CN1041900A

CN1041900A - Special metal pipe impact extrusion thermal diffusion welding technology

Info

Publication number: CN1041900A
Application number: CN 88105791
Authority: CN
Inventors: 张悦仁; 吕爱菊
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-10-15
Filing date: 1988-10-15
Publication date: 1990-05-09
Also published as: CN1013253B

Abstract

Dissimilar metal tube connector cold extrusion-thermal diffusion welding technology is a kind of extraordinary welding procedure of field of machining.It adopts cold extrusion and antivacuum, the thermodiffusion welding connection of unprotect atmosphere.Tube connector is a kind of cone socket join structure with the additional metal cover.This technology need not used complex device, and is easy to operate and safe, and the product technology performance is good, the qualification rate height, and cost is low.This technology is used for the welding of dissimilar metal tube connectors such as aluminum bronze that coefficient of expansion difference, weld seam easily generate intermetallic compound, al stainless steel, and its superiority is more obvious.

Description

Special metal pipe impact extrusion thermal diffusion welding technology

Dissimilar metal tube connector cold extrusion-thermal diffusion welding is a kind of extraordinary welding procedure in the field of machining.

In the prior art, friction welding (FW) is adopted in the welding of dissimilar metal (as aluminum bronze, al stainless steel) tube connector usually, carries out the end face butt joint, repaiies brill endoporus, size flash after welding; Vacuum diffusion welding, it need carry out (seeing " welding handbook the 3rd volume under the condition of high temperature, vacuum and certain pressure, American Welding Society (AWS), 1980), a kind of method of Cu-Al connecting pipe explosive welding is disclosed in CN-85 1 03380, it takes the low explosive internal explosion process, and tube connector is socket or docking structure.The weak point of said welding method is, the device therefor that has is complicated, to carry out the machining shaping after the welding that has, the percent defective that has is higher, and heat resistance is relatively poor, when aluminum pipe end and aluminum pipe subsequently, copper pipe end and the copper pipe welding, its weld seam only can bear the temperature below 300 ℃ in short-term as Cu-Al connecting pipe, and the weld seam bonding strength is far below the intensity of aluminum pipe mother metal.

The objective of the invention is to avoid above-mentioned weak point of the prior art, and a kind of dissimilar metal tube connector cold extrusion-thermal diffusion welding technology is provided.

Purpose of the present invention can reach by following measure: at first carry out getting the raw materials ready of weldment blank, these blanks are less metal tubes of thermal coefficient of expansion (as copper pipe), the additional metal cover (as steel bushing) of metal tube that thermal coefficient of expansion is bigger (as aluminum pipe) and thermal coefficient of expansion minimum.The welding ends of the metal tube that thermal coefficient of expansion is less is processed into cone (this part is hereinafter to be referred as the metal tube cone), thermal coefficient of expansion bigger as the metal pipe box, the thermal coefficient of expansion minimum then be the additional metal cover.Then the three is connected together, install on the special fixture, with common forcing press cone is clamp-oned pipe box, two kinds of oxide-films on the metal tube faying face are destroyed by extruding, expose the reactive metal surface, thereby make metal pipe box welding ends surfaces externally and internally overlap the closely pressing of taper hole surface with metal tube cone surface, additional metal respectively; The tube connector socket join structure that then will press together places in the general electric furnace; under the condition of antivacuum, unprotect atmosphere, heat; carry out thermodiffusion welding, utilize the difference of thermal coefficient of expansion between above-mentioned three kinds of metals to keep the needed welding pressure of diffusion welding (DW).Tube connector after at last thermal diffusion being welded cleans and suppresses check, spraying paint to obtain the dissimilar metal tube connector.

Below in conjunction with embodiment-aluminum bronze tube connector welding, the invention will be further described:

Weldment before Fig. 1 represents to push: copper pipe (1), additional steel bushing (2), aluminum pipe (3).

Fig. 2 is contained in to treat cold-stamped weldment blank profile on the special fixture.

Fig. 3 represents the aluminum bronze tube connector that welds.

The welding ends of copper pipe among Fig. 1 (1) needs car to make cone, and cone-apex angle α is the 7-10 degree, and cone microcephaly's external diameter is than the big 0.2-0.3 millimeter of internal diameter of aluminium pipe sleeve (3), and the cone surface roughness is

Additional steel bushing (2) is to adopt mild steel or the little martensitic stain less steel steel pipe of thermal coefficient of expansion, and inwall is processed into taper hole, and cone-apex angle β is the 4-7 degree; The taper hole top diameter is than the big 0.1-0.2 millimeter of external diameter of aluminum pipe (3).This additional steel bushing lock ring through cold extrusion-thermodiffusion welding, promptly is welded into one with tube connector outside the aluminum bronze tube connector, also this steel bushing turning can be removed in case of necessity.Aluminum pipe, copper pipe and additional steel bushing socket join structure on the special fixture after the cold extrusion pressing, copper pipe is clamp-oned the length of length in the aluminum pipe and additional steel bushing should be about equally, be the 8-20 millimeter, external diameter and pipe thickness by tube connector are decided, and Al pipe butt welding end end face grows 2 millimeter than steel bushing end face; Extruding force before cold extrusion stops is 100-200 kgf/every millimeter metal pipe box external diameter; The thermodiffusion welding jointing temp is 490 ℃-510 ℃, temperature retention time 10-20 minute.

