scholarly journals Multi-Layer Wear and Tool Life Calculation for Forging Applications Considering Dynamical Hardness Modeling and Nitrided Layer Degradation

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 104
Author(s):  
Bernd-Arno Behrens ◽  
Kai Brunotte ◽  
Hendrik Wester ◽  
Marcel Rothgänger ◽  
Felix Müller
Keyword(s):  
Tool Life ◽  
Nitrided Layer ◽  
Hot Forging ◽  
Base Material ◽  
Wear Depth ◽  
Extreme Loads ◽  
Wear Protection ◽  
Functional Representation ◽  
Wear Calculation ◽  
Protection Layer

As one of the oldest shaping manufacturing processes, forging and especially hot forging is characterized by extreme loads on the tool. The thermal load in particular is able to cause constant changes in the hardness of the surface layer, which in turn has a decisive influence on the numerical estimation of wear. Thus, also during numerical wear, modeling hardness changes need to be taken into account. Within the scope of this paper, a new implementation of a numerical wear model is presented, which, in addition to dynamic hardness models for the base material, can also take into account the properties of a nitride wear protection layer as a function of the wear depth. After a functional representation, the new model is applied to the wear calculation of a multi-stage industrial hot forging process. The applicability of the new implementation is validated by the evaluation of the occurring hardness, wear depths and the locally associated removal of the wear protection layer. Consecutively, a tool life calculation module based on the calculated wear depth is implemented and demonstrated. In general, a good agreement of the results is achieved, making the model suitable for detailed 2D as well as large 3D Finite Element calculations.

scholarly journals Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 355
Author(s):  
Jakub Krawczyk ◽  
Paweł Widomski ◽  
Marcin Kaszuba
Keyword(s):  
Numerical Modeling ◽  
Surface Layer ◽  
Laboratory Tests ◽  
Complex Analysis ◽  
Nitrided Layer ◽  
Hot Forging ◽  
Thermal Softening ◽  
Effect Of Temperature ◽  
Destructive Effect ◽  
Forging Process

This article is devoted to the issues of thermal softening of materials in the surface layer of forging tools. The research covers numerical modeling of the forging process, laboratory tests of tempering of nitrided layers, and the analysis of tempering of the surface layer of tools in the actual forging process. Numerical modeling was supported by measuring the temperature inside the tools with a thermocouple inserted into the tool to measure the temperature as close to the surface as possible. The modeling results confirmed the possibility of tempering the die material. The results of laboratory tests made it possible to determine the influence of temperature on tempering at different surface layer depths. Numerical analysis and measurement of surface layer microhardness of tools revealed the destructive effect of temperature during forging on the tempering of the nitrided layer and on the material layers located deeper below the nitrided layer. The results have shown that in the hot forging processes carried out in accordance with the adopted technology, the surface layer of working tools is overheated locally to a temperature above 600 °C and tempering occurs. Moreover, overheating effects are visible, because the surface layer is tempered to a depth of 0.3 mm. Finally, such tempering processes lead to a decrease in the die hardness, which causes accelerated wear because of the abrasion and plastic deformation. The nitriding does not protect against the tempering phenomenon, but only delays the material softening process, because tempering occurs in the nitrided layer and in the layers deeper under the nitrided layer. Below the nitrided layer, tempering occurs relatively quickly and a soft layer is formed with a hardness below 400 HV.

Study of the applicability of 22MnB5 sheet metal as protective masks to improve tool life in hot forging process

2020 ◽  
Vol 107 (1-2) ◽  
pp. 39-47
Author(s):  
Luana De Lucca de Costa ◽  
Alberto Moreira Guerreiro Brito ◽  
André Rosiak ◽  
Lirio Schaeffer
Keyword(s):  
Sheet Metal ◽  
Tool Life ◽  
Hot Forging ◽  
Forging Process ◽  
Hot Forging Process

The influence of thickness of CrN coating on the durability of hot forging dies

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Jerzy Smolik
Keyword(s):  
Coating Thickness ◽  
Nitrided Layer ◽  
Hot Forging ◽  
Sem Analysis ◽  
Internal Stresses ◽  
Main Role ◽  
Hybrid Layer ◽  
Crn Coating ◽  
Forging Process

AbstractThis article presents results which enabled the determination of the role of CrN coating and the influence of its thickness on the effectiveness of hybrid layer “nitrided layer / CrN coating” in the process of increasing the durability of forging dies. Dies coated with hybrid layers “nitrided layer / CrN coating” with various CrN coating thickness were — after different maintenance periods — subjected to metallographic testing, 3D shape testing and SEM analysis. Hardness distribution was also determined. The obtained results revealed that for all tested dies, independently from CrN coating thickness, the main mechanisms of their destruction was mechanical and thermal fatigue, and plastic deformation. It has been shown that the main role of CrN coating in the hybrid layer ”nitrided layer / PVD coating” is to counteract a high temperature influence the source of which is forging on die material. In order to do so the CrN coating should be characterized by a considerably lower thermal conductivity coefficient to steel and low hardness so that it can efficiently resist fatigue processes in the forging process. Based on testing conducted by means of the sin 2 φ method, it was revealed that internal stresses are vitally important for CrN coating for fatigue resistance of hybrid layer ”nitrided layer / CrN coating” during the forging process.

