Austenitic stainless steel-a welding characteristics: welding process chhunga elastic leh plastic stress leh strain te hi a lian hle a, mahse cold crack a lang tlem hle. Welded joint-ah hian quench hardening zone leh grain coarsening a awm lo a, chuvangin weld tensile strength a sang zawk a ni.
Austenitic stainless steel welding-a harsatna lian ber berte: welding lian lo tak deformation; A grain boundary characteristics leh trace impurities (s, P) thenkhat a sensitivity avang hian hot crack siam a awlsam hle.
Austenitic stainless steel hmanga welding lama harsatna lian tham leh enkawlna tehfung
1. Chromium carbide siam hian welded joint-te’n intergranular corrosion an do theihna a ti tlem a.
Intergranular corrosion: Chromium depletion theory ang chuan, chromium carbide chu grain boundary-ah a precipitate a, weld leh heat-affected zone chu sensitization temperature zone 450-850°C-a tihlum a nih chuan, chromium-depleted grain boundaries a awm a, chu chu spirrosion dona tur a ni lo.
(1) Target material-a weld seam leh sensitization temperature zone inkar a corrosion tihtlem nan a hnuaia hmalaknate hi hman theih a ni:
a. Base metal leh weld-a carbon awm zat tihtlem la, CR23C6 siam loh nan MC siamna chu dah pawimawh zawk turin base metal-ah stabilizing elements TI, NB leh element dangte dah belh rawh.
b. Weld chu austenite leh ferrite tlemte dual phase structure siam turin siam rawh. Weld-ah hian ferrite engemaw zat a awm chuan buhfai chu a thianghlim thei a, a buhfai awmna hmun chu a pung thei a, ??the grain boundary-a unit area khata chromium carbide precipitation chu tihtlem theih a ni. Chromium hi ferrite ah chuan a inthiar thei hle. CR23C6 hi chromium-ah austenite grain boundary a tlakchhiat loh nan ferrite-ah hian a duh zawk a; Austenites inkar a ferrite darh hian grain boundary zawh zawnga corrosion chu a chhung lam diffusion thlengin a veng thei a ni.
c. Sensitization temperature range-a awm hun chhung control. Welding thermal cycle chu siamrem a, a theih ang anga 600～1000°C-a awm hun chu ti tawi la, energy density sang tak nei welding method thlang rawh (Plasma Argon Arc Welding ang chi), welding heat input tlem zawk thlang la, weld hnung lamah argon pass la, copper pad tihpunna rate chu welded rate-in a awm ang a, chu chu a repeat leh a, a tawp thlengin a awm ang. Multilayer welding lai hian a tawp berah weld tur a ni.
d. Welding zawhah solution treatment emaw stabilization emaw annealing (850～900°C) leh air cooling te chu carbide te charge out leh chromium diffusion ti chak turin ti rawh).
(2) Welded joint-a chemte ang maia chhe tawh. Chuvangin, a hnuaia venna tur ruahmannate hi tih theih a ni:
carbon diffusion theihna chak tak avang hian grain boundary-ah a inthen darh ang a, cooling process laiin supersaturated state a siam ang a, TI leh NB chu diffusion theihna hniam avangin crystal-ah a awm reng ang. Welded joint chu sensitization temperature range-ah a lum leh chuan supersaturated carbon chu crystals inkar ah CR23C6 angin a precipitate ang.
ani. Carbon awm zat tihtlem. Stainless steel stabilizing elements awmna tan chuan carbon content chu 0.06% aia tam a ni tur a ni lo.
b. Welding process tling tak hmang rawh. Welding heat input tlem zawk thlang la, overheated zone awmna hun chu temperature sang takah tihtlem la, welding process chhunga 'medium temperature sensitization' effect pumpelh chu ngaihven rawh. Double-sided welding a nih chuan, corrosive medium nena inzawm weld chu weld hnuhnung ber tur a ni (hei hi a ni, pawn lam welding hnuah large-diameter thick-wall welded pipe chhunga welding an tih chhan a ni). A hman theih loh chuan welding specification leh weld shape chu corrosive medium nena inzawm overheated area awm loh nan siamrem a ngai a, chu chu sensitized leh heated a ni.
c. Post-weld heat hmanga enkawlna. Welding zawhah solution emaw stabilization emaw hmanga enkawlna kalpui thin ang che.
