Bath temperature, a direct impact on the quality of
Welding Electrode , bath temperature, bath, hot metal fluidity, easy fusion, but it is too high, the molten iron is easy to under drip, the side welding forming the back of easy to burn through, forming welding aneurysm, forming also difficult to control, and the the fitting plastic decline bending easy to crack. Low bath temperature, the molten pool is smaller darker molten iron, poor mobility, easy to produce incomplete penetration, lack of fusion, slag and other defects.
The bath temperature welding current, electrode diameter, electrode angle, arc burning time is closely related to the relevant factors to take the following measures to control the bath temperature.
1, the welding current and the electrode diameter: the welding current and the electrode diameter is selected in accordance with the spatial position of the weld, the welding level, when the open welding small selection of the welding current and the electrode diameter is large, vertical, horizontal supine position. 12mm tablet docking the downhand seal underlying selection φ3.2mm electrodes, welding current :80-85A, fill, cover surface layer selection φ4.0mm electrode, welding current :165-175A, a reasonable choice of welding current and electrode diameter, easy to control the bath temperature, the weld forming the foundation.
2, shipped Article, the circle shaped shipped Article bath temperature higher than the crescent shipped Article temperature, the crescent shipped Article temperature bath temperature is higher than the the serrated shipped bar in the 12mm flat welded shut underlying serrated shipped Article and the amplitude of the swing and pause on both sides of the groove, the effective control of the bath temperature, melting holes are basically the same size, the the groove roots not form a weld flash and burn through probability decline, lack of penetration have improved, almost plate butt the flat the side welding sided welding forming no longer is difficult.
3, Electrode angle, the electrodes and the angle of the welding direction at 90 degrees, concentrated arc, and the bath temperature is high, the angle is small, the arc dispersed, the bath temperature is low, such as the bottom of the 12mm flat welding seal, welding angle: 50 - 70 degrees, the decrease in the bath temperature, to avoid welding tumor from the back of the produce. In another example, the change in the 12mm the board vertical welding seal underlying electrode, the fittings, the Welding Rod angle of 90-95 degrees, rapid increase in the bath temperature, melt hole smoothly open, relatively flat to the back forming joint control point within concave phenomenon.
4,Arc burning time, internship teaching φ57 × 3.5 tube fixed horizontally and vertically fixed welding, using the broken arc method welding sealed underlying welding arc interruption frequency and arc burning time directly affects the bath temperature, due to thin wall, limited the capacity of the arc heat, slow down off the arc frequency to reduce bath temperature, easy to produce shrinkage, so the arc burning time can only be used to control the bath temperature, bath temperature is too high, melt hole large arc burning time can be reduced, so that the lowering of the bath temperature, then melt hole smaller, the inside of the pipe forming a moderate height, avoid the inside of the pipe weld ultra-high or a welding tumor.
With the rapid development of petrochemicals, medical equipment, food machinery, and the atomic energy industry, stainless steel production in both varieties have a larger growth. In 1995, stainless steel production has been the extraordinary development of the Western developed countries. Stainless steel production has been close to 3% of the crude steel production (of 0.3%). Manufacturing costs lower than in 1980, more than 50%, S31803 and 329 austenitic / ferritic duplex stainless steel scale production in 1987, this type of high-performance low-nickel stainless steel has been confirmed may gradually replace 316 stainless steel such as impurities such as nitrogen, hydrogen sulfide environment better materials, and also to develop a variety of Welding Rod supporting worthy cause of concern.
1, duplex stainless steel electrode, duplex stainless steel is the microstructure of 50% F 50% A state of equilibrium for a class of stainless steel, duplex structure, which both austenitic stainless steels and ferritic stainless steel characteristics, compared with the ferritic stainless steel, duplex stainless steel high toughness, low-brittle transition temperature, resistance to intergranular corrosion and welding performance are significantly improved, while retaining some of the characteristics of ferritic stainless steel, such as 475 ℃ brittleness high thermal conductivity, superplasticity and magnetic compared to austenitic steels, duplex stainless steel, high strength, resistance to intergranular corrosion, stress corrosion resistance can significantly improve the duplex stainless steel excellent cost performance stainless steel.
The characteristics of such steel is: chromium 22-25%, 5-7% nickel, less than 304,316 austenitic stainless steel horizontal, add a certain amount of molybdenum, and a small amount of nitrogen, and some also added copper and tungsten . Evaluation of duplex stainless steel in chloride environment, the ability to resist pitting, pitting resistance equivalent (the PRE)
PRE =% Cr +3.3 ×% Mo +16 ×% N
General PRE25-43, the PRE over 40 usually referred to as super duplex steel. Now at home and abroad have come up with all kinds of duplex stainless steel electrode, such as the British Man Chete (METRODE) duplex stainless steel varieties of 10 kinds, including standard dual-phase steel electrode, Li Yang Welding Electrode dedicated duplex, super duplex steel electrode steel electrodes. The domestic Central Iron and Steel Research Institute Aetna Technologies AG research the four duplex stainless steel electrode, and The Beijing Jinwei and Sichuan Atlantic also developed a 2209 duplex stainless steel electrode.
2, the development of new boiler with stainless steel electrode.
In order to further improve the boiler with stainless steel tube of high temperature creep strength, high temperature corrosion characteristics and resistance to steam oxidation resistance, Japanese existing of SA213-TP304H and TP310H two austenitic steels improved to develop a good overall performance of the supercritical ultra supercritical boiler with a new stainless steel pipe material Super 304H stainless steel and supporting electrode.
3, generic steel grades stainless steel electrode seriation and specialization.
For the commonly used industrial stainless steel species, such as the 304,316 type. Abroad to consider the needs of the welding process, the development of a variety of special electrodes are the the AVESTA company dedicated welded pipe 308L/MVR-PW electrode, vertical down welding 308L/MVR-VDX electrode and medical devices for food use in particular small splash in Japan grease the EX series electrodes.
In addition, with the development of stainless steel metallurgical industry abroad has also developed a stainless steel electrode with a variety of performance industrial hand to meet all the needs. Such as Nippon Oil and Fats (TASETO) In addition to the generic 308,308 L electrodes commonly used 308-type electrode, also developed the 308HL electrodes improve high temperature performance for 308LA electrode temperature control different carbon content in order to improve its corrosion resistance The 308L3, 308L2 electrode. Japan dissolved successor company apart from the above varieties, developed with certain nitrogen content, in order to improve weld strength WEL308N2, WEL316LN, such as nitrogen-containing stainless steel welding rod, foreign manufacturers are also committed to the development of special stainless steel electrode, in order to meet the special needs , welcomed by users.