Vuam txoj kev ntawm alloy structural steel rau kev lag luam valve - Kev qhia tshwj xeeb rau qis kub steel castings rau li qub

Vuam txoj kev ntawm alloy structural steel rau kev lag luam valve - Kev qhia tshwj xeeb rau qis kub steel castings rau li qub Lub zog steel, tseem hu ua lub zog siab steel, muaj lub zog tawm los ntawm tsis pub tsawg dua 1290MPa thiab lub zog tensile tsis tsawg dua 440MPa. Raws li qhov taw qhia tawm thiab kev kho cua sov hauv lub xeev, lub zog steel tuaj yeem muab faib ua cov kub dov normalizing steel, qis carbon tempered steel thiab nruab nrab carbon tempered steel. Kub dov normalizing steel yog ib hom kev kho cua sov uas tsis muaj zog steel, uas yog feem ntau nkag rau hauv kub dov los yog normalizing lub xeev. Nws tsuas yog tso siab rau kev sib cais loj ntxiv, ua kom cov txheeb ze ntawm pearlite, refining nplej thiab nag lossis daus ntxiv kom muaj zog. Tsawg carbon tempered steel yog nyob ntawm quenching, kub tempering kev kho cua sov txheej txheem (tempered kev kho mob) ntxiv dag zog rau cov loj alloy structural steel ... Vuam txoj kev rau alloy structural steels (1) Kev faib tawm ntawm alloy structural steels Alloy structural steel yog ib hom ntawm steel nrog qee cov ntsiab lus alloying ntxiv rau lub hauv paus ntawm cov pa roj carbon zoo tib yam kom tau raws li qhov xav tau ntawm ntau yam kev ua haujlwm thiab cov khoom siv. Alloy structural steels rau vuam feem ntau muab faib ua ob pawg hauv qab no. 1 Steel rau lub zog Lub zog steel, tseem hu ua lub zog siab steel, muaj lub zog tawm los ntawm tsis pub tsawg dua 1290MPa thiab lub zog tensile tsis tsawg dua 440MPa. Raws li qhov taw qhia tawm thiab kev kho cua sov hauv lub xeev, lub zog steel tuaj yeem muab faib ua cov kub dov normalizing steel, qis carbon tempered steel thiab nruab nrab carbon tempered steel. Kub dov normalizing steel yog ib hom kev kho cua sov uas tsis muaj zog steel, uas yog feem ntau nkag rau hauv kub dov los yog normalizing lub xeev. Nws tsuas yog tso siab rau kev sib cais loj ntxiv, ua kom cov txheeb ze ntawm pearlite, refining nplej thiab nag lossis daus ntxiv kom muaj zog. Tsawg carbon tempered steel yog ib tug loj alloy structural steel muaj zog los ntawm quenching thiab kub tempering tshav kub kev kho mob txheej txheem (tempered kev kho mob). Nws cov ntsiab lus carbon feem ntau yog wc0.25%, thiab nws muaj cov yam ntxwv ntawm lub zog siab, zoo yas toughness, thiab tuaj yeem welded ncaj qha rau hauv lub xeev tempered. Cov ntsiab lus carbon ntawm nruab nrab carbon tempered steel yog 0.3% siab dua wc, thiab lub zog tawm los tuaj yeem ncav cuag ntau dua 880MPa. Tom qab quenching thiab tempering kho, nws muaj lub zog siab thiab hardness, tab sis tsis tshua muaj toughness, yog li cov weldability tsis zoo. 2. Cov hlau tshwj xeeb Raws li kev siv ib puag ncig lossis kev ua haujlwm yuav tsum tau muab faib ua pearlite tshav kub resistant steel, tsis tshua muaj alloy corrosion resistant steel thiab tsis tshua muaj kub steel peb. Pearlite kub resistant steel wc≤5%, chromium thiab txhuas raws li hypoeutecoid steel. Nws muaj zoo thermal zog thiab stability. Nws lub ntsiab lus tshwj xeeb yog tias nws tseem muaj qee lub zog thiab oxidation tsis kam ntawm qhov kub txog li 500 ~ 600 ℃. Nws yog tsuas yog siv los tsim cov khoom kub kub hauv cov khoom siv hluav taws xob thermal thiab cov khoom siv petrochemical. Tsawg alloy corrosion resistant steels muaj xws li txhuas-cov kabmob corrosion resistant steels siv rau petrochemical khoom thiab phosphorus-cov kabmob thiab tooj liab-cov kabmob corrosion resistant steels siv rau seawater los yog atmospheric corrosion resistant steels. Ntxiv nrog rau kev txaus siab rau cov khoom siv kho tshuab zoo, cov hlau zoo li no kuj muaj kev tiv thaiv