Article hnuhnung berah khan stainless steel welded pipe defects awm chhan leh a venna tehfung thenkhat kan sawi tawh a. Vawiin hian an dang zawng chu kan thlir reng a ni.
6. Crater .
Stainless steel welded pipe weld tawp lama pil tawh chu arc crater an ti a. Arc crater hian chutah chuan weld chakna chu nasa takin a tichak lo mai ni lovin, bawlhhlawh tam tak a awm avangin arc crater crack a siam chhuak bawk.
A chhan: A chhan ber chu arc extinguishing-a dwell time a tawi lutuk vang a ni; Plate te tak te welding hian current a lian lutuk.
Preventive measures: Electrode arc welding khar a nih chuan electrode chu molten pool-ah rei vak lo awm tur emaw, circular motion-a tlan tur a ni a, chutah chuan a sir khatah chuan molten pool chu metal-a khat hnuah arc chu tihmit turin a hruai tur a ni Tungsten argon arc welding a nih chuan dwell time attenuated a awm tur a ni a, weld a khat hnuah arc chu a bo tawh bawk.
7. Stomata .
Sanitary stainless steel welded pipe welding hian molten pool chhunga gas chu a solidified hunah a tlanchhuak thei lo va, a awm reng avanga cavities siamte chu pores an ti a ni. Porosity hi welding defect tlanglawn tak a ni a, chu chu weld chhunga porosity leh external porosity ah then theih a ni. Stomata te hi an round, oval, insect ang maia siam, needle ang maia lian leh dense tak tak an ni. Pores awmna hian weld compactness a nghawng mai bakah weld effective area a tihtlem bakah weld mechanical property a ti tlem bawk ang.
A chhan: Sanitary stainless steel welded pipe chunglam leh groove-ah oil, rust, moisture leh thil dang a awm a; Arc welding lai hian electrode coating hi a damp a, hman hmain a vawt lo a; Arc hi a sei lutuk emaw, a then emaw a ni a, molten pool protection effect pawh a tha lo hle a, boruak hian molten pool a rawn luhchilh a Welding current a sang lutuk a, electrode a sen a, coating a tlak hma a, a venna effect a hloh a; Operation method chu a dik lo a, chu chu arc closing action a rang lutuk a, shrinkage cavity siam a awlsam a, joint a arc striking action pawh a dik lo a, chu chu dense stomata siam awlsam a ni a, etc.
Preventive measures: Welding hmain oil, rust, leh moisture te chu groove sir lehlamah 20-30mm chhungin paih chhuah tur a ni; electrode manual-a tarlan temperature leh hun bituk angin khauh takin bak rawh; Welding process parameters dik taka thlang la, dik taka hnathawh; A theih ang anga short arc hmang la, field construction hian windproof facility a nei tur a ni; Electrode dik lo, core corrosion welding, coating cracking, peeling, eccentricity tam lutuk, etc. te hi phal a ni lo.
8. Inclusions leh slag inclusions .
Inclusions chu non-metallic inclusions leh metallurgical reaction hmanga weld metal lo chhuakah oxide awm reng a ni. Slag inclusions hi molten slag a ni a, weld-ah hian a awm reng a ni. Stainless steel welded pipe slag inclusions hi chi hnih ah then theih a ni a, chungte chu spot slag inclusions leh strip slag inclusions te an ni. Slag inclusion hian weld effective section a tichak lo a, chu chuan weld mechanical property a ti tlem a ni. Slag inclusions hian stress concentration a thlen thei bawk a, chu chuan welded structure chu a load hunah awlsam takin a tichhia thei a ni. A chhan: Welding process chhung hian interlayer slag hi a thianghlim lo; Welding current hi a tlem lutuk a; Welding speed a rang lutuk a; Welding process chhung hian operation chu a dik lo a; Welding material leh base metal-a chemical composition chu a inmil tawk lo hle a;
Preventive measures: Slag removal performance tha tak nei electrode thlang la; Interlayer slag chu uluk takin la chhuak rawh; Welding process parameters te chu a remchan dan angin a thlang a; Electrode angle leh transport dan tur siam that.
A thlan hunah chuan . Welded Pipe Production Line , PLC system fing tak dah chu i ngaihtuah thei ang. Hangao Tech (Seko Machinery) PLC system hian a hun takah production data chu a enfiah thei mai bakah, specification hrang hrang welded pipe siam chhuahna formula dahna tur database a siam thei bawk a, chutiang chuan production process chuan engtik lai pawhin database record-te chu a hmu thei ang.
9. Burn through .
Welding process chhung hian groove hnung lam atang chuan molten metal chu a luang chhuak a, stainless steel welded pipe perforation defect chu burn-through an ti a. Burn-through hi arc welding-a chhiatna awm fo zinga mi a ni.
A chhan: Welding current lian tak, welding speed slow, welded pipe a lum lutuk; groove gap lian tak, a blunt edge te lutuk; Welder hnathawh dan tha lo, etc.
Preventive measures: Welding process parameter dik tak leh groove size dik tak thlang la; Welder-a hnathawh thiamna, etc. siam hat.
