Processing with Nitriding

2003 ◽  
pp. 153-161
Keyword(s):  
High Speed ◽  
High Speed Steel ◽  
Compound Layer ◽  
Case Depth ◽  
Low Alloy Steels ◽  
Layer Formation ◽  
Tool Steels ◽  
Maraging Steels ◽  
Alloy Steels ◽  
Hot Work Tool Steels

Abstract The nitriding process can be applied to various materials and part geometries. This chapter focuses on tool steels (hot-work tool steels, high-speed steel cutters, and gears), pure irons, low-alloy steels, and maraging steels. Various considerations such as the surface metallurgy requirements of the die, including case depth, compound layer formation, and temperature, are also discussed in this chapter.

On the Presence of Eta Carbide in the Cryogenically Treated High Speed Steel

2012 ◽  
Vol 602-604 ◽  
pp. 356-359 ◽  
Author(s):  
Chandrashekhar Gogte ◽  
Dilip Peshwe ◽  
Ravindra Paretkar
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
Cryogenic Treatment ◽  
High Speed Steel ◽  
The Other ◽  
Tool Steels ◽  
Wear Characteristics ◽  
Secondary Carbides ◽  
Alloy Steels

The research in the cryogenic treatment of tool steels and other alloy steels is important as it causes substantial increase in the wear characteristics of alloy and tool steels. The present day research of this technology indicates precipitation of submicroscopic carbides referred to as eta carbides. This work comprises of reviewing the carbide types that form during heat treatment of high speed steels and presenting the results of the experiment for finding eta carbide in the cryogenically treated AISI T42 high speed steels using advanced microscopy. The results of this work indicate the contribution from the other secondary carbides (other than eta carbides) in the enhancement of wear characteristics in high speed steels.

Materials for bullet core

2020 ◽  
Vol 2020 (10) ◽  
pp. 8-21
Author(s):  
A. G. Kolmakov ◽  
◽  
I. O. Bannykh ◽  
V. I. Antipov ◽  
L. V. Vinogradov ◽  
...  
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Low Alloy Steels ◽  
Hard Alloys ◽  
Small Arms ◽  
Alloy Steels ◽  
Materials Used ◽  
Basic Ideas ◽  
New Generation ◽  
Natural Composite

he basic ideas about the process of introducing cores into protective barriers and the most common core patterns and their location in conventional and sub-caliber small arms bullets are discussed. The materials used for manufacture of cores are analyzed. It is concluded that for mass bullets of increased armor penetration the most rational choice can be considered the use of high-carbon low-alloy steels of a new generation with a natural composite structure and hardness of up to 70 HRC. For specialized armor-piercing bullets, cores made from promising economically-alloyed high-speed steels characterized by a high complex of «hardness—bending strength» are better alternative than ones made of hard alloys or tungsten alloys.

scholarly journals Improving Properties of Tool Steels by Method of Dynamic Alloying

2019 ◽  
Vol 18 (5) ◽  
pp. 369-379
Author(s):  
A. S. Kalinichenko ◽  
V. I. Ovchinnikov ◽  
S. M. Usherenko ◽  
Javad F. Yazdani-Cherati
Keyword(s):  
Wear Resistance ◽  
High Speed ◽  
Matrix Material ◽  
Amorphous State ◽  
High Speed Steel ◽  
Deep Penetration ◽  
Structure And Properties ◽  
Tool Steels ◽  
Particle Flows ◽  
Dynamic Processing

The influence of high-speed particle fluxes on changes in the structure and properties of materials has been widely studied currently. The effect exerted by particles moving at very high speeds can have both negative (in spacecrafts) and positive character (dynamic processing of tool steels). Therefore a task for studying an effect of high-speed particle flows on structure change in tool steels and improving their performance properties has been set in the paper. The study has used an explosive method for creation of a high-speed flow of SiC + Ni and Al2O3 particles. Samples after dynamic alloying have been subjected to diffusion nitriding. Microstructure of specimens made of X12M, R18, R6M5K5steel has been studied using optical and electron metallography. Wear resistance of the samples has been also tested on a friction machine. Theoretical and experimental results on a complex effect of high-speed microparticle flows and nitriding on a structure and properties of tool steels have been obtained during the research. It has been established that dynamic alloying by particles leads to formation of a specific structure in a composite material reinforced with channels. Central fiber (channel) zone with powder particles residues is surrounded by areas of amorphous state which is succeeded by a zone with a nanocrystalline fragmented cellular structure. Then we observe a zone with a microcrystalline structure that transits to a zone with crystalline structure which is characteristic for a matrix material of structural steel. The obtained data can expand and complement some ideas about mechanisms for dynamic loading of solids and condensed matter, plastic deformation, physical mechanics of structurally inhomogeneous media at different levels, a number of effects arising from collision and ultra-deep penetration of microparticles into metals. It has been shown that wear resistance of high-speed steel subjected to dynamic alloying in the quenched state is increased by 1.2 times in comparison with wear resistance of steel alloyed in the annealing state.

