高抗热裂纹性能纯镍型的铸铁焊条

利用ＨＲＬ－１型热裂纹试验机，系统地研究了Ｃ，Ｙ，Ｃｏ，Ｍｏ，Ａｌ及Ｓｉ对纯镍型铸铁焊条热裂纹敏感性的影响。     

镍基合金与奥氏体不锈钢间的焊接

分析了镍基合金(Incoloy 825)和奥氏体不锈钢(S30403)的可焊性,为满足焊接接头使用性能,选用相应的焊接方法和焊接材料,通过合理的焊接工艺避免焊接热裂纹的产生,保证了焊接品质。     

提高镍铜铸铁焊条抗热裂纹性能研究

镍铜铸铁焊条对热裂纹敏感,为改善其热裂纹敏感性,研究了C,Mn,Si,CO,Bi,S,P及稀土对其热裂纹的影响。所用热裂纹试验机是基于临介变形速度的原理。测定了焊缝金属的最佳C,CO及稀土含量。高于或低于其最佳含量均将使抗热裂性能减低。Mn,Si,Bi,S,P均能提高焊缝金属的热裂纹敏感性。本文对这些现象的理由进行了讨论。综合利用C,CO及稀土能显著提高镍铜铸铁焊条抗热裂纹敏感性。     

Hot-cracking of high-alloyed steels evaluated by wedge rolling test

We present a new methodology of determination of hot-cracking of metallic materials, which is based on laboratory application of the wedge rolling test and computer processing of the results obtained. The experiment was made with selected new types of high-alloyed free-cutting (ferritic and austenitic) steels. The initial specimens underwent an additional modification enabling easier development of cracks which consisted in milling out of the defined V-shaped notches on a side wall of a specimen. After taking specimens from the rolled material, we performed the metallographic analysis of microstructures by means of optical microscopy as well as a SEM analysis of the cracks. The resulting microstructure in the propagating crack vicinity was markedly influenced by this fracture. In the crack vicinity, a noticeable refinement of grains was observed due to the stress-induced recrystallization and occurrence of deformation zones that were pronounced by the rolled-out and stretched sulphides. As a rule, fractures were created by the ductile failure with visible pits, caused by tearing of sulphides from the material. Susceptibility of the studied steels to hot-cracking was evaluated and compared. __________ Translated from Problemy Prochnosti, No. 1, pp. 60–63, January–February, 2008.