scholarly journals Influence of the nitrided layer thickness of dies made of two types of tool steel used in hot extrusion of valve forgings made of nickel–chromium steel on the durability of these tools

2021 ◽  
Vol 21 (4) ◽  
Author(s):  
Marek Hawryluk ◽  
Marzena Lachowicz ◽  
Marta Janik ◽  
Jacek Ziemba ◽  
Zbigniew Gronostajski
Keyword(s):  
Carbon Content ◽  
Layer Thickness ◽  
Nitrided Layer ◽  
Tool Material ◽  
Critical Factor ◽  
Hot Extrusion ◽  
Chromium Steel ◽  
Nickel Steel ◽  
Depth Analysis ◽  
Tool Replacement

AbstractThe study constitutes an analysis of the durability of dies used in the first operation of producing valve forgings from chromium–nickel steel (NCF 3015) for motor trucks. The average durability of the dies (subjected to standard thermal treatment and nitriding) in this operation equals about 800 forgings. To perform an in-depth analysis of the effect of the nitrided layer thickness (0.1 mm and 0.2 mm) and the tool material (W360 and QRO90) on the possibilities of increasing the die durability, complex studies were carried out, which included: a macroscopic analysis combined with 3D scanning, microstructural examinations using a scanning microscope and a metallographic microscope, as well as hardness measurements. A minimum of three tools were tested for different variants, and for each of them, one representative die was selected for detailed examinations. The research showed the presence of abrasive wear, thermo-mechanical fatigue and traces of adhesive wear as well as plastic deformation on the surface of the working impressions. Also observed was the effect of the extruded material sticking to the tools (high friction and the presence of intermetallic phases in the extruded material) and the forging being blocked in the smallest section of the die, which is a critical factor causing a production shutdown and the necessity of tool replacement. The highest mean durability equalling 2600 forgings was obtained for the dies with a lower carbon content and a higher content of vanadium and the nitrided layer thickness at the level of 0.2 mm. The lowest mean durability (after one forging item) was recorded for the dies made of steel with a higher carbon content and a higher chromium content, forming less stable compound carbides and the thickness layer at the level of 0.1 mm.

Machinability Analysis of Aluminum Alloy-Graphene Metal Matrix Composites Using Uncoated and DLC-Coated Carbide Insert

2017 ◽  
Author(s):  
J. Joel ◽  
M. Anthony Xavior
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Surface Hardness ◽  
Tool Material ◽  
Hot Extrusion ◽  
Cutting Parameters ◽  
Extrusion Process ◽  
Work Piece ◽  
Matrix Composites ◽  
Coated Carbide

Metal Matrix Composites (MMCs) based on Aluminum Alloys 2024, 6061 and 7075 reinforced with Graphene was fabricated using powder metallurgy process followed by hot extrusion process. The extruded samples were used for conducting the turning experiments to evaluate the machinability of the developed composites. Turning experiments were conducted in ACE Micromatic made CNC lathe as per the Design of Experiments (DOE) designed using L18 Taguchi’s mixed orthogonal array. Uncoated and DLC coated carbide inserts, along with three levels of cutting speeds, feed rates and depths of cut were considered for the turning experiments. During the experiments the cutting force generated was recorded “online” and subsequent to the experimentation the surface roughness generated on the work piece and the surface hardness for every trial were recorded. The influence of the cutting tool material and other cutting parameters on the machinability of composites was analyzed using ANOVA. The microstructural observation on the surface of the machined specimen reveals the detachment of reinforcement materials from the composite and their impact of the surface quality.

Possibilities of Preparing Tools Working in Conditions of Abrasion Wear with the Modification of the Tool Surfaces by Nitridation

2014 ◽  
Vol 635 ◽  
pp. 89-93
Author(s):  
Martin Orečný ◽  
Petra Lacková ◽  
Marián Buršák
Keyword(s):  
Wear Resistance ◽  
Nitrided Layer ◽  
High Hardness ◽  
Chromium Steel ◽  
Material Surface ◽  
Diffusion Annealing ◽  
Additional Increase ◽  
Abrasion Wear ◽  
Heat Treated

The proposed paper deals about the heat treatment of two types of chromium tool steels that are assigned to work in specific conditions of abrasion wear. The materials are heat treated to achieve high hardness for higher abrasion wear resistance. An additional increase of the materials abrasion wear resistance can be achieved by applying nitridation with diffusion annealing of the material surface. The paper deals about the influence of the material purity, his chemical composition on the process of diffusion, the quality of the nitrided layer of a vacuum smelted steel Bӧhler W400 VMR and a chromium steel X210Cr12.

