A kind of diffusion welding method of dissimilar metal
Technical field
The present invention relates to a kind of diffusion welding methods of dissimilar metal, belong to welding technology field.
Background technique
Diffusion welding (DW) (Diffusion Welding) is a kind of advanced solid phase joining technique, can carry out internal multiple spot, big
The connection of area construction and electric arc accessibility are bad, or are not easy with fusion welding method or irrealizable connection at all.Due to weldering
Part is non-fusible, and Diffusion Welding technology has stronger advantage in the connection side face of dissimilar metal, can get comprehensive performance better than normal
Advise the welding point of melting welding.Welding temperature, pressure and soaking time are the major parameters of diffusion technology for welding, and pressure is generally axis
To pressurization.
In order to improve carrier rocket reliability and meet valve loss of weight requirement, carrier rocket fill valve uses Al alloy shell
The connection structure form of body and stainless steel valve seat, be spirally connected and the mode of shrink fit of original adoption carry out the two connection, such as Fig. 1
It show between Al-alloy casing 1 and stainless steel valve seat 2 and is spirally connected and hot pressing structure type, due to not formed real connection, in length
The problem of Al-alloy casing and stainless steel valve base chamber leakage channel easy to form cause product failure during phase is on active service.
Aluminium alloy is one of the combination of materials for being most difficult to connect in dissimilar metal component with stainless steel, and especially large area connects
It connects, and pressure is that cylinder radially pressurizes shown in Fig. 1 b, difficulty is just more prominent.Aluminium alloy is able to achieve to connect with stainless steel large area
Technology have soldering, explosion weldering, diffusion welding (DW) etc., for aluminum steel soldered fitting intolerant to air corrosion, Joint Reliability energy is relatively low;It is quick-fried
The technical process of fried weldering is relative complex;In " plough groove type cylinder connector vacuum diffusion welding process " 201310301515.0 patents
Propose and realize the vacuum diffusion bonding of plough groove type copper nozzle by the way of cylinder pressurization, which only limit to and small size,
The welding of the connection of copper product of the same race, copper is easier than dissimilar material joining, and the plasticity and toughness of copper are good, small by what is proposed in patent
Angle assembly is easier to realize fitting closely for surface to be welded, and the more of complexity are wanted in the connection of dissimilar material, and two kinds of materials are huge
Physical and chemical performance difference makes it use welding method connection relatively difficult;It is only carried out 201310301515.0 pressurizeing in patent
The connection that the expansion constraint of copper housing both can be realized, and for dissimilar material, such as aluminium alloy and stainless steel steel xenogenesis
Material, only expansion constraint is the connection that cannot achieve the two at all in the outer part.
Summary of the invention
The purpose of the present invention is to provide a kind of diffusion welding methods of dissimilar metal, and this method is by using special designing
Welding tooling and welding technique, obtain joint performance and the excellent welding of dissimilar metal fitting of leakproofness, and entire welding
The soldering at interface is all right, and weld interface meets diffusion characteristic there are apparent concentration gradient.
What above-mentioned purpose of the invention was mainly achieved by following technical solution:
A kind of diffusion welding method of dissimilar metal, includes the following steps:
First hardware to be welded is fitted into the second hardware to be welded by step (1), and guarantee first to
The outer surface of welding metal structural member and the inner surface of the second hardware to be welded fit closely, and obtain Combination Welding part,
First hardware to be welded and the second hardware to be welded are dissimilar metal, and the first metal structure to be welded
The coefficient of expansion of the coefficient of expansion of part less than the second hardware to be welded;
Step (2) installs inner support limiting tool and outside limiting tool to Combination Welding part respectively, i.e., inner support is limited work
Dress is packed into inside the first hardware to be welded, and outside limiting tool (4) is mounted on the second hardware to be welded
Outside, and the outer surface of inner support limiting tool and the inner surface of the first hardware to be welded fit closely, outside limits work
The inner surface of dress and the outer surface of the second hardware to be welded fit closely;The inner support limiting tool and outside limit work
The coefficient of expansion of dress material therefor is respectively less than the coefficient of expansion of the first hardware to be welded, and it is to be welded that fusing point is above first
The fusing point of hardware, inner support limiting tool and outside limiting tool are used to constrain the radial direction of Combination Welding part in welding process
Expansion;
Step (3) carries out vacuum diffusion bonding to Combination Welding part, applies axial pressure to Combination Welding part in welding process
Power, the axial expansion of constraint combination weldment;
After the completion of step (4), welding, inner support limiting tool and outside limiting tool are removed, welding of dissimilar metal fitting is obtained.
