Market, there are a variety of solder alloys. The alloy technical, economic requirements more specific, the easier to find a suitable filler material. There are many factors that affect the integrity of the assembly, some of which include: joint design; clean the surface of the welding process; flux; proper cooling and removal of flux residues; heating methods; and solder alloy choice. Most of the time, design, methods, and choice of materials is clear, therefore, the remaining factors is limited. How to select brazing alloy it? What you need to anticipate the attention? This is the article to discuss the issue.
A wide range of brazing alloys can be divided into several groups, in these groups there are a variety of different melting temperature and other properties of the mixture; brazing alloy is also diversity in the form; many brazing filler alloy is used to serve different Welding Flux. Solder alloy is usually described as the brazing filler metal is used as the material to complete the joint connection, it is by definition higher than the melting temperature of 840 ° F but below the melting temperature of the workpiece. A solder alloy should have the following characteristics: 1, the welding surface must be kept moist, mobility and can be as small as 0.001 in. capillary action 2, in the welding process can stop the separation of solid and liquid alloy state 3, part of the role through the workpiece and welding can provide a strong enough knot 4, must be able to meet the corrosion resistance, ductility, thermal & electrical conductivity and other requirements of the quality of the user performance requirements. Brazing alloy from a variety of metal components, so a variety of melting temperature and melting range. So far, we use the "melting temperature" of this phrase to describe the metal from solid to liquid temperature. High and low temperature contrast Low-temperature solder, as the name stated on the alloy begins to melt at lower temperatures. The advantage is that with the shorter heating time increased their productivity, and low energy consumption, creating a greater economy. Despite this, sometimes you need a high melting temperature solder alloy. For example, components need to operate the engine temperature reaches 1200 ° F to work, then you must use a high melting temperature solder can be welded. Other brazing is not, otherwise it will lead to component failure. For brazing level, most of the time also need to use high-temperature solder. When welding two or more consecutive and proximity connectors typically used when the level of brazing. The first use of high temperature solder joints, and the second is to use a relatively low temperature of the alloy, and in the process, the second connector to the first joint below the melting temperature to be heated. Heating method, and some properties of the workpiece determines the temperature range of brazing alloys. If the first complete brazing, you need to select the high-temperature brazing; For example copper or copper-zinc solder (2000-2100 ° F) to weld low carbon steel alloy, 1500-1600F and then the temperature normalized and hardened workpiece. Silver - copper alloy Silver brazing alloys are sometimes used alone, but most of the time constant, and other common metals such as copper to form a mixture. Silver - copper alloy at a temperature of 600 ° F (below the melting temperature of pure copper) start melting. Silver addition can reduce the melting-givers can also improve capillary flow. Fusible silver - copper alloy (72% silver, copper, 28%) as described in the front, commonly used in the narrow range of degree of melting furnace Welding Supplies. Copper - Zinc Alloy Zinc and copper often used together to reduce the melting temperature alloy. These alloys can be used for the same base material of the workpiece welding, such as copper; but usually not enough to connect its corrosion resistance of copper, silicon bronze, copper - nickel or stainless steel. Copper - zinc alloy commonly used in a variety of soldering work, the most common repairs such as auto parts. Silver - Copper - Zinc Alloy Silver, copper and zinc for the first time is used to make common use of industrial silver brazing alloys. Set of these alloys silver - copper and copper - zinc alloy notable feature in one; compared to silver - copper alloy, the same silver content in the case of its low melting degrees. Zinc can also increase the moisture metallic iron. Compared to copper - zinc alloy, silver alloy to enhance the appearance of liquidity and corrosion resistance. Active alloy Active metals, such as titanium, can also be added to the silver alloy brazing so that it can directly, such as graphite, ceramic and other non-metallic surface, this alloy is usually a reactive alloy. Copper - phosphorus alloy Copper - phosphorus alloy widely used in copper and copper alloy connections. Phosphorus can not only reduce the melting temperature solder alloy, can also react with the workpiece surface to remove the copper oxide, or rust on the part of, this is the flux should play a role, so when copper - phosphorus brazing alloys When welding copper, flux can save not. Other oxides (such as brass in the zinc) phosphate can not be removed, so in order to obtain satisfactory joints flux is essential. Such alloy is especially suitable for connecting copper and copper alloys, but can also be used for silver, tungsten and molybdenum welding. Copper - phosphorus alloy can not be used on iron or nickel alloy, as iron, nickel and phosphorus will be produced glassy reaction mixture, and the resulting joint is easy to embrittlement. Silver - Copper phosphorus alloys Add 18% silver to copper 93%, 7% phosphorus alloy to change its melting properties and joint performance, with the silver content increased mobility of the alloy has also been improved, alloy and easier to use and suitable to fill large gap joints. Since the entry of other banks improved scalability and performance also includes conductive. Alloys in the form Brazing alloy exist in many forms: rods, wire, sheet and strip; other preformed include rings, washers, plate and block. Typically, the welding rod or wire used in the simple face-welding, solder preforms products are used in a longer production process or in the face welding is not feasible (lack of economic and technical) in the case, such as the welding torch can be used in furnace on. Alloy is also often paste form, paste containing alloy powder, binder and flux. Although the finished brazing paste is usually much more expensive than in some cases due to ease of operation and become the first choice. Economy Than the cost of welding the high cost of raw materials, which includes preparation time for soldering, brazing own costs, heating costs and other needs of the welding costs. There are many trade-offs for each welding part, in the calculation of the time should be strictly cost considerations.
Stainless steel electrode can be divided into chromium stainless steel electrode and chrome-nickel stainless steel electrode, and who meet the state target these two Types Of Welding Wire, according to GB the GB/T983-1995 delineated investigated. Chromium stainless steel with corrosion (oxidizing acids, organic acids, cavitation) heat and corrosion performance. Is usually chosen to interest the power plants, chemical, oil and other equipment and materials. But under ordinary circumstances of chromium stainless steel weldability is poor, should pay attention to the welding process, heat treatment conditions and selection of appropriate discount of welding stainless steel electrode which classification? . Chrome-nickel stainless steel electrode with good corrosion resistance and oxidation resistance, widely used in chemical, fertilizer, petroleum, medical equipment, making system. Is because the heat from the anti-eye intergranular corrosion, welding current is not too large, about 20 percent less than the carbon steel electrode, the arc should not be too long, rapid cooling between layers appropriate to the narrow stainless steel Stainless Steel ElectrodeMinutes A martensitic stainless steel welding: The martensitic stainless steel with exposed chrome 5 ~ 9% of chromium steel and high chromium steel containing 12% chromium. Such steel hardened bias, welding prone to high hardness of martensite with bainite brittle adds, residual stress, easily produce cold cracks. Therefore necessary to carry out the individual welding to preheat and warm, but not yet cold after welding back line low-temperature tempering. 2, chromium stainless steel welding: The welding of such chromium steel after hardening large and prone to crack, the use of similar chromium stainless steel electrode (CHK202, CHK207) Welding must be carried out more than 300 â„ƒ preheat and post-weld tempering around 700 â„ƒ by slow cooling. Weldments after welding can not be carried out, the use of chromium stainless steel electrode welding (CHS107, CHS207). 3, 17 chrome stainless steel welding: Such chrome steel for improved corrosion resistance and weldability and usually add the appropriate quality solid meta Yan titanium, niobium, molybdenum, can solderability evil compared with 13 chromium steel, can be common types of chromium stainless steel mesh electrode ( CHK302, CHK307) AC welding. Before welding, the weldment should be to join the pre-warm about 200 â„ƒ, welding behind the words 800 â„ƒ Zuozuo, owned by the fire disposal. Chrome-nickel stainless steel electrode (such as CHS107 CHS207) can also be taken into walking the heat treatment after welding.