scholarly journals Optimization of Pre-Heat Treatment for Nitriding

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7766
Author(s):  
Matthias Steinbacher ◽  
Stefanie Hoja
Keyword(s):  
Heat Treatment ◽  
Nitrided Layer ◽  
Special Treatment ◽  
Austenitization Temperature ◽  
Service Characteristics ◽  
Bainitic Microstructure ◽  
Core Hardness ◽  
Treatment Variant ◽  
Quenching And Tempering ◽  
Positive Effect

To achieve a core strength that meets the requirements during service life, components to be nitrided are subjected to a pre-heat treatment. Since a higher strength prior to nitriding also has a positive effect on the achievable strength in the nitrided layer, an optimization of the pre-heat treatment may lead to better service characteristics of nitrided components. For this purpose, different optimizations of pre-heat treatment were investigated on the nitriding and quenching and tempering steels EN31CrMoV9 and EN42CrMo4 (AISI4140). One strategy was a change of the austenitization temperature for EN31CrMoV9 from 870 °C to 950 °C in order to solve the coarse carbides of the as-delivered state and realize a finer distribution of the carbides in the quenched and tempered structure. This special treatment lead to a higher hardness compared to the conventional treatment. The second investigated pre-heat treatment variant was a bainitic treatment instead of quenching and tempering. The bainitic initial microstructure increased the diffusion depth compared to conventionally quenched and tempered specimens. In addition the maximum hardness of the nitrided layer, the core hardness was significantly higher on the specimens with the bainitic microstructure. During subsequent nitriding, however, the bainite is tempered and loses some of its hardness.

Evolution of Microstructure and Properties of a Disk Cutter Ring Material during Carburization and Heat Treatment

2013 ◽  
Vol 652-654 ◽  
pp. 1838-1841 ◽  
Author(s):  
Guo Biao Lin ◽  
Zhong Jian Zhang ◽  
Mao Qing Wang ◽  
Su Min Zhu
Keyword(s):  
Heat Treatment ◽  
Surface Hardness ◽  
Case Depth ◽  
Disk Cutter ◽  
The Core ◽  
Core Hardness ◽  
Evolution Of Microstructure ◽  
The Impact ◽  
Carbide Particles ◽  
Quenching And Tempering

This paper presents the research on the influence of carburizing and heat treatment on the properties and microstructure of a new medium carbon alloy steel Fe-0.39C-0.99Si -0.37Mn -5.06Cr-1.21Mo-0.75V (wt.%) used for disk cutter ring. The carburized case has secondary cementite besides those appeared in core such as pearlite and some carbides of Cr, Mo and V. Microstructure of the case is coarse and there are more and larger carbide particles than in core. After quenching and tempering, the carburized case and the core transformed into the microstructure comprised mostly of troostite and fully precipitated tiny carbide particles of Cr, Mo and V. The grains in the carburized case are still larger and the quantity of carbide precipitations including cementite is larger compared with that in the core. Finally, the case depth of about 1mm can be obtained; the surface hardness is above 60HRC; the core hardness is above 55HRC; and the impact toughness reaches 16.9 kJ/cm2.

scholarly journals Application of Reinforcing Thermocycling Treatment for Materials of Stamps Hot Deformation

2019 ◽  
Vol 6 (2) ◽  
pp. c6-c10
Author(s):  
K. Berladir ◽  
T. Hovorun ◽  
M. Bondarenko ◽  
S. Vorobiov
Keyword(s):  
Heat Treatment ◽  
Hot Deformation ◽  
Mechanical Characteristics ◽  
Diffusion Processes ◽  
Fine Grain ◽  
The Creation ◽  
Technological Methods ◽  
Quenching And Tempering ◽  
Thermocycling Treatment ◽  
Positive Effect

