What are the types of heat treatment processes for cov khoom siv tua hluav taws?

(1) Ua kua quenching

Single-liquid quenching is a quenching operation method in which the austenitic workpiece is quickly immersed in a certain quenching medium and cooled to room temperature. The selection of single liquid quenching cooling medium is based on the fact that the cooling rate of the workpiece in this medium must be greater than the critical cooling rate of the workpiece steel, and the workpiece should not be quenched and cracked. Single liquid quenching media include water, brine, alkaline water, oil, and some specially formulated water-based quenching agents.

(2) Ob chav ua kua quenching

Txhawm rau kom kov yeej qhov tsis txaus ntawm ib leeg-kua quenching thiab ua kom lub quenching thiab txias ntawm lub workpiece kom ze rau qhov zoo tagnrho qhov teeb meem raws li qhov ua tau, ob lub xov xwm uas muaj peev xwm ua kom txias sib txawv tuaj yeem siv ua ke, uas yog, lub tshuab ua haujlwm rhuab yog quenched rau hauv thawj qhov nruab nrab nrog lub peev xwm txias txias, thiab txias kom txias me ntsis. Saum toj no Ms kub (kwv yees li 300), ces tam sim ntawd hloov mus rau ib tug thib ob nruab nrab uas muaj tsawg cua txias peev xwm kom txias rau chav tsev kub. Txoj kev quenching txias no yog hu ua ob chav ua kua quenching. Rau qee qhov chaw ua haujlwm, txhawm rau txhawm rau txo qis qis qis qis qis dua Ms, dej quenching cua txias lossis roj quenching cua txias kuj siv tau, thiab cua kuj tuaj yeem siv los ua qhov nruab nrab txias.

(3) Staged quenching (martensite staged quenching)

Cov yam ntxwv ntawm txoj kev ua kom txias no yog tias cov khoom ua haujlwm yog thawj zaug rau hauv lub pas dej molten nrog qhov kub thiab txias me ntsis siab dua Ms, thiab tom qab ntawd muab tso rau hauv lub pas dej molten kom txog thaum lub npoo thiab qhov nruab nrab ntawm lub workpiece txias mus rau qhov kub ntawm lub pas dej molten, thiab ces muab tawm rau cua txias. Lub da dej kub feem ntau yog 10 mus rau 20. Qhov nruab nrab hauv da dej muaj nitrate da dej, da dej alkali thiab nruab nrab ntsev da dej.

(4) Pre-txias thiab quenching

Tom qab high-frequency quenching, lub workpiece tsis yog immersed nyob rau hauv lub txias nruab nrab tam sim ntawd, tab sis yog txias nyob rau hauv cov huab cua rau ib tug luv luv lub sij hawm, thiab ces immersed nyob rau hauv lub txias nruab nrab tom qab lub workpiece txias mus rau ib tug tej yam kub. Txoj kev quenching no yog hu ua pre-txias quenching lossis qeeb quenching.

Tus yuam sij rau pre-txias yog tswj lub sij hawm ua ntej txias, thiab cov nyhuv ntawm lub sij hawm ua ntej txias yog tsis zoo. Lub sij hawm ntev tuaj yeem txo qhov quenching hardness ntawm lub workpiece (tsis yog martensitic transformation). Vim yog cov khoom sib txawv, cov duab thiab qhov ntau thiab tsawg ntawm cov khoom ua haujlwm, nrog rau kev cuam tshuam ntawm qhov kub thiab txias ntawm lub qhov cub, lub sijhawm ua ntej txias yog qhov nyuaj rau kev xam kom raug thiab feem ntau yog nyob ntawm kev txawj thiab kev paub ntawm tus neeg teb xov tooj.

(5) Local quenching

Some workpieces only require one part to have a higher hardness, and other parts have no hardness requirements or require a lower hardness. In this case, a local quenching method can generally be used, that is, only a certain part of the workpiece is quenched. There are two main forms of local quenching: local heating and local cooling and bulk heating and local cooling. The former is mainly suitable for heating workpieces in salt bath furnaces, while the latter can be used in box furnaces and salt bath furnaces.

(6) Cold treatment

Cold treatment is a post-quenching operation in which the quenched steel is continuously cooled to a temperature below room temperature, so that the untransformed retained austenite at room temperature is continuously transformed into martensite.

Rau qee qhov chaw uas muaj kev ruaj ntseg siab, nws yog ib qho tsim nyog los txo cov austenite khaws cia hauv cov qauv quenched kom qis tshaj qhov kub thiab txias, kom tsis txhob ua tsis tiav vim qhov kev hloov pauv ntawm cov duab thiab qhov loj dua qhov raug cai thaum siv. Qhov ntawd yog dab tsi txias ua rau. Kev kho mob txias yog txiav txim siab raws li Ms point ntawm cov hlau, ua ke nrog cov kev cai ntawm cov khoom, cov txheej txheem cov txheej txheem thiab lwm yam. Tom qab quenched workpiece yog txias rau chav tsev kub, nws yuav tsum tau txias-kho tam sim ntawd, txwv tsis pub nws cov nyhuv yuav raug cuam tshuam. Kev kho mob khaub thuas ntawm cov khoom me me thiab nruab nrab feem ntau khaws cia rau 1 mus rau 3 teev, thiab yuav tsum tau maj mam muab tso rau hauv huab cua tom qab kev kho mob. Thaum lub workpiece yog rhuab mus rau chav tsev kub, nws yuav tsum tau tempered tam sim ntawd, uas yuav zoo tiv thaiv lub workpiece los ntawm cracking.