AWS G2.1M/G2.1 pdf free download

AWS G2.1M/G2.1 pdf free download.Guide for the Joining of Wrought Nickel-Based Alloys.
4. Introduction
The family of wrought nickel-based alloys can he divided into two categories and numerous classes according to composition. The categories include solid solution strengthened alloys and precipitation hardenable alloys.
The classes of solid solution nickel-based alloys are: nickel, nickel-copper, nickel-molybdenum, nickel-chromium and nickel-chromium-iron, nickel-iron-chromium, nickel-iron, and nickel-chromium-molybdenum. These classes are listed in Table I.
The classes of precipitation hardenable nickel-based alloys are: nickel, nickel-copper, nickel-iron-cobalt and nickel- chromium-iron, nickel-iron-chromium, and nickel-iron. These classes are listed in Table 2.
There are no precipitation hardenahie nickel-chromium or nickel-molybdenum alloys.
In general, the nickel-based alloys can be welded with practices and procedures similar to the austenitic series (3(X)) stainless steels.
This standard addresses these two categories of wrought nickel-based alloys. The first category addresses solid solution nickel alloys, which can he hardened only by cold working. The second category addresses precipitation hardening alloys, which can be hardened by heat treating in addition tO cold working. Additionally, Annex A addresses safety and health issues associated with welding nickel-based alloys.
5. The Solid Solution Strengthened Nickel-Based Alloys
Solid solution strengthening occurs when one or more elements are added to another element to form a homogenous composition. Strengthening occurs when the dissolving of one or more elements (such as chromium) in the other (such as nickel) stitTens the new resulting metal. There is flO appreciable increase in room temperature hardness after a solid solution alloy is exposed for relatively short period of time (such as 2 hours) to the intermediate temperature range (such as 650°C 1120()°F1) (as a comparison, such temperature exposure would harden precipitation hardening alloys).
5.1 General Alloy Background I)ata
5.1.1 Descriptions of the Alloys and Typical Applications. The chemical composition limits of many of the common solid solution strengthened nickel-based alloys arc given in Table 1. Solid solution strengthening occurs when one or more elements (such as chromium) are added to another element (such as nickel) to form a homogenous composition. Alloying elements are added to nickel to strengthen the metal and to improve its corrosion resistance. Depending on the alloy, some of the primary alloying elements added to nickel for solid solution strengthening include chromium, molybdenum. iron, cobalt, tungsten, and carbon. The material’s structure, even after alloying, is homogenous.These solid solution alloys cannot be strengthened by heat treatment and can only be further strengthened and hardened by cold working. For example, quenching a solid solution nickel-base alloy from a high temperature will not harden the alloy—neither will heating the ahoy at elevated temperatures. Precipitation-hardcnable nickel-base alloys, however, can experience a dramatic increase in strength by heating (aging) in the 540°C—815°C [l000°F—1500°F] range.
In addition to strengthening by the addition of solid solution alloying elements, the nickel-base ‘precipitation hardened” alloys are also strengthened by the inclusion of specific elements such as aluminum, titanium, and niobium. When appropriately heat treated, very small and discrete particles are produced and interspersed within the material’s structure. The presence of these small particles (termed “precipitates”) can greatly increase the material’s strength. These alloys are also able to he strengthened by cold working. The chemical composition limits of many of the common precipitation strengthened nickel-based alloys are given in Table 2. Precipitation strengthened nickel-based alloys is fully discussed in 6.1.AWS G2.1M/G2.1  pdf download.