Nyob rau hauv lub machining ntawm mechanical qhov chaw, lub workpiece yuav raug cuam tshuam los ntawm kev txiav quab yuam thiab txiav kub, uas yuav hloov lub cev thiab txhua yam khoom ntawm txheej txheej hlau. Nyob rau hauv cov txheej txheem ntawm kev sib tsoo, yas deformation thiab txiav cov cua sov yuav hnyav dua li txiav ntug. Txhawm rau kom ntseeg tau tias cov cuab yeej siv tshuab ntawm cov tshuab ua haujlwm ntawm qhov chaw, peb yuav tsum paub tias dab tsi cuam tshuam rau cov khoom siv tshuab ntawm machined nto ntawm qhov chaw.
1. Txias ua hauj lwm hardening thiab kev ntsuam xyuas tsis
(1) Kev ua haujlwm txias ntawm cov hlau
Nyob rau hauv tus txheej txheem ntawm machining, vim lub luag hauj lwm ntawm kev txiav quab yuam, yas deformation yog heev yooj yim mus tshwm sim, uas ua rau lub lattice distorted, distorted, thiab txawm tawg. Cov no yuav txhim kho lub hardness thiab lub zog ntawm cov hlau nto, uas yog hu ua txias ua hauj lwm hardening.
(2) Cov yam tseem ceeb cuam tshuam rau kev ua haujlwm txias txias
Nrog rau qhov nce ntawm blunt vojvoog ntawm cov ntug txiav, cov nyhuv extrusion ntawm cov hlau saum npoo yuav raug kho kom zoo, uas yuav ua rau cov yas deformation thiab ua rau kom muaj zog ntawm qhov txias hardness.
Kev hnav ntawm lub ntsej muag lub ntsej muag lub ntsej muag nce ntxiv, thiab kev sib txhuam ntawm lub ntsej muag lub ntsej muag thiab lub ntsej muag ntawm lub tshuab ua kom cov yas deformation, ua rau lub hardening.
Kev cuam tshuam ntawm blunt radius ntawm kev txiav ntug ntawm kev ua hauj lwm hardening txiav ceev nce, lub sij hawm sib cuam tshuam ntawm cov cuab yeej thiab workpiece shortens, yog li ntawd lub extension qhov tob ntawm yas deformation txo, thiab qhov tob ntawm hardened txheej txo. Thaum txiav ceev yog nce, lub sij hawm txiav txim ntawm lub tshav kub ntawm lub workpiece nto yog shortened, uas ua rau hardening.
2. Hloov cov qauv metallographic ntawm cov khoom txheej txheej
(1) Kev sib tsoo kub: thaum qhov kub ntawm qhov sib tsoo workpiece nto nce mus txog qhov kub ntawm cov theem hloov, cov hlau saum npoo yuav raug hloov pauv, uas yuav txo tau lub zog thiab hardness ntawm cov hlau saum npoo, ua rau muaj kev ntxhov siab thiab tawg me ntsis. Tempering burns, quenching burns thiab annealing burns yuav tshwm sim thaum sib tsoo ntawm quenched steel.
Tempering kub: qhov kub hauv qhov sib tsoo tsis tshaj qhov hloov pauv kub ntawm cov hlau quenched, tab sis tau dhau qhov kev hloov pauv kub ntawm lub cev ntxhib. Lub tempering martensite qauv ntawm cov hlau nto ntawm lub workpiece yuav hloov mus rau hauv tempering qauv nrog tsawg hardness.
quenching hlawv: Yog hais tias qhov kub ntawm qhov chaw txiav ntau tshaj qhov kub hloov pauv, ua ke nrog lub luag hauj lwm ntawm lub coolant quenching, cov hlau saum npoo yuav undergo thib ob quenching, thiab nws hardness yuav siab tshaj li ntawm tempered martensite, thaum lub txheej txheej. ntawm nws yuav txias maj mam, thiab ib daim ntaub tempering nrog ib tug hardness qis dua qhov qub tempered martensite yuav tshwm.
Annealing hlawv: Yog hais tias qhov kub ntawm qhov chaw txiav ntau tshaj qhov kub hloov pauv, thiab tsis muaj cov cua txias nkag mus rau hauv qhov chaw sib tsoo, cov hlau saum npoo yuav tsim cov qauv rov qab, ua rau muaj kev poob qis hauv qhov tawv tawv.
(2) Residual stress of deg txheej: nyob rau hauv qhov kev txiav txim ntawm txiav quab yuam, machined nto yuav cuam tshuam los ntawm tensile kev nyuaj siab, ua rau elongation yas deformation. Thaum qhov chaw saum npoo zoo li nce, cov txheej sab hauv yuav nyob rau hauv elastic deformation. Thaum txiav quab yuam raug tshem tawm, cov hlau sab hauv zoo li rov qab los, tab sis nws tsis tuaj yeem rov qab mus rau nws cov duab qub vim qhov kev txwv ntawm cov yas deformation ntawm txheej txheej. Yog li ntawd, yuav muaj residual compressive kev nyuaj siab nyob rau saum npoo txheej thiab tensile kev nyuaj siab nyob rau hauv lub puab txheej.