The Hardness of Boride Layer on the S45C Iron (A preliminary study on surface hardening of ferrous material) (original) (raw)

Production and characterization of boride layers on AISI D2 tool steel

Vacuum, 2010

a b s t r a c t AISI D2 is the most commonly used cold-work tool steel of its grade. It offers high hardenability, low distortion after quenching, high resistance to softening and good wear resistance. The use of appropriate hard coatings on this steel can further improve its wear resistance. Boronizing is a surface treatment of Boron diffusion into the substrate. In this work boride layers were formed on AISI D2 steel using borax baths containing iron-titanium and aluminium, at 800 C and 1000 C during 4 h. The borided treated steel was characterized by optical microscopy, Vickers microhardness, X-ray diffraction (XRD) and glow discharge optical spectroscopy (GDOS) to verify the effect of the bath compositions and treatment temperatures in the layer formation. Depending on the bath composition, Fe 2 B or FeB was the predominant phase in the boride layers. The layers exhibited ''saw-tooth'' morphology at the substrate interface; layer thicknesses varied from 60 to 120 mm, and hardness in the range of 1596-1744 HV were obtained.

Formation of Boride Layers on PM Steels during Sinter Boriding

Simultaneous sintering and pack boriding of PM steels was investigated. The Fe-C, and Fe-Ni-Mo-(Cu)-C powder steels in a boriding mix consisting of boron carrier, manganese and diluent were sintered under standard conditions, i.e. the treatment was carried out at 1120C for 1 h in dissociated ammonia. Hard surface layers were formed. The process increased the density and mechanical properties of the materials. Significant changes in microstructure character compared to plain as-sintered one were analysed. The sinter boriding process proceeded under the effect of the formed gas compound B3H3N3(g). The sinter boriding process for forming hard surface layer on parts for adhesive or abrasive wear resistance can be applied under conventional sintering conditions in a H/N atmosphere.

Surface modification of chromium-silicon martensitic steel by forming hard borides

Surface & Coatings Technology, 2017

In this study, an alternative surface hardening method called as "CRTD-Bor" (Cathodic Reduction and Thermal Diffusion based Boriding) was introduced for the heavy-duty applications of medium carbon, chromium-silicon martensitic steel, also known commercially Silchrome 1. The influences of process parameters (e.g. electrolyte temperatures and both electrolysis and phase homogenization durations) on the chemistry, thickness and hardness of boride structures were investigated to yield a modified surface within the industrially desired compositions, namely single Fe2B or the layer containing max. 10 % of FeB in vol. Furthermore, adhesion as well as thermal oxidation behaviors of borided substrates were examined. Cross sectional SEM investigations revealed that it was possible to grow 35 µm or 45 µm thick boride layers within the preferred compositions after 40 min and 55 min of CRTDbor, respectively. Thin film XRD analyses confirmed single Fe2B formation with minor Cr2B peaks. The hardness of boride layers varied in the range of 1400±200 HV. The grown boride layers exhibited the ideal adhesions to the steel matrix with either perfect HF1 or acceptable HF3 qualities according to their constitutions. CRTD-Bor boriding process improved the oxidation resistance of the steel at 650 °C remarkably by forming thin ~7µm thick protective layer composing of mixed iron-, chromium-oxides and borates as well as boron oxide (B2O3) which was firstly identified in the hexagonal crystalline structure after oxidizing borided steel samples at 450 °C and 650 °C.

Characterization of Boride Layers on Ryalloy Steel

Metal ..., 2022

Boronizing is a thermochemical process in which the boron atoms are introduced into the steel surfaces. During this process, the boride layers with high hardness, wear-and corrosion-resistance are formed. In this study, the Royalloy (0.05 wt.% C; 12.6 wt.% Cr; 0.4 wt.% Si and 1.2 wt.% Mn) steel was powder-boronized at 900, 950, 975, 1000 or 1050 °C, and for 1, 3, 5, 7 or 10 h. The boronized samples were analyzed by X-ray diffraction analysis (XRD) to analyze their phase composition, and by scanning electron microscope to analyze their thickness and morphology at the interface with the substrate. To investigate the chemical elements redistribution during the boronizing process, the EDS mapping and EDS point analysis were used. The treatments produced boride layers with a thickness from 8 to 168 µm, depending on the boronizing parameters. During the boronizing process, the chromium was redistributed between the boride layers, where creates the chromium borides, and the transient region underneath the boride layers, where creates the particles with the biggest amount of chromium. The silicon was focused at the layersubstrate interfaces. The concentration of manganese was slightly higher in substrate compared to the boride layers.