A Numerical Simulation of Fretting Wear considering the Dynamic Evolution of Debris for the Coated Contact Surface

2021 ◽  
pp. 1-49
Author(s):  
Li Xiao ◽  
Yingqiang Xu ◽  
Zhiyong Chen
Keyword(s):  
Fretting Wear ◽  
Contact Pair ◽  
Dynamic Evolution ◽  
Wear Depth ◽  
Wear Coefficient ◽  
Wear Model ◽  
Wear Process ◽  
Dlc Coating ◽  
Wear Life ◽  
Wear Calculation

Abstract In this paper, a multi-layer body model in which material properties and wear coefficient change with node coordinates is proposed, so that the wear profile is not restricted by the singularity of the interface of the coated contact pairs. The conversion rate of the adhered particles was obtained to describe the growth and expansion of the debris at the fretting interface based on experiments, and the wear model of coated contact pair considering the dynamic evolution of the debris layer was established. By comparing the previous experimental and computational results, the wear calculation method proposed in this paper is more reasonable to predict the wear profile of the coated contact pair. In addition, the influence of the debris layer on the wear depth, friction width, and contact pressure in the fretting process is analyzed, indicating that the existence of the debris layer can delay the wear process. Finally, the fretting wear life of the SCMV steel contact pair deposited with the W-DLC coating is estimated.

scholarly journals Simulation Study on Friction and Wear Law of Brake Pad in High-Power Disc Brake

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
S. Zhang ◽  
Q. Hao ◽  
Y. Liu ◽  
L. Jin ◽  
F. Ma ◽  
...  
Keyword(s):  
High Power ◽  
Friction And Wear ◽  
Element Model ◽  
Calculation Model ◽  
Brake Disc ◽  
Disc Brake ◽  
Wear Depth ◽  
Brake Pad ◽  
Wear Calculation ◽  
Wear Law

For the serious and uneven wear of the brake pad in the high-power disc brake during braking, the dynamic variation of the brake disc and the brake pad interface variable is considered, the wear calculation model is established based on the friction and wear mechanism, and the wear depth and volume of the brake pad can be calculated by equations. A finite element model of the brake disc and the brake pad is established by DEFORM software which can analyze wear of the brake pad directly. The variation trend of wear during braking is studied, and influences of braking load and initial braking speed on the wear are analyzed. The results show that the amount of the wear increases rapidly in the early wear stage of braking, and it becomes slow in the later stage; the wear of the brake pad is serious at the friction inlet and outlet, and the middle area of the brake pad is lightly worn; heavy braking load and high initial braking speed can exacerbate the wear of the brake pad.

scholarly journals The application of a new, innovative, hybrid technology combining hardfacing and nitriding to increase the durability of forging tools

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Marcin Kaszuba
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Layer Structure ◽  
Nitrided Layer ◽  
New Technology ◽  
Hot Forging ◽  
Hybrid Technology ◽  
Multiple Treatment ◽  
Operational Tests ◽  
The Impact

Abstract The article deals with the wear of forging tools used in hot forging processes. The research presented in the work includes analysis of tool life used in a selected industrial hot die forging process. Multiple treatment variants were used to increase wear resistance, including thermo-chemical treatment (nitriding), welding methods (surfacing) and an innovative new hybrid technology combining surfacing and nitriding. First of all, the research focused on determining the impact of the phase structure of the nitrided layers used and the surfacing layer on resistance to destructive factors occurring in the analyzed process. Next, hybrid treated tools combining surfacing and nitriding were also subjected to operational tests. Each of the tools analyzed in this work was operated until it was withdrawn due to excessive wear, and then subjected to comprehensive analysis. The tests of tools after operation included: surface scanning to determine the amount of wear of the analyzed tools after work, microhardness measurement, and microscopic tests. A detailed analysis of changes in the surface layer of tools in selected areas was made using a scanning microscope. The aim of the study was to assess the effectiveness of the hybrid surface treatment process used to increase the wear resistance of the surface layer of tools and thereby improve the durability of the forged tools analyzed. The obtained research results indicate a beneficial effect of using the new technology resulting in 300% increase in the durability of the analyzed tools. The effect of improving durability confirmed by obtained results arises from the use of hybrid layers, which are more resistant to abrasive wear and to cracking due to thermo-mechanical fatigue. Moreover, the study shows that nitriding may have a beneficial influence on improving the lifetime of forging tools, under the condition that the nitrided layer has an α diffusive layer structure, without a larger amount of γ’ and ε nitride precipitates.

