Welding su a ɛwɔ austenitic stainless steel mu: elastic ne plastic stress ne strain bere a welding no yɛ no yɛ kɛse paa, nanso wɔntaa nhu mpaapaemu a ɛyɛ nwini. Ɛnnyɛ quenching hardening zone ne grain coarsening wɔ weld no mu, enti tensile ahoɔden a ɛwɔ weld no mu no yɛ kɛse.
Ɔhaw atitiriw a ɛwɔ austenitic stainless steel welding mu: welding kɛse a ɛyɛ mmerɛw; Esiane sɛ ɛwɔ aburow hye so su ne sɛnea ɛyɛ mmerɛw wɔ efĩ nketenkete bi ho (S, P) nti, ɛnyɛ den sɛ wɔbɛma mpaapaemu a ɛyɛ hyew aba.
Welding ho haw atitiriw anum ne ayaresa ho nhyehyɛe a ɛfa austenitic stainless steel ho .
01 Chromium carbide a ɛba no ma tumi a weld no wɔ sɛ ɛbɛko atia intergranular corrosion no so tew.
Intergranular corrosion: Sɛnea chromium a ɛso tew ho nkyerɛkyerɛ kyerɛ no, chromium carbide no pue wɔ aburow hye so bere a wɔma weld ne ɔhyew a ɛwɔ beae no yɛ hyew kodu sensitization temperature zone a ɛyɛ 450-850 °C no so, na ɛde chromium-depleted grain boundaries ba, a ɛno ntumi nnyina corrosion ano.
(1) Wobetumi de gyinaesi ahorow a edidi so yi adi dwuma de asiw nsɛe a ɛda weld seam ne nsɛe a ɛwɔ sensitization temperature zone no ntam wɔ ade a wɔde asi wɔn ani so no ano:
bi. Tew carbon a ɛwɔ dade a ɛwɔ ase ne weld no mu no so, na fa nneɛma a ɛma nneɛma gyina Ti, NB ne nneɛma afoforo ka dade a ɛwɔ ase no ho ma ɛde MC a wɔbɛhyehyɛ no di kan na wɔakwati CR23C6 a wɔbɛhyehyɛ no.
b. Ma weld no nyɛ austenite a ɛwɔ afã abien ne ferrite kakraa bi. Sɛ ferrite dodow bi wɔ weld no mu a, wobetumi ayɛ aburow no yiye, wobetumi ama aburow no fã no ayɛ kɛse, na chromium carbide a ɛtɔ wɔ beae biara a ɛwɔ unit no mu no betumi atew aburow hye no so.
Chromium yɛ nea ɛtumi nwura mu kɛse wɔ ferrite mu. CR23C6 yɛ nea wɔpɛ wɔ ferrite mu a ɛmma austenite aburow hye no so tew wɔ chromium mu; ferrite a ɛtrɛw austenites no ntam no betumi asiw nsu a ɛwɔ aburow no hye so no ano wɔ mu a ɛtrɛw no.
c. Hwɛ bere a wɔde tra hɔ wɔ sensitization temperature range no mu. Yɛ nsakrae wɔ welding thermal cycle no mu, ma bere a ɛtra hɔ no yɛ 600～1000°C sɛnea ɛbɛyɛ yiye, paw welding kwan a ahoɔden a ɛwɔ mu no yɛ kɛse (te sɛ plasma argon arc welding), paw welding ɔhyew a ɛba fam ketewaa bi, na fa argon gas a ɛwɔ welld no akyi no di dwuma anaasɛ fa di dwuma de kwati bere a wɔde yɛ no, ma onwini a wɔde fi ase no ne nea wɔde fi ase no yɛ kɛse na wo ne no ntra ase na woatu ase Ɛsɛ sɛ wɔde welded weldew medium a ɛwɔ multilayer welding mu no sɛnea ɛbɛyɛ yiye biara.
d. Sɛ welding wie a, yɛ solution treatment anaasɛ stabilization annealing (850d no 900°C) ne mframa a ɛma onwini ma carbide no charge fi mu na ɛma chromium no trɛw ntɛmntɛm).