Development and Future Potential of Maraging Steels

1966 ◽  
Vol 70 (668) ◽  
pp. 766-772 ◽  
Author(s):  
A. G. Haynes
Keyword(s):  
Maraging Steel ◽  
High Strength ◽  
Production Costs ◽  
Fatigue Properties ◽  
Low Alloy Steels ◽  
Corrosion Failure ◽  
Maraging Steels ◽  
Aerospace Applications ◽  
Laboratory Test Results ◽  
Alloy Steels

SummaryConventional low-alloy steels at strengths above 100 ton/in2 have been successfully used in various aerospace applications, but laboratory test results, service-performance data and problems in production indicated a need for steels which possessed improved mechanical properties, and which were simpler to machine and fabricate. The 18% Ni-Co-Mo maraging steels were developed in 1961 with the aim of fulfilling this need, and since that date several thousand tons of the steels have been produced and used in all common shapes and forms. In comparison with low-alloy steels of equivalent strength, 18% nickel maraging steels have greater resistance to fracture at highly-stressed notches, defects or cracks, and their susceptibility to hydrogen embrittlement/stress-corrosion failure is generally far superior. The un-notched rotating bend fatigue properties of machined and mar aged specimens of 18% Ni-Co-Mo maraging steels tend to be superior in the low-cycle range and similar in the low-stress range to the properties of low-alloy steels of comparable strength. The fatigue properties of unnotched, in contrast to those of notched, specimens are affected by heat-treatment/machining procedure. Experience gained in production of components has proved that the 18% nickel maraging steels are extremely simple to heat treat, to machine, to cold form and to weld. Exploitation of these advantages can frequently offset the higher initial cost of maraging steel. For example, an analysis of production costs for a complex aircraft component has demonstrated that the use of maraging steel enabled the component to be made by forging and machining at 5-20% lower cost than with a conventional low-alloy steel, despite the fact that initial material costs were five times greater. 18% Ni-Co-Mo maraging steels retain high strength at temperatures up to 350-400°C, and have given good service in short-duration heating cycles at much higher temperatures. Maraging steels may be surface hardened by various methods, and gears and dies treated by simultaneous nitriding and maraging have given excellent performance.The tremendous technological efforts which have been made in the past five years have yielded the majority of data and experience necessary to ensure successful use of the 18% Ni-Co-Mo maraging steels in the aerospace industry.

Fatigue Characteristics of Laser Surface-Hardened Cast Irons

1987 ◽  
Vol 109 (3) ◽  
pp. 179-187 ◽  
Author(s):  
P. A. Molian
Keyword(s):  
Continuous Wave ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Case Depth ◽  
Laser Surface ◽  
Low Alloy Steels ◽  
Surface Layers ◽  
Cast Irons ◽  
Co2 Gas ◽  
Alloy Steels

Contrary to expectations, laser surface heat treatment has a deleterious effect on the fatigue performance of pearlitic gray and ductile cast irons. A 1.2 kW, continuous wave, CO2 gas laser, operating in square beam mode, was employed to heat-treat the surfaces of standard fatigue specimens. Rotational-bending fatigue tests were then conducted on untreated (as-cast) and laser treated specimens. Results indicated that the effect on fatigue behavior of case depth, microstructure and hardness of laser-hardened surface layers were opposite to that observed in carbon and low alloy steels. A fracture model based on the presence of graphite, residual stresses, and strain-induced transformation is postulated to explain the adverse effect of laser hardening of cast irons.

The Effect of Dwell Time on Die Wear in High Speed Hot Forging

1970 ◽  
Vol 185 (1) ◽  
pp. 1171-1186 ◽  
Author(s):  
S. M. J. Ali ◽  
B. W. Rooks ◽  
S. A. Tobias
Keyword(s):  
High Speed ◽  
Dwell Time ◽  
Hot Forging ◽  
High Energy ◽  
Low Alloy Steels ◽  
Die Wear ◽  
High Energy Rate ◽  
Alloy Steels ◽  
Small Force ◽  
Improved Performance

