Abstract: This paper briefly reviews the development process of flux cored wire at home and abroad, introduction of the aluminum-cored wire manufacturing technology and its applications. With the steel flux cored wire manufacturing principles-based study of the aluminum flux cored wire manufacturing process. Aluminum-cored welding wire made of several manufacturing methods to study the aluminum-cored wire manufacturing process characteristics. The results show that: suitable for aluminum-cored wire manufacturing technology is the continuous casting - squeeze - pulling roller - fine drawing - super fine scratch - layer around the law, which, based on laminar flow under isothermal rheological extruded aluminum-cored wire is to create the key technologies.

Keywords: aluminum wire cored isothermal rheological squeeze roller die drawing laminar

0 Introduction

Aluminum and its alloys in industrial production and social life has been used widely, because the proportion of small, good electrical and thermal conductivity, casting and machining of quality aluminum materials in modern industry's important role is irreplaceable. Compared with black metal, aluminum welding more difficult. Poor welding of aluminum is mainly manifested in the oxide film is difficult to remove.

The early 1960s, Ukraine Institute of Barton welding titanium welding was invented in the active flux. In titanium and stainless steel welding, the main role of reactive flux compression arc, rather than the chemical reaction of the bath, but in aluminum welding, flux activity can take advantage of the reduction and evaporation of broken and also aluminum oxide film. Cored aluminum wire is made based on this principle, in cored Welding Electrode Manufacturers, the wire itself contains some active elements, these elements can play a role in flux.

Reducing agent and the reaction product of Al2O3 is AlCl3 and AlxFy, AlCl3 can evaporate into a gas, AlCl3 evaporation process also broken Al2O3 thin films; AlxFy is a compound salt, good fluidity, density less than aluminum, floating on the weld surface and edge of the light gray color.

Use of aluminum-cored wire welding aluminum can save energy, improve production efficiency, particularly in enhancing the quality of the weld with remarkable success. Based on aluminum-cored welding wire for TIG welding process is polar, with the traditional AC TIG welding compared to many advantages, such as weld appearance, smooth, melt deeply, less slag, almost no holes and so on.

1 Several cored aluminum wire manufacturing technology

The manufacture of aluminum-cored wire can draw steel flux cored wire manufacturing method, the steel flux cored wire manufacturing process consists of rolling, wire drawing, processing and after a few layers around the other processes.

Principles of powder metallurgy mechanical alloying of the manufacturing process is to restore the powder, aluminum powder, metal powder, mixing the other add, to a certain temperature mixed metal powder under pressure, to form a certain strength of powder tablet, in the can controlled atmosphere, heat, and pressure to form a powder, tablet, "Brazing spindles", eventually squeeze the timber and die drawing method with reduced roll diameter. Figure 1 is the Al-10Si-type aluminum-cored wire metallographic photos, small black spots are oval or round primary silicon, a large black spot is the activator, and the rest of Al-Si solid solution.

Seamless flux cored wire for the raw materials into a plate of steel. Tubular cored electrode manufacturing method is to first cored powder mixing and sintering into a sintering flux form, then fill pipe (φ16 ~ 25mm) cored through the vibration of the solid fill, and then by rolling, rough drawing, annealing, small pull, copper, and other processes in the system layer around the finished product. Course of the study have tried this method, the reducing agent into the aluminum in the alloy powder, rolling - drawing - diffusion annealing, the final formation of tubular electrode. The main problem is low productivity, powder filling factor of instability.

Squeeze casting method is to restore the powder into aluminum ingots, fully compacted to form a drug core tablet. The first step to solder made of porous cast blank, and then immersed in the honeycomb blank activity flux solution, immersed in the solution in the blank spaces, ingot to cool before squeezing. The process of this method lies in the pre-activated flux and add process.

Laminar flow is the use of continuous extrusion and isothermal extrusion ingot manufacturing flux-cored wire. Continuous casting technology can be homogeneous, composition and stability of the "Lotus" ingot, extrusion technology, such as temperature stability of the fill factor can be rough flux-cored wire.

2 cored wire extrusion of the rheological behavior of aluminum

2.1-cored Cast Iron Electrodes cross-sectional shape of the

In aluminum welding flux cored aluminum wire core of the research process in order to improve the use of flux cored wire performance, developed various types of wire cross-section, Figure 2 is to study the extrusion of aluminum-cored solder cross-section, from left to right, the number of cores were 6,4,3,2,1,0 drugs.