It is to be welded by first by assembly tooling in the step (1) in the diffusion welding method of above-mentioned dissimilar metal
Hardware is fitted into the second hardware to be welded, and the assembly tooling is step column construction, wherein level-one step
The outer diameter of column construction and the internal diameter of the first hardware to be welded match, the outer diameter of two stage steps column construction and second
The internal diameter of hardware to be welded matches.
In the diffusion welding method of above-mentioned dissimilar metal, in assembling process, it is to be welded that assembly tooling is packed into second first
Connect inside hardware, the first hardware to be welded be sleeved on to the outer surface of level-one step column construction, first to
It is interference fit between welding metal structural member and the second hardware to be welded;By pressing the first metal knot to be welded
Component is pressed into the second hardware to be welded, and the assembly tooling and the first hardware to be welded and second are to be welded
It is clearance fit between hardware;The assembly tooling is nonmetallic materials.
In the diffusion welding method of above-mentioned dissimilar metal, first hardware to be welded and the second gold to be welded
Belonging to the magnitude of interference being interference fitted between structural member is 0.1-0.3mm;First hardware to be welded and second to be welded
Hardware is 2-10mm along axial contact height;The assembly tooling and the first hardware to be welded and second to
The fit clearance of clearance fit is 0.05-0.1mm between welding metal structural member.
In the diffusion welding method of above-mentioned dissimilar metal, the outer surface of first hardware to be welded opens up ring
Connected in star, the annular groove are single slot, double flute or multiple-grooved.
In the diffusion welding method of above-mentioned dissimilar metal, the depth of the annular groove is 0.5-1mm, along axial length
Degree is the 1/4-1/2 of the first hardware total length to be welded.
In the diffusion welding method of above-mentioned dissimilar metal, inner support limiting tool is step cylindricality knot in the step (2)
Structure, wherein the outer diameter of level-one step column construction and the internal diameter of the first hardware to be welded match, outside limiting tool
Outer diameter for the cylindrical structure of both ends open, internal diameter and the second hardware to be welded matches.
In the diffusion welding method of above-mentioned dissimilar metal, the material of the inner support limiting tool and outside limiting tool is equal
To be nonmetallic, specially molybdenum, ceramics or graphite.
In the diffusion welding method of above-mentioned dissimilar metal, the outer diameter of the level-one step column construction and first to be welded
The internal diameter of hardware matches, fit clearance 0.05-0.1mm, the outside limiting tool internal diameter and second to be welded
The outer diameter of hardware matches, fit clearance 0.05-0.1mm.
In the diffusion welding method of above-mentioned dissimilar metal, the wall thickness of the outside limiting tool is greater than 20mm.
In the diffusion welding method of above-mentioned dissimilar metal, diffusion in vacuum is carried out to Combination Welding part in the step (3)
The process conditions of welding are as follows: it is 10- that welding temperature, which is 520 DEG C -560 DEG C, soaking time 90-120min, axial constraint pressure P,
15MPa。
In the diffusion welding method of above-mentioned dissimilar metal, first hardware to be welded and the second gold to be welded
The material for belonging to structural member includes following three kinds of combinations: the first hardware to be welded is stainless steel, the second metal knot to be welded
Component is aluminium;First hardware to be welded is stainless steel, and the second hardware to be welded is copper;First metal to be welded
Structural member is stainless steel, and the second hardware to be welded is titanium alloy.
In the diffusion welding method of above-mentioned dissimilar metal, active layer is plated on the first hardware surface to be welded,
Active layer material is nickel or silver, and active layer thickness is 5-15 microns.
Compared with prior art, the present invention has the following advantages:
(1), the present invention carries out the assembly of dissimilar metal to-be-welded pieces using the assembly tooling specially designed, effective to guarantee
The concentricity assembled before weldering, ensure that the welding quality and welded rate of welding point.
