Cov txheej txheem rau tshem tawm Internal Residual Stress nyob rau hauv Seamless Steel Pipes

Thaum cov txheej txheem xws li dov, vuam, ua haujlwm txias, thiab kho cua sov,seamless steel kavNws ua rau muaj kev ntxhov siab sab hauv vim qhov kub thiab txias hloov pauv, hloov pauv microstructure, lossis tsis sib xws ntawm cov yas deformation. Yog tias tsis raug tshem tawm, qhov kev ntxhov siab nyob hauv yuav ua rau deformation thiab tawg, txo cov yeeb nkab load-cov kabmob muaj peev xwm thiab kev pabcuam lub neej. Cov hauv qab no qhia txog peb txoj hauv kev tshem tawm kev ntxhov siab, raws li kev siv cov txheej txheem engineering, uas sib npaug kev ua tau zoo thiab kev ua tau zoo.

 

 

1. Kev kho cua sov: Qhov kev daws teeb meem zoo tshaj plaws thiab cov ntsiab lus tseem ceeb

Kev kho cua sov, uas siv cov cua sov kom rov kho cov atoms hauv cov yeeb nkab steel thiab txo kev ntxhov siab, yog txoj kev siv dav tshaj plaws thiab zoo tshaj plaws hauv kev lag luam. Nws feem ntau suav nrog qis -kub tempering thiab kev ntxhov siab rau annealing.

Tsawg-kub tempering yog tsim rau quenched kav xws li siab- carbon steel thiab hlau alloy. Cov yeeb nkab steel yog rhuab mus rau 150-250 degree, tuav ntawm qhov kub no rau 1-3 teev, thiab tom qab ntawd maj mam txias. Thaum lub sij hawm tus txheej txheem no, cov qauv martensite ib nrab decomposes, precipitating nplua carbides uas alleviate lattice distortion thiab yuav tshem tawm 60% -80% ntawm residual kev nyuaj siab yam tsis muaj txo hardness. Piv txwv li, tom qab quenching, 45 # seamless steel yeeb nkab undergoes low-temperature tempering ntawm 200 degree, txo qhov seem seem ntawm 800 MPa mus rau hauv qab 200 MPa thaum tuav ib tug hardness ntawm 25-30 HRC, ua rau nws haum rau siv nyob rau hauv mechanical qhov chaw.

 

Kev ntxhov siab kev ntxhov siab yog tsim nyog rau qis - carbon steel, nruab nrab - carbon steel, thiab welded steel kav. Cov yeeb nkab yog rhuab mus rau 550-650℃(hauv qab ntawm qhov hloov pauv kub), tuav rau 2-4 teev, thiab tom qab ntawd maj mam txias hauv qhov cub. Cov txheej txheem no tshem tawm cov kev ntxhov siab sab hauv los ntawm cov yas deformation los ntawm atomic diffusion, tshem tawm 70% -90% ntawm cov kev ntxhov siab uas nyob nrog tsawg heev ntawm cov khoom siv kho tshuab. Piv txwv li, tom qab vuam ASTM A106 Gr.B steel yeeb nkab, kev ntxhov siab annealing ntawm 600℃txo qhov kev ntxhov siab nyob hauv qhov chaw vuam los ntawm 500 MPa mus rau 80 MPa, tiv thaiv cov kab nrib pleb zoo thiab ua kom haum rau cov kav xa dej.

 

2. Mechanical Stress Reduction: Ib txoj hauv kev yooj yim thiab siv tau zoo

Kev txo cov neeg kho tshuab kev ntxhov siab siv cov quab yuam sab nraud los ntxias cov yas deformation hauv cov kav hlau, tshem tawm cov kev ntxhov siab sab hauv. Txoj kev no tsim nyog rau cov kav dej loj uas cua sov tsis yooj yim lossis rau ntawm - qhov chaw tsim kho. Nws feem ntau suav nrog kev vibration aging thiab siab straightening.

