Sandvik 20AP (Free-cutting wire)

Transcription

1 Datasheet updated :57:37 (supersedes all previus editins) Sandvik 20AP (Free-cutting wire) Sandvik 20AP is a hardenable, free cutting carbn steel characterized by excellent machinability and high hardness, high wear resistance and exceptinal dimensinal stability after hardening. The material is suitable fr lng, narrw cmpnents with tight tlerance. Service temperature 50 t 100 C ( 55 t 210 F). Prlnged service at elevated temperatures causes decreased hardness when used in the hardened and tempered cnditin. CHEMICAL COMPOSITION (NOMINAL) % C Si Mn P S Others max Pb=0.2 FORMS OF SUPPLY Frms f supply/ finishes Diameter mm Cu Sn cating Standard tlerance Length, m Wire in cils Drawn Straightened wire Drawn Drawn/grund D4 D4 D4 D4 D3 h7 h7 h Other sizes n request. Ovality: Fr D1 and D2, max. 50% f the tlerance width, fr D3 max. 25% f the tlerance width. Fr D4 in accrdance with the tlerance table, see brchure S 245. MECHANICAL PROPERTIES

2 O AT 20 C, NOMINAL VALUES Frms f supply/finishes Diameter Tensile strength Prf strength Elngatin mm Rm 1) 2) 3) Rp0.2 1) 3) A MPa MPa % Wire in Cil Drawn Straightened wire Drawn >980 > >920 > >900 >830 7 Drawn/grund >920 > ) Nminal values. Other prperties n request. 2) Crrespnds t 0.2% prf strength. 3) R p0.2 and elngatin values are given fr infrmatin nly. Impact strength Observe that quenching time and temperature is dependent n material size. The specimens fr impact strength are larger than standard wire dimensins. Figure 1. Impact strength after recmmended hardening prcedures, valid fr all dimensins. Saking time 30 minutes. Standard Charpy V specimens at 20 C. PHYSICAL PROPERTIES DENSITY Annealed g/cm, 0.28 lb/in Resistivity Cld drawn Heat treated 0.18 µωm 0.21 µωm O -6 THERMAL EXPANSION, PER C (X10 ), MEAN VALUES IN TEMPERATURE RANGES Temperature, C Cld drawn Heat treated Sandvik 20AP is a magnetic material. HEAT TREATMENT

3 Sft-annealing When required, sft annealing shuld be cnducted fr a perid f ne hur at a temperature f C ( F). Hardening Wire is nrmally delivered in a cld drawn cnditin. If increased hardness is required the fllwing is recmmended. HARDENING Diameter Temperature Saking time Quenching mm C apprx. min in il at 50 C > in water The smaller the diameter, the shrter the saking time. T avid xidatin and decarburizatin, hardening shuld be cnducted in a prtective gas atmsphere using nitrgen, argn r vacuum. Cntact Sandvik fr advice. Prlnged service at elevated temperatures causes decreased hardness when used in the hardened and tempered cnditin. See als "Impact strength". TEMPERING Temperature, C Tempering time, min The cre f the material needs a tempering time f at least 30 minutes. T reduce the risk f cracking, tempering shuld be cnducted immediately after hardening. The heating rate shuld nt be t high, particularly in the case f intricately shaped cmpnents. Hardness Hardness after recmmended hardening prcedures, valid fr all dimensins. Saking time 30 minutes. MACHINING The recmmended values, based n Sandvik Crmant cemented carbide cutting tls r high speed steel tls frm Sandvik, are t be regarded as starting data. T btain the ptimal cmbinatin f finishes, tlerances and prductivity the values shuld be adjusted fr each individual peratin. The data assumes the use f a suitable cutting fluid. In machining withut a cutting fluid, the values shuld be reduced by abut 10%. Detailed recmmendatins can be btained frm yur nearest Sandvik Crmant r Sandvik ffice. In the manufacture f sphisticated precisin cmpnents, the material's highly unifrm and very gd machinability ffers reliable prductin with high prductivity. This is f majr imprtance since cmpnent prcessing csts can be several hundred times greater than the cst f the raw material. Material in the drawn cnditin up t Ø 3 mm has a Cu/Sn surface layer. The layer enables cmpnents t be machined t lathes equipped with guide bushing. Turning The charts belw give guidance f hw speed and feed affect diameter tlerances and surface rughness f turned cmpnents. The charts are based n lngitudinal turning. The tlerances are given by using the ISO system, i.e. IT7 culd mean h7, k7 r js7.