Surface Modification Using Electric Discharge Machining (EDM) with Powder Addition

2011 ◽  
Vol 110-116 ◽  
pp. 725-733 ◽  
Author(s):  
Ahsan Ali Khan ◽  
Mohammed Baba Ndaliman ◽  
Zakaria Mohd Zain ◽  
Mohammad F. Jamaludin ◽  
Umar Patthi
Keyword(s):  
Surface Modification ◽  
Layer Thickness ◽  
Electrical Discharge Machining ◽  
Tool Material ◽  
Dielectric Medium ◽  
Tungsten Electrode ◽  
Machined Surface ◽  
Al2o3 Powder ◽  
Recast Layer Thickness ◽  
Powder Addition

Powder mixed electrical discharge machining (PMEDM) is one of the recent innovations for the enhancement of the capabilities of EDM process. In this study, the effects of powder addition on the surface modification of mild steel were investigated. Copper tungsten electrode was used in the machining. Two different powders namely TiC and Al2O3 were used in the study with kerosene as the dielectric medium. The powder types and currents were manipulated to study their effects on the machined surface. The results show that increasing the current leads to increase in recast layer thickness, and the cracks. The Al2O3 powder gave higher layer thickness than TiC powder. TiC Powder addition also produced higher hardness, more tool material and carbon depositions on the work surface than Al2O3 powder.

scholarly journals Evolution of the Fretting Wear Damage of a Complex Phase Compound Layer for a Nitrided High-Carbon High-Chromium Steel

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1391
Author(s):  
Yong Duan ◽  
Shengguan Qu ◽  
Siyu Jia ◽  
Xiaoqiang Li
Keyword(s):  
Wear Resistance ◽  
Wear Behavior ◽  
Nitrided Layer ◽  
Compound Layer ◽  
Chromium Steel ◽  
Fretting Wear ◽  
Complex Phase ◽  
Phase Compound ◽  
Loading Case ◽  
Wear Damage

In this paper, the X210CrW12 steel was subjected to gas nitriding to obtain a complex phase compound layer with limited porosity. The nitrided layer was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The fretting wear behavior and the evolution of fretting wear damage of the compound layer were studied, and the worn surfaces were characterized by SEM/EDS and 3D optical profilometry. The results indicated that the compound layer showed superior fretting wear resistance and sufficient load-carrying capacity in the low loading case of 35 N, but the fracture of coarse nitrides (transformed primary carbides) was obviously detrimental to wear resistance. For the high loading case of 70 N, the low toughness of the compound layer led to the occurrence of brittle cracks, and the decrease in the thickness of the compound layer due to wear resulted in the cracking and spalling of the compound layer.

The Effects of Carbon on Ion-Nitriding

1980 ◽  
Vol 102 (2) ◽  
pp. 229-233 ◽  
Author(s):  
K. S. Cho ◽  
C. O. Lee
Keyword(s):  
Carbon Content ◽  
Layer Thickness ◽  
Diffusion Layer ◽  
Treatment Time ◽  
Compound Layer ◽  
Maximum Hardness ◽  
Ion Nitriding ◽  
Diffusion Layer Thickness ◽  
Nitriding Time ◽  
Gas Atmosphere

This paper deals with ion-nitride processing and is primarily concerned with the effects of carbon content in the workpiece and of added carbon in the gas atmosphere on hardness, compound layer thickness, and diffusion layer thickness. Increased carbon content in the workpiece increases the compound layer thickness, but decreases the diffusion layer thickness. On the other hand, an optimal amount of added carbon in the gas atmosphere will increase the compound layer thickness as well as the diffusion layer thickness and hardness. It is found that the ion-nitriding temperature at which maximum hardness is attained is governed by the ion-nitriding time. When the treatment time is made sufficiently long, the maximum hardness is obtained at a temperature near 450°C.

Investigation and Comparison of Heat Transfers Analysis Used in Commercial FEM for Metal Forming

2013 ◽  
Vol 773-774 ◽  
pp. 176-185
Author(s):  
Isaac Flitta ◽  
Thomas Hatzenbichler ◽  
Bruno Buchmayr
Keyword(s):  
Heat Transfer ◽  
Fem Simulation ◽  
Tool Material ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Material Interface ◽  
Transfer Parameter ◽  
Aluminium Extrusion ◽  
Definition Of ◽  
Heat Transfer Parameter