(2), the present invention is to be welded to the dissimilar metal assembled using the outside limiting tool and internal stay tool specially designed
Fitting carries out the expansion constraint in welding process, so that radial welding surface obtains enough and uniform welding pressure, it is xenogenesis gold
Belong to Diffusion Welding and reliable welding guarantee is provided.
(3), the lesser to-be-welded pieces of the coefficient of expansion are assemblied in inside the biggish to-be-welded pieces of the coefficient of expansion by the present invention, are made
The problem of stress release is not present under cooling and normal temperature state is obtained, has ensured the welding quality of weldment.
(4), it carries out dissimilar metal interface the invention proposes the theory of expansion constraint pressurization radially to pressurize, by interior outside
Limiting tool constraint part to be welded is radially expanded, and the axial expansion of the axial compressive force constraint part to be welded of application has the bulbs of pressure
Being applied on different-metal material welding interface for effect, obtains the weldment met the requirements.
(5) welding method of the present invention is used, the soldering of the entire weld interface of postwelding metallographic observation is all right, weld interface
There are apparent concentration gradients, meet diffusion characteristic.
(6), the present invention is by carrying out notching construction design, and the form of cross-notching to the lesser to-be-welded pieces of the coefficient of expansion
And size optimizes, and cooperates the use of assembly tooling, reduces assembling pressure, reduces weldment deformation, it is more efficient
Ensure that welding quality.
Detailed description of the invention
Fig. 1 is to be spirally connected between Al-alloy casing and stainless steel valve seat in the prior art and hot pressing structure type figure, wherein scheming
1a is spiro connection structure form figure, and Fig. 1 b is hot pressing structure type figure.
Fig. 2 is that assembly tooling of the present invention assembles and shows with the first hardware to be welded, the second hardware to be welded
It is intended to;
Fig. 3 is that inner support limiting tool of the present invention, outside limiting tool, the first hardware to be welded and second are to be welded
Hardware assembling schematic diagram.
Fig. 4 is the first hardware structural schematic diagram to be welded of the invention, and wherein Fig. 4 a is to open single slot structure schematic diagram,
Fig. 4 b is to open dual-slot structure schematic diagram.
Fig. 5 is that the first hardware to be welded of the invention and the second hardware even circumferential pressurization to be welded are illustrated
Figure;
Fig. 6 is LD10 aluminium alloy and stainless steel Diffusion Bonded Joint micro-organization chart in the embodiment of the present invention.
Specific embodiment
The present invention is described in further detail in the following with reference to the drawings and specific embodiments:
The diffusion welding method of dissimilar metal of the present invention specifically comprises the following steps:
(1), first hardware 1 to be welded is fitted into the second hardware 2 to be welded by assembly tooling 5,
And guarantee that the outer surface of the first hardware 1 to be welded and the inner surface of the second hardware 2 to be welded fit closely, it obtains
To Combination Welding part, wherein the first hardware 1 and the second hardware 2 to be welded to be welded is dissimilar metal, and the
The coefficient of expansion of one hardware 1 to be welded less than the second hardware 2 to be welded the coefficient of expansion, in the present embodiment
One hardware 1 to be welded is stainless steel, and the second hardware 2 to be welded is aluminium.
It is illustrated in figure 2 assembly tooling of the present invention and the first hardware to be welded, the second hardware to be welded
First hardware 1 to be welded is packed into the second hardware to be welded by assembly tooling 5 by assembling schematic diagram, the present invention
In 2, assembly tooling 5 is step column construction, wherein the outer diameter of level-one step column construction 5-1 and the first metal structure to be welded
The internal diameter of part 1 matches, and the outer diameter of two stage steps column construction 5-2 and the internal diameter of the second hardware 2 to be welded match.
In assembling process, assembly tooling 5 is packed into inside the second hardware 2 to be welded first, it is to be welded by first
Hardware 1 is sleeved on the outer surface of level-one step column construction 5-1, the first hardware 1 to be welded and second to be welded
It connects between hardware 2 as interference fit, magnitude of interference 0.1-0.3mm.By pressing the first hardware 1 to be welded
It is pressed into the second hardware 2 to be welded, assembly tooling 5 and the first hardware 1 and the second metal to be welded to be welded
It is clearance fit between structural member 2, gap is as small as possible, fit clearance 0.05-0.1mm.
