Refractory Tube Research Articles

Refractory Tubes with Innovative Liner Technology for Flow Control and Clean Steel Applications

Refractory Tubes with Innovative Liner Technology for Flow Control and Clean Steel Applications

Creep rupture in HP-Nb refractory steel tubes due to short-term overheating

Creep rupture in HP-Nb refractory steel tubes due to short-term overheating

Unsteady‐state lumped heat capacity system design for tube furnace for continuous inline wire annealing process

AbstractA continuous annealing furnace is developed, which incorporates the principle of electric resistance heating for obtaining the desired temperature in the furnace. The concept of lumped heat capacity system is applied for the determination of annealing time of a continuously moving wire through the refractory tube. Also, the heat transfer inside the system and heat losses to the atmosphere are considered using the principles of conduction, convection, and radiation. The parameters related to the dynamics of moving wire are also designed. The designed furnace is fabricated and tested for its working, the observations of which show that 30 minutes are required to reach about 400°C furnace temperature and 30 seconds for annealing 1 m length of wire. The morphological testing of annealed and nonannealed wire is done to study the microstructure, which shows more traces of pearlite in annealed wires than in nonannealed wires. Thus, continuous annealing furnaces are more effective for inline annealing of wires; so as to relieve the internal stresses, induced by the step cold rolling process.

Optimized Gating System for Steel Castings

Computer modeling using a commercially available software package was used to explore the optimization of filling systems based on the relatively new concepts of avoiding entrainment of air bubbles and oxides by avoiding surface turbulence. The test casting was based on a pattern for a traditional top poured test bar, whose cross section was a tri-lobed clover-like shape. The study illustrates clearly that the detailed design of the filling system has a major influence on the conditions for defect generation during filling. Traditional steel casting systems using the widely popular assembly of preformed refractory tubes were found to behave poorly. Systems were demonstrated which were capable of delivering highly controlled filling behavior. The latest systems to be developed employed (1) a naturally pressurized filling system and (2) the use of filters placed flush on the top of the runner to act as bubble diverters, together with (3) terminal spin traps. These novel filling systems demonstrated excellent performance in simulation, in agreement with practical experience of the capability (of the trident gate in particular) to produce, for the first time in the history of casting, defect-free castings on a routine basis.

Fabricating SiC Nanowire by Vacuum Heating Multilayer Graphene in Silicate Refractory Tube

One dimension silicon carbide (SiC) was synthesized by vacuum heating multilayer graphene sheets in silicate refractory tube. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Raman spectroscopy were used to study the microstructures and components of the vacuum heated materials. SEM images show the morphology of the synthesized SiC nanowires. XRD patterns and Raman spectra verified that graphene sheets remained and the wire like material was SiC nanowire. Therefore, vacuum sintering technology can be used to synthesize SiC nanowires.

The utility of comprehensive genomic profiling in selection of actionable targeted therapy in recurrent or refractory epithelial ovarian, fallopian tube and peritoneal carcinoma

The utility of comprehensive genomic profiling in selection of actionable targeted therapy in recurrent or refractory epithelial ovarian, fallopian tube and peritoneal carcinoma

Improving Refractory Constructions in the System “Steel-Pouring Ladle – Pouring Basket” of CBCM

The refractory equipment of the system “steel-pouring ladle – pouring basket” of continuous billet casting machines (CBCM) is considered. Designs of elements of the unit intended for protecting streams of metal in the course of pouring steel are developed. Designs of the unit with the use of inserts made of plastic refractories to prevent passage of air into the metal stream as it is being poured and assure rational parameters of the delivery of argon into the annular groove of the refractory tube are considered. Stability of the pouring process and an increase in the quality of the poured metal are achieved as a result.

