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结合实验研究和热力学计算对不同间隙元素含量下Ti和Nb微合金化对超纯11%Cr铁素体不锈钢铸态、轧态和焊接热影响区(HAZ)的影响进行了研究和分析.研究结果表明:钢中间隙元素含量在0.0163%时Ti和Nb微合金化效果较好,在相同的轧制工艺下可获得更好的轧态组织,相同焊接工艺条件下HAZ晶粒尺寸也较细小.分析表明:在相同的凝固条件下,随着C和N含量的提高及Ti和Nb的加入,固/液两相区温度区间增大,有助于提高柱状晶前沿过冷度,提高非均质形核几率,进而使得铸态组织中等轴晶比例提高,晶粒尺寸减小.另一方面,随着Ti的加入和N含量的提高,TiN生成区域从固相区提高到固/液两相区,有助于促进高温铁素体的非均质形核.
The effects of Ti and Nb microalloying on the as-cast, as-rolled and welded heat-affected zone (HAZ) of ultra-pure 11% Cr ferritic stainless steel with different interstitial element contents were studied by means of experimental and thermodynamic calculations. The results show that the micro-alloying effect of Ti and Nb is better when the content of the intermediate element in the steel is 0.0163%, and the better rolled microstructure can be obtained under the same rolling process. The HAZ grain size is also smaller under the same welding conditions The analysis shows that under the same solidification conditions, with the increase of C and N content and the addition of Ti and Nb, the temperature range of solid / liquid two-phase region increases, which helps to increase the undercooling of columnar frontier and increase the non- Homogeneous nucleation rate, and then make the proportion of equiaxed grains in the as-cast microstructure increase and the grain size decreases.On the other hand, with the addition of Ti and the increase of N content, the TiN generation region increases from solid phase to solid / liquid The two-phase zone helps to promote heterogeneous nucleation of high-temperature ferrites.