Tribological Stress Behaviour of Cast Iron without and with Surface Treatment under Concentrated Contact Load*

2021 ◽  
Vol 76 (4) ◽  
pp. 298-317
Author(s):  
A. Holst ◽  
A. Buchwalder ◽  
R. Zenker
Keyword(s):  
Cast Iron ◽  
Surface Treatment ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Wear Test ◽  
Local Stress ◽  
Compound Layer ◽  
Cast Irons ◽  
Stress Behaviour ◽  
Pore Fraction

Abstract The graphite inclusions typical of grey solidified cast iron materials reduce the load-bearing capacity under locally concentrated pressure and simultaneous sliding stress. Surface treatment processes such as nitriding and electron beam remelting are known to improve the local stress behaviour. In this paper, the effects of the above-mentioned individual processes and their combination on the tribological stress behaviour of ferritic and pearlitic cast irons with different graphite morphologies are discussed. The results obtained in the model wear test ball-plate show that the specific wear coefficient of the investigated cast irons with different graphite morphology can already be reduced by at least one order of magnitude by an approx. 0.5–0.9 mm thick remelted surface layer with a surface hardness of 650–750 HV1. This treatment eliminates the graphite and produces ledeburitic carbides instead. The potential of an additional nitriding treatment depends on the parameters used, i. e. the nitrided layer thickness produced as well as the phase composition and the pore fraction of the compound layer. Based on stress calculations, the experimentally determined main influences such as the coefficient of friction, the pore fraction in the compound layer and the magnitude of the Hertzian pressure on the contact stress could essentially be confirmed.

scholarly journals The Joint Effects of Nitriding and Parameters Related to the Destabilisation of Austenite on Wear Resistance in White Cast Iron with 25% Cr

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Alejandro González-Pociño ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Nitrided Layer ◽  
Erosive Wear ◽  
Air Cooling ◽  
Cast Irons ◽  
Eutectic Carbides ◽  
Noticeable Increase ◽  
Ionic Nitriding

In this article, the effects of an ionic nitriding treatment are analysed, together with deliberate variation of different thermal parameters associated with the destabilisation of austenite, on erosive wear resistance of white cast irons with 25% Cr. The methodology followed in this research was an experimental design, where six factors were analyzed by performing eight experiments. The thickness of the nitrided layer is much smaller than in white cast iron with lower percentages in Cr, never reaching 20 microns. The nitriding treatment entails considerable softening of the material underneath the nitriding layer. This softening behaviour becomes partially inhibited when the destabilisation temperature of austenite is 1100 °C and dwell times at such temperature are prolonged. This temperature seems to play a significant role in the solubilization of non-equilibrium eutectic carbides, formed during industrial solidification. The nitriding treatment leads to additional hardening, which, in these cases, favours a second destabilisation of austenite, with additional precipitation of secondary carbides and the transformation of retained austenite into martensite. Despite softening of the material, the nitriding treatment, together with air-cooling after destabilisation of the austenite, allows a noticeable increase in resistance to erosive wear.

scholarly journals Interaction of N with White-solidified Cast Iron Model Alloys: The Effect of Mn and Cu on the Formation of Fe and Si Nitrides

2021 ◽  
Vol 5 (4) ◽  
pp. 66-70
Author(s):  
Stefan Kante ◽  
Andreas Leineweber
Keyword(s):  
Corrosion Resistance ◽  
Surface Layer ◽  
Cast Iron ◽  
Surface Properties ◽  
Compound Layer ◽  
Process Conditions ◽  
Cast Irons ◽  
Promoting Effect

Surface remelting and subsequent nitriding improves the surface properties of cast irons. Upon remelting, a white-solidified surface layer forms, which contains coarse Si-free eutectic cementite (θ) and Si-enriched ferrite, pearlite or martensite in the intercarbidic regions between the eutectic θ. Nitriding produces a compound layer at the surface, which is composed of ε and γ’-iron (carbo)nitrides and enhances the corrosion resistance. Nitriding of white-solidified Fe-C-Si alloys, being model materials for remelted low-alloy ferritic cast irons, has shown that Si dissolved in α-Fe notably affects the formation of ε and γ’ in intercarbidic regions while Si simultaneously precipitates as amorphous nitride, X. Under process conditions only allowing for the formation of γ’ in pure Fe, Si dissolved in α-Fe promotes the formation of ε over the formation γ’, whereas Si-free eutectic θ transforms into nitride following the sequence θ → ε → γ’. The present work studies the nitriding of white-solidified Fe-3.5wt.%C-3wt.%-M alloys with additions of M = 1 wt.% Mn, 1 wt.% Cu or 1 wt.% Mn + 1 wt.% Cu, serving as model materials for remelted pearlitic cast irons. The presence of Mn and/or Cu causes notable deviations from the nitriding behavior known from Fe-C-Si alloys. Mn accelerates the precipitation of X in intercarbidic regions and obstructs the transformation of ε formed from Si-free θ into γ’. Cu promotes the formation of γ’ in Si-rich intercarbidic regions, surpassing the ε-promoting effect of Si.