First hardware 1 and the second hardware 2 to be welded to be welded is 2-10mm along axial contact height.
Assembly tooling 5 plays importing, it is ensured that assembly is unbiased, assembly tooling 5 is removed later, by the first hardware 1 to be welded
It is downwardly applied to pressure, is cooperated with the second hardware 2 to be welded.Assembly tooling 5 is nonmetallic materials, is poly- in the present embodiment
Acid imide.
It is illustrated in figure 4 the first hardware structural schematic diagram to be welded of the invention, wherein Fig. 4 a is to open single slot structure
Schematic diagram, Fig. 4 b are to open dual-slot structure schematic diagram.The outer surface of first hardware 1 to be welded opens up annular groove 1-1, institute
Annular groove is stated as single slot, double flute or multiple-grooved.The depth of annular groove 1-1 is 0.5-1mm, is first to be welded along axial length
Meet the 1/4-1/2 of 1 total length of hardware.In addition, as shown in fig. 4 a, the end face of the first hardware 1 to be welded is adopted
With chamfer design, the fifth wheels such as metal inclusion, the angle of chamfering 1-3 not will cause while wiping out the oxidation film of aluminum alloy surface
Range is 30-45 °.
(2), inner support limiting tool 3 and outside limiting tool (4) are installed to Combination Welding part respectively, i.e., limited inner support
Tooling 3 is packed into inside the first hardware 1 to be welded, and outside limiting tool 4 is mounted on the second hardware 2 to be welded
Outside, and the outer surface of inner support limiting tool 3 and the inner surface of the first hardware 1 to be welded fit closely, outer lateral confinement
The outer surface of the inner surface and the second hardware 2 to be welded of position tooling 4 fits closely.Inner support limiting tool 3 and outer lateral confinement
The coefficient of expansion of position 4 material therefor of tooling is respectively less than the coefficient of expansion of the first hardware 1 to be welded, and fusing point is above first
The fusing point of hardware 1 to be welded, inner support limiting tool 3 and outside limiting tool 4 combine weldering for constraining in welding process
Fitting is radially expanded.
It is illustrated in figure 3 inner support limiting tool of the present invention, outside limiting tool, the first hardware to be welded and second
Hardware assembling schematic diagram to be welded.Inner support limiting tool 3 is step column construction as seen from the figure, wherein level-one step column
The outer diameter of shape structure 3-1 and the internal diameter of the first hardware 1 to be welded match, fit clearance 0.05-0.1mm.Outside
Limiting tool 4 is the cylindrical structure of both ends open, and the outer diameter of internal diameter and the second hardware 2 to be welded matches, between cooperation
Gap is 0.05-0.1mm.The material of inner support limiting tool 3 and outside limiting tool 4 is nonmetallic, such as can be molybdenum, ceramics
Or graphite.And the wall thickness of side limiting tool 4 is greater than 20mm.
(3), vacuum diffusion bonding is carried out to Combination Welding part, axial compressive force is applied to Combination Welding part in welding process,
The axial expansion of constraint combination weldment.It is illustrated in figure 5 the first hardware to be welded and the second gold to be welded of the invention
Belong to structural member even circumferential pressurization schematic diagram, the process conditions of vacuum diffusion bonding is carried out to Combination Welding part are as follows: welding temperature
It is 520 DEG C -560 DEG C, soaking time 90-120min, axial constraint pressure P for 10-15MPa.
First hardware 1 to be welded includes following three kinds with the material of the second hardware 2 to be welded and combines: the
One hardware 1 to be welded is stainless steel, and the second hardware 2 to be welded is aluminium;First hardware 1 to be welded is
Stainless steel, the second hardware 2 to be welded are copper;First hardware 1 to be welded is stainless steel, the second metal to be welded
Structural member 2 is titanium alloy.
Active layer is plated on first 1 surface of hardware to be welded, and active layer material is nickel or silver, active layer thickness 5-15
Micron.
(4), after the completion of welding, inner support limiting tool 3 and outside limiting tool 4 is removed, welding of dissimilar metal fitting is obtained.
