Kub Isostatic Pressing yog dab tsi?
Txheej txheem cej luam
Kub Isostatic Pressing (HIP) thev naus laus zis tau npaj rau xyoo 1950 los ntawm Battelle Memorial Institute. Nws yog thawj zaug siv rau diffusion bonding ntawm nuclear reactor qhov chaw. Nws tau pom sai sai tias nws yog ib qho cuab yeej zoo tshaj plaws rau cov hmoov sib xyaw thiab tshem tawm cov porosity hauv cemented carbide. Hot isostatic pressing has developed into a recognized technology in industry for densification and alloy densification to improve its mechanical properties, smoothness and plating ability. Nws lub luag haujlwm tseem ceeb yog tshem tawm cov voids hauv cov khoom. Feem ntau cov hlau txhaj tshuaj molding manufacturers outsource cov txheej txheem no rau kev MIM kub isostatic pressing cov chaw muab kev pab los yog ntawv pov thawj HIP ua lwm tus neeg.
Vim hais tias cov txheej txheem yog yooj yim thiab tsuas yog yuav tsum tau kub thiab siab kub kev kho mob ntawm qhov chaw, kub isostatic nias cov cuab yeej tshwj xeeb tsim los ua kom tiav cov kev mob no, thiab cov khoom siv nqi siab. Thaum lub sij hawm kub isostatic nias txheej txheem, kub kub ua rau cov khoom muag heev thiab yooj yim rau deform, thaum lub siab compresses lub micropores hauv cov khoom. Cov pores yog tshem tawm los ntawm creep thiab diffusion mechanisms. Lub zog tawm los (YS) ntawm cov khoom txo qis thaum kub nce. Thaum cov pa oxygen siv rau cov ntaub ntawv hlau, cov khoom sov so yuav tsis ya mus rau hauv cov ntaub ntawv hlau. Cov txheej txheem ua ntej -deformation mechanisms nyob rau theem pib ntawm kub isostatic nias suav nrog Nabarro-Herring creep (diffusion los ntawm sab hauv ntawm cov nplej), Coble creep (grain boundary creep) thiab dislocation creep.
Qhov kawg theem ntawm kub isostatic pressing muaj xws li diffusion bonding ntawm kaw pore phab ntsa rau ib leeg. Vim tias qhov sintered ntom ntom ntawm cov hlau txhaj tshuaj molded qhov chaw siab txaus thiab cov pores sab hauv raug kaw (tsis cuam tshuam) thiab compressible, lawv tsim nyog rau kub isostatic pressing tshuab. Yog tias cov hlau txhaj tshuaj molded qhov chaw tau nthuav tawm thiab tsis kaw qhov hws, cov pa cua compressed yuav sau cov pores yam tsis muaj compressing. Tom qab npaj titanium alloy los ntawm cov hmoov kub isostatic pressing tshuab, cov hmoov hlau yuav tsum tau muab tso rau hauv ib qho kub isostatic nias rau qhov cub thiab nqus, thiab tom qab ntawd lub qhov cub qhov cub raug kaw, kom cov kev sib raug zoo ntawm cov hmoov tuaj yeem ua tiav raws li qhov kev txiav txim siab thiab kub. Hmoov zoo, qhov sintered ntom ntawm cov hlau txhaj tshuaj molded qhov feem ntau ncav cuag ntau dua 95%, thiab feem ntau tshaj 98%, thaum qhov tsawg kawg nkaus ntawm cov ntaub ntawv kub isostatic nias yog nyob nruab nrab ntawm 92% thiab 94%. Table 9.1 qhia qhov tsawg kawg nkaus ntawm cov hlau txhaj tshuaj molded qhov chaw tom qab kub isostatic nias. Los ntawm kev kos rau ntawm cov hlau txhaj tshuaj molded qhov chaw nrog qhov siab - qhov ntsuas kub tuaj yeem kuaj seb nws puas tuaj yeem kub isostatically nias.
