Effect of ion nitriding on the microstructure and properties of Maraging steel (250 Grade)

Effect of vacuum oxy-nitrocarburizing on the microstructure of tool steels: an experimental and modeling study

“…In that event, since the Cr diffuses more rapidly in ferrite than the other metallic alloying elements (such as V, Mo, W), Crcontaining nitride precipitates are encountered even in the ONC H21 -the tool steels with lower Cr content. The Cr in this area participates in the formation of Cr 2 N phase where the ordered arrangement of metal atoms corresponds to hcp lattice and the nitrogen atoms are distributed in the interstitial voids such as in İ-Fe [2][3] (N,C). Simultaneously, the precipitation of the nitrides of the alloying elements has no considerable effect on the concentration distribution in depth of the diffusion layer of all samples, although the coarsening process is additionally benefited from the preliminary single tempering and, therefore, the lower amount of nitride forming elements tied as carbides.…”

“…The results obtained from the surface composition and phase analysis of the compound layer demonstrate that the reaction product after 7 hours of ONC is composed of pure İ -iron carbonitride. As opposed to alloying niritrides, only the diffraction line of the İ-Fe [2][3] (N,C) is considered to be unaffected by the superimpositions. Concerning the lack of Ȗǯ -nitride, this phase appears to be absent during the ONC of the tool steels because of four main reasons: 1) crystallographic resemblance of İ, Cr 2 N, orthorhombic carbides; 2) the higher carbon content in the surface area (coming from C, released from the alloy carbides transformation [22] together with that from the external source) that stabilizes the İ-phase [23]; 3) the low solubility range of N and C in Ȗǯ-Fe 4 N [24]; 4) the delayed compound layer formation because M. Somers at al.…”

“…The results from the thermo-chemical treatment vary considerably depending on the substrate material chosen, gas atmosphere and treatment conditions [2,3]. During the nitrocarburizing process hard compound and supporting diffusion layers underneath are formed.…”

Short-term Creep Properties and Fracture Surface of 18 Ni (300) Maraging Steel Plasma Nitrided

“…Plasma nitriding is specially designed for low temperature nitriding, and it is adequate for maraging steels avoiding the overaging [11][12][13] . Plasma nitriding of maraging steels has been extensively investigated with the aim of improving the alloy's tribological and mechanical properties [13][14] . 18 for the same material but without surface treatment.…”

Microstructure and corrosion resistance of the layers formed on the surface of precipitation hardenable plastic mold steel by plasma-nitriding

“…The layer beneath the compound layer is known as the so-called diffusion layer, which consists mainly of interstitial atoms in solid solution and fine, coherent nitride precipitates when the solubility limit is reached. The thickness and compositions of these layers are functions of treatment temperature, and time and composition of the base material [6][7][8][9]. The diffusion layer determines the strength of the nitrided layer, as well as its fatigue strength [10,11], while the compound layer determines the tribological characteristics and corrosion resistance [12][13][14].…”