Txheej txheem cej luam ntawm Hardening txheej txheem ntawm hlau kaw pob Valve

1 Txheej txheem cej luam

Nyob rau hauv nruab nrab ntawm high viscous kua, sib tov kua nrog hmoov av thiab khoom hais, thiab muaj zog corrosive kua nyob rau hauv lub tshav pob ntawm thermal fais fab nroj tsuag, petrochemical system thiab thee chemical kev lag luam, lub pob valve yuav tsum xaiv cov hlau hard seal pob valve, yog li nws Nws yog ib qho tseem ceeb heev uas yuav tau xaiv cov txheej txheem hardening ntawm cov hlau nyuaj foob pob valve pob thiab lub rooj zaum valve.

2 txoj kev hardening ntawm hlau nyuaj foob pob valve pob thiab lub rooj zaum valve

Tam sim no, cov txheej txheem hardening feem ntau siv rau saum npoo ntawm cov hlau nyuaj foob pob li qub feem ntau suav nrog cov hauv qab no:

(1) Surfacing (los yog tsuag welding) cemented carbide nyob rau saum npoo ntawm tus kheej muaj ib tug hardness ntawm ntau tshaj 40HRC. Cov txheej txheem saum npoo ntawm cemented carbide nyob rau saum npoo ntawm tus kheej yog txoj hauv kev, kev ua haujlwm ntau lawm yog qhov tsawg, thiab qhov loj ntawm qhov chaw surfacing yog ib qho yooj yim rau deform qhov chaw. Tam sim no, cov txheej txheem ntawm deg hardening ntawm tus kheej yog tsis tshua muaj siv.

(2) Qhov saum npoo ntawm tus kheej yog plated nrog cov tawv chromium nrog hardness ntawm 60 ~ 65hrc thiab thickness ntawm 0.07 ~ 0.10mm. Cov txheej txheej chromium plating muaj siab hardness, hnav tsis kam, corrosion kuj thiab tuaj yeem ua kom lub ntsej muag ci rau lub sijhawm ntev. Cov txheej txheem yog qhov yooj yim thiab tus nqi qis. Txawm li cas los xij, qhov nyuaj ntawm cov tawv chromium txheej yuav txo qis sai vim qhov tso tawm ntawm kev ntxhov siab sab hauv thaum qhov kub thiab txias, thiab nws qhov kub ua haujlwm tsis tuaj yeem siab dua 427 degree. Tsis tas li ntawd, lub zog sib txuas ntawm chromium plating txheej yog qhov tsawg, thiab cov txheej txheem yooj yim poob tawm.

(3) Plasma nitriding yog saws nyob rau saum npoo ntawm tus kheej, nrog ib tug deg hardness ntawm 60 ~ 65hrc thiab ib tug nitriding txheej thickness ntawm 0.20 ~ 0.40mm. Vim tsis zoo corrosion kuj, plasma nitriding hardening txheej txheem yuav siv tsis tau nyob rau hauv lub teb ntawm cov tshuaj muaj zog corrosion.

(4) Cov txheej txheem kev kub ceev (HVOF) cov txheej txheem ntawm qhov chaw muaj qhov siab tshaj plaws hardness ntawm 70 ~ 75hrc, siab aggregate lub zog thiab thickness ntawm 0.3 ~ 0.4mm. Supersonic spraying yog cov txheej txheem tseem ceeb txhais tau tias rau lub ntsej muag hardening ntawm tus kheej. High viscous kua nyob rau hauv thermal fais fab nroj tsuag, petrochemical system thiab thee chemical kev lag luam; Cov txheej txheem hardening feem ntau yog siv hauv cov kua dej sib xyaw nrog cov hmoov av thiab cov khoom siv thiab cov kua dej tawm tau zoo heev.

Supersonic spraying txheej txheem yog txheej txheem txheej txheem uas cov pa roj combustion ua rau huab cua ceev ceev kom nrawm cov hmoov nplej kom cuam tshuam rau qhov chaw ua haujlwm thiab tsim cov txheej txheej tuab. Nyob rau hauv cov txheej txheem ntawm kev cuam tshuam, vim hais tias cov particle tshaj tawm yog ceev (500 ~ 750m / s) thiab particle kub yog tsawg ({3}} degree), lub txheej nrog siab bonding zog, tsis muaj porosity thiab tsawg oxide cov ntsiab lus yuav tau txais. tom qab cuam tshuam lub workpiece nto. Qhov nrawm ntawm cov khoom yog 4 npaug ntawm qhov nrawm ntawm lub suab, txawm tias ntau tshaj qhov nrawm ntawm cov suab ntawm cov khoom.

