August 2020 Volume 2

FORGING RESEARCH

the benefits of fine precipitation over large precipitation, reiterating the need for proper control of Ti and N in the steels. Here it is shown that higher strengthening increments are achieved for finer precipitation distributions. Similarly, Figure 15 shows the grain size impact of precipitation distributions varying in volume fraction and particle size. Here, the lines descending to the right represent distributions of equal particle sizes, but with higher volume fractions as they go to the right. This effect is simple, since the higher quantity of precipitates provides higher levels of grain pinning to resist grain coarsening. Also seen in this figure is again the impact of the finer precipitation distributions. Here, smaller precipitate sizes produce finer microstructures than the coarser particles of equal particle volume fractions. een in this figure is again the impact of the finer precipitation distributions. Here, sizes produce finer microstructures than the coarser particles of equal particle

The roles of each of these three primary precipitates in the system are predominantly derived through the relative solubility products of the respective precipitates, and the ratio of the constituent elements relative to the stoichiometry of the compounds. In this regard, Figure 16 and Table 2 have been included, and elucidate the range of precipitation for each precipitating compound. [39, 42, 43]

Figure 16: Precipitation of microalloying elements vs temperature [39,43] Figure 16: Precipitation of microalloyi g elements vs temperature [39, 43]

Table 2: Empirical solubility products of microalloying precipitates [39, 42]

Figure 16: Precipitation of microalloying elements vs temperature [39, 43]

Figure 15: Impact of precipitate volume fraction and particle size on the grain size in steel [41]

Table 2: Empirical solubility products of microalloying precipitates [39, 42] Table 2: Empirical solubility products of microalloying precipitates [39,42]

mpact of precipitate volume fraction and particle size on the grain size in steel [41]

As Figure 16 shows, with decreasing temperature, the first element in the experience precipitation with falling temperature is Ti, which begins to form well before t microalloying elements. [39] Titanium nitride, which has a much lower solubility prod titanium carbide in the austenite region, has a complete dissolution temperature which exc dissolution temperature of all other microalloying carbonitrides, and the melting temper the steel. [38] For example, evaluation of the empirical solubility products in Table 2 determ solubility product of TiN in austenite at 1000 ° C to be [Ti%][N%] = 1.05*10 -8 (wt%) 2

of each of these three primary precipitates in the system are predominantly e relative solubility products of the respective precipitates, and the ratio of the ts relative to the stoichiometry of the compounds. In this regard, Figure 16 and n included, and elucidate the range of precipitation for each precipitating

FIA MAGAZINE | AUGUST 2020 73 As Figure 16 shows, with decreasing temperature, the first element in the steel to experience precipitation with falling temperature is Ti, which begins to form well before the other 27

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