Kev kho cua sov ntawm cov hlau castings

Kev kho cua sov ntawm cov hlau castings yog hais txog kev tso cov castings hauv qhov nruab nrab ntawm qhov kub thiab txias rau kev txuag hluav taws xob, kom ib lossis ob peb yam tshuaj tuaj yeem nkag mus rau saum npoo. Kev kho cua sov tuaj yeem hloov kho cov tshuaj muaj pes tsawg leeg, cov qauv metallographic thiab cov khoom siv ntawm qhov chaw ntawm qhov casting. Feem ntau siv cov txheej txheem kho cua sov xws li carburizing, nitriding, carbonitriding, boronizing thiab metalizing. Thaum ua cov tshuaj tua hluav taws kub ntawm cov castings, cov duab, qhov loj me, qhov chaw nyob, thiab kev kho cua sov ntawm cov casting yuav tsum tau txiav txim siab.

 

1. Carburizing

Carburizing yog hais txog cua sov thiab insulating lub casting nyob rau hauv ib tug carburizing nruab nrab, thiab ces infiltrating carbon atoms rau saum npoo. Lub hom phiaj tseem ceeb ntawm carburizing yog nce cov ntsiab lus ntawm cov pa roj carbon monoxide nyob rau saum npoo ntawm cov casting, thaum tsim ib qho carbon cov ntsiab lus gradient hauv casting. Cov ntsiab lus carbon ntawm carburizing hlau feem ntau yog 0.1% -0.25% kom ntseeg tau tias cov tub ntxhais ntawm cov casting muaj txaus toughness thiab lub zog.

Lub hardness ntawm lub carburized txheej feem ntau yog 56HRC-63HRC. Lub metallographic qauv ntawm carburized txheej yog zoo koob martensite + ib tug me me ntawm khaws cia austenite thiab uniformly faib granular carbides. Network carbides tsis raug tso cai, thiab qhov ntim feem ntawm khaws cia austenite feem ntau tsis tshaj 15% -20%.

Lub hardness ntawm lub casting tom qab carburizing feem ntau yog 30HRC-45HRC. Cov qauv metallographic tseem ceeb yuav tsum yog cov pa roj carbon tsawg lossis qis dua bainite. Nws tsis raug tso cai kom muaj ferrite loj heev los yog precipitated ferrite raws tus ciam teb nplej.

Hauv kev tsim khoom tiag tiag, muaj peb txoj hauv kev carburizing: khoom carburizing, kua carburizing thiab roj carburizing.

2. Nitriding

Nitriding yog hais txog cov txheej txheem kho cua sov uas infiltrates nitrogen atoms rau saum npoo ntawm cov casting. Nitriding feem ntau ua rau qis dua Ac1 kub, thiab nws lub hom phiaj tseem ceeb yog txhawm rau txhim kho hardness, hnav tsis kam, qaug zog, qaug zog tsis kam thiab atmospheric corrosion kuj ntawm casting nto. Nitriding ntawm steel castings feem ntau yog ua los ntawm 480 ° C-580 ° C. Castings uas muaj txhuas, chromium, titanium, molybdenum, thiab tungsten, xws li cov hlau tsis tshua muaj hlau, stainless hlau, thiab cov pwm kub pwm hlau, yog tsim rau nitriding.

Txhawm rau kom ntseeg tau tias cov tub ntxhais ntawm cov casting muaj cov khoom tsim nyog thiab cov qauv metallographic, thiab txo qhov deformation tom qab nitriding, kev kho mob ua ntej nitriding yuav tsum tau ua. Rau cov qauv hlau, quenching thiab tempering kev kho mob yuav tsum tau ua ntej nitriding thiaj li yuav tau ib tug uniform thiab zoo tempered sorbite qauv; rau castings uas yooj yim distorted thaum lub sij hawm kho nitriding, kev nyuaj siab nyem annealing kev kho mob kuj yuav tsum tau tom qab quenching thiab tempering; rau stainless hlau thiab kub-resistant steel castings feem ntau yuav quenched thiab tempered los txhim kho cov qauv thiab lub zog; rau austenitic stainless hlau, kev kho cua sov tuaj yeem siv tau.