Hybrid surface treatment technology for increase of hot forging dies

2012 ◽  
Vol 57 (3) ◽  
pp. 657-664 ◽  
Author(s):  
J.A. Smolik
Keyword(s):  
Surface Treatment ◽  
Nitrided Layer ◽  
Hot Forging ◽  
Composite Layer ◽  
Rolling Bearing ◽  
Ion Nitriding ◽  
Treatment Technology ◽  
Hybrid Technology ◽  
Gas Nitriding ◽  
Hybrid Plasma

Hot working dies are influenced by three main factors causing their destruction: the cyclically changeable mechanical loads, intensive thermal shocks, as well as intensive friction, and erosion. Modification of surface properties with the use of hybrid plasma methods seems to be an effective way of improving its durability. The best known and widely used surface treatment hybrid technology is a combination of the nitriding process with the deposition of hard antiwear coatings by means of PVD methods. The designed composite layer “nitrided layer / Cr-CrN” was obtained with the use of the hybrid technology, which consist of ion nitriding followed by arc-evaporation coating deposition. The maintenance testing was performed on the forging dies employed for production of various parts in the automotive industry. The best durability was obtained for the dies used for the forging of rolling bearing tracks. In comparison with the durability of the dies subjected solely to the gas nitriding, nearly an increase of 600% in the durability was noticed.

Railway Vehicle Wheel Restoration by Submerged Arc Welding and Its Characterization

Sci ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 25
Author(s):  
Byeong-Choo Coo ◽  
Young-Jin Lee
Keyword(s):  
Arc Welding ◽  
Stress Measurement ◽  
Base Material ◽  
Diffraction Method ◽  
Submerged Arc Welding ◽  
Structural Safety ◽  
Railway Vehicle ◽  
Wear Depth ◽  
Minimum Thickness ◽  
Submerged Arc

When a railway vehicle moves on a curved rail, sliding contact occurs between the rail head side and wheel flange, which wears the wheel flange down. The thinned flange needs to be restored above the required minimum thickness for structural safety. In this study, a new process and welding wire for restoring worn-out railway wheels by submerged arc welding was developed. To characterize the properties of the restored wheel, dilatometric analysis of phase transformation, SEM/EDX analyses, hardness measurement, and residual stress measurement using the X-ray diffraction method were performed. Finally, wear tests with full-size wheel/rail specimens were carried out. It was confirmed that the weld metal was composed of bainitic microstructures as intended, and welding defects were not observed. The wear amount of the restored wheel was greater than that of the base material, but it was less than half of the wear depth of the weld-repaired wheel with ferritic–pearlitic microstructures. The developed process seems applicable to industry.

Combined Surface Treatment of Electron Beam Alloying and PVD Hard Coating for Al Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 187-192 ◽  
Author(s):  
Anja Buchwalder ◽  
Rolf Zenker ◽  
Erik Zaulig ◽  
Jürgen Liebich ◽  
Dietmar Leuteritz
Keyword(s):  
Electron Beam ◽  
Physical Vapor Deposition ◽  
Combined Treatment ◽  
Surface Hardness ◽  
Base Material ◽  
Hard Coatings ◽  
Beam Deflection ◽  
Al Alloy ◽  
Wear Protection ◽  
Wide Range

Due to their typically high hardness, excellent resistance against wear, and their low coefficient of friction, Physical Vapor Deposition (PVD) hard coatings are used on steels for a wide range of tools and components. Currently, however, the potential for wear protection of Al alloy components cannot be exploited. The thin PVD layers tend to collapse and disintegrate due to plastic deformation of the soft base material. Present research is focused on electron beam (EB) surface alloying, using Co-based additives to increase the surface hardness of the Al base material, producing an improved supporting effect for PVD coatings. The influence of different beam deflection techniques and EB parameters on the microstructure and hardness of alloyed layers was investigated. The properties of the duplex composite layers produced are strongly dependent on the thermal stability of the EB alloyed layers (type and amount of intermetallic compounds, coarsening effects) which are affected by the temperature-time cycle of the PVD process. This will be discussed by means of SEM and EDX investigations in correlation with XRD analysis. Measurements using scratch test with increasing load result in critical load values for the combined treatment that are 3 to 5 times higher when compared to only PVD-coated base material.

FEA Based Tool Life Quantity Estimation of Hot Forging Dies Under Cyclic Thermo-Mechanical Loads

2011 ◽  
Author(s):  
B.-A. Behrens ◽  
A. Bouguecha ◽  
F. Schäfer ◽  
T. Hadifi ◽  
Francisco Chinesta ◽  
...  
Keyword(s):  
Tool Life ◽  
Hot Forging ◽  
Mechanical Loads
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