During an Aluminium extrusion process, the extrusion parameters, i.e. friction, heat transfer, etc. are significantly influence by the temperature gradients produced in the billet during transfer to the container and after upsetting the container. The heat transfer at the tool/billet interface governs the temperature profile throughout the billet and tools during extrusion and consequently has a critical influence on the results. Although FEM technique offers great potential, care must be taken when applying the analysis to the hot extrusion of rate sensitive alloys. The most useful approach of an FEM simulation would thus be to include both the tooling and the billet in the calculation as discretised meshes. Because of the occurrence of the conductive and convective heat transfer, the deformation during hot extrusion is not adiabatic and estimation of the temperature increase is alloy dependent. The aim of this paper is to investigate and to compare how commercial FEM codes assign and deal with the heat transfer parameter at the tool/material interface. Three commercial FEM codes were investigated and compared; Simufact, Deform and Forge. The usefulness and limitation when using commercial FEM codes are discussed. Methods to assess difficulty of comparison are presented. The work illustrates the essentials of numerical analysis in the comprehension of the thermo-mechanical events occurring during large deformation. Results are presented for velocity distribution and temperature evolution in both materials and tools. It is shown that the heat transfer parameter to be extremely sensitive when attempting to simulate the hot deformation. Moreover, the accuracy of the results does not only depended on the geometric definition of the tooling and material data but also the governing boundary conditions between the material and tooling.

scholarly journals Effect of heat treatment on hardness and wear resistance of high carbon-high chromium steel (fmu-11)

10.30544/596 ◽  
2021 ◽  
Author(s):  
Alireza Darvishi ◽  
Aria Daneshmayeh ◽  
Alihosein Salehi ◽  
Mahdi Ahmadi ◽  
Alireza Soleymani
Keyword(s):  
Wear Resistance ◽  
Cryogenic Treatment ◽  
Wear Test ◽  
Optical Microscope ◽  
Chromium Steel ◽  
Steel Matrix ◽  
High Carbon ◽  
High Chromium ◽  
Heat Treated ◽  
Depth Analysis

In the present study, microstructure, hardness, and abrasion resistance of a heat-treated high carbon-high chromium steel (FMU-11) used in the cement mills were investigated. To investigate the best heat-treating cycle for the FMU-11 steel, three sets of samples were heat treated. The first set was tempered two times, the second set was re-hardened, and the third set was cryogenically heat treated. These samples were then compared with the conventionally heat-treated samples. The samples' microstructure was studied using an optical microscope, where traditional black and white etching, as well as color etching, were used. Scanning electron microscopy (SEM) was applied for higher magnification studies and in-depth analysis of the chemical composition. The mechanical properties were investigated by measuring the hardness and the wear resistance for the samples heat-treated in different cycles. The results showed that the cryogenic treatment and double-tempered samples had the highest hardness and wear resistance. In addition, the results showed that the re-hardening operation caused the carbides to be finely separated and evenly distributed in the steel matrix. The wear test results illustrated that the wear mechanism could be the delamination wear and the abrasive wear combined.

Microstructural Evaluation of Similar and Dissimilar Welding of Aluminum Metal Matrix Hybrid Composite by Friction Stir Welding

2020 ◽  
Vol 979 ◽  
pp. 124-128
Author(s):  
K. Sekar ◽  
P. Vasanthakumar
Keyword(s):  
Friction Stir Welding ◽  
Hybrid Composite ◽  
Metal Matrix ◽  
Hybrid Composites ◽  
Tool Material ◽  
Traverse Speed ◽  
Chromium Steel ◽  
Dissimilar Welding ◽  
Friction Stir ◽  
Aluminum Metal

To address the challenges of reducing the CO2 emission in automotives, Aluminum metal matrix hybrid composites have been extensively used in automotive and aerospace industries for the fabrication of light weight structure. Huge demand in joining dissimilar metals increased day by day, because it reduces the weight and cost of components by utilizing hybrid structures. The friction stir welding is adopted for dissimilar AA5754 rheo-squeeze cast (RSC) with AA7075 stir casted hybrid composite. Micro sized B4C and nanosized Al2O3 are reinforced into this material. Friction stir welding of these alloys by varying the tool material, pin and shoulder profiles, rotational speed, tool traverse speed and tilt angle. Microstructure of the joint are studied and inferences drawn are presented. The better welding was obtained with triangular and square pin profile when compared to cylindrical pin whereas triangular pin profile was more better than square pin. Tapered shoulder possessed greater strength, which resulted in a good weld in contrast to flat shoulder. The high carbon high chromium steel (HCHCr) tool exhibited a higher tool wear rate than stainless steel (SS) tool and found to be an appropriate one to weld aluminum hybrid composite.

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