Embodiment 1
Below to be illustrated for the Diffusion Welding of dissimilar metal aluminium alloy and stainless steel.Aluminium and steel are typical xenogenesis
It is most difficult to one of the combination of materials of weldering in metal welding joints and dissimilar metal, 0Cr18Ni9 stainless steel is used in the present embodiment
With LD10 aluminium-alloy pipe.
(1), welding point designs:
(1), the joint form of aluminium Baogang: since the thermal expansion coefficient of aluminium is much larger than stainless steel, connector is in room temperature or lower
At a temperature of, aluminium shrinkage, which is greater than stainless steel steel, keeps aluminum steel connector stronger;
(2), the mode of cylindrical interference cooperation: aluminium-alloy pipe inner wall, stainless steel tube outer wall are processed as interference before weldering and matched
Cylindrical surface is closed, mentality of designing: 1. removing the oxidation film of aluminum alloy surface in such a way that interference is sheared, reduces oxidation film to diffusion
The adverse effect of welding procedure;It is fitted closely 2. enabling aluminum alloy to realize with stainless steel, it is equiatomic to be conducive to Fe, Al in welding process
Dispersal behavior generates.
(2), welding tooling designs:
In conjunction with aluminum steel diffusion welding (DW) feature, the present invention devises outside limiting tool and two kinds of inner support limiting tool, wherein in
Support limiting tool is served only for cylinder fit structure.
(1), outside limiting tool: outside limiting tool plays the role of inhibiting the expansion of aluminium alloy outer wall, passes through stainless steel
Expansion make aluminium/steel fit closely realize diffusion purpose.Tool structure: adapting to the external surface size of weldment, and weldment can be complete
It is fitted into tooling entirely, fit clearance is controlled in 0.05mm-0.1mm.Tooling selection principle: a. tooling material melting point, which should be higher than that, is welded
Product material fusing point, b. tooling material are not easy that physical reaction occurs with product to be welded;C. tooling material thermal expansion coefficient is far below
Thermal expansion coefficient of aluminum alloy, such as molybdenum, ceramics, graphite;D. tooling material processing performance is good.
(2), inner support limiting tool: inner support limiting tool plays the role of two:
A. positioning action: the tooling material is made of nonmetallic materials, and tooling longitudinal section is in " L-type ", outer diameter point
Not with stainless steel internal diameter, aluminium alloy internal diameter transition fit, guarantee the concentricity of workpiece assembly to be welded, prevents axial application pressure not
The generation of the diffusion interfacial contact unfavorable condition of aluminum steel caused by balancing.It can get different length not using tooling outer diameter scale value
Become rusty steel and aluminium alloy diffusion connector.
B. it constrains the effect of stainless steel medial expansion: in heating welding process, constraining stainless steel medial expansion, promote aluminum steel
Diffusion Welding interface generates enough bulbs of pressure and realizes aluminum steel welding.Using tooling material with outside limiting tool material phase
Together.
(3), aluminum steel diffusion technology for welding control technology
(1), the quality control on the surface of front connector is welded;
For diffusion welding (DW), material surface machining state directly affects joint quality, therefore joint surface roughness will be use up
It may be low.There are excessive interface impurities and greasy dirt can make to contain air and oxide in weld seam for connector, to influence welding ginseng
Several stability and contamination weld vacuum drying oven.Therefore it after being machined test specimen welding surface to be welded, needs to use alcohol before weldering
Or acetone carries out wiping and degreases and surface impurity, to increase the stability of welding process.
In addition, aluminium alloy inner surface, stainless steel outer surface need strict control verticality, because excessive out of plumb surface will
Welding and assembling process aluminium/steel mating surface compactness can be had an impact, therefore when actual welding, it is desirable that the processing of weld interface is hung down
Straight degree control is within 0.05mm.
(2), in welding process technological parameter control
Process parameter optimizing control is to realize the necessary condition of aluminum steel connection, and Control Welding Process is also product final mass
Effective guarantee, control Diffusion Welding temperature, soaking time, welding pressure, magnitude of interference, metallic intermediate layer etc. are to aluminum steel diffusion welding (DW)
The influence that connector generates carries out parameter optimization, realizes the connection of aluminum steel connector high quality.
