Molybdenum alloy has high strength and hardness, poor toughness, brittleness, easy to break, and poor machinability. However, because of its high melting point, low density, and low coefficient of thermal expansion, it is often used to manufacture various high-temperature parts in aviation and aerospace. The two molybdenum parts are the molybdenum ntsia hlau and molybdenum bolt, as shown in the attached figure. The blank is hot rolled Ф 16mm molybdenum alloy steel bar. During processing, it is found that the material has a low density and very high skin hardness, which should be annealing residual hardness. Within the surface layer, the hardness is still very high, the toughness is poor, and the heat conduction is slow.
Nws yog qhov nyuaj heev los ua cov txheej txheem siab zoo tib yam - ceev steel lossis cemented carbide cov cuab yeej. Ua ntej ntawm tag nrho cov, pem hauv ntej thiab nram qab flanks thiab cov lus qhia ntawm lub cuab tam hnav sai sai. Ntxiv cov kua txiav thiab siv cov kev txiav sib txawv raws li ib txwm muaj rau ntau qhov kev sim, uas tsis tuaj yeem tau txais txiaj ntsig zoo. Feem ntau, yog tias tsuas muaj 4 daim ntawm cylindrical hniav, lawv yuav tsum tau hloov; Qhov thib ob, thaum lub cuab yeej hnav me ntsis, cov khoom muaj slag ntog tsis xws luag, thiab slag ntog tshwm sim thaum lub ntsej muag tiaj tus, txiav thiab threading. Lub voj voog sab nrauv machining thiab kawg lub ntsej muag machining tuaj yeem ua tau raws li qhov xav tau ntawm kev kos duab thaum lub cuab yeej tig tiav tseem ntse, tab sis cov slag poob ntawm xov machining tsis tuaj yeem zam.
Hauv kev ua haujlwm tiag tiag, cov nyhuv tig ntawm M6molybdenum screwstsis zoo, thiab cov xov seem feem ntau tawg los ntawm qhov kawg ntawm kev ua, uas tsis tuaj yeem zam. Tsuas yog cov ntsia hlau tuag machining yog siv.M12 txais CNC siab - ceev ob npaug rau cutter xov tig, thiab cov nyhuv yog zoo tagnrho. Vim qhov ntev ntev ntawm ob qho tib si, nyob rau hauv qhov tseeb ua, xov tig kauj ruam yog feem ntau nqa tawm tom qab tag nrho ntev ntawm kev txiav dav hlau ntawm lub voj voog sab nrauv. Los ntawm M6molybdenum ntsia hlauthiab M12 ntsia liaj qhov rooj nyob rau hauv cov ntaub ntawv txheej txheem tsis pub muaj lub hauv paus qhov, uas yuav tsum tau leveled tawm thaum kawg nyob rau hauv kab rov tav tshuab dhos machining.
The method of subsection processing is adopted in several vehicles, and a central hole is not drilled. Segmented processing Ф 12mm outer circle (M12 large end diameter) cut off; Segmented processing Ф 6mm outer circle (M6 large end diameter) is cut by turning cone. The procedure is relatively simple and is omitted here. It should be noted that Ф 6mm outer circle size machined to Ф 5.85- Ф 5.93mm is obviously conducive to threading. Outer circle greater than Ф 5.93mm has a large nesting allowance, which is prone to incomplete tooth profile such as thread slag dropping and lack of thread. Outer circle less than Ф 5.85mm, the extrusion deformation during threading is limited. If the size of the machine tool fluctuates, it is easy to make the large end size of the M6 thread close to the limit or out of tolerance. In addition, when cutting, the total length allowance shall be more than 1.5mm. To prevent the cutting knife from becoming blunt or the chip removal is not smooth, the slag on the conical surface (screw) at the root of the part can not be repaired after the end face is flattened. That is after the end face is flattened, the parts still have slag-dropping defects.