HVOF yog cov txheej txheem tshiab, nrog cov tshuaj tsuag tuab ntawm {{0}}.3 ~ 0.4mm, mechanical bonding ntawm txheej thiab workpiece, siab bonding zog (77MPa) thiab tsawg porosity ntawm txheej (< 1%).="" the="" heating="" temperature="" of="" the="" workpiece="" is="" low="">< 93="" ℃),="" the="" workpiece="" is="" not="" deformed,="" and="" cold="" spraying="" can="" be="" carried="" out.="" when="" spraying,="" the="" powder="" particle="" velocity="" is="" high="" (1370m="" s),="" there="" is="" no="" heat="" affected="" zone,="" the="" composition="" and="" structure="" of="" the="" workpiece="" have="" no="" change,="" and="" the="" coating="" hardness="" is="" high,="" so="" it="" can="" be="">

Txau vuam yog ib hom thermal txau txheej txheem rau saum npoo ntawm cov ntaub ntawv hlau. Tom qab cov hmoov (hlau hmoov, alloy hmoov thiab ceramic hmoov) yog rhuab mus yaj los yog mus txog ib tug siab yas lub xeev los ntawm lub tshav kub qhov chaw, nws yog sprayed los ntawm huab cua ntws thiab tso rau ntawm pre-kho workpiece nto los tsim ib txheej (welding) txheej. nrees ua ke nrog lub workpiece nto (substrate).

Nyob rau hauv cov txheej txheem tshuaj tsuag welding thiab surfacing hardening txheej txheem, cov cemented carbide thiab cov matrix muaj cov txheej txheem melting, thiab muaj qhov kub yaj cheeb tsam ntawm kev sau ntawm cemented carbide thiab matrix. Txhawm rau kom ua tiav qhov kev ua tau zoo ntawm cov tshuaj tsuag welding lossis surfacing cemented carbide txheej thiab zam qhov vuam kub yaj cheeb tsam raws li cov hlau sib txuas tom qab ua tiav, nws raug pom zoo tias cov thickness ntawm cov tshuaj tsuag vuam los yog ntog cemented carbide yuav tsum ntau tshaj 3 hli.

3 hardness txuam ntawm kev sib cuag nto ntawm lub foob pob valve thiab lub rooj zaum valve

Cov hlau zawv zawg qhov chaw yuav tsum muaj qhov sib txawv hardness, txwv tsis pub nws yooj yim rau tom. Hauv kev siv tswv yim, qhov sib txawv ntawm qhov sib txawv ntawm lub pob valve thiab lub rooj zaum valve feem ntau yog 5 ~ 10hrc, uas ua rau lub pob valve kom muaj kev pabcuam zoo dua. Vim yog kev ua haujlwm nyuaj thiab kev ua haujlwm siab ntawm lub pob, txhawm rau tiv thaiv lub pob los ntawm kev puas tsuaj thiab hnav, qhov tawv ntawm lub pob feem ntau siab dua li ntawm lub rooj zaum valve.

Muaj ob hom hardness txuam dav siv rau hardness txuam ntawm kev sib cuag ntawm lub pob valve thiab lub rooj zaum valve: ① lub hardness ntawm lub pob valve yog 55HRC thiab qhov chaw ntawm lub rooj zaum valve yog 45hrc. Qhov saum npoo ntawm lub pob valve tuaj yeem txau nrog Stellite 20 alloy ntawm qhov nrawm nrawm, thiab qhov chaw ntawm lub rooj zaum valve tuaj yeem muab tso rau ntawm Stellite 12 alloy. Qhov kev sib tw hardness no yog qhov siv dav tshaj plaws hardness txuam rau cov hlau kaw pob li qub, uas tuaj yeem ua tau raws li cov qauv coj los ntawm cov hlau tawv kaw pob li qub; ② Lub hardness ntawm lub pob valve yog 68hrc, qhov saum npoo ntawm lub rooj zaum valve yog 58hrc, qhov saum npoo ntawm lub pob valve tuaj yeem txau nrog tungsten carbide ntawm supersonic ceev, thiab qhov chaw ntawm lub rooj zaum valve tuaj yeem txau nrog stellite20 alloy ntawm supersonic ceev. Qhov hardness no yog siv dav hauv kev lag luam thee chemical, nrog kev hnav tsis kam thiab kev pabcuam lub neej.

