scholarly journals Influence of rolling speed during hot forming using HDQT-R 30-12 machine on the properties of stainless steel 08Ch18N10T

Author(s):  
H Jirkova ◽  
T Janda ◽  
M Peković ◽  
J Říha ◽  
J Mach ◽  
...  
2018 ◽  
Vol 22 (3) ◽  
pp. 728-742
Author(s):  
Mehran Kamali Andani ◽  
Habib Daneshmanesh ◽  
Seyed Ahmad Jenabali Jahromi

In this study, a metal/polymer tri-layer composite was produced by direct adhesion (without adhesive), and mechanical locks were created using the warm rolling process. The effect of the process parameters including preheating temperature, rolling speed, thickness reduction, surface roughness, and the orientation of the surface scratches on the bond strength between layers was investigated. The results indicated that the suitable polymer fluidity and penetration, to provide stronger mechanical locks and higher bond strengths, could be achieved at an optimum preheating temperature and a rolling speed of 240°C and 36 r/min, respectively. In addition, the most appropriate surface pretreatment was obtained in the wire brush in the rolling direction mode with the surface roughness of 0.65 µm, so that the failure mechanism in this case was cohesive and the optimum thickness reduction was achieved at 40%. Furthermore, the mechanical properties of the sandwich sheet with highest bonding strength were evaluated.


2008 ◽  
Vol 571-572 ◽  
pp. 169-174
Author(s):  
Mirza Candic ◽  
Bao Hui Tian ◽  
Siegfried Kleber ◽  
Manfred Wießner ◽  
Masayuki Kamaya ◽  
...  

For the investigation of retained strains during hot forming, which are related to the dislocation structure, single and double hit compression tests were carried out at different temperatures and strain rates for a stainless steel. Using microhardness measurements the retained strains after the first and second pass were investigated as a function of the amount of deformation, temperatures as well as strain rates and dwell durations. In general, the retained strain decreases with increasing dwell durations in both the deformed and recrystallized grains, respectively. At a given total amount of deformation in a double hit compression, the retained strains for the as deformed unrecrystallized grains are reduced for a lower deformation in the first hit. For the recrystallized grains the retained strain increases, when comparing double hit with single hit compression.


2010 ◽  
Vol 139-141 ◽  
pp. 1392-1395
Author(s):  
Xiao Xia Zhang ◽  
Yong Tang ◽  
Zhen Ping Wan ◽  
Su Lian Tao

A new method of rolling-plowing-extrusion is proposed for fabricating outside 3D integral fins on the stainless steel tube. The fabricated process of fins is divided into two stages, rolling and plowing-extrusion, at first ribs are obtained on the stainless steel tube by the rolling process, and then 3D integral fins are obtained by the plowing-extrusion process. In this study, the principle of the rolling-plowing-extrusion is briefed; rolling process and plowing-extrusion process are analyzed, respectively. Through the experiments, the effect of technical parameters on fins forming and structures is investigated; experimental results are shown that accurate matching technical parameters and plowing tool angles is the key to the fins forming and structures; further analytical results indicate that when rolling speed and plowing speed is 50r/min, rolling feed rate is 0.16 mm/r, rolling depth is approximately 0.80-1.00mm, plowing feed rate is above 2.16mm/r, plowing depth is approximately 0.25-0.45mm, the optimal fins are obtained


Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.


Author(s):  
J. A. Korbonski ◽  
L. E. Murr

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.


Author(s):  
R. Gonzalez ◽  
L. Bru

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.


Author(s):  
Y. L. Chen ◽  
J. R. Bradley

Considerable effort has been directed toward an improved understanding of the production of the strong and stiff ∼ 1-20 μm diameter pyrolytic carbon fibers of the type reported by Koyama and, more recently, by Tibbetts. These macroscopic fibers are produced when pyrolytic carbon filaments (∼ 0.1 μm or less in diameter) are thickened by deposition of carbon during thermal decomposition of hydrocarbon gases. Each such precursor filament normally lengthens in association with an attached catalyst particle. The subject of filamentous carbon formation and much of the work on characterization of the catalyst particles have been reviewed thoroughly by Baker and Harris. However, identification of the catalyst particles remains a problem of continuing interest. The purpose of this work was to characterize the microstructure of the pyrolytic carbon filaments and the catalyst particles formed inside stainless steel and plain carbon steel tubes. For the present study, natural gas (∼; 97 % methane) was passed through type 304 stainless steel and SAE 1020 plain carbon steel tubes at 1240°K.


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