This paper describes an automatic high energy-rate forging system, consisting of a Petro-forge machine linked to an induction furnace with an automatic billet transfer mechanism. The system contains also automatic die lubrication, as well as pyrometric and other safety interlocks, permitting the feeding and forging of hot billets at a rate of one every 5 s. Hot upsetting tests carried out with this automatic forging system, aiming at the determination of the effect of dwell time on die wear, are discussed. Two series of experiments were carried out, with dwell times of 40 and 250 ms respectively. In the shorter dwell time tests, five different die materials were evaluated with the aim of establishing their relative wear resistance. It was found that the higher alloyed die steels offer improved performance over the conventional low alloy steels, ‘good value for money’ being obtained by WEX 779. An analysis of the dwell time, performed by taking a high speed cine film of the whole forging operation, showed that it consisted of forging, bouncing and after-forging phases. In both the short and the long dwell time tests the forging phase and the bouncing phase were 4 and 30 ms, respectively. However, the after-forge phase was 6 ms for the short dwell time and 216 ms for the long dwell time experiments. During the after-forge phase, the dies, with the upset workpiece between them, are pressed together by a relatively small force and in view of this heat transfer is poor. Nevertheless, the increase of the dwell time has a very large effect on die wear, doubling the rate of wear in some cases, depending on the type of die material used.

Evolution of White Layer during Wire-Cutting and Comparison of Several Methods to Improve Surface Integrity for Fineblanking Tools

2018 ◽  
Vol 920 ◽  
pp. 141-148 ◽  
Author(s):  
Xiang Lin Zhang ◽  
Han Lin Peng ◽  
Li Yun Zhang ◽  
Chuan Liang Cao ◽  
Jing Wen Yi ◽  
...  
Keyword(s):  
Surface Integrity ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
High Speed Steel ◽  
Tool Steels ◽  
Surface Residual Stress ◽  
Fine Blanking ◽  
Superior Mechanical Properties ◽  
Wire Cutting

Powder metallurgical high speed steel (such as S390) has superior mechanical properties and been used as fineblanking tools. The electrical discharge machining has been widely used for cutting fine blanking tools which are made of especially hard tool steels. Whereas, its thermal nature causes great concerns regarding surface integrity, which matters a lot to tool life. In the present study, the evolution of surface integrity of the S390 with multi-cutting is comprehensively compared. The result shows that the surface roughness, white layer thickness and surface residual stress decrease with the increase of cutting pass. Additionally, the effectiveness to remove white layer on HSS S390 by manual and towed polishing and electrolytic polishing are compared. At last, a device of abrasive water jet polishing is designated to remove the white layer resulted from wire-cutting.

scholarly journals About the Surface Hardening of Tool Steels by Electrical Discharge Treatment in Electrolyte

2010 ◽  
Vol 159 ◽  
pp. 137-140 ◽  
Author(s):  
Dimitar Krastev ◽  
Boyan Yordanov
Keyword(s):  
Corrosion Resistance ◽  
Metal Matrix ◽  
Electrical Discharge ◽  
Surface Hardening ◽  
High Speed ◽  
High Speed Steel ◽  
Metallic Surface ◽  
Tool Steels ◽  
Discharge Treatment ◽  
Nonequilibrium Phase Transformations

In this study are given some results about the influence of electrical discharge treatment in electrolyte on the microstructure of high speed steel HS 6-5-2. The metallic surface after electrical discharge treatment in electrolyte has a different structure in comparison with the metal matrix, which determines different properties. It is observed remarkable increasing of hardness, strength and corrosion resistance related to the nonequilibrium phase transformations and the obtained finecrystalline microstructure.

Comparative Studies on Medium Carbon Low Alloy Steels and Maraging Steels

2021 ◽  
Vol 903 ◽  
pp. 17-26
Author(s):  
Nikhil Kumar ◽  
C.M. Ramesha ◽  
T. Anilkumar ◽  
P. Rajendra ◽  
B.R. Chandan
Keyword(s):  
Maraging Steel ◽  
Technological Development ◽  
Aerospace Industry ◽  
High Strength ◽  
Advanced Materials ◽  
Low Alloy Steels ◽  
Medium Carbon ◽  
Maraging Steels ◽  
Alloy Steels ◽  
The Cost

The maraging steel are considered ultra-high strength due to its yield strength greater than 1400Mpa and are part of a set of advanced materials of interest for technological development, mainly for aeronautics and aerospace industry. For this purpose they should exhibit good toughness, fatigue resistance and acceptable weldability. Since the maraging steels are of higher cost we are intended to make the Medium Carbon Low Alloy Steel (MCLA) for the purpose of aeronautical and aerospace industry instead of Maraging steel as the cost of MCLA is comparatively less. An attempt is made to study on the basic properties of MCLA steels and Maraging steels by process modifications and comparing the results with that of the standard properties of the Maraging steel.

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