Kev kho cua sov ntawm cov saw hniav feem ntau yog tsom rau ib txhij txhim kho cov tawv nqaij ntawm cov hniav thiab tag nrho cov tawv nqaij, ua rau lawv ob leeg hnav- tiv taus thiab tsis tshua muaj kev tawg thaum txiav. Cov ntaub ntawv saw hniav feem ntau dhau los ua kom sov tag nrho tom qab sib sau. Qhov no suav nrog cua sov hauv qhov ntsuas kub austenitizing tom qab txias txias, hloov cov qauv matrix rau hauv martensite, yog li ua kom muaj zog tag nrho.
Tom qab zuag qhia tag nrho hardening, tempering feem ntau yog ua los txo cov kev ntxhov siab sab hauv thiab txhim kho toughness. Yog tsis muaj tempering, thaum saw hniav yuav muaj siab hardness, nws yuav ua nkig thiab nquag tawg nyob rau hauv kev ntxhov siab los yog kev co. Lub tempering kub feem ntau yog hloov kho raws li cov khoom kom ua tiav qhov sib npaug ntawm hardness thiab toughness, yog ib kauj ruam tseem ceeb hauv kev ua kom cov saw hniav lub neej ntev.
Rau siab -kev ua tau zoo saw hniav, cov txheej txheem kho cua sov hauv zos kuj tau ua haujlwm, xws li induction hardening lossis laser hardening ntawm cov hniav. Cov hniav yog rhuab mus rau qhov kub thiab txias sai sai, ua rau muaj zog hardness ntawm cov hniav, thaum lub nraub qaum ntawm cov saw tuav zoo dua toughness. Qhov no "nyuaj rau pem hauv ntej, tawv tom qab" kev tsim qauv ua rau cov saw hniav tsis tshua muaj kev tawg nyob rau hauv kev cuam tshuam thiab khoov, thaum ua kom ntseeg tau qhov hnav tsis kam ntawm kev txiav ntug.
Qee qhov tshwj xeeb- lub hom phiaj pom cov hniav kuj raug kho kom muaj zog, xws li carburizing, nitriding, lossis txheej txheej txheej, txhawm rau txhim kho lawv cov hnav tsis kam thiab qaug zog. Cov txheej txheem no feem ntau yog siv rau hauv cov hlau txiav lossis siab - cov khoom siv zog ua haujlwm, kom ntseeg tau tias cov saw hlau tuav ruaj khov kev ua haujlwm nyob rau hauv siab -load tej yam kev mob.