The paper is devoted to the search for technological methods of increasing the resistance of the stamp tool for hot deformation. New non-standard combinations of cyclization schemes and parameters of thermocycling processing within the regime were developed. This is allowed the creation of managed structural states in the metal due to the grinding of grain, the creation of high density of defects, and the acceleration of diffusion processes to effectively manage the structure, increase the mechanical, operational properties and prevent the destruction of the working surfaces of the tool. New modes of thermocycling treatment, which have a positive effect on the mechanical characteristics of HNM5 steel, have been developed and tested. The conducted heat treatment in experimental modes, consisting of thermocycling treatment as a preliminary, quenching and tempering as the final, allows obtaining a more homogeneous structure with the preservation of fine grain and a given hardness. The grain size of the steel HNM5 structure after the use of thermocycling treatment decreases from 5–6 to 7–8 points, and after the final heat treatment – to 9–10 points. Keywords: stamp of hot deformation, thermocycling treatment, strength, relative narrowing, thermal resistance.

INFLUENCE THE QUENCHING AND TEMPERING ON THE MICROSTRUCTURE, MECHANICAL PROPERTIES AND SURFACE ROUGHNESS, OF MEDIUM CARBON STEEL

2018 ◽  
Vol 18 (1) ◽  
pp. 125-135
Author(s):  
Sattar H A Alfatlawi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Surface Roughness ◽  
Carbon Steel ◽  
Cold Water ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Heating And Cooling ◽  
Treatment Processes ◽  
Quenching And Tempering

One of ways to improve properties of materials without changing the product shape toobtain the desired engineering applications is heating and cooling under effect of controlledsequence of heat treatment. The main aim of this study was to investigate the effect ofheating and cooling on the surface roughness, microstructure and some selected propertiessuch as the hardness and impact strength of Medium Carbon Steel which treated at differenttypes of heat treatment processes. Heat treatment achieved in this work was respectively,heating, quenching and tempering. The specimens were heated to 850°C and left for 45minutes inside the furnace as a holding time at that temperature, then quenching process wasperformed in four types of quenching media (still air, cold water (2°C), oil and polymersolution), respectively. Thereafter, the samples were tempered at 200°C, 400°C, and 600°Cwith one hour as a soaking time for each temperature, then were all cooled by still air. Whenthe heat treatment process was completed, the surface roughness, hardness, impact strengthand microstructure tests were performed. The results showed a change and clearimprovement of surface roughness, mechanical properties and microstructure afterquenching was achieved, as well as the change that took place due to the increasingtoughness and ductility by reducing of brittleness of samples.

Bioaccessibility of Tudela artichoke (Cynara scolymus cv. Blanca de Tudela) (poly)phenols: the effects of heat treatment, simulated gastrointestinal digestion and human colonic microbiota

2021 ◽  
Author(s):  
Maite Domínguez-Fernández ◽  
Iziar A. Ludwig ◽  
María-Paz De Peña ◽  
Concepción Cid
Keyword(s):  
Heat Treatment ◽  
Gastrointestinal Digestion ◽  
Cynara Scolymus ◽  
Simulated Gastrointestinal Digestion ◽  
Catabolic Activity ◽  
Colonic Microbiota ◽  
Positive Effect

Heat treatment exerts a positive effect on the bioaccessibility of artichoke (poly)phenols after gastrointestinal digestion. In the first 2 h of fermentation, native (poly)phenols were readily degraded by an important microbial catabolic activity.