10. A chhe lai te .
Sanitary stainless steel welded pipe crack te chu a lumna leh a lo thlen hun a zirin cold crack, hot cracks leh reheat cracks ah te then theih a ni a Anni hi longitudinal crack, transverse crack, weld root crack, arc crater crack, fusion line crack leh heat-affected zone crack-ah te then theih an ni a, welded structure-a crack hi defect hlauhawm ber a ni a, hei hian products scrapped a siam mai bakah accident na tak a thlen thei bawk.
(1) Hot crack .
Welding process chhung hian welding seam atanga welding crack siam leh heat-affected zone cooling a metal te chu solidus line bula temperature sang ber thlenga cooling te chu hot cracks an ti a. Welding defect hlauhawm tak a ni a, awm phal loh a ni. Mechanism, welded pipe thermal cracks te temperature range leh shape ang chuan thermal crack te chu crystallization crack, high-temperature liquefaction crack leh high-temperature low-plasticity crack ah te then theih a ni.
A chhan ber chu a chhan ber chu molten pool metal-a melting point hniam tak eutectic leh impurities te hian crystallization process chhungin serious intragranular leh intergranular segregation an siam a, chutih rual chuan welding stress action hnuaiah an awm bawk. Grain boundary zawh zawngin an inthen a, hot crack an siam a ni. Hot crack hi a tlangpuiin austenitic stainless steel, nickel alloy leh aluminum alloy-ah te a awm thin. A tlangpuiin low-carbon steel hi welding lai hian hot crack siam awlsam a ni lo a, mahse steel-a carbon awm zat a san chuan hot cracking tendency pawh a sang chho zel bawk. Preventive measures: Stainless steel welded pipe leh welding material-a sulfur leh phosphorus ang chi bawlhhlawh hlauhawm tak takte chu khauh takin control la, hot cracks sensitivity tihtlem Weld metal-a chemical composition siamrem, weld structure siam that, buhfai tihthianghlim, plasticity siam that, segregation degree tihtlem emaw thehdarh emaw Weld-a bawlhhlawh awm zat tihtlem nan leh segregation degree tihchangtlun nan alkaline welding material hmang la; Welding process parameter dik tak thlang la, weld forming factor chu a remchan dan angin tihpun la, multi-layer leh multi-pass welding method hmang la; Base metal ang bawka lead-out plate hmang la, a nih loh leh zawi zawiin arc chu tihthianghlim la, arc crater chu arc crater-a thermal crack awm loh nan fill rawh.
(2) Cold cracks .
Welded joint chu temperature hniam zawka tihlum a nih chuan (m. temperature hnuai lam steel tan) crack siam chhuah chu cold crack an ti a. Welding zawhah cold crack a lo lang nghal thei a, a nih loh leh hun engemaw chen (hours, days emaw a aia rei emaw) a lo lang thei bawk. Hetiang crack hi delayed crack an ti bawk. Hlauhawm tak a ni.
A chhan: Martensite transformation atanga siam hardened structure, welding residual stress chu restraint nasa tak avanga lo awm a ni a, weld-a hydrogen awm chhunte chu cold crack thlentu lian ber pathum an ni.
Preventive measures: low-hydrogen welding materials thlang la, hman hmaa thupek angin khauh takin siam la; Welding hmain weldment-ah oil leh moisture la chhuak la, weld-a hydrogen awm zat tihtlem la; Weld seam-a hardening tendency tihtlem nan welding process parameter leh heat input dik tak thlang la; Welded joint atanga hydrogen tlanchhuah theihna turin welding zawhah hydrogen elimination treatment hi tih nghal a ni a; Stainless steel welded pipe tan chuan hardening tendency sang tak nei tan chuan welding hmaa preheating leh welding hnua a hun taka heat treatment te hian joint structure leh quality a ti tha thei a ni. Chetdan; Welding stress tihziaawmna turin technological measure hrang hrang hmang rawh.
(3) Reheat crack te .
Welding zawhah stainless steel welded pipe chu temperature range engemaw zat (stress relief heat treatment emaw heating process dang emaw) chhungah a lum leh a, crack te chu reheat cracks an ti a.
A chhan: Reheat crack hi a tlangpuiin low-alloy high-strength steel, pearlitic heat-resistant steel leh stainless steel vanadium, chromium, molybdenum, boron leh alloying element dangteah a awm thin. Welding thermal cycle an neih hnuah chuan sensitive area (550 ~650°C) ah an lum a. A crack tam zawk hi welding heat-a nghawng zone-a coarse-grained zone atanga lo chhuak a ni. Reheat crack tam zawk hi stainless steel welded pipe leh stress concentration place-ah a awm a, reheat crack hi multi-layer welding-ah a awm fo bawk.
Preventive measures: Design mamawh phuhrukna hmunah chuan, weld strength chu base metal aiin a hniam zawk a, chu chu base metal aiin a hniam zawk a, chu chu weld-ah stress a awm a, chu chuan heat-affected zone-a crack awm lohna turin a relax a welding residual stress leh stress concentration tih tlem; Welded pipe-a welding heat input control la, preheating leh heat treatment temperature chu a remchan dan angin thlang la, a theih ang angin sensitive area chu pumpelh rawh.