STUDYCONDITIONS OF NON-METALLIC INCLUSIONS FLOTATION DURING ARGON INJECTION OF LIQUID BATH TUNDISH CCM. REPORT 3

The research results were used to create the original purging block for industrial tests on slab caster PJSC “Alchevsky Iron and Steel Works”. Design feature of the purge block is its geometrical form as a ring covering the tundish nozzle. This injection argon through calibrated holes made in special refractory tubes. As a result of tests, that maximum refining effect is achieved at a flow rate of 10 – 12 l/min.

Flotation of nonmetallic inclusions during argon injection into the tundish of a continuous-casting machine. Part 2

On the basis of previous research on a physical model and analytical estimates, a new injector design is proposed. Industrial tests of the new design are conducted on the continuous slab-casting machine at Alchevsk metallurgical works. The new design includes a ring covering the dosing nozzle. The gas is injected through calibrated holes in special refractory tubes. The tests indicate that a refining effect is obtained at gas flow rates of 10–12 L/min.

Extraction of Metals from Sea-nodules Using Buffered Sodium Chloride Media

The effect of addition of buffering agent in sodium chloride solution has been studied for the extraction of metals from sea-nodules by electrochemical leaching method. These experiments were performed in a glass cell, containing at one end a closed refractory diaphragm tube having a ground sea-nodules mixture with a platinum wire spiral as an inert anode and two identical titanium plates as cathodes. The influence of various concentration ratios of buffering agent to buffering agent and sodium chloride concentration (NH4Cl/NH4Cl + NaCl) on leaching rate was studied by keeping other conditions constant. The results indicate that, with the increase in concentration ratio, total metal recovery (%) increases up to a certain value, above which it decreases, whereas metal recovery at the cathode deposit increases continuously with the increase in the concentration ratio. The leaching rates of metals (Cu, Ni, Co, Mn and Fe) are compared. The difference in leaching rate is explained. The experimental results of the present work are also compared with those available in the literature. The agreement is good.

Casting of steel into ingot molds as a “submerged” jet

A method is proposed for casting steel in ingot molds by directing a “submerged” jet through a long refractory tube. The method is proposed as an alternative to the top- and bottom-pouring of steel. A slag-forming mixture is fed onto the surface of the molten steel. The method makes it possible to obtain a quality surface on the ingot.

Sensitivity Formulation Including Velocity Effects for Electromagnetic Induction Systems

Sensitivity formulation and calculation is an important task in several electromagnetic induction systems, notably those used for measurement, nondestructive testing (NDT), and inductive imaging systems such as magnetic induction tomography (MIT). Previously, the sensitivity formulation used in these cases did not consider the velocity of the objects being imaged as these are considered to be static compared to the rate of change of the applied ac field. More recently, practical applications such as eddy current NDT for high-speed rail or wheel inspection and liquid metal flow imaging have used the interaction between the velocity of the material and an applied magnetic field for inspection purposes. Clearly in these applications the effects of velocity are fundamental to the operation of the technique. However, a direct sensitivity formulation for the velocity term has not yet been reported. In this paper, we present a derivation of the sensitivity coefficients for general induction measurement systems taking into account of the effect of moving objects. The sensitivity formulation is derived from electromagnetic field theory. It is believed that this is a more complete formulation than those previously reported. The sensitivity formulation has been validated on a test example based on contactless inductive flow tomography (CIFT). This example consists of a refractory tube carrying liquid metal. The tube is surrounded by an array of coils which apply a dc field. The secondary magnetic field caused by the velocity of the liquid metal is measured with an array of magnetometers. The sensitivity of the magnetometer signal to the axial component of the velocity, derived from the new formulation, is compared to values obtained from an independent numerical model based on the finite difference method. A good agreement was obtained for the cases considered, some of which are reported here.