corrosion nyob rau hauv cov khoom nruab nrab. Nws yog feem ntau yog siv rau hauv kub dov los yog normalizing lub xeev, yog ib tug uas tsis yog-kub kev kho mob ntawm ntxiv dag zog rau steel. Tsis tshua muaj kub steel ntawv yuav tsum tau siv nyob rau hauv -40 ~ 196 ℃ tsawg kub cov cuab yeej thiab cov yam ntxwv, lub ntsiab yuav tsum tau ntawm tsawg kub toughness, lub zog tsis siab. Nws feem ntau muab faib ua cov hlau tsis muaj npib tsib xee thiab cov hlau tsis muaj npib tsib xee, feem ntau yog siv rau hauv normalizing lossis normalizing hluav taws lub xeev, belongs rau cov uas tsis yog-kub kev kho mob ntawm ntxiv dag zog rau steel. 3. Weldability tsom xam ntawm siab zog steel Cov teeb meem tseem ceeb ntawm weldability ntawm siab zog steel yog: crystallization tawg, liquefaction tawg, txias tawg, reheat tawg thiab tshav kub cuam tshuam cheeb tsam kev ua tau zoo hloov (1) Crystal crack Lub crystal crack nyob rau hauv lub weld yog tsim nyob rau hauv Lub sij hawm welding lig solidification vim lub eutectic nrog tsawg melting point ua kua zaj duab xis nyob rau hauv lub grain ciam teb thiab tawg raws li grain ciam nyob rau hauv qhov kev txiav txim ntawm tensile kev nyuaj siab. Nws cov khoom tsim muaj feem xyuam rau cov ntsiab lus ntawm impurities (xws li sulfur, phosphorus, carbon, thiab lwm yam) nyob rau hauv lub vuam. Cov impurities no yog cov ntsiab lus uas txhawb nqa crystallization tawg thiab yuav tsum tau tswj nruj me ntsis. Manganese muaj cov nyhuv desulphurization, uas tuaj yeem txhim kho qhov tawg tsis kam ntawm vuam. (2) Thaum tshav kub kub cuam tshuam cheeb tsam ntawm liquefied tawg vuam Liquefaction tawg yog tshwm sim los ntawm lub zos melting ntawm tsawg melting eutectic nyob ze ntawm cov hlau lis ciam teb nyob rau hauv ntau txheej vuam nyob rau hauv tensile kev nyuaj siab vim lub thermal cycling ntawm vuam. 4 Vuam txheej txheem ntawm lub zog siab steel Cov txheej txheem vuam muaj xws li kev xaiv cov txheej txheem vuam thiab cov khoom siv vuam, kev txiav txim siab ntawm vuam specifications, kev tsim cov neeg ua haujlwm kho cua sov thiab kev tsim cov vuam sib dhos thiab vuam ib ntus. Cov txheej txheem vuam tsim nyog yog qhov tseem ceeb los xyuas kom meej cov khoom zoo, txhim kho kev ua haujlwm thiab txo nqi. (1) Kub dov thiab cov txheej txheem vuam ntawm cov hlau ib txwm kub dov ib txwm hlau muaj qhov zoo weldability, tsuas yog thaum cov txheej txheem vuam tsis raug yuav tshwm sim cov teeb meem kev sib koom tes. Kub dov thiab ib txwm hlau yog tsim rau ntau yam vuam txoj kev, feem ntau raws li lub thickness ntawm cov khoom, cov qauv khoom, weld txoj hauj lwm thiab tej yam kev mob nyob rau hauv daim ntawv thov. Feem ntau, vuam tuaj yeem ua tau los ntawm arc vuam, arc vuam, carbon dioxide gas shielded vuam thiab electroslag vuam. Yuav kom tsis txhob embrittlement nyob rau hauv overheated cheeb tsam, me me tshav kub input yuav tsum tau xaiv. Cov khoom siv hluav taws xob me me thiab kev ntsuas kub ua ntej tuaj yeem siv los tswj qhov kub ntawm qhov nruab nrab los tiv thaiv cov kab nrib pleb thaum vuam hlau nrog cov tuab loj thiab cov ntsiab lus hlau alloy. Lub hom phiaj ntawm kev xaiv cov khoom siv vuam yog ob: ib qho yog kom tsis txhob muaj txhua yam tsis xws luag hauv cov vuam, lwm qhov yog kom phim cov khoom siv ntawm lub hauv paus hlau. Vim qhov tshwj xeeb ntawm weld crystallization, nws cov tshuaj muaj pes tsawg leeg feem ntau txawv ntawm cov hlau puag. Thaum siv electrode arc vuam, koj tuaj yeem xaiv cov electrode uas nws lub zog theem sib haum rau lub hauv paus hlau, uas yog, raws li b ntawm lub hauv paus hlau xaiv. Cov kub dov hlau uas tsis tshua muaj vuam lub zog thiab kev sib tsoo me me tuaj yeem xaiv cov calcium electrode nrog cov txheej txheem kev ua tau zoo