Titanium and titanium alloy because density small, intensity corrosion resistance of tall, heat-resisting can be exceedingly good and apply at the branch such as aerospace, petro-chemical, shipbuilding widely. At present high-powered plane, tank is using titanium alloy part, and the range that uses in component of alloy of the titanium in petro-chemical branch also is expanding gradually. And the titanium alloy application on plane and its engine and petro-chemical branch, inevitable need uses solder to take over Duan Jin to join all right, this has important sense to enlarging the applied limits of titanium alloy. The article basically introduces titanium alloy to solder a few issues that the attention needs in the process, with period the attention that causes a person of the same trade. One, titanium alloy can use the weldability great majority of titanium alloy the method of oxygen acetylene welding undertakes soldering, and all titanium alloy all can use solid state solder the method undertakes soldering (if solder of TIG, MIG, plasma arc, laser is mixed,electron beam solders) . In fact, titanium alloy solders the tendentiousness of contact happening crackle should compare black metal (like alloy of ferroalloy, nickel) small much. Although if this good quality is mixed,titanium alloy is had a few otherer solder exceedingly goodly characteristic, a few engineers still think of titanium alloy soldering is quite difficult, the demand that basically soldering to be protected to gas at titanium alloy is particularly high, the personnel ability that has special major only commonly makes sure aeriform protection accords with a requirement. Actually, a lot of solder take over Duan Jun to be able to be used solder titanium alloy. Because soldering,the airy N2 that introduces in the process, O2 makes with the material that contain carbon the fused solder connect of titanium alloy becomes fragile, because this waits for solder area,must clear clean and use inert gase protection. Solder material also basically is the basis is made choose by the character of solder material. The weldability of titanium alloy is general the basis solders of contact extend gender and intensity to evaluate. If the weldability of common titanium alloy expresses place to show. Accepting current applied trend about the laser beam welding of titanium alloy is more and more extensive, laser beam welding receives be out of shape small, manufacturing efficiency is tall, and the rate that achieves automation wants than electron beam and TIG tall. Solder to be compared with electron beam, laser beam welding does not need the sophisticated equipment such as vacuum room, so laser solders practical stronger, and laser beam welding can solder with differring condition solders directly. CO2 laser because power is great, use 25kW/h is OK one-time solder appears 20mm, thick titanium board. Nd: Because YAG laser can use light to fine undertakes energy is transmitted and make of YAG solder to provide flexibility more, but because power is low and make penetration is restricted. When laser beam welding is received, easy generation splatters, make the surface not clean so, when cannot undertake solder aftertreatment must special caution. 2, the stomatic titanium alloy in titanium alloy solders the stomatic generation in contact basically suffers the cleanness before soldering degree and solder the influence of the preparation of contact and weld time accident, still have at the same time a few otherer element. The suction that although the surface is not clean,brings about the main reason that hydrogen is generation of stoma of arc solder connect, but other factor if oxygen, nitrogen, carbon dioxide and the generation that all bring about air hole likely with the inert gase that makes protection. Like be the same as aluminous oxide, the oxide of titanium is had hygroscopic, absorb moisture very easily from inside environmental air. Titanium alloy component is the same as hydrous (or hydrous steam) the hydrogen that there can be gaseous state when contact undertakes soldering dissolves in contact, be in subsequently caky when form alveolus. Reduce titanium alloy to solder the stomatic measure in contact basically has: (Component of 1) titanium alloy and solder want dry. (The solder that 2) prepares suggests to be used inside 48h. (The place that 3) needs part of solder titanium alloy and solder undertake going grease and clean, undertake pickling next. (4) is used high pure argon is enraged or helium gas undertakes protective. 3, below aeriform protection normal temperature, titanium and its alloy are stabler, but the rise as temperature, titanium and its alloy absorb the ability of hydric, oxygen and nitrogen to rise gradually. Titanium begins to suck hydrogen from 250 ℃ , begin to absorb oxygen from 400 ℃ , begin to suck nitrogen from 600 ℃ . The affinity that is the same as O2, N2, H2 as a result of titanium alloy is tall, the meeting when these gas are being contained in contact makes contact becomes fragile, reduce titanium alloy to solder the concussion function of contact, plasticity and tenacity. The meeting when hydrogen is being contained in titanium alloy affects an area to produce defer crackle in heat. And oxygen, nitrogen should be contained in welding line when the volume is higher, welding line or hot influence area also are met below bigger welding stress effect occurrence crackle, this crackle also attributes defer flaw. Because of this inert gase (or vacuum room) protection is very necessary. Because use vacuum room cost taller, use the method that inert gase protects commonly so. Protective gas basically has helium gas and argon energy of life, because helium is angry argon of price prep above is angry, generally speaking, of the titanium alloy that is not special requirement to solder contact and hot influence area, use high pure argon gas undertakes protective can preventing combustion. 