難治性再建胃管潰瘍から右心房穿孔を起こした１例

近年胃管潰瘍は，食道癌術後合併症のひとつとして認識されてきている。胃管潰瘍の穿孔は致命的であり，消化器以外の症状にも注意しなければならない。症例は72歳の男性で，過去に食道癌に対し食道亜全摘と後縦隔再建を行っていた。入院6か月前より胃管潰瘍を認め，保存的加療するも悪化していた。入院当初は肺炎として加療していたが，画像上で心嚢水が貯留，発熱と炎症反応高値が続き，精査中に突然のショックとなり，ICUに入室となった。入室後は抗菌薬，昇圧薬と輸血で一時ショックから離脱できたが，最終的に出血性ショックで永眠された。病理解剖で胃管潰瘍からの右心房穿孔が判明した。今回の症例を通して，食道癌術後合併症として，胃管潰瘍が重篤な状態を惹起することを十分認識し，潰瘍側が心嚢に接している場合や保存的加療に抵抗性のときは，心タンポナーデや心房穿孔に対する診断，治療の時機を失しないことが肝要である。

Phase I study of pemetrexed (P) and pegylated liposomal doxorubicin (PLD) in patients with refractory breast, ovarian, primary peritoneal, or fallopian tube cancer

e13515 Background: P and PLD are clinically active as single agents and synergistic in preclinical models. This phase I, open-label trial determined the maximum tolerated dose (MTD) and safety profile of P followed by PLD in patients (pts) with breast or gynecologic cancers. Methods: Using standard phase I (3+3 dose escalation) study design, cohorts of 3–9 pts received escalating doses of P followed by PLD in 28-day cycles: P 400–500 mg/m2 on Days 1 and 15 and PLD 30–45 mg/m2 on Day 1. All pts received folic acid (350–1000 μg daily) and vitamin B12 (1000 μg) until 21 days after last dose of P. Pts continued until dose-limiting toxicity (DLT) or disease progression (PD) occurred. Results: From 11/05 to 1/08, 29 pts were registered/treated. Median age: 60.6 years (range, 47.5–80.1); ECOG performance status 0/1: 28%/72%; primary disease sites: ovarian (55%), breast (35%), peritoneal (10%); prior therapies: chemotherapy (100%), surgery (72%), hormones/biologics (35%), radiation (21%). Dosing results are shown below. At dose level (L) 2 and L3, 1 pt/cohort had DLTs; L5 was added and 3/3 pts had DLTs; 4 more pts were treated at L4 (1 pt replaced). Most frequent drug-related Grade 3–4 hematologic toxicities: neutropenia (86%), leukopenia (59%), thrombocytopenia (48%), anemia (41%). Most frequent drug-related Grade 3–4 nonhematologic toxicities: hand-foot syndrome (14%), hypokalaemia (10%). Major reasons for discontinuation: PD (48%), toxicity (28%), pt request (14%). Overall best responses (n=24): 5 pts (21%) had partial response (PR), 14 pts (58%) had stable disease (SD), 2 pts (8%) had PD, 3 pts (13%) were not evaluable. All 5 PR and 8 SD pts were ovarian; 5 SD and both PD pts were breast. Conclusions: P followed by PLD was reasonably tolerated in this heavily-pretreated population. The MTD was P 500 mg/m2 and PLD 40 mg/m2. These dose levels may be carried forward to phase II studies in more specific patient populations. [Table: see text] [Table: see text]

