Fatigue Focused Optimization of Treatment Parameters – A Case Study about Deep Cryogenic Treatment

2011 ◽  
Vol 488-489 ◽  
pp. 498-501
Author(s):  
Paolo Baldissera ◽  
Cristiana Delprete
Keyword(s):  
Cryogenic Treatment ◽  
Likelihood Estimation ◽  
Deep Cryogenic Treatment ◽  
Soaking Time ◽  
Surface Method ◽  
Treatment Parameter ◽  
Standard Response ◽  
Proper Scaling ◽  
Two Parameters

The problem of treatment parameter optimization focused on the fatigue resistance is analysed through a case study about Deep Cryogenic Treatment (DCT) of AISI 302 steel. In particular, the possibility to integrate fatigue data fittings through the Maximum Likelihood Estimation (MLE) method in the optimization process is evaluated. Two levels of two parameters (soaking time and temperature) are considered and then expanded to three by proper scaling of their values in order to include the untreated case as a “zero” level. Fatigue focused optimization is then achieved by standard Response Surface Method (RSM) and by MLE with two models for comparison purposes.

Internal Friction Study of the Influence of Deep Cryogenic Treatment on the Microstructure of a Bainitic Steel

2012 ◽  
Vol 184 ◽  
pp. 239-244
Author(s):  
Na Min ◽  
Tian Yu Ji ◽  
Li Juan Zhu ◽  
Xiao Chun Wu ◽  
Hong Bin Wang
Keyword(s):  
Internal Friction ◽  
Cryogenic Temperature ◽  
Cryogenic Treatment ◽  
Cryogenic Cooling ◽  
Bainitic Steel ◽  
Deep Cryogenic Treatment ◽  
Soaking Time ◽  
Transmission Electron ◽  
Dislocation Pinning ◽  
Friction Study

The influence of deep cryogenic treatment (DCT) on the microstructure of a bainitic steel is investigated by means of internal friction and transmission electron microscopy (TEM). Two relaxation peaks (Pc1and Pc2) are observed during cooling and one relaxation peak (Ph) during heating from 100 to 320K. Peak Pc1may be related to dislocation pinning. Peak Phis attributed to dislocation-carbon atoms interaction. The decreasing of peak Phafter cycles deep cryogenic cooling indicates that soaking time under the deep cryogenic temperature is not contributed to the precipitation of carbides, while the cycles cryogenic treatment lead to more fine carbides precipitation.

Study of Deep Cryogenic Treatment Process Effect on Microstructure and Properties of CuBeZr Alloy

2020 ◽  
Vol 841 ◽  
pp. 335-339
Author(s):  
Nuwan Wannaprawat ◽  
Karuna Tuchinda
Keyword(s):  
Treatment Process ◽  
Cryogenic Treatment ◽  
Microstructure Analysis ◽  
Surface Wear ◽  
Deep Cryogenic Treatment ◽  
Maximum Increase ◽  
Soaking Time ◽  
Materials Properties ◽  
Alloy Microstructure ◽  
Sem Microstructure

The aim of this research was study the influence of the Deep Cryogenic Treatment (DCT) on the microstructure transformation and materials properties of beryllium copper alloy (CuBeZr alloy). Microstructure analysis such as size, shape and number of precipitates were studied by Optical microscopy (OM) and Scanning Electron Microscopy (SEM). Microstructure analysis showed that transformation into the rod shape precipitates appeared after the process. The dispersion of CuNi precipitates and CuNiZr precipitates in the ⍺ matrix after deep cryogenic treatment was found to be increased. The change in number of CuNi precipitates and CuNiZr precipitates led to an increase in hardness and wear resistance. The maximum increase in hardness of 11% was observed with 48 hours soaking time with a reduction in surface wear of approx. 60%.

scholarly journals Cryogenic treatment of tool steels: A brief review and a case report

2021 ◽  
Vol 4 (1) ◽  
pp. Manuscript
Author(s):  
Thee Chowwanonthapunya ◽  
Chaiyawat Peeratatsuwan ◽  
Manote Rithinyo
Keyword(s):  
Heat Treatment ◽  
Tool Steel ◽  
Retained Austenite ◽  
Cryogenic Treatment ◽  
Cold Treatment ◽  
Tool Steels ◽  
Deep Cryogenic Treatment ◽  
Conventional Heat Treatment ◽  
Wide Range

Tool steels used in marine industries demand for the effective approach to enhance their properties. Normally, conventional heat treatment is widely used to increase the performance of tool steels. However, this method cannot fully enhance the tool steel performance. On the other hand, cryogenic treatment is a supplementary process to the conventional heat treatment, which can promote the conversion of retained austenite to martensite and accelerate the precipitation of fine carbides. In this paper, a systematic review of cryogenic treatment of tool steels was presented. A wide range of useful investigations was reviewed, particularly in the details of the transformation of retained austenite to martensite and the precipitation of the fine carbides. A case study on a tool steel subjected to conventional heat treatment, conventional cold treatment, and deep cryogenic treatment was also given and discussed to give an insight in the cryogenic treatment of tool steels.