lossis qis hydrogen electrode. Rau siab zog steel, tsawg hydrogen electrode yuav tsum tau xaiv. Tsis tshua muaj kub steel castings rau li qub Cov qauv no yog siv rau li qub, flanges thiab lwm yam castings nyob rau hauv siab siv nyob rau hauv qis kub ntawm -254 ℃ to -29 ℃. Tag nrho cov castings yuav tsum tau kub-kho raws li tus tsim thiab tshuaj muaj pes tsawg leeg ntawm cov khoom. Txhawm rau ua kom tuab-phab ntsa castings ua raws li qhov yuav tsum tau muaj cov khoom siv kho tshuab, nws feem ntau yuav tsum tau tua cov hlau castings ntawm lub cev cable. Ua ntej normalizing los yog quenching, nws yog tso cai kom txias lub casting ncaj qha rau hauv qab ntawm qhov kub thiab txias ntawm lub theem hloov tom qab casting thiab solidification. Thaum cov txheej txheem ntawm *** casting nto defect yuav ua rau kub siab, lub casting yuav tsum tau preheated rau qhov tsawg kawg nkaus kub teev nyob rau hauv Table 4 ua ntej yuav siv. Lub Scope ntawm Cov Qauv no qhia txog cov kev cai, kev xeem, kev soj ntsuam cov cai thiab cov cim rau qhov kub thiab txias steel castings rau li qub (tom qab no hu ua "castings"). Cov qauv no muaj feem xyuam rau li qub, flanges thiab lwm yam castings nyob rau hauv siab siv ntawm qhov kub thiab txias ntawm -254 ℃ to -29 ℃. Normative reference document Cov nqe lus hauv cov ntaub ntawv hauv qab no dhau los ua cov ntsiab lus ntawm Tus Qauv no los ntawm kev siv rau Tus Qauv no. Rau cov ntawv sau hnub tim, tag nrho cov kev hloov kho tom ntej (tsis suav nrog errata) lossis kev hloov kho tsis muaj feem xyuam rau Tus Qauv no, txawm li cas los xij, cov tog neeg rau kev pom zoo raws li Tus Qauv no raug txhawb kom tshawb nrhiav kev siv cov qauv ntawm cov ntaub ntawv no. Rau cov ntaub ntawv tsis raug lees paub, lawv cov qauv siv tau rau tus qauv no. GB / T222-2006 steel rau tshuaj ntsuam xyuas - Qauv qauv qauv thiab tso cai sib txawv ntawm cov khoom tiav cov tshuaj lom neeg muaj pes tsawg leeg GB / T 223 (txhua qhov chaw) Cov txheej txheem tshuaj ntsuam xyuas ntawm hlau, hlau thiab alloys GB / T 228-2002 Cov khoom siv hlau - Tensile Kev sim ntawm chav sov (ISO 6892: 1998 (E), MOD) GB / T 229-1994 Hlau Charpy notch impact test method (eqv TSG 148:1983) Dimensional tolerances and Machining allowances for Castings (eqv ISO 8062:1994) GB/ TS EN ISO 3752-2003 Kev kho cua sov rau cua sov - Kev txiav txim siab ntawm thaj chaw ua kom sov tau zoo Cast carbon steel qhov chaw rau kev tsim vaj tsev dav dav (neq ISO 3755: 1991) GB / T 12224-2005 steel li qub Kev cai dav dav GB / T 12230-2005 stainless hlau castings rau General li qub - Cov ntsiab lus dav dav rau kev ruaj ntseg zoo (> GB / T 13927 General valve siab kuaj (GB / T 13927-- ​​1992.neq ISO 5208: 1382) GB / T15169-2003 Hlau melting vuam vuam kev soj ntsuam (ISO DIS 9606-1: 2002) JB/T 6439 Valve compression cam khwb cia hlau magnetic particle soj ntsuam Radiographic soj ntsuam ntawm compression cam khwb cia steel qhov chaw ntawm JB / T 6440 Valve JB / T 6902 valve cam khwb cia hlau - xeem txoj kev rau kua nkag JB / T 7927 valve steel castings zoo li yuav tsum tau ASTM A3S1 / A3S1M Austenite thiab austenite rau qhov chaw siab. Kev qhia tshwj xeeb rau ferritic (biphase) steel castings ASTM A352 / A352M Specification rau Ferritic thiab Martensitic Steel Castings rau Qhov Chaw Nyob Hauv Qhov Kub Kub Kub Compression Technical Requirements Cov khoom qib thiab kev pabcuam kub Cov khoom siv qib thiab kev pabcuam kub ntawm cov casting yog qhia hauv Table 1. Casting Cov khoom siv qib thiab kev pabcuam kub Cov tshuaj muaj pes tsawg leeg thiab cov khoom siv kho tshuab Cov tshuaj muaj pes tsawg leeg ntawm castings yuav tsum ua raws li qhov yuav tsum tau ua hauv Table 2. Table 2 Tshuaj muaj pes tsawg leeg ntawm castings (feem ntau)