a, with a special high-temperature corrosion resistance welding energy (creep rupture strength and elongation) b, excellent resistance to intergranular corrosion and high toughness -196 â„ƒ urea grade stainless steel electrodes. c, cavitation-resistant stainless steel welding electrodes. d, poor welding of chromium stainless steel special electrodes. e, moisture absorption resistance of stainless steel welding rod. f, directed under the special stainless steel welding electrodes, such as AVESTA VDX330, PHILIPS BM316-V. g, special stainless steel welding electrodes positioned as PHILIPS BM316L.
6, electrode manipulation of process performance. Since the intrinsic properties of stainless Welding Wire Chinais insignificant, so the stainless steel welding electrode of the control process is to compare the main performance, the following are a few to determine the level or standard.
a, off the slag. Requirements in the T-joint fillet welds, fillet and butt welding Ying positions, such as boat off the net and in the flat welding slag, slag can fillet weld location from Alice, the entire loss, edges and weld surface without sticky residue. b, splash size. Statement by AVESTA sample can be divided into three levels of spatter (litter spatter or usually spatter), flying small (very little spatter) and no splash (no spatter). The majority of domestic at the first level, a few manufacturers at the second level, there were no third-level non-flying stainless steel electrode. c, then arc, require drug leather sleeve dark straight, depth of 3mm or more, and then arc very easily, under general conditions, without interval restrictions. d, all-position welding, especially large size of 4mm above the all-position welding electrode is better. e, weld shape and color, required weld thin beauty bright, in most cases, weld silver or gold color was yellow.
As the petrochemical industry, medical equipment, food machinery and the rapid development of atomic energy industry, steel production, or both species have a larger growth. Since 1995, the Western developed countries, the development of stainless steel production has been extraordinary. Stainless steel crude steel production output is close to 3% (only 0.3% of China). Manufacture of capital lower than in 1980, more than 50%, and 329 for the United States on behalf of S31803 austenitic / ferritic duplex stainless steel scale production in 1987, these low nickel stainless steel has been recognized performance may gradually replace the 316 stainless steel as in nitrogen, hydrogen sulfide and other impurities in the use of better materials, the environment, while also supporting the development of a variety of electrodes, deserves our attention.
1, duplex stainless steel welding rod, is the microstructure of duplex stainless steel by the 50% F and 50% A balance of a class composed of stainless steel, due to a bipolar organization, both austenitic and ferritic stainless steel characteristics, compared with the ferritic stainless steel, duplex stainless steel, high toughness, brittle transition temperature, resistance to intergranular corrosion and weldability are obvious progress, while preserving the ferritic stainless steel of some of the features, such as 475 â„ƒ brittle, high thermal conductivity, and magnetic properties with superplasticity, compared with the austenitic steels, duplex stainless steel, high strength, resistance to intergranular corrosion, stress corrosion resistance, and significant progress, excellent price-performance duplex stainless steel is stainless steel.
These steels are characterized by: 22-25% chromium, nickel, 5-7% below the 304,316 level of austenitic stainless steel, have added a certain amount of molybdenum, and a small amount of nitrogen, and some also add copper and tungsten . Duplex stainless steel for the evaluation of pitting corrosion in chloride environment the ability to resist the establishment of a pitting resistance equivalent values ??(PRE)
PRE =% Cr +3.3 ×% Mo +16 ×% N
General PRE25-43, when the PRE is usually referred to as more than 40 super duplex steel. Now have developed all kinds of domestic and duplex stainless steel welding rod, such as the UK Manche Te (METRODE) duplex stainless steel company more than 10 varieties, including standard dual-phase steel welding rod, super duplex steel electrode, Li Yang welding dual-phase-specific Aluminum Electrode. Iron and Steel Research Institute, domestic happiness Technologies AG of four duplex stainless steel welding rod, Beijing Jin Wei and Sichuan Atlantic, also developed a 2209 duplex stainless steel welding rod.
2, the new boiler with stainless steel electrode development.
In order to further progress with a stainless steel tube boiler high temperature creep strength, high temperature corrosion properties and resistance to steam oxidation, Japan and the existing SA213-TP304H TP310H two kinds of austenitic steels has been improved, the development of supercritical good overall performance , ultra-supercritical boiler with stainless steel tube new material that is super-304H stainless steel and supporting electrode.
3, general stainless steel welding rod of the series, professional.
Stainless steel commonly used for industrial species, such as 304, 316 type. Consider the needs of foreign welding process, developed a variety of special electrodes such as AVESTA company dedicated 308L/MVR-PW pipe welding, welding vertical down welding 308L/MVR-VDX food and medical equipment for the use of very small splash Japan Oil, EX-series electrodes.
Also with stainless steel metallurgy industry, has developed a variety of foreign performance of stainless steel welding rod, hand to meet the needs of various industries. Such as Japan Oil (TASETO) for the common electrode 308 of the 308,308 L in addition to common electrode, but also developed a progressive high performance 308HL electrode for a very low temperature 308LA electrode to control the carbon content in order to progress their different corrosion resistance The 308L3, 308L2 electrode. Japan taking over the company in addition to the above dissolved species, but also developed with a certain amount of nitrogen in order to progress the weld strength WEL308N2, WEL316LN other nitrogen-containing stainless steel electrode, foreign companies also committed to develop some special stainless steel electrode in order to meet special needs by users.
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.
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
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.
(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.