SE184929C1

SE184929C1 -

Info

Publication number: SE184929C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: P Kaesmacher och K Kellermann Prioritet begard friin den 24 december 1956 (österrike) Vid rotsvetsning (framstallning av rotsammar) for forbindelse av austenitiska stal, speciellt dylika stal, som skola ha hag kryphallfasthet i varrne, kunna fina sprickor uppsti, om elektrosvetsningen utfores med kalkbasiska elektroder eller om skyddsgassvetsningen genomfores under anvandning av en indifferent (inert) gas. ,Denna sprickbildning har uppenbarligen samband med den omstandigheten, att syre har tilltra.de fran rotsidan, och den kan motverkas genom: anvandning av en reducerande at-mosfar eller genom anvandning av en starkt forhojd halt av exempelvis argon, varigenom emellertid stora kostnader uppkomma. Inventors: P Kaesmacher and K Kellermann Priority requested free on 24 December 1956 (Austria) In root welding (production of root frames) for connection of austenitic steels, especially such steels, which must have creep resistance in the warrants, fine cracks can arise if the electric welding is performed with lime-based electrodes or if the shielding gas welding is carried out using an inert (inert) gas. This cracking is obviously related to the fact that oxygen has entered from the root side, and it can be counteracted by: using a reducing atmosphere or by using a strongly elevated content of, for example, argon, whereby, however, large costs arise.

For fOrminskning av tilltradet av luftens syre fran rotsidan kan vidare sarskilda underlag anvandas, sasom exempelvis kopparremsor. Med hjalp av dessa kan man dessutom hestamma laget av den under ibildning varande roten. Dylika underlag ha emellertid den ,olagenheten, att man of icke kan undvika att desamma smaltas fast. Delia fenomen ar sarskilt stOrande vid rorsvetsning. To reduce the inflow of oxygen from the air from the root side, special substrates can also be used, such as, for example, copper strips. With the help of these, you can also equip the team of the root that is in the imagination. Such a basis, however, has the disadvantage that it is impossible to avoid them being melted down. Delia phenomenon is particularly disturbing in pipe welding.

Man liar (Mil& foreslagit att i stallet for kopparremsor anvanda liknande underlag av molybden, soin ju har hog smaltpunkt, eller att anvanda svetsunderlag med pasprutade molybdenskikt. Risken for fastsmaltning av underlaget kan emellertid darigenom icke undvikas, framfor allt icke, nar det ar fraga cm en svets av austenitiska stallegeringar. It is suggested (Mil & suggested to use similar substrates of molybdenum instead of copper strips, which have a high melting point, or to use welding substrates with spray-painted molybdenum layers. However, the risk of solidification of the substrate can thus not be avoided, especially when a weld of austenitic stable alloys.

Det har dven foreslagits att anvanda keramiska rformkroppar, exempelvis ringar av kvarts eller annat eldfast material. PA grund av den otillrackliga varmeavledningen intrader emellertid en stark temperaturstegring och kan sasom foljd darav en fastbranning uppkomma. Vid anvandning av dylika kera miska delar uppkommer dessutom den risken, att svetsen kan fororenas genom inneslutningar av slagg. Avensa har man fareslagit att anvanda svetsunderlag, som aro uppbyggda av vanliga mantelkedjor. It has also been proposed to use ceramic shaped bodies, for example rings of quartz or other refractory material. Due to the insufficient heat dissipation, however, a strong rise in temperature occurs and as a result a solidification can occur. When using such ceramic parts, there is also the risk that the weld may be contaminated by slag inclusions. Avensa has been threatened with the use of welding bases, which are made up of ordinary mantle chains.

For svetsning av ror ha vidare svetsunderlag foreslagits, vilka bestA av ett i syra losligt material, sasom olegerat kolstal eller andra metaller av jarn, vilka pa underlagets anliggningssida ha ett oxidskikt, som ar bildat genom oxiderancle glodgning eller g,enom paforing a-v andra oxider rued hog smaltpunkt. For welding pipes, welding substrates have also been proposed, which consist of an acid-soluble material, such as unalloyed carbon steel or other metals of iron, which on the contact side of the substrate have an oxide layer formed by oxidative annealing or g, by applying other oxides. high melting point.