Vibration aging yuav txuas lub vibrator rau cov yeeb nkab steel thiab siv cov vibrations ntawm ib zaus (50{10}}100 Hz) ua rau cov yeeb nkab resonate. Thaum lub sij hawm no resonance, residual kev nyuaj siab tshaj cov khoom yield point, inducing microscopic yas deformation thiab yog li tso cov kev ntxhov siab. Txoj kev no siv lub zog qis (tsuas yog 1/10 ntawm kev kho cua sov) thiab siv sijhawm li 1-2 teev xwb. Nws tuaj yeem tshem tawm 30% -50% ntawm kev ntxhov siab uas tsis muaj kev puas tsuaj rau saum npoo. Piv txwv li, qhov loj-inch Q345 seamless steel yeeb nkab nrog txoj kab uas hla ntawm 1 meter tuaj yeem txo qhov kev ntxhov siab ntawm 400 MPa mus rau kwv yees li 200 MPa los ntawm kev co aging. Txoj kev no yog tsim rau kev ntxhov siab ntawm qhov chaw ntawm cov kav dej siv hauv cov txuas hniav thiab cov qauv hlau.

 

Siab ncaj siv lub hydraulic xovxwm los siv lub siab rau khoov los yog kev ntxhov siab nyob rau hauv cov yeeb nkab steel, inducing thim rov qab yas deformation thiab ntsuas qhov seem seem. Lub siab yog kho raws li cov yeeb nkab specifications (feem ntau yog 50% -70% ntawm cov khoom yield zog) thiab khaws cia rau 10-30 feeb. Txoj kev no tuaj yeem tshem tawm cov kev ntxhov siab hauv zos (xws li kev ntxhov siab ntawm qhov kawg ntawm cov yeeb nkab tom qab kos duab txias) nrog tus nqi txo ntawm 40% -60%. Nws yog feem ntau siv rau kev kho kev ntxhov siab hauvseamless steel kavrau precision machinery, kom ntseeg tau tias tom qab ua tiav.

 

3. Natural Aging: Tsawg-Nqis, Ntev-Lub Sij Hawm Kho

Kev laus ntuj tsim muaj kev nthuav tawm cov yeeb nkab steel rau sab nraum zoov, ib puag ncig ntuj (kub -}20-40 degree, av av 40%-80%). Lub sijhawm ntev - kub hloov pauv thiab kev co me ntsis maj mam tso cov kev ntxhov siab sab hauv. Txoj kev no yuav tsum tsis muaj cov cuab yeej siv peev thiab tsis tshua muaj nqi, tab sis nws siv sijhawm ntev (feem ntau 3-12 lub hlis) thiab tsuas yog tsim nyog rau cov kav hlau uas tsis tshua muaj carbon steel nrog lub sijhawm ua haujlwm luv thiab qis qis, xws li 20 #seamless steel kavrau kev thauj dej dav dav. Kev laus ntuj tuaj yeem tshem tawm 20% -30% ntawm cov kev ntxhov siab seem thiab tiv thaiv cov teebmeem ntawm cov cua sov ntawm cov yeeb nkab saum npoo, ua rau nws tsim nyog rau cov ntawv thov uas xav tau kev zoo nkauj siab.

 

Hauv cov ntsiab lus, hauv kev siv tiag tiag, cov qauv yuav tsum raug xaiv raws li cov khoom siv steel yeeb nkab, kev qhia tshwj xeeb, theem kev ntxhov siab, thiab kev ua haujlwm: kev kho cua sov yog nyiam rau kev ntxhov siab thiab siab precision; Cov txheej txheem siv tshuab tuaj yeem siv rau ntawm - qhov chaw tsim kho lossis cov kav dej loj; thiab kev laus tej yam ntuj tso yuav siv tau rau cov nqi qis -nqi, ntev- tej yaam num. Kev sib xyaw ua ke ntawm cov txheej txheem no (xws li kev ntxhov siab nyem annealing ua raws li kev co kev laus tom qab vuam) tuaj yeem txhim kho kev ntxhov siab ntxiv thiab ua kom muaj kev ua tau zoo thiab kev nyab xeeb ntawm seamless steel kav.