Network Carbide Inheritance during Heat Treatment Process of Large Shield Machine Bearing Steel GCr15SiMn

2015 ◽  
Vol 817 ◽  
pp. 115-120 ◽  
Author(s):  
Dan Zhang ◽  
Le Yu Zhou ◽  
Chao Lei Zhang ◽  
Chao Huang ◽  
Min Zhao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Bearing Steel ◽  
Treatment Temperature ◽  
Heat Treatment Process ◽  
Soaking Time ◽  
Hot Rolled ◽  
Chinese Standard ◽  
Shield Machine ◽  
Quenching And Tempering

Network carbide inheritance during heat treatment process of large shield machine bearing steel GCr15SiMn was investigated by heat treatment experiments and quantitative metallographic. Samples with the proeutectoid cementite network thickness in the range of 0.19~0.54 μm were obtained by changing austenitizing temperature and soaking time of pearlite transformation. The results show that the network in hot rolled bar can be improved when the pre-heat treatment temperature is 950 °C. When the network thickness is above 0.40 μm, the undissolved cementite networks present in microstructures after quenching and tempering. In a Chinese standard, the network grades are 1.5 and 3.0 degree when the networks thickness are 0.40 μm and 0.54 μm, respectively. The critical network thickness that can be eliminated by heat treatment is 0.29 μm.

Study of Raman Spectroscopy on Graphene Phase from Heat Treatment of Coconut (Cocus nucifera) Shell

2015 ◽  
Vol 827 ◽  
pp. 290-293 ◽  
Author(s):  
Fandi Angga Prasetya ◽  
Muhammad Nasrullah ◽  
Ananda Yogi Nugraheni ◽  
Darminto
Keyword(s):  
Heat Treatment ◽  
Raman Spectroscopy ◽  
Atmospheric Condition ◽  
Peak Position ◽  
Special Treatment ◽  
Distilled Water ◽  
X Ray ◽  
Heat Treated ◽  
Reduced Graphene ◽  
Two Samples

Coconut (Cocus Nucifera) shell as the main ingredient in this research has been heat-treated at temperature of 1000°C in atmospheric condition aiming to obtain the expected phase of graphene. After heat treatment, an additional special treatment was given, where sample was then rinsed with distilled water. Furthermore, the heated coconut shell was characterized by Raman Spectroscopy (785 nm) and X-ray diffractometry. Based on the treatment and characterization conducted, all samples were likely to contain reduced graphene oxide (RGO) phase.The XRD data have supported the existence of RGO with the diffraction peak position (2q) at 25o and 45o. Evidence is also given by the result of Raman Spectroscopy which produces peaks (denoted by D and G bands) located at wave numbers of 1300 cm-1 and 1590 cm-1. The value of the ratio ID/IG of the two samples in the figures are 2.6 and 2.51 (matched with ratio ID/IG of RGO). The ID/IG ratio of sample which was rinsed by distilled water is higher that those without rinsing treatment.

Mechanical Behaviour of Gas Nitrided Ti6Al4V Bars Produced by Selective Laser Melting

2016 ◽  
Vol 704 ◽  
pp. 225-234 ◽  
Author(s):  
Peter Franz ◽  
Aamir Mukhtar ◽  
Warwick Downing ◽  
Graeme Smith ◽  
Ben Jackson
Keyword(s):  
Heat Treatment ◽  
Selective Laser Melting ◽  
Nitrided Layer ◽  
Xrd Analysis ◽  
Compound Layer ◽  
Processing Parameters ◽  
Heat Treatments ◽  
Laser Melting ◽  
Gas Nitriding ◽  
Heat Treated

Gas atomized Ti-6Al-4V (Ti64) alloy powder was used to prepare distinct designed geometries with different properties by selective laser melting (SLM). Several heat treatments were investigated to find suitable processing parameters to strengthen (specially to harden) these parts for different applications. The results showed significant differences between tabulated results for heat treated billet Ti64 and SLM produced Ti64 parts, while certain mechanical properties of SLM Ti64 parts could be improved by different heat treatments using different processing parameters. Most heat treatments performed followed the trends of a reduction in tensile strength while improving ductility compared with untreated SLM Ti64 parts.Gas nitriding [GN] (diffusion-based thermo-chemical treatment) has been combined with a selected heat treatment for interstitial hardening. Heat treatment was performed below β-transus temperature using minimum flow of nitrogen gas with a controlled low pressure. The surface of the SLM produced Ti64 parts after gas nitriding showed TiN and Ti2N phases (“compound layer”, XRD analysis) and α (N) – Ti diffusion zones as well as high values of micro-hardness as compared to untreated SLM produced Ti64 parts. The microhardness profiles on cross section of the gas nitrided SLM produced samples gave information about the i) microhardness behaviour of the material, and ii) thickness of the nitrided layer, which was investigated using energy dispersive spectroscopy (EDS) and x-ray elemental analysis. Tensile properties of the gas nitrided Ti64 bars produced by SLM under different conditions were also reported.

