One, general solder criterion
The distinction of stainless steel of 1.1 pairs of photographs and austenite stainless steel
Of austenite stainless steel solder the problem often is concerned with itself of welding line metal, be in especially complete austenite or austenite are dominant the hot crack liability that welding line produces in caky process. To general austenite stainless steel, adjust the composition of fill metal, the made ferrite content with be had certain, can reduce these problems to lowermost rate. Stainless steel of tall alloy austenite needs to use metal of nickel radical fill, austenite is caky inevitable, need is controlled through reducing hot input, multi-pass welding.
Because content of ferrite of double photograph stainless steel is high, have fight hot tearing sex first-rately, hot tearing considers rarely when soldering. Double photograph stainless steel solders the mainest problem and hot influence area are concerned, is not welding line metal. Heating up the issue that affects an area is to be able to bear or endure the craze after corrode sex and tenacity loss or solder. To avoid to produce afore-mentioned problems, solder the key of craft is the oldest rate decreases in " red heat " temperature limits total retention period, is not to control any hot inputs that solder together. Experience makes clear, this kind of method can make solder craft is mixed from the technology economic angle optimization.
A few average standard that double photograph stainless steel solders will give out here, and these basic knowledge and criterion are in specific solder the application in the method.
The choice of 1.2 raw material
Double photograph stainless steel can follow chemistry to composition changes with what manufacture technology and produce marked change to soldering adaptability. Already had emphasized mother capable person containing the value of full amount nitrogen repeatedly. If raw material cools adagio,pass ℃ of 700 - 1000 (℉ of 1300 - 1800) temperature interval, or allow to be in Shui Cuiqian air is cold through this interval one minute is controlled, should leave a solderer to finish the time that solder and does not produce any harmful photograph separate out originally so by extinct. Those who need an attention is, undertake actually processing production material, its composition and the metallurgy condition that produce a course ought to with use at soldering the quality condition of the material of craft assess is same.
Clear before 1.3 solder
Should clear before solder heat entirely place, this one requirement applies to double photograph stainless steel not only, and apply to all stainless steel. The premise condition of affirmatory mother capable person and composition of fill metal chemistry is to do not have additional contaminative source. Dirt, grease, smeary, paint and the water of any forms divide metropolis interference to solder to operate and be opposite of weldment be able to bear or endure corrode sex and mechanical function produce adverse effect. If incorrect data undertakes clearing thoroughly before solder, no matter assess of how many craft all is,disable.
1.4 joint design
The joint design of double photograph stainless steel must conduce to complete solder appearing and prevent the mother capable person in incomplete fusion of the existence in caky welding line metal. Had better use machine treatment and do not use groove of emery wheel burnish, so that make weld zone ply or clearance even. Must when burnish, should special attention agrees what groove treatment reachs his to assemble equably. To make sure complete fusion and solder are appeared, ought to take out any burnish burr. To austenite stainless steel, the solderer that has experience can overcome the certain limitation that groove machines through controlling solder fire. But to double photograph stainless steel, these skill can cause material to grow than maleficence time in retention period of harmful temperature interval, bring about a result to exceed eligible craft requirement.
A few joint design of double photograph stainless steel are shown 1 times like the graph. If other design can make sure complete solder shows welding line and burn the dangerous lowest that wear, criterion they also are reasonable.
1.5 warm-up
Because warm-up may be harmful, do not recommend warm-up commonly so. If do not have special and legitimate reason, ought not to regard a working procedure as warm-up. When the damp that if be used at eliminating day of cold or nightly condensation,forms, warm-up may be beneficial. When using warm-up purify fungus infection of hand or foot, should heat steel equably to make an appointment with 100 ℃ (200 ℉) and can undertake after groove clears only.
The temperature between 1.6 hot inputs and layer
Double photograph stainless steel can concessional and opposite tall hot input. What the double photograph after welding line metal is caky organizes is heatproof crack a gender greatly metal of excel austenite welding line. Double photograph stainless steel has higher heat conduction rate and lesser hot coefficient of expansion, welding line place does not have tall in that way like austenite stainless steel local thermal stress. Although be necessary to ask to put forward to be restricted strictly to welding line, but hot crack is not a common problem.
Extremely low hot input can bring about bond of mother capable person and content of ferrite of hot influence area exorbitant, tenacity and be able to bear or endure corrode sex is reduced. Extremely tall hot input increased to form the danger of the photograph between the metal. Affect the issue of the area to prevent heat, solder after procedure should allow this area solder, cool quickly. Workpiece temperature is very important, the cooling impact of area of because it is right hot influence is the biggest. As average standard, limitation of the temperature between the economy top layer with stainless steel of standard double photograph is in 150 ℃ (300 ℉) , super limitation of double photograph stainless steel is in 100 ℃ (210 ℉) . Make soldering this limitation should be used to be worth when craft assess, productivity solders in also should monitor in order to ensure the temperature that the temperature between the layer does not use when assess of prep above craft. Electronic temperature probe and thermocouple are the step with the better temperature between monitoring layer. Soldering in craft assess, make the temperature between the layer of multi-pass welding test specimen under in be being made actually can the temperature between the layer that economy achieves reasonably, this kind of practice is not discreet. When undertaking a large number of soldering, the program is good welder foreword makes each second having enough cooling time is good, economic practice.
