AWS G2.3M/G2.3 pdf free download

AWS G2.3M/G2.3 pdf free download.Joining of Solid Solution Austenitic Stainless Steels.
sensitization. The formation of chromium-depleted regions adjacent to chromium-rich carbides that nucleate and grow on austenite grain boundaries during exposure to temperatures of about 48() C to 850 C 190() <F to 1560 <Fl. Regions depleted of chromium are susceptible to preferential attack by a corroding medium.
sigma phase. A hard, brittle, nonmagnetic phase with a tetragonal crystal structure containing large amounts of chromium and iron. It can form after extended time in the temperature range of about 600 C to 925 C [1100 F to 1700 F] and can significantly reduce corrosion resistance and produces a marked reduction in room temperature ductility. It forms most readily from weld-metal delta ferrite.
solid solution. A solid solution alloy is a homogeneous mixture of two or more elements. The type and proportions of alloying elements are such that the final alloy mixture is formulated to he homogenous without separating into multiple different structure types or chemical compounds.
solution annealing. Heating austenitic stainless steels and holding at a temperature (typically 1040 C [1900 <F] minimum) long enough to redissolve constituents to enter into solid solution. Cooling must be sufficiently rapid to hold constituents into solution.
stress-relief anneal. A heat treatment performed to reduce residual stresses. See 10.2.
superaustenitic stainless steel. A series of solution strengthened austenitic stainless steels typically containing high alloying levels of chromium. nickel, nitrogen, and molybdenum. These alloying additions provide superior resistance to pitting corrosion and stress corrosion cracking relative to standard austenitic stainless steel grades.
Wavehrm controlled power sources. Terminology used to describe GMAW welding equipment that has the capability to simultaneously adjust various electrical parameters such as voltage, wave shape. or pulsing frequency when the operator adjusts wire feed speed.
weld metal solidification cracking. A form of intergranular cracking occurring as the cooling weld metal transitions from liquid to solid in the simultaneous presence of low melting points compounds and shrinkage stresses. This form typically appears as either centerline or crater cracks.
whiskers. Short pieces of unmelted GMAW electrode attached to the material being welded. Whiskers are occasionally found on the interior surface of pipe welds when the GMAW electrode passes through the root opening then shorts out and welds itself to the weld joint root face.
worm tracks. A linear depression in the surface of a weld as a result of insufficient outgassing of the weld puddle.
4. General Information
4.1 History. Austenitic stainless steels were first researched by Leon Guillet in France in 1904. In 1906. Guillet published a detailed study of the iron-nickel-chromium alloys: this study established the basic metallurgical characteristics of austenitic steels. Between 1908 and 1912, E. Maurer of the research department at Germany’s F. Krupp steel plant developed the first commercial austenitic stainless steel.
From the late l920s. different forms of austenitic stainless steels were produced. The most notable is the use of Type 302 on the roof of the Chrysler Building in New York.
Until 1968, stainless steels were produced by melting the charge in an electric furnace and refining it by certain slag practices. Carbon contents were lowered by blowing the melt with oxygen; however, they were limited to about 0.05%. To produce very low levels of carbon (under 0.03% is ideal for welding), special charges were required and the resultant alloys were designated with the letter “L” After 1968, the use of argon-oxygen decarburization refining practices began in conjunction with the electric melt furnace. producing very low levels of carbon as a matter of course. Many of today’s alloys may be dual certified to both standard and low-carbon compositions and mechanical properties.AWS G2.3M/G2.3  pdf download.