scholarly journals Variations of microstructure and resistance to fish-scaling of a hot rolled enamel steel before and after enamel firing

2021 ◽  
Vol 11 ◽  
pp. 466-473
Author(s):  
Xueqi Huang ◽  
Zhimin Zhang ◽  
Xianghua Liu ◽  
Yang Zhao ◽  
Xiaolin Li
Keyword(s):  
Before And After ◽  
Hot Rolled

Manufacturing of LSAW Pipes Using Hot Rolled Sheets for Sour-Service Application

2021 ◽  
Author(s):  
Rajesh Kumar Goyal ◽  
Mahesh Gajjar ◽  
Ashok Joshi ◽  
Anupkumar Tamhane
Keyword(s):  
Steel Mill ◽  
Corrosion Resistant ◽  
Behavioural Changes ◽  
H2s Corrosion ◽  
Before And After ◽  
Service Application ◽  
Hot Rolled ◽  
Sour Service ◽  
Geographical Locations ◽  
Selection Of

Abstract The exploration and transportation of fluids from corrosive fields or reserves demand corrosion-resistant pipelines. The pipelines for sour-service application demand higher resistance to H2S corrosion because of higher sulphur content observed in the geographical locations. The pipelines laid in the corrosive and marshy lands demand high wall thickness to allow for wall thinning due to corrosion. The linepipes manufactured using TMCP plates are widely accepted for sour-service applications. The use of cut-to-length sheets from hot rolled coils for the manufacturing of LSAW pipes is economical but having limited acceptance by the pipeline operators. Welspun took an initiative to develop the linepipes for an onshore sour-service application using API 5L X60MS grade cut-to-length sheets from TMCP hot rolled coils procured from an approved steel mill. The LSAW pipes of 24” OD × 14.27 mm WT were manufactured by the JCO-E press at Welspun Pipes Mill in Anjar-Gujarat-India. The experience of 24”OD × 14.30 mm WT, API 5L X60MO grade pipes manufacturing using TMCP plates procured from another approved steel mill, was used to decide factors such as alloy design, cleanliness, strength, DWTT, hardness, HIC, SSCC, CVN for the selection of cut-to-length sheets. This paper deals with sheet-to-pipe behavioural changes in properties before and after cold mechanical expansion. Wherever possible, the comparison was also made with plate-pipe behavioural changes in properties.

Sour Resistant High Strength Seamless Pipes for Risers

2013 ◽  
Author(s):  
Matteo Ortolani ◽  
Ettore Anelli ◽  
Paolo Novelli ◽  
Emanuele Paravicini Bagliani
Keyword(s):  
Heat Treatment ◽  
Mechanical Testing ◽  
High Strength ◽  
Post Weld Heat Treatment ◽  
Water Quenching ◽  
Potential Solution ◽  
Steel Pipes ◽  
Before And After ◽  
Hot Rolled ◽  
Sour Service

In case of a Weld On Connector’s riser using ASTM A182 F22 forged joints, high strength (SMYS of 80 ksi) steel pipes for sour service (hardness below or equal to 250 HV10) suitable for welding to the connectors are required. Welding is challenging because of the Post Weld Heat Treatment (PWHT) needed to reduce the hardness in the F22 HAZ while maintaining the required strength in the pipe. Theoretical evaluations were performed by means of metallurgical models and a potential solution was identified in grade P22-like steel (2¼ Cr - 1 Mo), with minor modifications with respect to the standard ASTM A335 and supplied in Q&T condition. A trial heat was cast and hot-rolled into pipes. After water quenching, the response to tempering was assessed by means of laboratory heat treatments and subsequent mechanical testing, together with metallurgical examination. Simulated PWHTs were also performed on Q&T material. 80 ksi grade P22 seamless pipes were finally produced and qualification involved mechanical testing before and after simulated PWHT: SMYS of 80 ksi and HV10 ≤ 250 requirements were met. The material also exhibited excellent toughness and resistance to HIC and SSC cracking.

Improvement of carbon segregation in cast bloom and heredity in hot-rolled bar

2021 ◽  
Vol 118 (6) ◽  
pp. 610
Author(s):  
Mengyun Zhang ◽  
Yanping Bao ◽  
Lihua Zhao ◽  
Xin Li
Keyword(s):  
Casting Speed ◽  
Reduction Process ◽  
Rolling Process ◽  
Solidification Structure ◽  
Soft Reduction ◽  
Carbon Segregation ◽  
The Core ◽  
Before And After ◽  
Core Areas ◽  
Hot Rolled

In this study, the effect of mechanical soft reduction on carbon segregation in the continuous casting of 300 × 400 mm 42CrMo alloy structural steel blooms was comparatively investigated by adjusting the casting speed, which was systematically optimized through numerical simulation. When the casting speed is 0.60 m · min−1, during the soft reduction process, the central solidification structure of the bloom becomes dense, and carbon segregation is improved. Moreover, the distribution of carbon in the samples before and after rolling was analyzed. Combined with the soft reduction process, the uniformity of carbon across the cross section of the bloom /bar distinctly improved for casting speeds of 0.50 m · min−1, 0.55 m · min−1 and 0.60 m · min−1, this was predominantly reflected in the core areas. The effective segregation length proportion of the bloom and rolled bar is approximately 40%. This phenomenon fully verifies the heredity characteristics of the elements in the rolling process.

