Micro Hole Piercing for Ultra Fine Grained Steel

Ultra fine grained steels have been developed by many researchers. However, the study of influence on processes and product functions from different grain size are limited because the size of bulk material was small for these products. Authors have developed the production process of thin ultra fine grained stainless steel coil, and the effects are able to be clarified. This paper will firstly report the influence on micro hole piercing by comparing different grain size materials. Secondly, orifices are produced from these materials, and the liquid flow volume is measured as the functional effect of different grain size. The effects of grain size differences were discussed with observing the hole conditions and measuring flow volume. The effects of reduction of the grain size were summarized as follows: (1) Accurate small hole is produced when ultra fine grained stainless steel is employed. (2) Product functional improvement is possible, and the phenomena are useful for liquid control devices.

Download Full-text

Micro Hole Piercing for Ultra Fine Grained Steel

International Journal of Automation Technology ◽

10.20965/ijat.2012.p0802 ◽

2012 ◽

Vol 6 (6) ◽

pp. 802-808 ◽

Cited By ~ 4

Author(s):

Takafumi Komatsu ◽

◽

Hitoshi Kobayashi ◽

Shiro Torizuka ◽

Shin-ichi Nagayama ◽

...

Keyword(s):

Bulk Material ◽

Flow Volume ◽

Functional Effect ◽

Steel Coil ◽

Fine Grained ◽

Grain Sizes ◽

Micro Hole ◽

Different Grain Size ◽

Fine Grained Steels ◽

Stainless Steel Coil

Ultra fine grained steels have been developed by many researchers. However, studies on the effects of different grain size on processes and product functions have been limited because the size of the bulk material has been small for these products. The authors have developed a production process for thin ultra fine grained stainless steel coil, and the effects have been clarified. This paper first reports the effects onmicro hole piercing by comparing materials with different grain sizes. Secondly, orifices are produced from these materials, and the liquid flow volume is measured as the functional effect of different grain sizes.

Download Full-text

The Impact of Grain Size on Oxidation Behavior of TP304H Austenitic Stainless Steel at High Temperature in Air

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.117-119.990 ◽

2011 ◽

Vol 117-119 ◽

pp. 990-994

Author(s):

Wei Wei ◽

Zhi Wu Wang ◽

Mao Lin Liu

Keyword(s):

Grain Size ◽

Stainless Steel ◽

Austenitic Stainless Steel ◽

Oxide Scale ◽

Grain Refinement ◽

Coarse Grained ◽

X Ray ◽

Fine Grained ◽

Different Grain Size ◽

The Impact

Exposed to 650°C air, TP304H stainless steel with two different grain size was oxidized at this temperature. At the meantime, comparison of their oxidation was through the oxidation kinetics curves and analysis of the morphology and composition of oxide scale which conducted by SEM and X-ray. The results showed that the oxidation rate of TP304H stainless steel was slowed down by grain refinement and oxide scale of fine-grained TP304H steel was thinner than that of coarse-grained steel. The nucleation and the growth of nuclei of coarse-grained oxide scale were more rapid. In addition, the grain refinement of austenitic stainless steel accelerated the diffusivity of Cr and made for the formation of dense and continuous oxide scale, so that the oxidation of stainless steel can be effectively inhabited.

Download Full-text

Influence of Grain Size on Work-Hardening Behavior in 12Cr Stainless Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.879.2228 ◽

2016 ◽

Vol 879 ◽

pp. 2228-2233

Author(s):

Masataka Yoshino ◽

Chikara Kami

Keyword(s):

Grain Size ◽

Stainless Steel ◽

Cold Rolling ◽

Work Hardening ◽

Reduction Rate ◽

Recrystallization Annealing ◽

Work Hardening Behavior ◽

Fine Grained ◽

Hardening Behavior ◽

Fine Grained Steels

Grain refinement is attracting attention as a strengthening method which does not depend on the alloying elements added to steels. Many reports have described the manufacturing methods and mechanical properties of ultra-fine grained steels. In ultra-fine grained steels, it is well known that yielding stress drastically increases in accordance with the Hall-Petch relationship, while uniform elongation significantly decreases. These tendencies imply that grain size affects not only yielding but also work-hardening behavior. However, the influence of grain size on work-hardening behavior has not been clearly understood. Therefore, in this study, we investigated the work-hardening behavior during tensile deformation of 12Cr stainless steel with various grain sizes. Grain refining was conducted by cold-rolling of annealed and quenched steel specimens, followed by recrystallization annealing. The grain size of the specimens decreased as the cold-rolling reduction rate increased. The minimum grain size obtained by this method was approximately 5 μm. With decreasing grain size, 0.2% proof stress increased and the strain which reached the plastic instability condition decreased. In the session, we report the dislocation accumulation behavior estimated by grain hardness and XRD and the dynamic recovery behavior assessed by the Kocks-Mecking model.

