procedures, valid for all dimensions.
Soaking time 30 minutes. Standard Charpy V specimens at 20°C.
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 assume the use of a suitable cutting fluid.
When machining without a cutting fluid, the values should be reduced by around 10%. Detailed recommendations can be obtained from your nearest Sandvik Coromant or Sandvik office.
The charts below give guidance of how speed and feed affects 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. Brazed cemented carbide tools with the following data have been used: Sandvik Coromant tool 310 L197-1212-200 grade H10F, rake angle 0°, clearance angle 6° and entering angle 90°.
Figure 3. Wire diameter 1.00 mm, depth of cut between 0.15-0.25 mm. Brazed cemented carbide.
Figure 4. Wire diameter 2.00 mm, depth of cut between 0.30-0.50 mm. Brazed cemented carbide.
Indexable insert tools. For diameters d < approx. 20 mm lower cutting speeds should be used.
|Feed mm/rev.||Cutting speed m/min.|
|GT 4015||CT 525||GC 235|
|CT 5015||GC 4015||GC 4035|
Diameter < approx. 10 mm
|Operation||Cutting depth,||Feed, mm/rev.|
|mm||Finish turning (1)||Medium||Rough turning (2)|
|Single point turning
Plunge cutting and parting off
1) For parts requiring high precision.
2) For parts with moderate tolerance requirements and parts that must subsequently be machined finished
|Tool||Feed mm/rev.||Cutting speed m/mm.|
|GC 235, 4025||0.05-0.15||80-160|
Diameter > approx. 2 mm
|Tool||Cutting speed m/min|
Diameter >approx. 10 mm
|Finish turning||Rough turning|
|Plunge cutting and parting off||0.02-0.05||0.05-0.10|
|Tool||Grade||Cutting speed m/mm.|
|Self-opening die heads||HSS||2-5|
|Drill diameter, mm||Feed mm/rev.||Speed rpm|
1) Cemented carbide drills of Delta type with the following data can also be used:
Grade GC1020, speed 70-110 m/min.
|Finish milling with high cutting speed under favorable working conditions||530 or
|Finish and medium-rough milling under normal to difficult working conditions||4030 or
|Medium-rough to rough milling under difficult conditions||SM30 or
|Tool type||Grade CC||Cutting speed m/min.|
|Indexable insert tools||530||240|
|Solid carbide end mills||1025||220|
|Brazed helical fluted end mills||4040
|Tool||Cutting speed m/mm.|
|Reamer||Grade||Cutting speed m/min.|
|Gun drill geometry||CC
|Diameter mm||Feed mm/rev.||Allowance mm|
All data is nominal. Values refer to 20oC unless otherwise stated.
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.