XRD, STEM, and Tensile Properties of AISI S1 Tool Steel after Deep Cryogenic Treatment

2015 ◽  
Vol 1088 ◽  
pp. 195-199
Author(s):  
Seyed Ebrahim Vahdat ◽  
Keyvan Seyedi Niaki
Keyword(s):  
Tensile Properties ◽  
Tool Steel ◽  
Cryogenic Treatment ◽  
X Ray Diffraction ◽  
Deep Cryogenic Treatment ◽  
Soaking Time ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Successful Employment ◽  
Advanced Tool

Successful employment of advanced tool steel in engineering applications is related to its ability in terms of meeting service life requirements and fabrication with proper dimensions. Deep cryogenic treatment may be used to produce advanced tool steel by simultaneously increasing toughness, strength, and hardness. Twelve sets of specimens were tested in this paper, 9 of which were deep cryogenic treated and then tempered. Tensile properties, hardness, X-ray diffraction, and scanning transmission electron microscopy were applied for macroscopic and microscopic investigations. The best results of simultaneous improvement in toughness, hardness, and strength were obtained for 36 h soaking time and 1 h tempering time.

The Research on Process of Deep Cryogenic Treatment for W4Mo3Cr4VSi HSS Drill

2010 ◽  
Vol 97-101 ◽  
pp. 457-460 ◽  
Author(s):  
Hong Juan Yan ◽  
Hong Hai Xu ◽  
Ying Liu
Keyword(s):  
Orthogonal Experiment ◽  
Cryogenic Treatment ◽  
Deep Cryogenic Treatment ◽  
Soaking Time ◽  
Experiment Method ◽  
Before And After ◽  
Orthogonal Experiment Method ◽  
Enhance Wear Resistance ◽  
Carbide Particles ◽  
Soaking Temperature

The Deep Cryogenic Treatment(DCT) process of W4Mo3Cr4VSi HSS was studied by orthogonal experiment method. The paper analysed the effect of various DCT process parameters on mechanical properties and observed microstructure before and after DCT treatment by the SEM. The results show that the effect of soaking temperature on the properties of drill is the first factor, the soaking time is second and the cooling rate is third. DCT enhances the transformation of austenite to martensite, and distributable carbide particles are precipitated from martensite. Therefore DCT increase hardness and enhance wear resistance of twist drill.

scholarly journals A New Extension of Thinning-Based Integer-Valued Autoregressive Models for Count Data

Entropy ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 62
Author(s):  
Zhengwei Liu ◽  
Fukang Zhu
Keyword(s):  
Likelihood Estimation ◽  
Real Data ◽  
Autoregressive Models ◽  
Superior Performance ◽  
Data Sets ◽  
Binomial Thinning ◽  
Free Case ◽  
Two Parameters ◽  
Conditional Maximum ◽  
Thinning Operator

The thinning operators play an important role in the analysis of integer-valued autoregressive models, and the most widely used is the binomial thinning. Inspired by the theory about extended Pascal triangles, a new thinning operator named extended binomial is introduced, which is a general case of the binomial thinning. Compared to the binomial thinning operator, the extended binomial thinning operator has two parameters and is more flexible in modeling. Based on the proposed operator, a new integer-valued autoregressive model is introduced, which can accurately and flexibly capture the dispersed features of counting time series. Two-step conditional least squares (CLS) estimation is investigated for the innovation-free case and the conditional maximum likelihood estimation is also discussed. We have also obtained the asymptotic property of the two-step CLS estimator. Finally, three overdispersed or underdispersed real data sets are considered to illustrate a superior performance of the proposed model.

scholarly journals Effect of deep cryogenic treatment on surface chemistry and microstructure of selected high-speed steels

2021 ◽  
Vol 548 ◽  
pp. 149257
Author(s):  
Patricia Jovičević-Klug ◽  
Monika Jenko ◽  
Matic Jovičević-Klug ◽  
Barbara Šetina Batič ◽  
Janez Kovač ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
High Speed ◽  
Cryogenic Treatment ◽  
Deep Cryogenic Treatment
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