(2) Welds a ɛte sɛ sekan. Esiane eyi nti, wobetumi ayɛ nneɛma a edidi so yi a wɔde besiw ano:
Esiane sɛ carbon tumi a ɛyɛ den no tumi trɛw nti, ɛbɛtetew mu wɔ aburow hye no so ma ayɛ tebea a ɛyɛ den yiye wɔ bere a wɔreyɛ onwini no mu, bere a Ti ne Nb da so ara wɔ ahwehwɛ no mu esiane tumi a ɛba fam a ɛtrɛw nti. Sɛ wɔma weld no yɛ hyew bio wɔ sensitization temperature range mu a, supersaturated carbon no bɛtɔ wɔ CR23C6 ntam wɔ crystals no ntam.
bi. Tew carbon a ɛwɔ mu no so. Wɔ stainless steel a ɛwɔ stabilizing elements ho no, ɛnsɛ sɛ carbon a ɛwɔ mu no boro 0.06%.
b. Fa welding nhyehyɛe a ntease wom di dwuma. Paw welding ɔhyew a ɛyɛ ketewaa bi na ama bere a ɛwɔ beae a ɛyɛ hyew dodo no atra ɔhyew a ɛkorɔn mu, na hwɛ yiye sɛ wobɛkwati nkɛntɛnso a 'medium temperature sensitization' nya wɔ welding nhyehyɛe no mu.
Sɛ welding a ɛwɔ afã abien a, ɛsɛ sɛ wɔde weld a ɛne corrosive medium no di nkitaho no welded last (eyi ne nea enti a wɔyɛ welding a ɛwɔ mu a ɛyɛ kɛse-diameter thick-wall welded pipes no wɔ abɔnten welding no akyi). Sɛ wɔantumi amfa anni dwuma a, ɛsɛ sɛ wɔyɛ welding specification ne weld shape no mu nsakrae, na wɔbɔ mmɔden sɛ wɔbɛkwati beae a ɛyɛ hyew dodo a ɛne corrosive medium no di nkitaho no bio no yɛ nea ɛyɛ mmerɛw na ɛyɛ hyew.
c. weld akyi ɔhyew ayaresa. Yɛ ano aduru anaasɛ stabilization ayaresa akyi welding.
02 Adwennwene a ɛyɛ corrosion mpaapaemu .
Wobetumi de nneɛma a edidi so yi adi dwuma de asiw nhyɛso a ɛpaapae no ano:
bi. Paw nneɛma no yiye na yɛ nsakrae wɔ weld no mu wɔ ntease mu. High-purity chromium-nickel austenitic stainless steel, high silicon chromium-nickel austenitic stainless steel, ferritic-austenitic stainless steel, high-chromium ferritic stainless steel, etc. wɔ adwennwene a ɛyɛ papa a ɛma adwennwen no nsɛe, na weld metal no yɛ austentic it-fan a ɛyɛ den.
b. Yi adwennwen a aka no fi hɔ anaasɛ ɛtew so. Wobetumi de adi dwuma ama post-welding adwennwen-relieving ɔhyew ayaresa, te sɛ A Ahobanbɔ wim tebea wɔ-line ɔhyew ayaresa induction anneing fononoo . a ɛfa nnyinasosɛm a ɛfa induction ɔhyew ho. fononoo a ɛyɛ hyew a ɛyɛ annealing a ɛwɔ . Hangao Tech (Seko Machinery) nhia preheating, egye sikɔne 15 pɛ na ama woatumi adu ɔhyew a ɛfata a ɛyɛ annealing no ho ntɛmntɛm. Bere koro no ara mu no, ɛwɔ mframa a ɛyɛ den a ɛkorɔn, a ebetumi asiw mframa a ɛsan kɔ akyi no ano yiye bere a wɔreyɛ annealing no. Annealed welded pipe no wɔ dade nhyehyɛe a ɛyɛ pɛ na intergranular stress no yɛ ketewaa. Bio nso, mfiridwuma akwan te sɛ polishing, shot peening ne hammering nso betumi atew surface residual stress so.
c. Ntease nhyehyɛe ho nhyehyɛe. Sɛnea ɛbɛyɛ a wɔrenhaw adwennwen kɛse.