LOW-TEMPERATURE NITRIDING BEHAVIOR OF COMPRESSIVE DEFORMED AISI 316Ti AUSTENITIC STAINLESS STEELS

2019 ◽  
Vol 26 (05) ◽  
pp. 1850188 ◽  
Author(s):  
FATIH KAHRAMAN ◽  
GÖKÇE MEHMET GENÇER ◽  
AYÇA D. KAHRAMAN ◽  
COŞKUN YOLCU ◽  
HAYDAR KAHRAMAN
Keyword(s):  
Low Temperature ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Cold Deformation ◽  
Surface Hardness ◽  
Compound Layer ◽  
Optical Microscope ◽  
Layer Growth ◽  
Nitrogen Diffusion ◽  
Undeformed Sample

The effects of compressive cold deformation under the quasi-static loads on the nitride formation, nitride layer growth and surface hardness properties were researched in this study. Martensite structure did not form in AISI 316Ti stainless steel as a result of quasi-static deformation. Diffusion layer did not form in all nitrided samples. Both the deformed and undeformed samples have only compound layer on the surfaces at the low-temperature nitriding conditions (400∘C, 7[Formula: see text]h). According to the X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS) and electron probe microanalysis (EPMA) results, S-phase and chromium nitride (CrN) were formed in the compound layers of the deformed samples. However, CrN did not form in the compound layer of the undeformed sample. The optical microscope (OM) results showed that the compressive cold deformation increased the nitrogen diffusion rate and led to thicker nitrided layer than the undeformed sample under the same plasma-nitriding conditions. All nitrided layers presented higher microhardness values ([Formula: see text][Formula: see text]HV) when compared with the untreated sample hardness. It was also verified that the deformation amount did not affect significantly the nitrided layer hardness.

The Characteristics of Surface Layers Produced on SKD 61 Steel by Plasma Radical Nitriding Compared with Conventional Plasma Ion Nitriding

2006 ◽  
Vol 118 ◽  
pp. 155-160
Author(s):  
Insup Lee ◽  
Yong Ho Park ◽  
Ik Min Park
Keyword(s):  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Compound Layer ◽  
Hardened Layer ◽  
Processing Parameters ◽  
Polished Surface ◽  
Nitrogen Diffusion ◽  
Ion Nitriding ◽  
Surface Layers

Plasma radical nitriding has been performed to harden the surface of SKD 61 steel for 1- 10 hours at temperature range of 450-550°C. A NH radical, which has played a key role to produce a nitrogen diffusion layer without the formation of the brittle compound layer, has been generated in a gas mixture of NH3 and H2 . One of the main advantages of the plasma radical nitriding is to improve the surface hardness by maintaining the roughness of the initial polished surface. The microstructures and material properties of the radical nitrided layer have been characterized in order to investigate the effects of various radical nitriding processing parameters. The hardness and surface roughness of the hardened layer were compared between two processes. In addition, PVD CrN coating has been deposited on both the radical nitrided substrates and conventional nitrided substrates by an arc ion plating (AIP) technique. The effect of two different of plasma nitriding treatments on the adhesive strength of the coating layer on the substrates was also investigated.

The Effects of Processing Temperature and Time on the Surface Properties of Plasma Radical Nitrided SCM 440 Steel

2007 ◽  
Vol 124-126 ◽  
pp. 1453-1456
Author(s):  
Insup Lee ◽  
Ik Min Park
Keyword(s):  
Residual Stress ◽  
Surface Properties ◽  
Diffusion Layer ◽  
Diffusion Zone ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Compound Layer ◽  
Treatment Temperature ◽  
Processing Temperature ◽  
Diffusion Depth

Plasma radical nitriding was performed to harden the surface of SCM 440 steel for 1-10 hours at temperature range of 450-550°C. No compound layer was formed during this process except the experiment carried out at 500 for 10 hours. A diffusion depth increased with increasing treatment temperature and time ( up to about 250). The surface hardness of radical nitrided layer was two times higher than that of the untreated surface. The main phase produced in the diffusion zone was identified to be γ΄-Fe4(N,C). The residual stress of the diffusion layer also increased with increasing treatment temperature and time due to the increase of precipitates.

