博文

Four Popular Types of Welding Procedures

图片
The four main types of welding are: Gas Metal Arc Welding (GMAW/MIG), Gas Tungsten Arc Welding (GTAW/TIG), Shielded Metal Arc Welding (SMAW), and Flux Cored Arc Welding (FCAW) Gas Metal Arc Welding (GMAW/MIG) Also known as Metal Inert Gas or MIG welding, this process uses a thin wire as an electrode. The wire heats up as it is fed through the welding instrument and towards the welding site. Shielding gas must be used to protect the weld from contaminants in the air. Typically, this comes in the form of carbon dioxide, oxygen, argon or helium. This method is often used to work on metals such as stainless steel, copper, nickel, carbon steel, aluminum, and more. Of all the welding processes, this one is most popular across the construction and automotive industries. Gas metal arc welding is believed to be one of the easier welding techniques to learn, which makes it a great area of focus for beginning welders. It also calls for minimal cleanup, offers high welding speeds and better contro
发表评论
阅读全文

What is the first choice of filler metal for brazing work?

图片
 Select filler metal for a brazed joint depends on five main points:  properties of the filler metal  joint design  service requirements  base metal composition cost and availability 1.Properties. Melting point or melting range determines whether the material flows all at once or over a range of temperatures. Fluidity, poor or good fit up of the braze joint determines if the job needs sluggish or rapid-flowing filler. Knowing the fluidity of the filler metal lets the technician prescribe proper joint clearance. Joint remelt temperature. Filler material alloys with the base material at rates depending on the compositions of both materials and temperature. This interaction determines the composition and the melting temperature of the brazed joint, the temperature at which it will fail by fusion. Vapor pressure. In vacuum brazing the filler metal should have a vapor pressure lower than the vacuum pressure to prevent out gassing of filler metal elements. Such out gassing results in a braze
发表评论
阅读全文

The brazing properties of copper and copper alloys

图片
The brazing properties of copper and copper alloys mainly depend on the following factors: 1. The stability of the oxide formed on the surface. 2. The influence of brazing heating process on material properties. 3. The sensitivity of the material to stress cracking. Two oxides of Cu2O and CuO may be formed on the surface of pure copper. The copper surface is covered by Cu2O at room temperature; the oxide scale at high temperature is divided into two layers, the outer layer is CuO, and the inner layer is Cu2O. Copper oxides are easy to remove, so the brazing properties of pure copper are very good. Oxygen copper is copper refined by fire and electrolytic toughening grade copper. It contains oxygen with a mass fraction of 0.02% to 0.1%. Oxygen exists in the form of copper oxide and forms a eutectic structure with copper. This eutectic structure is distributed in the copper matrix in the form of small balls. If aerobic copper is brazed in a reducing atmosphere containing hydrogen, hydroge
发表评论
阅读全文

The best soldering temperature must be considered

Another thing to consider is not just to consider the influence of temperature and time on the quality of welded joints. As the temperature of the welding alloy increases, the alloying and wettability of the filler will increase. Under normal circumstances, the welding temperature must be selected as a filler metal higher than the melting point. However, there are several factors that affect the temperature selection of the welding design.  The best welding temperature must take into account: (1) the lowest possible welding temperature, (2) minimize the influence of thermal effects on the assembly, (3) keep the interaction of the filler/base metal to a minimum, and (4) ) Maximize the use of jigs or fixtures. In some cases, choose a higher welding temperature to accommodate other factors in the design (such as allowing the use of different filler metals, or controlled metallurgical effects, or adequate removal of surface contamination). Time is an important factor for welding joints, bu
发表评论
阅读全文

classification of brazing

Soldering iron brazing is used for soft soldering of small simple or thin parts. Wave soldering is used for the assembly and soldering of large quantities of printed circuit boards and electronic components. When welding, the molten solder at about 250°C passes through the narrow seam to form a wave crest under the pressure of the pump, and the workpiece is welded through the wave crest. This method has high productivity and can realize automated production on the assembly line. Flame brazing uses a flame of combustible gas mixed with oxygen or compressed air as a heat source for welding. The flame brazing equipment is simple and easy to operate. According to the shape of the workpiece, multiple flames can be heated and welded at the same time. This method is suitable for welding small and medium parts such as bicycle racks and aluminum kettle spouts. Dip brazing involves immersing a part or whole of the workpiece in a solder bath covered with flux or a salt bath with only molten salt
发表评论
阅读全文

Need filler metal for brazing, soldering or welding applications?

图片
A filler metal is a metal added in the making of a joint through welding, brazing, or soldering. Four types of filler metals exist—covered electrodes, bare electrode wire or rod, tubular electrode wire, and welding fluxes. Sometimes non-consumable electrodes are included as well, but since these metals are not consumed by the welding process, they are normally excluded.   A variety of alloys are used as filler metals for brazing depending on the intended use or application method. Such as Copper, Copper-zinc(brass), Nickel alloy and Silver. In general, braze alloys are made up of three or more metals to form an alloy with the desired properties. The filler metal for a particular application is chosen based on its ability to: wet the base metals, withstand the service conditions required, and melt at a lower temperature than the base metals or at a very specific temperature. Braze alloy is generally available as rod, ribbon/strips, powder, paste, wire and preforms (such as stamped wash
发表评论
阅读全文

Characteristics of brazing

图片
 Characteristics of brazing: 1. The surface of the joint is smooth and clean, the air tightness is good, the shape and size are stable, the structure and performance of the weldment have little change, and the same or different metals and some non-metals can be connected. When brazing, heating the workpiece as a whole can also be used to weld many welds at one time, which improves productivity. However, the strength of brazed joints is low, and lap joints are often used to increase the strength of the joint by increasing the length of the lap; in addition, the preparation work before brazing requires higher. 2. The solder melts but the weldment does not melt. In order to make the brazing part firmly connected and enhance the adhesion of the brazing material, brazing flux should be used during brazing to remove the oxides on the surface of the brazing material and the weldment. 3. The brazing filler metal has high strength and can be used to connect load-bearing parts. It is widely use
发表评论
阅读全文