One embodiment of dissimilar metal tube connector cold extrusion provided by the present invention-thermal diffusion welding technology is the welding of aluminum steel or rustproof aluminum alloy stainless steel tube connector, and its method is identical with above-mentioned technical process, and the metal tube cone material then adopts steel pipe or stainless steel tube.

The present invention compared with prior art has following advantage;

1, equipment needed thereby is fairly simple, and is easy to operate and safe;

The pressure-resistant seal performance of the dissimilar metal tube connector that 2, is welded by this technology is good, tensile strength greatly for example the weld seam compression resistance of 8 millimeters aluminum bronze tube connectors of φ reach 16 kgfs/centimetre²More than, the pull test that tube connector is carried out shows that fracture occurs in aluminum pipe mother metal part, the aluminum bronze seam is intact;

When 3, the aluminum pipe end of aluminum bronze tube connector and aluminum pipe, copper pipe end and copper pipe welded, its weld seam was not lost the pressure-resistant seal performance after bearing 510 ℃ of high temperature in short-term;

4, welding cost is low;

5, the applied range of this technology, as be used for the welding of dissimilar metal tube connectors such as aluminum bronze that thermal coefficient of expansion difference, fusing point difference, weld seam generate intermetallic compound, al stainless steel, its superiority is more obvious.

Claims

1, a kind of dissimilar metal tube connector cold extrusion-thermal diffusion welding technology, tube connector weldment blank is combined into socket join structure, cold extrusion under certain pressure, carry out the thermal diffusion welding more at a certain temperature, it is characterized in that this technology is applicable to the welding between the different different kinds of metal tubes of thermal coefficient of expansion, method is that the blank that will get ready is contained on the special fixture, clamp-on the bigger metal pipe box of thermal coefficient of expansion with the common baby press metal tube cone that thermal coefficient of expansion is less, oxide-film on both faying faces is destroyed by extruding, expose the reactive metal surface, and make metal pipe box welding ends surfaces externally and internally additional metal surperficial with the metal tube cone respectively and the thermal coefficient of expansion minimum overlap the closely pressing of taper hole surface; The tube connector socket join structure that will press together then places in the general electric furnace, heats under the condition of antivacuum, unprotect atmosphere, carries out thermodiffusion welding, utilizes that the difference of thermal coefficient of expansion keeps the necessary welding pressure of diffusion welding (DW) between the different metal.

2, special metal pipe impact extrusion thermal diffusion welding technology as claimed in claim 1, the cone-apex angle α that it is characterized in that described metal tube cone is the 7-10 degree, and the cone top diameter is than the big 0.2-0.3 millimeter of metal pipe box internal diameter, and metal tube cone surface roughness is ; Additional metal cover inner cone apex angle ss is the 4-7 degree, and the taper hole top diameter is than the big 0.1-0.2 millimeter of metal pipe box external diameter.

3, dissimilar metal cold extrusion-thermal diffusion welding technology as claimed in claim 1, it is characterized in that, described socket join structure is through on special fixture after the cold extrusion, the metal tube cone is clamp-oned length that length and additional metal in the metal pipe box overlap about equally, and metal pipe box welding ends end face grows 2 millimeters than the same end end face of additional metallic sheath.

4, dissimilar metal cold extrusion-thermal diffusion welding technology as claimed in claim 1 is characterized in that it is the 8-20 millimeter that the metal tube cone is clamp-oned the length of metal pipe box, is decided by the external diameter and the wall thickness of tube connector; Stopping preceding extruding force for aluminum bronze, the extruding of al stainless steel tube connector is every millimeter metal pipe box of 100-200 external diameter

5, special metal pipe impact extrusion thermal diffusion welding technology as claimed in claim 1; it is characterized in that it be under the condition of antivacuum, unprotect atmosphere, carry out for the aluminum bronze tube connector; the temperature of thermodiffusion welding is 490 ℃-510 ℃, and temperature retention time is 10-20 minute.

6, special metal pipe impact extrusion thermal diffusion welding technology as claimed in claim 1, it is characterized in that described this additional metal cover by the low mild steel of thermal coefficient of expansion or martensitic stain less steel and so on material make, and become the part of metal connecting tube, also this additional metal can be harnessed an animal to a cart in case of necessity reams.

7, special metal pipe impact extrusion thermal diffusion welding technology as claimed in claim 1 is characterized in that the metal tube cone also can adopt steel pipe or stainless-steel pipe.