Wear behavior of pits textured grey cast iron rings with Zr/ZrN coatings under dry sliding

2020 ◽  
pp. 135065012094091
Author(s):  
Risheng Long ◽  
Shaoni Sun ◽  
Youwei Zhang
Keyword(s):  
Cast Iron ◽  
Physical Vapor Deposition ◽  
Wear Behavior ◽  
Normal Load ◽  
Surface Hardness ◽  
Wear Test ◽  
Surface Characteristics ◽  
Grey Cast Iron ◽  
Dry Sliding ◽  
Grey Cast

This study presents the influence of Zr/ZrN coatings on the tribological performance of pits textured grey cast iron parts under dry sliding. A laser marking system and a physical vapor deposition equipment were applied to manufacture pits textured grey cast iron rings combined with Zr/ZrN coatings. A pin-on-disc wear test rig was used to reveal the wear behavior of samples under dry wear condition, at a rotating speed of 200 r/min, with a normal load of 70 N. The wear losses and the worn surfaces of all rings were obtained by an electronic balance and a three-dimensional surface profilometer, respectively. The results show that Zr/ZrN coatings can significantly increase the surface roughness and surface hardness of grey cast iron rings. As a result, Zr/ZrN coatings increase the friction coefficients of all coated GCI rings, and reduce the wear losses of some ones. In this work, when surface texturing combines with Zr/ZrN coatings, the final tribological properties of coated grey cast iron rings may be either improved or deteriorated, depending on surface characteristics, texturing parameters and loads. Compared with the uncoated smooth grey cast iron ring, Zr/ZrN coatings cannot effectively improve the wear behavior of pits textured samples. Among all coated grey cast iron rings, when the diameter of the pit is 0.8 mm, and the distance between pits is 1.25 mm, the pits textured grey cast iron ring can provide the optimal anti-wear performance. This work would provide a valuable reference for the surface design of journal bearings and roller bearings.

Research on the Wear Resistance of High-Chromium White Cast Iron and Multi-Component White Cast Iron

2013 ◽  
Vol 859 ◽  
pp. 64-69
Author(s):  
Chien Lung Yen ◽  
Fu Je Chen ◽  
Yung Ning Pan
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Linear Relationship ◽  
White Cast Iron ◽  
Wear Test ◽  
Specimen Surface ◽  
Testing Time ◽  
Cast Irons ◽  
High Chromium ◽  
Treatment Conditions

The pin-on-disk wear test and solid particle erosion test were used to investigate the wear resistance property of both high chromium white cast iron and multi-component white cast iron with optimal alloy compositions and heat treatment conditions. Experimental results indicate that a linear relationship between the wear lose and the testing time exists for high chromium white cast irons. Apparent scratch grooves and sheared pits appeared on the specimen surface. Subsurface observations found pit depths of some 4.5~8.0 mm. Crack propagation routes were clearly visible along the martensitic grain boundaries for alloys in the as-quenched state. Tempering treatment increases the toughness of the alloy, resulting in an increase in the resistance to crack formation. On the other hand, the multi-component white cast irons exhibited a non-linear relationship between the wear lose and the testing time. Relatively shallow scratches were found on the specimen surface, and pit depths of about 4.0 mm were observed through subsurface observations. Tempering at 570°C caused a reduction in hardness of the alloy, and therefore, the fracture mode tends to be ductile. As a result, deformation only occurred in crater regions with no clear evidence of spreading.

MEEHANITE GF-20

Alloy Digest ◽  
1973 ◽  
Vol 22 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Cast Iron ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Gray Cast Iron ◽  
Heat Treating ◽  
Gray Cast

Abstract MEEHANITE GF-20 is a gray cast iron designed principally for high machinability and is used where strength is not an important factor. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: CI-39. Producer or source: Meehanite Metal Corporation.