4, the examination after solder solders to titanium alloy place undertakes visual examination, basically be to evaluate the stand or fall that gas protects. When the surface shows silvery white, state aeriform protection is first-rate; And it is buff or deep yellow when the surface, state titanium alloy gets slight pollution, but still still can accept; The surface is blue-black, state pollution is more serious, but as a result of use operating mode different, some can be used; The surface is shallow blue, pollution is serious, use almost impossibly; When the surface is bice or gray, pollution is very serious, cannot use; When same appearance is white, pollution is very serious, not usable. 5, chromatic detected method hardness test and backset detect can use detect whether does contact contain impurity, because contain property of the connect when foreign matter to be able to produce a change, the hardness of the connect when main watch contains impurity now and resistor rate can become high significantly. Portable it is OK to hold hardness instrument former a hardness that undertakes checking weldment. The application of this one technology can detect expediently piece solder the stand or fall of quality. Usually, titanium alloy appears solder the state of affairs of crackle is less. However, also can be in sometimes welding line or because of containing impurity generation crackle. Right now, blemish can pass chromatic examination to discover, this method is right at the same time loose also have certain effect. What must notice is, must clean chromatic fluid clean before proceed solders. 6, the rehabilitate of blemish 1.
The tiny flaw on the connect of alloy of local rehabilitate titanium of tiny flaw (be like loose) repair is very easy. The method that uses bore or burnish clears the area that suffers an effect clean, undertake fill next. Those who need an attention is to must ensure solder filling metal is already complete fill revamp a division. 2.
The rehabilitate that linear shows if X smooth negative shows loose had shown linear to show, the method that can use exterior remelting has repair. The energy that the energy that uses when this surface remelting ought to compare the place when soldering before to use wants big, in order to ensure will potential loose all fuse fully. If this method not be successful, or this blemish itself is very serious, be forced to clear whole weld zone clean, solder afresh next. Of this one blemish repair arduous and can raise cost, must notice to assure quality when the operation. 3.
Local hot input is bigger when because solder,be out of shape, and titanium alloy thermal conductivity is poor, arise around weld thereby nonlinear stress. In the begining bath is heated as a result of the metal and form, produce stress concentration around bath thereby. However, because metallic matrix is big, and bath and hot influence area want relative to area small, thereby stress is accumulated around contact and hot influence area. If expand as a result of heat,the force of generation exceeded base metal press stress, local plasticity is out of shape what bring about a structure is permanent be out of shape. The design of degree of the quality that metabolic type and degree basically get data, controlled controlled, connect, add stuff kind and solder process place influence. 4.
Property of base material of metabolic of influence of base material property basically has hot coefficient of expansion (coefficient is bigger, it is easier to be out of shape) , the thermal capacitance of unit volume (thermal capacitance Yue Xiaoyue is out of shape easily) etc. Because be out of shape,be the outcome that tensile stress and material control interaction getting power, because this heats up coefficient of expansion,have crucial effect to deformation. Simple calculation and degree of metabolic of alloy of titanium of real operation discovery are located in between steel and stainless steel (namely deformation is tallish at steel a bit under) of austenite stainless steel. 5.
If the spare parts does not undertake placing holding when solder,control clamping apparatus, criterion its be out of shape can bring about stress to get releasing. Accordingly all sorts of come using prevent shift and metabolic clip to hold a method to get applied when solder. But what need points out is, clip is held closer, the stress that arises in material is greater. Be out of shape to decrease so, should use rigid clamping apparatus above all and undertake cooling on clamping apparatus, restrict thereby be out of shape; Solder those who adopt symmetry want to operate and solder reasonable on craft ordinal, because although metabolize gets inhibition,used rigid clamping apparatus, but still can arise to be out of shape newly after clamping apparatus take out; The pressure of fixture must even, also can arise otherwise be out of shape. 7, epilogue is current of titanium alloy although,solder not extensive, but should note above problem only or can of alloy of titanium of very good implementation solder. Above is a bit experience that we fumble when component of repair titanium alloy summary comes out ceaselessly only, more problems still discover likely in real work, it is cast a brick to attract jade-offer a few commonplace remarks by way of introduction so that others may come up with valuable opinions only here. CNC Milling