Comprehensive survey of the ingot, extrusion and drawing process of aluminum-cored wire feasibility and reliability of the use. The feasibility of starting from the flux filled, single-hole and two holes optimal; from the use of reliability considerations, the more holes the better reliability. Summing up all the test results for the three-hole final to determine the cross-sectional form.

2.2 The impact of cored aluminum wire extrusion of the main factors

Laminar flow is extrusion of aluminum containing active solder flux ingot to form laminar flow extrusion. Does not contain other groups yuan cast aluminum solder to form porous ingot casting, ingot diameter and bore size constant, the activity to fill the hole in the flux and compaction.

After compaction of the tablet containing the active solder flux has the following characteristics: at different cross-section, the proportion of constant flux and solder; activity can be added to enhance the flux of particles (eg SiC) to form a composite material; full package solder flux is deposited .

Extrusion of aluminum-cored wire, solder stress and deformation is very complex, and with the extrusion process and the process conditions change. Extrusion process technology is the key sequence of flux and solder flow, making the entire extrusion process with the formation of solder and flux laminar rheological deformation.

The formation conditions of the order flow is consistent rheological properties of two materials or similar nature, the main material of the rheological properties of materials and deformation temperature and stress-related.

Extrusion temperature and extrusion pressure adjustment allows the rheological properties of two different materials, similar to well-designed extrusion die shape can always make the two materials form stable laminar flow deformation.

Findings that affect the rheological behavior of the extrusion process, there are seven main factors: In addition to extrusion temperature, extrusion method, solder the organization and structure (in this case is not the phase structure geometry), mold geometry, squeeze factor, extrusion speed and lubrication conditions six factors pushed the material by changing the stress state influence cored aluminum wire of the rheological behavior.

3 under the conditions of isothermal extrusion laminar flow rheology

Used in the research process is isothermal extrusion technology, in particular extrusion temperature and extrusion speed can be obtained under conditions of stable cross-section, uniform filling factor of flux cored wire.

Extrusion temperature on the rheological behavior of the extrusion process mainly works by changing the mechanical properties of solder, solder cored aluminum, in addition to the mechanical properties of Al-Si alloys affected by temperature, the flux of the viscous, plastic and aluminum-silicon alloy and flux friction affected by temperature even more.

Analysis of test results shows that: extrusion temperature setting should be based on the flux used to determine, for the same flux at low temperature extrusion, the extrusion pressure; at a higher temperature extrusion, rheology uneven solder. Actual production in combination with the extrusion temperature results of the tests.

4 flux-cored wire for drawing

Compared with solid wire, cored aluminum wire of the internal organization of the main features are as follows: drug-like core was loose sand, no viscosity, plasticity, cored mainly by the deformation and flow around the material deformation resulting squeeze pressure and friction; wire deformation was significantly reduced.

In the flux-cored wire drawing process, the wire deformation is divided into two parts, the plastic deformation of the metal, the other part is the internal volume of the powder flow and compression, these two variants influence each other. Metal to plastic deformation determine whether the continuous drawing, cored and size of rheological behavior of the degree of compression related to the stability of flux cored wire fill factor, thereby affecting the use and flux-cored welding process stability.

Because the presence of cored, flux cored wire and effective cross-sectional area smaller than the solid welding wire, therefore the flux-cored wire broken in the process of drawing widespread. Wire drawing process optimization is to improve the deformation of aluminum-cored wire drawing process an effective way to study the model used in roller wire drawing technology to improve the deformation, significantly increased the wire deformation.

5 Conclusion

(1) This paper discusses several aluminum-cored solder to obtain the technical means, including: powder synthesis method is a new filler metal manufacturing technology, cast - aluminum extrusion prepared cored wire manufacturing process in China is still the blank.

(2) preliminary study of the various forms of access methods cored ingot, continuous casting technology can be homogeneous, composition and stability of the "lotus" ingot.

(3) isothermal extrusion technology can fill factor to obtain a stable flux-cored rough. Among them, the drug core shape and composition, the weight factor, extrusion index, extrusion speed, extrusion temperature and extrusion die shape is affected cored aluminum wire extrusion process of the main factors.