Weld metal ductility

The ductility of Ti-6Al-6V-2Sn weldments is poor unless a postweld annealing treatment is used. Solution heat treatment followed by water quenching does not improve weld ductility, and subsequent aging of such conditioned material results in weld metal embrittlement. Solution of the weld metal ductility problem is possible in some applications by using an cinnealing treatment. The treatment of 4-h exposure at 725 °C (1340 °F), followed by air cooling has been recommended. 

Weld test plates of the type shown in Fig. 13-8 have also been used for studying the mechanical properties of welded joints. Such test plates were side-bend tested in the apparatus illustrated in Fig. 13-10. The results of the tests, presented in Table 13-3, indicate excellent weld metal ductility. For example, the ductility of heat M-5 material is greater than 40% at temperatures un to and including 1500°F. 

Welding Problems With Cr-Mo Pipe. Do not use low-chromium steel pipe unless you are willing to pay for more careful welding and post-weld heat treatments. At a given hardness, low-alloy chromium-molybdenum steels have somewhat more ductility than carbon steels. However, because they air harden so much, they usually require post-weld heat treatments to toughen the weld metal and heat-affected zone. This heat treatment complicates field welding. 

Ironically, their reasoning that the hardened, heat-affected zone of the 5-Cr steel would have ductile, austenitic stainless steel weld metal on one side of it and ductile, 5-Cr steel parent metal on the other, is equally valid in the rejected case where the weld met is carbon steel. 

A.J. Ramirez, J.C. Lippold, High temperature behavior of Ni-base weld metal Part II—insight into the mechanism for ductility dip cracking. Mater. Sci. Eng. A 380 (2004) 245—258. 

An area where savings may be possible with improved materials data is on evaluation of welded joints. The material properties of the complete weld joint, as opposed to the weld metal alone, are needed. Ductility under multiaxial loading plays a key role in the structural adequacy of weldments subject to cyclic loading. 

Use of higher-purity filler wire in welding the 3- and 8-mm-thick plates with square edges had little effect on the joint strength, but the weld metal had a higher ductility and toughness. 

Throughout the world, many arc welding methods are used to fabricate large-capacity structures from these steels. The weldability of both steels was evaluated using various methods of welding. Thin samples of both steels were satisfactorily welded. Nevertheless, weld metal of the same composition was susceptible to pore and hot crack formation and resulted in decreased ductility and low impact strength at low temperatures. Both steels were sensitive to the welding heat effect this was... 

Preparation of the modified Hastelloy N data for ASTM standard and ASME coding (tensile test data ductility data creep test data toughness data for both base and welded metal). 

Forms extrusions and billet. The alloy has excellent weldability the weld metal develops the same strength, ductility, and toughness as those of the base metal. Machinability of Ti-621/0.8 is similar to that of other titanium alloys. Hot working is nor-... 

The aluminum alloy, 5086 (4,0 per cent Mg, nominal), which was developed for structural use and particularly for welded structures, has been found to be one of the strongest as well as one of the most ductile of the aluminum alloys. Because this alloy was expected to exhibit a higher strength but still retain most of its ductility at low temperatures, a program was undertaken which involved the testing of both the parent and welded metals down to 20 K,... 

Impact Tests, Figure 17 illustrates the results of impact testing the parent and weld metals. The welded impact specimens broke at a lower value and decreased more rapidly in impact strength with decreasing temperature than did the parent specimens because the weld metal in which the notch was machined is less ductile. 

These results confirmed suspicions that failure was due to excessive amounts of nitrogen, carbon, and oxygen. To characterize the condition of the vessel further, Charpy V-notch impact tests were run on the unaffected base metal, the HAZ, and the uncorroded (sound) weld metal. These tests gave the data in Table 12.7 for ductile-to-brittle transition temperatures. 

Cold Welding (CW) Ductile metals such as carbon steels, aluminum, copper and precious metals. Friction Welding (FRW) can weld many material types and dissimilar metals effectively, including aluminum to steel. Also thermoplastics and refractory metals. 

The choice of material, the structural design, the welding and the heat treatment should be such as to ensure a sufficiently ductile state of the material of the pressure vessel throughout the plant lifetime. The ductihty of the pressure vessel wall facing the core should be ensured by hmiting the maximum neutron fluence and by the use of base material and weld metal of a chemical composition such as to keep radiation embrittlement below an acceptable level. 

It has been known for many centuries that iron ore, embedded in burning charcoal, can be reduced to metallic iron (1,2). Iron was made by this method as early as 1200 BC. Consisting almost entirely of pure iron, the first iron metal closely resembled modem wrought iron, which is relatively soft, malleable, ductile, and readily hammer-welded when heated to a sufficientiy high temperature. This metal was used for many purposes, including agricultural implements and various tools. 

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