ANALISA KETAHANAN AUS BESI COR EN-JN2019 DENGAN METODE FACTORIAL DESIGN TERHADAP UNSUR PADUAN DAN LAJU PENDINGINAN

2016 ◽  
Vol 6 (1) ◽  
pp. 11
Author(s):  
Kus Hanaldi
Keyword(s):  
Cast Iron ◽  
Factorial Design ◽  
Cast Irons ◽  
Wear Resistant

Salah satu material yang dapat digunakan pada kondisi lingkungan abrasif adalah white cast irons atau abrasion-resistant cast iron. EN-JN2019 adalah salah satu jenis besi cor yang dapat digunakan pada kondisi ini. Pada besi cor  ini terkandung unsur karbon, silikon, mangan, dan chromium. Analisa ketahanan aus material ini telah dilakukan dengan menggunakan factorial design terhadap dua kombinasi kandungan chromium (1% dan 2%), dua kombinasi kandungan silikon (1% dan 1,5%) dan dua kombinasi ketebalan sampel (5mm dan 30mm). Ketebalan sampel merupakan representasi dari laju pendinginan. Kajian terhadap kekerasan, struktur mikro, uji impact dan uji aus dari delapan sampel yang dihasilkan dari proses pengecoran telah dilaksanakan pula. Hasil pengujian kekerasan menunjukkan bahwa kekerasan menurun dengan meningkatnya ketebalan dan disertai dengan perubahan struktur mikro sebagai hasil dari laju pendinginan yang semakin lambat. Penambahan kandungan chromium meningkatkan kekerasan karena adanya pembentukan karbida. Penambahan kandungan silikon menurunkan kekerasan akibat pembentukan grafit yang lebih mudah. Pengaruh kandungan chromium dan silikon terhadap kekerasan memiliki ketergantungan  satu  dengan  lainnya,  karena  penambahan  silikon  menekan  pertumbuhan  karbida.  Dari  hasil pengujian impact didapatkan hasil, pada semua variasi chromium, silikon dan ketebalan tidak memiliki pengaruh terhadap harga impact. Sedangkan dari hasil pengujian keausan  didapatkan bahwa kekerasan  berbanding lurus dengan nilai wear resistant, semakin tinggi kekerasan maka nilai wear resistant akan semakin meningkat.Kata kunci: ketahanan aus, EN-JN2019, kandungan chromium, kandungan silikon, laju pendinginan, factorial design, pembentukan karbida.

scholarly journals Solidification Pattern of Si-Alloyed, Inoculated Ductile Cast Irons, Evaluated by Thermal Analysis

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 846
Author(s):  
Iuliana Stan ◽  
Denisa Anca ◽  
Stelian Stan ◽  
Iulian Riposan
Keyword(s):  
Cast Iron ◽  
Eutectic Reaction ◽  
Influencing Factor ◽  
Cooling Curve ◽  
Major Influence ◽  
Cast Irons ◽  
Minor Elements ◽  
Si Content ◽  
Si Effect ◽  
Positive Effect

The solidification cooling curve itself as well as its first derivative, and related temperatures, reported to the calculated equilibrium temperatures in stable and metastable solidification systems, are used to predict the solidification characteristics of the cast iron. Silicon, as the most representative cast iron element, and inoculation, as graphitizing metallurgical treatment, have a major influence on the transition from the liquid to the solid state. Six experimental programs are performed, with Si content typically for non-alloyed (<3.0% Si), low (3.0–3.5% Si) and medium alloyed (4.5–5.5% Si) ductile cast irons, as Si-content increasing, and inoculation simultaneous effects. Silicon is an important influencing factor, but the base and minor elements also affect the equilibrium eutectic temperatures, much more in the Fe-C-Si-Xi stable system (15–20 °C) than in the metastable system (5–10 °C), comparing with their calculation based only on a Si effect (Fe-C-Si system). The highest positive effect of inoculation is visible in non-Si alloyed cast irons (2.5% Si): 9–15 °C for the eutectic reaction and 3 to 4 times increased at the end of solidification (37–47 °C). Increased Si content decreases inoculation power to 7–9 °C for low alloying grade (up to 3.5% Si), with the lowest contribution at more than 4.5% Si (0.3–2.0 °C). 2.5–3.5% Si ductile cast irons are more sensitive to high solidification undercooling, especially at the end of solidification (but with a higher efficiency of inoculation), compared to 4.5–5.5% Si ductile cast irons, at a lower undercooling level, and at lower inoculation contribution, as well.

Sign in / Sign up

Export Citation Format

Share Document