Hauv cov teb chaws txawv teb chaws, kev sib txuam nrog tib qhov chaw hardness ntawm lub pob valve thiab lub rooj zaum valve yog siv. Qhov nyuaj ntawm lub pob valve thiab lub rooj zaum valve yog ntau dua 72hrc los ntawm supersonic txau cov txheej txheem tungsten carbide. Txawm tias nyob rau hauv cov xwm txheej ntawm ultra-siab hardness, kev sib cuag nto ntawm lub pob valve thiab lub rooj zaum valve tsis yooj yim rau tom. Txawm li cas los xij, tam sim no, tsis muaj cov txheej txheem sib tsoo uas paub tab rau lub pob valve thiab lub rooj zaum lub rooj zaum nrog qhov tawv tawv ntau dua 72hrc hauv Suav teb, yog li nws tsis yooj yim los xyuas kom meej qhov sib txuam ntawm lub pob valve thiab lub rooj zaum valve, yog li nws tsis tshua siv.

4 kev ceev faj rau hardening ntawm lub zog foob pob valve pob thiab lub rooj zaum valve

Lub pob thiab lub rooj zaum ntawm cov hlau nyuaj kaw lub pob valve feem ntau yog ua los ntawm cov hlau tsis muaj steel lossis cov khoom siv corrosion-resistant. Txwv tsis pub, txheej txheej ntawm cemented carbide thiab lub rooj zaum valve (los yog lub pob valve) yog ib qho yooj yim rau corroded los ntawm nruab nrab, thiab cov cemented carbide txheej ntog, cuam tshuam rau lub neej kev pab cuam ntawm lub pob valve.

Tsis tas li ntawd, cov txheej txheem hardening tsim nyog yuav tsum raug xaiv rau cov khoom sib txawv ntawm lub rooj zaum (los yog lub pob valve). Duplex stainless hlau cov ntaub ntawv yog dav siv nyob rau hauv lub tshav pob ntawm kev lag luam tshuaj. Duplex stainless hlau cov ntaub ntawv muaj kev tiv thaiv zoo corrosion thiab hnav tsis kam.

Duplex stainless hlau yog ib hom hlau nrog ob qho tib si ferrite thiab austenite qauv. Ferrite thiab austenite qauv suav txog li 50 feem pua, thiab cov qauv ob-theem muaj nyob ntawm nws tus kheej. Nws qhov kev ua tau zoo yog cov yam ntxwv ntawm ob qho tib si austenitic stainless hlau thiab ferritic stainless hlau. Nyob rau hauv cov yam ntxwv ntawm ferritic stainless hlau, thaum qhov kub thiab txias nyob rau hauv thaj tsam ntawm 400 ~ 500 degree, muaj zog embrittlement yuav tshwm sim tom qab lub sij hawm ntev rwb thaiv tsev. Qhov tshwm sim no feem ntau hu ua 475 degree embrittlement; Thaum qhov kub siab tshaj 400 ~ 500 degree, cov khoom ntawm duplex stainless hlau yuav raug puas tsuaj.

Yog hais tias cov tshuaj tsuag welding los yog surfacing cemented carbide txheej txheem yog saws rau dual theem stainless hlau, cov txheej txheem melting ntawm cemented carbide thiab matrix (kub feem ntau yog ntau tshaj 900 degree) yuav ua puas lub metallographic qauv ntawm dual theem stainless hlau, yog li dual theem stainless hlau khoom. yog tsis haum rau tshuaj tsuag vuam (los yog heap vuam) cemented carbide hardening txheej txheem. Cov txheej txheem deg hardening ntawm duplex stainless hlau yog tsim rau supersonic txau txheej txheem. Cov txheej txheem hardening yuav tsum xyuas kom meej tias nws tsis tuaj yeem ua puas lub metallographic qauv ntawm matrix ntawm duplex stainless hlau.