Download Full-text

Influence of Steel Grain Size on Residual Stress in Grinding Processing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.2389 ◽

2010 ◽

Vol 638-642 ◽

pp. 2389-2394 ◽

Cited By ~ 3

Author(s):

Masahide Gotoh ◽

Katsuhiro Seki ◽

M. Shozu ◽

Hajime Hirose ◽

Toshihiko Sasaki

Keyword(s):

Mechanical Properties ◽

Residual Stress ◽

Grain Size ◽

Stress State ◽

Mechanical Grinding ◽

Fine Grained ◽

Residual Stress State ◽

Analysis Methods ◽

Average Grain Size ◽

Fine Grained Steels

The fine-grained rolling steels NFG600 and the conventional usual rolling steels SM490 were processed by sand paper polishing and mechanical grinding to compare the residual stress generated after processing. The average grain size of NFG600 and SM490 is 3 μm and 15μm respectively. Therefore improvement of mechanical properties for such fine-grained steels is expected, it is important to understand the residual stress state of new fine-grained materials with processing. In this study, multi axial stresses of two kinds of specimens after polishing and grinding were measured by three kinds of analysis methods including cos-ψ method. As a result, as for σ33, the stress of NFG was compression, though that of SM490 was tension.

Download Full-text

Experimental and Numerical Investigations on Microcoining of Stainless Steel 304

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2953235 ◽

2008 ◽

Vol 130 (4) ◽

Cited By ~ 21

Author(s):

Gap-Yong Kim ◽

Muammer Koç ◽

Jun Ni

Keyword(s):

Grain Size ◽

Stainless Steel ◽

Bulk Material ◽

High Strength ◽

304 Stainless Steel ◽

Feature Size ◽

Stainless Steel 304 ◽

Metallic Parts ◽

Type 304 ◽

Type 304 Stainless Steel

Increasing demands for miniature metallic parts have driven the application of microforming in various industries. Only a limited amount of research is, however, available on the forming of miniature features in high strength materials. This study investigated the forming of microfeatures in Type 304 stainless steel by using the coining process. Experimental work was performed to study the effects of workpiece thickness, preform shape, grain size, and feature size on the formation of features ranging from 320μmto800μm. It was found that certain preform shapes enhance feature formation by allowing a favorable flow of the bulk material. In addition, a flow stress model for Type 304 stainless steel that took into consideration the effects of the grain and feature sizes was developed to accurately model and better understand the coining process. Weakening of the material, as the grain size increased at the miniature scale, was explained by the Hall–Petch relationship and the feature size effect.

Download Full-text

Effect of Temperature and Grain Size on the Corrosion Behavior of 316L Stainless Steel in Seawater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.299-300.175 ◽

2011 ◽

Vol 299-300 ◽

pp. 175-178 ◽

Cited By ~ 1

Author(s):

Sen Sen Xin ◽

Jian Xu ◽

Feng Jun Lang ◽

Mou Cheng Li

Keyword(s):

Grain Size ◽

Stainless Steel ◽

Corrosion Behavior ◽

316L Stainless Steel ◽

Seawater Temperature ◽

Effect Of Temperature ◽

Coarse Grain ◽

Pitting Potential ◽

Fine Grain ◽

Different Grain Size

The corrosion behavior of 316L stainless steel was investigated in seawater at different temperature by using cyclic anodic polarization. The results indicated that two 316L specimens with different grain size showed similar pitting potential at 25°C. The increase of seawater temperature led to the linear decrease of pitting potential and repassivation potential. Because the pitting resistance of fine grain steel reduced larger than that of coarse grain steel with increasing temperature, the latter had a higher pitting potential about 60 mV at 85°C. Compared with the coarse grain steel, the fine grain steel showed a longer induction time for pitting at 65°C.

Download Full-text

Effect of alloy grain size on oxidation resistance of silica-coated stainless steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171110 ◽

1994 ◽

Vol 52 ◽

pp. 676-677

Author(s):

C. S. McDowell ◽

S. N. Basu

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Stainless Steel ◽

Oxidation Resistance ◽

Powder Processing ◽

Hot Isostatic Pressing ◽

Silica Coating ◽

Austenitic Steels ◽

Coarse Grained ◽

Fine Grained

Oxidation resistance of stainless steels, which rely on the formation of a Cr2O3 (chromia) scale, can be further improved through minor alloying additions such as Al or Si, or by application of coatings to the exposed surfaces. Although, additions of Si to austenitic steels have demonstrated an improvement in oxidation resistance, high Si contents can be detrimental to the mechanical properties of these alloys. The application of a silica coating on the surface of the stainless steel provides improved oxidation resistance without detrimental effects on the mechanical properties. This study examines the effect of the grain size of the stainless steel on the effectiveness of a silica coating as an oxidation barrier.Fully austenitic stainless steel of composition Fe-18(wt%)Cr-20Ni-1.5Mn was produced in both coarsegrained and fine-grained form. The coarse-grained alloy, with a grain size of approximately 100 μm, was produced by casting and hot rolling. The fine-grained alloy, with a grain size of approximately 5 μm, was produced by rapid solidification powder processing, followed by consolidated by hot isostatic pressing and swaging.

Download Full-text