08-16-2017, 09:29 PM
Welding of dissimilar metals
Abstract:
There are many applications where welding constructions are produced from materials of different structures. the same applies to mechanical problems of wear, in a situation of high temperature or other conditions in which different properties required from different parts of the same weld.
This leads to the necessity of connection of dissimilar metals. Between a successful weld dissimilar metals is one that is as strong as the weaker of the two metals being joined, i.e. with sufficient tensile strength and flexibility, so that the joint will not fail in the weld. Such connections can be made in a variety of different metals and welding processes.
Procedures for obtaining describes mainly the quality of welds in the literature Have Been among at least the same metal or similar composition and properties. There are many applications, but I, in which the welded constructions are produced from materials of different structures. the same applies to mechanical problems of wear, in a situation of high temperature or other conditions in which different properties required from different parts of the same weld.
This leads to the necessity of connection of dissimilar metals. Welding of dissimilar metals are Being more frequently; Therefore, this article is dedicated to providing information for the successful accession of some of the most common combinations of metals.
Between a successful weld dissimilar metals is one that is as strong as the weaker of the two metals being joined, i.e. with sufficient tensile strength and flexibility, so that the joint will not fail in the weld. Such connections can be made in a variety of different metals and welding processes.
The problem of creation of joints between dissimilar metals refers to the transition zone between metals and intermetallic compounds formed ESTA transition zone. For the type of Fusion welding processes it is important to investigate the phase diagram of the two metals involved. If there is a mutual solubility of two dissimilar metals joints can be made successfully. If little or no solubility Between two metals must not be connected to the weld will not be successful.
Intermetallic compounds formed between dissimilar metals should be investigated to determine their sensitivity to crack, plasticity, the propensity to rust, etc. connection intermetalli eskoe ESTA Microstructure is extremely important. In some cases, you must use third metal soluble from of each metal in order to get a successful connection.
Another factor involved in predicting successful life for dissimilar metal joint replacement refers to the thermal expansion coefficient of both materials. If they differ, then the stress will be set up in the intermetalli eskom area during any changes in temperature of welded construction. If the area is extremely brittle intermetalli eskij services, may soon occur.
The difference in the temperatures of melting both metals to be joined, that must also be addressed. This is the main concern When welding process using heat from the molten metal is going to be long before other when exposed to the same source of heat. When metals of different melting temperatures and levels of thermal expansion must be connected to the welding process with high thermal capacity, which will make the weld Quickly have an advantage.
The difference of metals on the electrochemical scale indicating their susceptibility to corrosion in the intermetalli eskom zone. If they are far apart on the scale, corrosion can be a serious problem.
In certain situations, the only way to make a successful joint is the use of transition between two dissimilar materials of metals. An example of this is the attempt of copper-steel welding. The two metals are not mutually soluble, but soluble nickel with both of them. Therefore, using metallic nickel as an interim joint can be done. There are two methods:
use a piece of nickel, or
make several layers of nickel alloy steel, i.e., dipping or coating the steel with nickel metal weld deposit.
Nickel or nickel deposit can be welded to copper nickel alloy using filler metal. Such a page link would provide a satisfactory properties and be successful.