Slutligen har man aven foreslagit svetsunderlag av en pA lampligt satt formad metalldel, exempelvis av stal ellen koppar, med ett utbytbart inlagg, sona, dr bojligt och glasfiberartat. Finally, it has also been proposed to weld a substrate of a suitably shaped metal part, for example of steel or copper, with a replaceable insert, sona, flexible and fiberglass-like.

Enligt foreliggaancle uppfinning anvandes en kopparplat med ett keramiskt Overdrag, som bestar av kvartsmjal i blandning med vattenglas, sasom svetsunderlag for framstallning av rotsvetsar for forbindelse av austenitiska stal, speciellt dylika stal med hog kryphallfasthet. Kopparplaten ar .formad pa lampligt satt for att passa till foremMet, som skall svetsas, och for att styra svetsgodset. According to the present invention, a copper plate with a ceramic coating is used, which consists of quartz flour mixed with water glass, as a welding substrate for the production of root welds for connection of austenitic steels, especially such steels with high creep resistance. The copper plate is suitably shaped to fit the object to be welded and to guide the weld metal.

Utomordentliga resultat kunna erhallas exempelvis med ett svetsunderlag, som bestar av en kopparplat, som forsetts med ett ungefar 0,2 mm tjockt pastruket skikt av kvartsmjal med en kornstorlek under 60 pc och air en vattenhaltig losning air vattenglas riled specifika vikten 1,3& i proportionerna 3: 2, varvid naannda skikt efter paforingen pa: pia-ten fatt torka vid ungefar 12° C. Outstanding results can be obtained, for example, with a welding base, which consists of a copper plate, which is continued with an approximately 0.2 mm thick paste-coated layer of quartz flour with a grain size below 60 pc and air an aqueous solution air water glass riled specific weight 1.3 & in proportions 3: 2, with the said layers after the application on: the plate being allowed to dry at about 12 ° C.

Ett dylikt svetsunderlag uppfyllde icke endast kravet pa tillracklig varmeavledning utan aven det villkoret, att det skall kunna latt skiljas eller losgoras frail det stelnade svets- 2— — godset. Vid provning av de erhallna svetssOmmarna saval i obearbetat tillstand som efter avslipningen kunde man _icke konstatera nagra sprickor eller andra fel. Sprickkontrollen skedde med hj alp av den kanda zyglometoden, vid vilken metod i vatten emulgerad olja Wares pa ytan, denna olja darefter bortspolas med vatten och den i eventuella sprickor kvarvarande oljan bringas att fluorescera med hjalp av ultraviolett ljus. Such a weld base not only met the requirement for sufficient heat dissipation but also the condition that it could be easily separated or detached from the solidified weld material. When testing the obtained weld seams in an unprocessed state as after grinding, no cracks or other defects could be found. The crack control was carried out with the aid of the known zyglo method, in which method in water emulsified oil Wares on the surface, this oil is then rinsed off with water and the oil remaining in any cracks is caused to fluoresce by means of ultraviolet light.

For att ytterligare Iftirbattra den latthet, med vilken svetsunderlaget kan skiljas frail den nedsmalta metallmangden efter svetsningen, kan man med ifordel .forsatta den keramiska overdragsmassan med sadana amnen, som vid svetsvarmen bilda en gas. HarfOr lampliga amnen aro exempelvis sonderdelbara karbonat, speciellt kalciumkarbonat. In order to further improve the lightness with which the weld base can be separated from the amount of molten metal after welding, it is advantageous to continue the ceramic coating composition with such substances which form a gas during the welding heat. For example, suitable substances are separable carbonates, especially calcium carbonate.

Det ma sarskilt framhallas, att man sasom svetsunderlag med utomordentligt gott resultat har anvant en kopparplat med ett keramiskt overdrag av kalkspatmjal i blandning med: vattenglas. It must be emphasized in particular that a copper plate with a ceramic coating of lime spatula mixed with: water glass has been used as a welding substrate with exceptionally good results.

Claims

Patent claim:

Welding substrate for the production of root welds for the connection of austenitic, in particular such steels with high creep resistance, can be characterized in that this substrate consists of a. copper plate with a ceramic coating, soil consists of quartz flour 81 mixed with water glass.

Welding substrate according to patent claim 1, characterized in that the ceramic coating furthermore contains decomposable carbonates, such as, for example, calcium carbonate. Request publications: Patents from Great Britain 464 191; Germany 962 307; USA 2 623 148.