Characterizations and Kinetic Modelling of Boride Layers on Bohler K190 Steel

In this study, the Bohler K 190 steel was used. The steel was manufactured by the powder metallurgy (PM) process. The boronizing process was carried out in the range of 1173 to 1323 K, for 1-10 h. The samples were boronized in solid medium, called the Durborid powder mixture. For the microstructural observations, the scanning electron microscopy was utilized for determining the morphology of interfaces and measuring the layers’ thicknesses. The phase composition of boride layers was also determined with X-ray diffraction analysis. To investigate the redistribution of chemical elements redistribution during the boronizing process, the EDS mapping and EDS point analysis were used. The boride layers were constituted by FeB and Fe2B phases except for 1173 K for 1 h. The values of Vickers microhardness of Fe2B, FeB and transition zone were estimated. Finally, to assess the boron activation energies in FeB and Fe2B, the so-called integral method was applied and the results in terms of act...

Characterization of boronized layers on a XC38 steel

Surface and Coatings Technology, 2006

Boronizing of an XC38 steel was performed by immersion in molten salts. These were based on a borax containing three reducing agents: boron carbide (B 4 C), aluminium (Al) and silicon carbide (SiC). This work gives a survey on the nature and quality of the layers which were obtained according to the boronizing bath. The mechanical features (hardness, scratch and wear resistance) of the deposited layers are discussed according to the experimental conditions used for their characterization. Effects of the boronizing bath composition on the obtained layers' quality are also discussed. According to the borax's reducing agents, the boronized layer deposited on the XC38 steel was either single-or double-phase. Al and B 4 C led to double-phased boronized layers, whereas SiC gave way to a single-phase layer. All the layers were of comparable hardness which was about 2100 HV on the samples for the boride FeB and 1800 HV for the boride Fe 2 B. The scratch and "pin-on-disk" wear resistance depended on the layers' microstructure. The best values of scratch and wear resistance were obtained for SiC which led to the formation of a single-phase layer. The apparition of scaling occurred at loads superior to 200 N.

Growth kinetics of the boride layers formed on SAE 1035 steel

Matériaux & Techniques, 2013

Growth kinetics of the boride layers formed on SAE 1035 steel has been investigated during the boriding treatment. This treatment was carried out in slurry salt bath consisting of borax, boric acid and ferrosilicon for temperatures ranging from 1073 to 1273 K and treatment times of 2, 4 and 8 h. The presence of both FeB and Fe2B phases formed on the surface of SAE 1035 steel was confirmed by X-ray diffraction. Scanning electron microscopy (SEM) and optical microscopy examinations showed that the boride layers have a saw-tooth morphology. The thickness of boride layers was found to be increased when the treatment time and the boriding temperature increase, its value ranged from 20 to 387 µm. The average hardness of the boride layer was about 1760 ± 200 HV0.1, while the hardness of un-borided steel was about 225 ± 20 HV0.1. The fracture toughness of boride layers (KC) was found to be ranged between 3.42 and 4.57 MPa m 1/2. The kinetic study showed a parabolic relationship between the boride layer thickness and the process time. The value of boron activation energy for the borided SAE 1035 steel was estimated as 227.51 kJ mol −1 .

Characterization of boride coatings on a ductile cast iron

Protection of Metals and Physical Chemistry of Surfaces, 2017

⎯In this work, the EN-GJS-400-15 cast iron was pack-borided in a powder mixture composed of 5% B 4 C, 5% NaBF 4 and 90% SiC at the three temperatures: 900, 950 and 1000°C for 2, 4 and 6 h, respectively. The pack-borided EN-GJS-400-15 cast iron was characterized by the following experimental techniques: optical microscopy, XRD analysis and Microhardness Vickers tester. The growth kinetics of boride layers was also investigated. As a consequence, the boron activation energy was found to be 212.28 kJ mol-1 for the EN-GJS-400-15 cast iron. Based on a regression model, a useful equation was derived to estimate the boride layer thickness as a function of the boriding parameters (time and temperature). A good agreement was then obtained between the predicted values of boride layers thicknesses and those measured experimentally. In addition, an iso-thickness diagram was proposed to be used as a simple tool to select the boride layers thicknesses according to the potential applications of EN-GJS-400-15 cast iron in industry.