2. Stress corrosion a chhe thei cracking .
A hnuaia tehfungte hi stress corrosion cracking lo awm loh nan hman theih a ni:
a. Material dik taka thlang la, weld composition chu a remchan dan angin siamrem rawh. High-purity chromium-nickel austenitic stainless steel, high silicon chromium-nickel austenitic stainless steel, ferritic-austenitic stainless steel, high-chromium ferritic stainless steel, etc. te hian stress corrosion resistance tha tak an nei a, Weld metal hian a austenitic a nei a, chu chu ferrite steel-a ferrite-a ferrite-a ferrite-a ferrite leh ferrte-a ferrite-a ferrite-a ferrite leh ferrite-te ferrite-a ferrite leh ferrite-te ferrite-a ferrte-a a awm dan a ni.
b. Residual stress tihbo emaw tihtlem emaw. Post-weld stress relief heat treatment kalpui la, mechanical method hmangin polishing, shot peening leh hammering te hmangin surface residual stress tihziaawmna tur a ni.
c. A rilru a hah lutuk a, a rilru a buai em em bawk. stress concentration lian tak awm lo turin.
3. Welding hot cracks (weld-a crystallization crack, heat-a nghawng zone-a liquefaction cracks)
Thermal cracking sensitivity hi a bik takin a thil siam chemical composition, organization leh a performance ah a innghat a ni. Ni hi low melting point compound emaw eutectic emaw siam awlsam a ni a, bawlhhlawh s leh P. Boron leh silicon te inthen darh hian thermal cracking a tichak ang. Weld hi coarse columnar crystal structure siam a awlsam a, directionality chak tak a nei a, hei hi thil tha lo leh element hrang hrang hlauhawm tak takte thliar hranna atan a tha hle. Hei hian continuous intergranular liquid film siam a tichak a, thermal cracking sensitivity a ti tha bawk. Welding chu uniform taka tihlum a nih loh chuan tensile stress lian zawk siam a, welding hot crack siam chhuah a awlsam.
Invenna tur ruahmanna:
a. Thil bawlhhlawh hlauhawm tak takte thupui chu khauh takin thunun rawh s leh p.
b. Weld metal structure chu siam tha rawh. Dual-phase structure weld hian crack resistance tha tak a nei a. Weld-a delta phase hian grains te chu a tithianghlim thei a, single-phase austenite-a directionality a ti bo thei a, grain boundary-a bawlhhlawh hlauhawm tak takte thliar hranna a tihtlem thei a, delta phase hian S a ti bo thei a, P chuan interface energy a tihtlem thei a, intergranular liquid film siamna a buatsaih thei bawk.
c. Weld metal alloy composition chu siam tha rawh. Single-phase austenitic steel-a Mn, C, leh N awm zat chu a remchan dan angin a tipung a, trace element tlemte cerium, pickaxe, leh tantalum (weld structure tithianghlim thei leh grain boundary tithianghlim thei) te pawh a dah tel bawk a, hei hian thermal cracking sensitivity a ti tlem thei a ni.
d. Process measures tih te a ni. Columnar crystal thick tak tak lo awm tur ven nan molten pool overheating tih tlem rawh. Heat input te tak te leh cross-section weld beads te hmang la.
Entirnan, 25-20 austenitic steel hian liquefaction crack a thlen awlsam hle. Base material-a impurity content leh grain size khauh taka tihtlem te, high energy density welding methods hman te, heat input tlem te leh joint-te cooling rate tihsan te a theih a ni.
4. Welded joint te chu a embrittlement .
Heat-strength steel hian welded joint plasticity a enfiah tur a ni a, chu chuan high-temperature embrittlement a veng thei ang; Low-temperature steel te hi welded joint te low-temperature brittle fracture ven nan low-temperature toughness tha tak neih a ngai a ni.
5. Welding distortion lian tak .
Thermal conductivity hniam leh expansion coefficient lian tak avang hian welding deformation a lian hle a, deformation awm loh nan clamp hmangin clamp hman theih a ni bawk.
A chunga kan sawi tak harsatnate pawh i neih chuan pipe welding process enin phenomenon chu i thlirlet thei ang. Tichuan, a inmilna dinhmun azirin buaina chinfel nân a inmil tûr ruahmanna siam rawh. Material ngeia element awm zat bakah hian mold, arch-te insem darh dan, welding current, welding pipe unit-a welding speed hian welded pipe quality-ah nghawng engemaw tak a nei ang. as a . Professional Manufacturer of Industrial Welded Pipe Production Equipment , nena inbiak pawhna tur, leh hmasawnna thlen theih nan kan lo lawm a che . hangao tech a ni a. Austenitic welded pipe siamna kawnga harsatna i tawh mekte