Effect of Edge Masking on Residual Stress of Hot-Rolled Strip on Run-Out Table

2015 ◽  
Vol 1095 ◽  
pp. 732-735
Author(s):  
Xiao Hua Liu ◽  
Feng Dong ◽  
Dong Cheng Wang
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Numerical Model ◽  
Rolled Strip ◽  
Hot Rolled Strip ◽  
Strip Flatness ◽  
Before And After ◽  
Microstructural Model ◽  
C Program ◽  
Hot Rolled

A numerical model including thermal and microstructural model is established for precisely prediction of residual stress of hot-rolled strip on run-out table. Temperature and phase transformation fraction are coupled and formulated for the calculation of thermal and transformation expansion that could induce internal stress. Residual stress for hot-rolled strip before and after coiling are calculated using C++ program. Influence of edge masking on residual stress is analyzed. It is concluded that edge masking makes the strip flatness better after coiling.

Dissolution of Precipitates in Hot Rolled Low Mn, Ti Added Pipeline Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3182-3187 ◽  
Author(s):  
Ali Dehghan-Manshadi ◽  
Rian Dippenaar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Dispersive Spectrometry ◽  
Low Carbon ◽  
Eds Analysis ◽  
Transmission Electron ◽  
Before And After ◽  
Hot Rolled ◽  
Scanning Electron

The dissolution of different sulphides, carbides, carbo-sulphides and nitrides during re-heating of hot rolled low carbon, low manganese, titanium added steel have been studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analysis. In addition, the chemical composition and size distribution of the different precipitates have been determined before and after reheating to analyze the modification of these precipitates in the course of the reheating cycle. The TEM and EDS analyses showed the presence of a wide variety of simple and/or complex precipitates in as rolled samples. The reheating of these samples to temperatures as high as 1350 °C, caused dissolution of most particles, although titanium nitride (TiN) did not dissolve even after reheating. By decreasing the reheating temperature more and more precipitates remained un-dissolved, but some spherodization occurred at higher temperatures.

Deformation Replication

1970 ◽  
Vol 28 ◽  
pp. 280-281
Author(s):  
J. Temple Black
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Rake Face ◽  
Orthogonal Machining ◽  
Aluminum Chips ◽  
Before And After ◽  
Materials Used ◽  
Glass Knife ◽  
Very High

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.

The Clinical, Roentgenological and Morphological Effects of an Acute Exposure of Phosgene on the Lungs of Dogs

1971 ◽  
Vol 29 ◽  
pp. 236-237
Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth
Keyword(s):  
Latent Period ◽  
Chemical Industry ◽  
Toxic Substance ◽  
Lung Edema ◽  
X Rays ◽  
Beagle Dogs ◽  
Male And Female ◽  
Morphological Alterations ◽  
Before And After ◽  
Electron Microscopes

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.

Ultrastructure of Melanin Formation in Curvularia sp., Alternaria sp., and Drechslera Sorokiniana

1977 ◽  
Vol 35 ◽  
pp. 398-399
Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
A. A. Bell
Keyword(s):  
Potassium Phosphate ◽  
Thielaviopsis Basicola ◽  
Wild Type ◽  
Potassium Phosphate Buffer ◽  
Transmission Microscopy ◽  
Electron Transmission ◽  
Melanin Formation ◽  
Before And After ◽  
Alternaria Sp ◽  
Electron Transmission Microscopy

(+)-Scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2Hj-naphthalenone] and 1,8-di- hydroxynaphthalene (DHN) have been proposed as intermediates of melanin synthesis in the fungi Verticillium dahliae (1, 2, 3, 4) and Thielaviopsis basicola (4, 5). Scytalone is enzymatically dehydrated by V. dahliae to 1,3,8-trihydroxynaphthalene which is then reduced to (-)-vermelone [(-)-3,4- dihydro-3,8-dihydroxy-1(2H)-naphthalenone]. Vermelone is subsequently dehydrated to DHN which is enzymatically polymerized to melanin.Melanin formation in Curvularia sp., Alternaria sp., and Drechslera soro- kiniana was examined by light and electron-transmission microscopy. Wild-type isolates of each fungus were compared with albino mutants before and after treatment with 1 mM scytalone or 0.1 mM DHN in 50 mM potassium phosphate buffer, pH 7.0. Both chemicals were converted to dark pigments in the walls of hyphae and conidia of the albino mutants. The darkened cells were similar in appearance to corresponding cells of the wild types under the light microscope.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

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