Kev kho cua sov "plaub hluav taws"

1. normalizing

Lo lus "normalization" tsis qhia qhov xwm txheej ntawm tus txheej txheem. Ntau precisely, nws yog ib tug homogenization los yog grain refinement txheej txheem tsim los ua kom cov muaj pes tsawg leeg zoo ib yam thoob plaws ib feem. Los ntawm cov ntsiab lus thermal ntawm qhov pom, normalizing yog txheej txheem ntawm kev ua kom txias hauv qhov tseem ceeb lossis cua sov tom qab lub austenitizing cua sov seem. Feem ntau, lub workpiece yog rhuab mus txog 55 ° C saum toj no qhov tseem ceeb ntawm daim duab Fe-Fe3C. Cov txheej txheem no yuav tsum tau rhuab kom tau ib theem homogeneous austenite. Qhov tseeb kub siv nyob ntawm qhov muaj pes tsawg leeg ntawm cov hlau, tab sis feem ntau yog nyob ib ncig ntawm 870 ° C. Vim muaj cov yam ntxwv ntawm cov cam khwb cia hlau, normalizing feem ntau yog ua ntej ingot machining thiab ua ntej hardening ntawm steel castings thiab forgings. Cua quench hardened steels tsis raug cais raws li cov hlau tsis muaj zog vim tias lawv tsis tau txais cov pearlitic microstructure raug ntawm cov hlau tsis zoo.

2. Annealing

Lo lus annealing sawv cev rau ib chav kawm uas hais txog kev kho cua sov thiab tuav ntawm qhov kub thiab txias thiab tom qab ntawd txias ntawm tus nqi tsim nyog, feem ntau kom muag cov hlau thaum tsim lwm yam khoom xav tau lossis kev hloov microstructural. Yog vim li cas rau annealing suav nrog kev txhim kho machinability, yooj yim ntawm kev ua haujlwm txias, txhim kho cov khoom siv hluav taws xob lossis hluav taws xob, thiab kev ruaj ntseg ntxiv, thiab lwm yam. Nyob rau hauv cov hlau-raws li alloys, annealing feem ntau yog ua los saum toj kawg nkaus kub tseem ceeb, tab sis lub sij hawm-kub sib xyaw ua ke nws txawv nyob rau hauv qhov kub thiab txias npaum li cas, nyob ntawm seb steel muaj pes tsawg leeg, lub xeev thiab xav tau kev pab. Thaum lo lus annealing siv tsis muaj qhov tsim nyog, lub neej ntawd yog tag nrho annealing. Thaum kev ntxhov siab yog lub hom phiaj nkaus xwb, cov txheej txheem raug xa mus rau kev ntxhov siab los yog kev ntxhov siab annealing. Thaum lub sij hawm tag nrho annealing, cov hlau yog rhuab mus rau 90 ~ 180 ° C saum toj no A3 (hypoeutectoid steel) los yog A1 (hypereutectoid steel), thiab ces txias maj mam kom cov khoom yooj yim txiav los yog khoov. Thaum tag nrho annealed, tus nqi txias yuav tsum qeeb heev los tsim cov pearlite ntxhib. Nyob rau hauv cov txheej txheem annealing, qeeb txias yog tsis tsim nyog, vim hais tias ib tug txias npaum li cas hauv qab no A1 yuav tau txais tib lub microstructure thiab hardness.

3. Quenching

Quenching yog qhov txias txias ntawm cov hlau los ntawm qhov kub thiab txias, feem ntau ntawm 815 txog 870 ° C. Stainless hlau thiab high-alloy hlau tuaj yeem quenched kom txo tau cov carbide uas twb muaj lawm nyob rau hauv lub lis ciam teb los yog txhim kho kev faib ntawm ferrite, tab sis rau feem ntau steels, xws li carbon steel, low-alloy steel thiab cuab yeej steel, quenching yog rau microscopic ib tug tswj tus nqi ntawm martensite yog tau nyob rau hauv cov ntaub so ntswg. Lub hom phiaj yog kom tau txais qhov xav tau microstructure, hardness, lub zog los yog toughness nrog me ntsis peev xwm rau residual stress, deformation thiab cracking li sai tau. Lub peev xwm ntawm tus neeg sawv cev quenching rau harden steel nyob ntawm qhov txias zog ntawm qhov nruab nrab quenching. Cov nyhuv quenching nyob ntawm qhov muaj pes tsawg leeg ntawm cov hlau, hom quenching tus neeg saib xyuas thiab cov xwm txheej ntawm kev siv cov quenching agent. Kev tsim thiab kev saib xyuas ntawm quenching system kuj yog tus yuam sij rau kev ua tiav ntawm quenching.

4. Tempering

Hauv qhov kev kho no, yav tas los hardened los yog normalized steel feem ntau yog rhuab mus rau ib tug kub ntawm qhov qis dua qhov tseem ceeb thiab txias ntawm ib tug nruab nrab tus nqi, feem ntau yog ua kom cov yas thiab toughness, tab sis kuj yuav ua rau kom lub matrix grain loj. Tempering ntawm steel yog reheating tom qab hardening kom tau ib tug tej yam nqi ntawm txhua yam khoom thiab tso quenching kev nyuaj siab los xyuas kom meej qhov seem stability. Tempering feem ntau yog ua raws li los ntawm quenching los ntawm qhov kub tseem ceeb.