1.7 solder postheat is handled
The stress after double photograph stainless steel does not need to undertake solder eliminates processing, and becoming a possibility so is harmful, because heat treatment can make the photograph between the metal (F) of ° of C/1300 - 1830 of ° of 700 - 1000 or α ' (475 ℃ / 885 ℉) brittleness photograph separate out, reduce tenacity and be able to bear or endure corrode sex. Temperature of the heat treatment after solder exceeds 315 ℃ (600 ℉) the separate out that can cause harmful appearance.
The heat treatment after the solder of double photograph stainless steel ought to include anneal of complete solid dissolve, next water temper by dipping in water (11) seeing a table. Should consider anneal of complete solid dissolve after fusion welding, because if soldering,the fill metal that alloy melts had not been used in the process, criterion content of the ferrite in microstructure will be very high.
If plan to undertake dissolve anneal is mixed originallying completely after solder,quench, for example the production of component, criterion heat treatment should regard as solder the one part of craft. Anneal processing can solve ferrite to reach the pertinent question between the metal too much, before workmanship allows to be handled in final anneal, exist a few not quite flexibly mediacy.
The photograph of 1.8 ideal is balanced
The look that often says double photograph stainless steel is evenly " 50-50 " , wait for the austenite of the quantity and ferrite. However, saying this strictly is incorrect, because contemporary the ferrite in double photograph stainless steel is 40 ％ about - 50 ％ , the others is austenite. Think normally, when be austenite for ％ of 25 - 30, the others at least when ferrite content, can gain the good point with double photograph peculiar stainless steel.
In a few solder in the method, in protecting the method that is a foundation with welding flux especially, balance to austenite content taller direction is adjusted in order to improve tenacity, compensation makes because of welding flux content of welding line oxygen increases the tenacity loss that cause. The tenacity of these fill metals is far the very high tenacity cost that achieves under the likelihood after armor plate or steel tube solution treatment, but the tenacity of welding line metal still enough satisfies expectant demand. Solder without a kind the tenacity that the method can make the tenacity of welding line metal and material of forge make friends achieve after complete anneal processing is euqally tall. Over the least value that the double photograph stainless steel that if limit the ferrite content of welding line metal,processes in rolling mill anneal asks, can solder to practicable the method forms needless limitation.
Heat affects the photograph balance of the area, namely make friends armor plate or steel tube add primitive forge to solder additionally hot loop, its ferrite content summary prep above is normally primitive material. Determine accurately with metallographic law the photograph of hot influence area is impossible almost evenly. If content of this area ferrite is very high, perhaps the specification has appeared the unusual situation of extremely fast refrigeration, bring about ferrite content thereby sex of exorbitant He Ren is reduced.
Of 1.9 heterogeneous metals solder
Double photograph stainless steel but rather he double photograph stainless steel, austenite stainless steel, carbon steel and low-alloy steel solder.
Double photograph stainless steel and other when double photograph stainless steel solders, the metal of fill of double photograph stainless steel that uses material of mother of nickel content prep above normally. The nickel content that raises fill metal can make sure welding line forms enough austenite in cooling process.
When double photograph stainless steel and austenite stainless steel solder, often use low carbon and molybdenum content mind the metal of fill of austenite stainless steel between both; Use AWS E 309LMo/ER309LMo normally. Of double photograph stainless steel and carbon steel and low-alloy steel solder to use afore-mentioned same fill metals or AWS E309L/ER309L commonly. If use metal of nickel radical fill, criterion they ought not to contain niobium. The intensity as a result of austenite stainless steel is lower than double photograph stainless steel, of metal of fill of stainless steel of reason use austenite solder contact is inferior to double photograph stainless steel intensity of mother capable person is high.
Watch 1 induced the commonly used fill metal when double photograph stainless steel and heterogeneous metal solder. These example gave out brand of AWS welding rod (E) , but according to soldering appearance of craft, connect is mixed of other condition different, can consider to use welding wire (AWS brand ER) and medical core welding wire.
Express 1 heterogeneous metal to solder with solder material
2, solder craft assess
To standard austenite stainless steel, solder craft assess experiment is quite simple, undertake the method is eligible experimenting a certain quantity ofly to solder in order to prove material of material, solder is mixed only. These assess experiments include hardness experiment and bend test (examine respectively martensite and hot tearing) , reflected the problem that use ferrite, martensite for a long time or may appear when austenite stainless steel. Double photograph stainless steel satisfies these requirements to do not have difficulty, but the photograph between the metal that these experiments discover impossibly to the likelihood in double photograph stainless steel appears or excessive ferrite problem. In the meantime, because need to limit the total time inside limits of temperature of hot influence area, the function of double photograph stainless steel will be mixed to sectional ply solder actually the detail of the operation is very sensitive. Accordingly, must broad sense ground considers " assess " , prove to solder in what make process lieutenant general use namely the project that craft won't cause material is characteristic, especially tenacity and be able to bear or endure corrode sex appears not acceptability loss.
The solders to undertake craft assess is to be sure quite soldering practice to every kinds of ply and appearance, the difference in because the little difference on plan is in,producing a result actually may be very big. However, the complexity that machines actually makes such experiment cost very high. If every kinds solder,the method undertakes soldering to the largest section craft assess, can achieve managing goal.
