High temperature behavior of Ni-base weld metal

Effects of Boron on the Microstructure, Ductility-dip-cracking, and Tensile Properties for NiCrFe-7 Weld Metal

“…It is also used in dissimilar welding between several Ni-base alloy, stainless steel and carbon steel in building nuclear power plants [9] . However, it has been pointed out that NiCrFe-7 weld metal is susceptible to ductility-dip-cracking (DDC) under heavy restraint conditions such as welding thick components [10][11][12][13] . DDC is a solid-state hot cracking, caused by GB embrittlement at homologous temperatures that ranges from about 0.5 to 0.8 of the alloy melting points, which is observed at grain boundaries (GBs) [14,15] .…”

The dependence of crack properties on the Cr/Ni equivalent ratio in AISI 304L austenitic stainless steel weld metals

“…The MGB normally presented a high-angle boundary with misorientations in the fully austenitic weld metal, as shown in Fig. 8(b) [22,23]. Sulfide, phosphorus and titanium may have been heavily enriched on the grain boundary [10].…”

“…7 [10]. Ductility dip is divided from BTR, where solidification cracking and liquation cracking occur, by the highest ductility region of the temperature range of approximately 200 • C. Ramirez [22,23] reported that austenitic SS undergoes a severe ductility drop at temperature between 0.5 and 0.7 of its melting temperature, the so-called the DTR, when subjected to a large restraining condition. Therefore, in this region, DDC is highly likely to be formed with thermal contractions caused by welding process.…”

Solidification Behavior and Weldability of Dissimilar Welds Between a Cr-Free, Ni-Cu Welding Consumable and Type 304L Austenitic Stainless Steel

“…A similar transition of TiN particles to Ti(C,N) was observed in Ni-base weld metals of the FM-52 variety, but the particles contained higher levels of Cr. [37] The type of particle that forms may be important with respect to impeding grain growth, which is critical for maintaining adequate resistance to ductility dip cracking in high restraint, multipass, Ni-base weld deposits. In general, particles that are richer in N would be expected to maintain stability to higher temperatures, whereas those rich in C would dissolve more readily when subjected to multiple weld thermal cycles.…”