Due to special product structure form, the connection type of aluminium alloy 1 and stainless steel 2 is that cylinder is radially connected, such as Fig. 5
It is shown.It is not easy to realize the radially uniform pressurization of aluminum steel linkage interface using the conventional axial pressuring method of machinery.This patent proposes
Aluminum steel interface is carried out using the theory of expansion constraint pressurization radially to pressurize: in Diffusion Welding temperature-rise period, aluminium alloy and stainless steel
The two there are difference of expansion stress, in aluminum steel weld interface can generate certain pressure but without periphery constraint in the case where, the pressure compared with
It is small, therefore the periphery expansion (axial, radial) of aluminium alloy and stainless steel is constrained simultaneously, the bulbs of pressure can be promoted effectively to be applied to
On aluminum steel weld interface.Constraint aluminium alloy and stainless steel shaft directly pass through to the axial mechanical pressure of application, the constraint is expanded through
Equipment can be realized;Constraining the expansion of aluminium alloy outer radial periphery need to realize by outside 3 and internal stay tool 4.
(3), aluminum steel connector vacuum diffusion welding performance rating technology
The difference of aluminum steel physical and chemical performance makes its welding point be also easy to produce weld metal zone brittle intermetallic thing, while technological specification does not conform to
The defects of non-soldering, hole are easy to appear in the case where reason, inside weld seam is realized to guarantee that aluminum steel spreads welding line joint quality
The reliability of weld seam is connected with consistency, needs to carry out the destructive detection such as metallographic cutting inspection, mechanics properties testing of test specimen
Etc. being evaluated.Simultaneously required according to design objective, aluminum steel Diffusion Welding connector also need by hydraulic pressure strength, helium Mass Spectrometer Method and
The circumstantial evidences methods such as high/low temperature verifying are detected.
(4), aluminum steel dissimilar metal vacuum diffusion bonding
After guaranteeing that welding quality, test specimen welding surface are machined, still need to carry out using alcohol or acetone before weldering
Wiping removes weldment surface and oil contaminant and impurity, and as needed, stainless steel surface can be 5-10 μm of nickel plating.After weldment cleans up, adopt
0Cr18Ni9 stainless steel is uniformly pressed into LD10 aluminium-alloy pipe with the mode of indentation assembly, and is fitted into graphite tooling, is put into
In diffusion in vacuum furnace, welding parameter is adjusted, starts to weld.Welding condition specifically: 520 DEG C -560 DEG C of temperature, when heat preservation
Between 90-120min, axial constraint pressure P be 10-15MPa.
(5), postwelding is processed
Postwelding requires to be processed according to drawing size.Due to the difference of aluminium alloy and stainless steel dissimilar material thermophysical property
It is different, formed connector biggish heat input or biggish mechanical impact force effect under, may butt joint generate it is unfavorable
It influences, therefore guarantees that aluminum steel connector bears lesser machining stress using fine feed.
(6), the performance detection of postwelding connector
The performance detection of aluminum steel Diffusion Welding connector can pass through following detection means:
(1), it non-destructive testing: since Diffusion Welding is Solid-phase welding, the i.e. infusible mode of raw material, therefore is melted with conventional
It is different to weld the welding defect generated, except a small number of volumetric defects, is such as mingled with, intermetallic compound etc., most welding defect
For area-type defect, do not weld such as and, crackle etc., therefore expanded in such a way that C-scan ultrasound detection is in conjunction with X-ray detection
Dissipate the detection of plumb joint defect.
(2), aluminum steel Diffusion Welding connector can also take the index identical with actual condition such as hydraulic, airtight, explosion, vibration
It is tested.
(3), destructive testing: Metallographic Analysis and mechanical property test test.Postwelding is to LD10/0Cr18Ni9 Diffusion Welding
Head carries out metallographic and shearing test, the soldering of the entire weld interface of metallographic observation are all right.
It is illustrated in figure 6 LD10 aluminium alloy and stainless steel Diffusion Bonded Joint micro-organization chart in the embodiment of the present invention.Welding
Interface meets diffusion characteristic there are apparent concentration gradient.Shearing strength of joint reaches 110MPa.
The above, optimal specific embodiment only of the invention, but scope of protection of the present invention is not limited thereto,
In the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of by anyone skilled in the art,
It should be covered by the protection scope of the present invention.
The content that description in the present invention is not described in detail belongs to the well-known technique of professional and technical personnel in the field.