Sintered Structural Cu-Ni-Mo-C Low Alloyed Steels with Small Niobium Additions

Abstract:

This paper investigates the possibilities of niobium using for the mechanical properties of the common low alloyed Cu-Ni-Mo-C structural sintered steels enhancing by a similar technique with that used in the classical HSLA steels obtaining. For this purpose, both thermodynamic and experimental investigations were carried out, their results showing that the added Nb to these steels form at sintering in a nitrogen containing atmosphere, rather then the other alloying elements, carbides, nitrides, carbonitrides. They are solved in austenite and precipitate at the sintered steels cooling / artificial aging, forming precipitates of an expected strengthening effect. The results for 0.2 ÷ 1.0 % fine Nb powder and 0.3 % graphite additions to Distaloy AB powder cold compacted and sintered in dissociated ammonia proved that such a strengthening effect, which leads to higher mechanical properties of the processed steels than of the Cu-Ni-Mo-C ones, can be achieved.

• Periodical: Materials Science Forum (Volumes 534-536)
• Pages: 725-728
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.534-536.725
• Online since: January 2007
• Authors: Magdalena Orban, Radu L. Orban
• Keywords: Low Alloyed Sintered Steels, Sintered Steel with Niobium, Sintered Structural Steels

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[60] [65] [70] [75] [80] [85] [90] [95] 0 0. 25 0. 5 0. 75 1 1. 25 Niobium content, wt. [%] Hardeness, HRB HRB 1150 C HRB 1285 C Fig. 6. Variation of Hardness of the processed steels vs. Nb content.

100 200 300 400 500 600 700 800 900.

0. 2 0. 4 0. 6 0. 8 1 Niobium content, [wt. %] Ultimate Tensile Strength, UTS [MPa].

[1] [2] [3] [4] [5] [6] [7] [8] [9] Elongation, E [%] Rm 1150 C Rm 1285 C An 1150 C An 1285 C Fig. 5. Ultimate Tensile Strength and Elongation of sintered steels vs. Nb content.