4 The tls used in Figure 3 6 have been brazed cemented carbide tls and in Figure 7 indexable cemented carbide inserts. Brazed tls used: Sandvik Crmant tl 310 L grade H10F, rake angle 0, clearance angle 6 and entering angle 90. Indexable tls used: Sandvik Crmant insert TCMT UF GC415 and tl hlder STGCL 1212F 11. Figure 3. Wire diameter 1.20 mm, high tensile strength, drawn cnditin, depth f cut between mm. Brazed cemented carbide. Figure 4. Wire diameter 1.20 mm, medium tensile strength, drawn cnditin depth f cut between mm. Brazed cemented carbide. Figure 5. Wire diameter 3.00 mm, drawn cnditin, depth f cut between mm. Brazed cemented carbide.

5 Figure 6. Wire diameter 3.50 mm, grund cnditin, depth f cut between mm. Brazed cemented carbide. Figure 7. Wire diameter 6.0 mm, grund cnditin, depth f cut between mm. Indexable cemented carbide inserts. CNC lathes and similar Indexable insert tls. Fr diameters d < apprx. 20 mm lwer cutting speeds shuld be used. Feed mm/rev. Cutting speed GC 4015 CT525 GC 235 CT 5015 GC 4025 GC Bar autmatics Diameter > apprx. 2 mm Tl Cutting speed CC HSS Single and multiple spindle autmatic lathes Diameter > apprx. 10 mm

6 Operatin Feed, mm/rev. Finish turning Rugh turning Single pint Frming Plunge cutting and parting ff LONGITUDINAL TURNING AUTOMATICS, PLUNGING AUTOMATICS AND SIMILAR MACHINES 1) 2) Diameter Cutting depth Feed, Finish turning Medium Rugh turning < apprx. 10 mm Operatin mm mm/rev. Single pint turning < Frming Plunge cutting and parting ff > ) Fr parts requiring high precisin. 2) Fr parts with mderate tlerance requirements and parts that subsequently must be finishmachined. Parting ff and grving PARTING OFF IN CNC LATHES AND SIMILAR Tl Feed Cutting speed mm/rev. GC 235, HSS THREADING Tl Grade Cutting speed m/mm. Threading dies HSS 3 6 Self pening die heads HSS 5 10 Thread chasers Thread rlling HSS CC HSS CC Thread turning GC DRILLING Drill diameter Feed Speed mm mm/rev. rpm ) ) ) ) ) Cemented carbide drills f Delta type with the fllwing data can als be used: Grade GC1020, speed

7 MILLING Operatin Grade Feed Cutting speed mm/tth m/mm. Finish milling with high cutting speed under favurable wrking cnditins 530 r Finish and medium rugh milling under nrmal t difficult wrking cnditins 4030 r Medium rugh t rugh milling under difficult cnditins SM30 r END MILLING Tl type Grade Cutting speed Indexable insert tls Slid carbide end mills 4040 GC1020 CC m/mm Brazed helical fluted end mills P40 40 HOBBING Tl Cutting speed CC HSS Reaming Cutting speed fr diameters > abut 2 mm Reamer Grade Cutting speed Straight/helical fluted HSS CC Gun drill gemetry HSS 15 FEED IN REAMING Diameter Feed Allwance mm mm/rev. mm All data is nminal. Values refer t 20 C unless therwise stated Fr ther requirements and further infrmatin please cntact yur Sandvik ffice. DISCLAIMER: Recmmendatins are fr guidance nly, and the suitability f a material fr a specific applicatin can be cnfirmed nly when we knw the actual service cnditins. Cntinuus develpment may necessitate changes in technical data withut ntice. This datasheet is nly valid fr Sandvik materials.

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