Yog tias lub cim tsis tau sau meej meej thiab tsis nthuav dav rau sab hauv ntawm ib feem, kub isostatic nias tuaj yeem siv kom tau txais qhov ntom ntom dua. Yog hais tias nws nkag mus rau sab hauv ntawm ib feem, kub isostatic nias tsis tuaj yeem siv kom tau txais kev ceev dua. Ntau lub ntiaj teb kev txhaj tshuaj molding HIP densification cov chaw muag khoom tam sim no muab ib qho - nres tom qab - cov kev pabcuam ua haujlwm los pab cov neeg siv khoom ua tiav - ntom ntom MIM cov khoom.
Table 9.1 Yam tsawg kawg nkaus ntawm cov hlau txhaj Moulded qhov chaw tom qab kub Isostatic nias (g / cm³)
| Alloy | Theoretical ntom ntom | Yam tsawg kawg nkaus ceev tom qab HIP |
|---|---|---|
| Ti-6Al-4V | 4.43 | 4.1 |
| F2886 (F75) | 8.4 | 7.8 |
| 17–4 PH SS | 7.8 | 7.2 – 7.10 |
| 316L SS AW | 8.0 | 7.4 |
| Tsawg- hlau alloy | 7.6 – 7.9 | 7.1 – 7.3 |
| S7 | 7.83 | 7.2 |
Kub Isostatic Pressing txheej txheem
Cov txheej txheem kub isostatic nias siv compressed inert kub roj los siv lub siab rau lub workpiece. Rau cov hlau txhaj tshuaj molded qhov chaw, qhov kub isostatic nias yog feem ntau 100 ~ 200℃qis dua qhov kub ntawm sintering, thiab lub siab feem ntau yog nyob rau hauv thaj tsam ntawm 15 000 ~ 20 000 psi (105 ~ 140 MPa). Cov roj uas nyiam tshaj plaws rau kub isostatic nias yog argon vim nws qhov loj me atomic loj. Nitrogen kuj siv tau, tab sis cov nyhuv tsis zoo li argon. Daim duab 9.1 qhia ib daim duab schematic ntawm kub isostatic nias. Cov txheej txheem yog txheej txheem ua batch thiab feem ntau kav 4 ~ 10 h. Cov kauj ruam yog raws li nram no:
(1) Thauj khoom rau hauv lub cub tawg thiab kaw lub qhov rooj rau qhov cub;
(2) Nqus thiab ntim nrog cov roj inert;
(3) Thaum tshav kub kub thiab nias rau tib lub sijhawm;
(4) Txias thiab depressurize tib lub sijhawm;
(5) Ncua tseg;
(6) Tshem tawm cov khoom.
Cov kab ke no sawv cev rau kev ywj pheej kub isostatic nias txheej txheem thiab feem ntau yog siv los tsim cov pob zeb ntom ntom rau casting thiab hlau txhaj tshuaj molded qhov chaw. Hauv kev lag luam cemented carbide, txheej txheem hu ua kub isostatic nias sintering lossis siab sintering yog cov txheej txheem siv los ua kom cov cemented carbide / cobalt hmoov raws li cov khoom siv. Txij li thaum sintering thiab kub isostatic nias tau ua tiav hauv ib kauj ruam, tag nrho cov sijhawm ua haujlwm thiab tus nqi raug txo. Lub siab feem ntau yog 1.5 ~ 10 MPa, uas yog qis dua tus qauv kub isostatic nias, tab sis nws txaus los tshem tawm qhov pores hauv cemented carbide. Ua Tuam Tshoj MIM qhov chaw kub isostatic nias cov neeg muag khoom thiab thoob ntiaj teb hlau txhaj tshuaj molding puv -cov chaw muab kev daws teeb meem dav siv cov thev naus laus zis sib xyaw no kom xa cov kev ua haujlwm qaug zog ntau dua rau aerospace, kho mob thiab tsheb cov neeg siv khoom.