scholarly journals Austenite Reversion Tempering-Annealing of 4 wt.% Manganese Steels for Automotive Forging Application

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 575 ◽  
Author(s):  
Alexander Gramlich ◽  
Robin Emmrich ◽  
Wolfgang Bleck
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Chemical Composition ◽  
Impact Toughness ◽  
Temperature Control ◽  
Annealing Process ◽  
Air Cooling ◽  
Metastable Austenite ◽  
Quenching And Tempering ◽  
Manganese Steels

New medium Mn steels for forged components, in combination with a new heat treatment, are presented. This new annealing process implies air-cooling after forging and austenite reversion tempering (AC + ART). This leads to energy saving compared to other heat treatments, like quenching and tempering (Q + T) or quenching and partitioning (Q + P). Furthermore, the temperature control of AC + ART is easy, which increases the applicability to forged products with large diameters. Laboratory melts distinguished by Ti, B, Mo contents have been casted and consecutively forged into semi-finished products. Mechanical properties and microstructure have been characterized for the AC and the AC + ART states. The as forged-state shows YS from 900 MPa to 1000 MPa, UTS from 1350 MPa to 1500 MPa and impact toughness from 15 J to 25 J. Through the formation of nanostructured retained metastable austenite an increase in impact toughness was achieved with values from 80 J to 100 J dependent on the chemical composition.

Microstructure and Mechanical Properties of High Strength Alloyed Steel for Aerospace Application

2018 ◽  
Vol 284 ◽  
pp. 351-356 ◽  
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength ◽  
Single Stage ◽  
The Novel ◽  
Tempering Temperature ◽  
Quenching And Partitioning ◽  
Aerospace Application ◽  
Cooling Conditions ◽  
Quenching And Tempering

The high strength aerospace steel alloyed with Cr, Mn, Si, Ni, W and Mo was studied. The austenite transformations under continuous cooling conditions were investigated using the dilatometer analysis at the cooling rates 0.1...30 °C/s. The mechanical properties of the studied steel were determined after the conventional quenching and tempering heat treatment. The dependences of the mechanical properties on the tempering temperature were obtained. The novel quenching and partitioning heat treatment was applied to the steel under consideration. The microstructure and the mechanical properties were studied after three different modes of the quenching and partitioning (QP) treatment: single-stage QP, two-stage QP and single-stage QP with subsequent tempering (QPT).

Analysis of Material and Heat Treatment of the High-Pressure Fracturing Pump Valves

2011 ◽  
Vol 339 ◽  
pp. 502-505
Author(s):  
Qi Ming Yang ◽  
Li Jie Yang
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Working Life ◽  
Nickel Steel ◽  
Treatment Technology ◽  
The Core ◽  
Heat Treatment Technology ◽  
Heat Hardening ◽  
Wear And Tear ◽  
Core Hardness

Fracturing pump valve's failure, except wear and tear factors, and also decided by the scope of it's contact stress, material and heat treatment in technology. Through the analysis of these, some conclusions had been found: The content of remnant austenite would be affected the performance of wear resistance, and the core hardness would be directly affected the working life of it. If the choice of the material and heat treatment technology was not been suitable, and the core intensity was not enough, it could loss the capability of sealing. According to the failure mechanism, used low chrome(nickel) steel, and the heat treatment of carburize+heat hardening+low-temperature tempering was reasonable.

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