Control of combustion in a thermally stabilized burner

A model has been developed with the assumption of a plug flow reactor that simulates heat transfer originating from the combustion of premixed reactants within a refractory tube. The work depicted in this article successfully implemented a transient one-dimensional coupled model of a plug flow reactor, which finds practical applications in a batch-type heat treatment furnace. All modes of heat transfer, namely conduction, convection, and radiation, were included in the model with single-step global chemistry for combustion of both methane and propane. Effects of variations of parameters such as inlet gas temperature, mass flux, and inlet fuel mass fraction on the gas and tube wall temperature profiles were studied to understand the shift in flame position along the tube length. It is established that the inlet gas temperature or the preheating level is one of the major governing parameters that determines the position of the flame in the tube. Similarly, reduction in mass flowrate shifted the flame location significantly upstream of the tube. It was also observed that the flame temperature exhibits a monotonic decay with depletion in mass flowrate. Results also show that for fixed inlet gas temperature and mass flowrate, the flame location shifts upstream for an increase in inlet fuel mass fraction. Thermally stabilized sustained combustion mode with optimum inlet gas preheating requirement was analysed as a function of mixture stoichiometry and mass flux. Open-loop and closed-loop control schemes were effectively implemented to establish the thermally stabilized scheme of heating and desired flame position within the tube. For open-loop control, with reduction in the mass flowrate (= 0.01 kg/s), an inlet gas temperature as low as 650 K can be maintained for sustaining combustion inside the tube. The joint variation of these inlet parameters has been well predicted by a correlation developed for a particular aspect ratio for high Reynolds number flows. The problem of absence of combustion and its solution towards stable flame position for tubes having smaller ratio of cross-sectional area to surface area have been addressed, which leads to the study for low Reynolds number flows. In the small Reynolds number flow cases, a thermally stabilized scheme has been successfully implemented that eliminates the necessity of preheating the gas prior to its combustion inside the tube.

Effect of dendritic segregation in the continuous-cast semifinished product on the formation of the stucture of high-carbon-steel wire rod

This article examines the hereditary effect of microscopic dendritic segregation in the continuous-cast semifinished product on the structure (the presence of segregation-related striae and martensitic sections and their distribution over the cross section) of wire rod made of high-carbon steel. To improve the quality indices of wire rod, the casting technology should be stabilized by adding equipment for stopper-assisted pouring, fully protecting the stream with submersible refractory tubes, using modern mold-oscillation mechanisms (such as lever-type mechanisms), using parabolic molds that speed up crystallization of the CCS, and employing other measures. Maximum use should be made of heat treatment of the CCSs and rolled products, one of the goals here being to increase the degree of homogenization of the cast structure and rolled product and/or residues of that structure. This can often be achieved through longer heating of the CCS in walking-beam furnaces prior to the rolling operation.

A Case of Refractory Gastric Tube Ulcer with Surgical Staple in the Ulcer Floor

症例は71歳，女性。平成16年11月当院にて難治性良性食道狭窄に対し非開胸食道抜去，胸壁前経路胃管再建を施行した。また3カ月前から腰痛症にてNSAIDを内服している。今回，平成17年4月胃管に一致した前胸部に皮膚の発赤と同部位からの出血を認め当科を受診した。緊急内視鏡にて胃管潰瘍穿孔と診断され入院となった。入院後はNSAIDを中止し，禁食，高カロリー輸液，PPIによる保存療法を行った。改善傾向を認め経口摂取開始後退院となった。同年8月，再び前胸部の出血を認め胃管潰瘍の再燃・穿孔の診断で入院となった。初回と同様の治療を行い穿孔部は閉鎖，潰瘍自体も改善傾向となったが経口摂取開始後に再び増悪した。Helicobacter pylori感染は陰性であった。内視鏡所見では潰瘍底に手術時のstapleを認めこれが再燃・治癒遷延の要因と考えられ内視鏡的に除去した。以後速やかに改善し同年11月退院となった。

Automotive and industrial applications of structural ceramics in Japan

This paper reviews the status of structural ceramics in Japan. Until around 1980, successful applications of these materials were limited to wear-resistant parts and structural components working under very low stresses. Considerable work has been done over the years on applying ceramics to mechanical parts used under higher stresses. This led to some successful applications of silicon nitride to automotive components, including turbocharger rotors and glow plugs. However, the recent market for silicon nitride automotive components has not been as large as was expected. Cordierite honeycombs for catalysts and diesel particulate filters made of silicon carbide are becoming more important applications in Japan. It is noteworthy that the Japanese market for structural ceramics has been steadily increasing since 1985, with the leading applications being apparatus for purifying the exhaust gas of automotive engines and parts for semiconductor manufacturing equipment. Alumina, for example, is widely used for vacuum process chambers. High-purity alumina is also used for the components of liquid crystal device manufacturing equipment and various mechanical parts. The recent applications of structural ceramics in Japan summarized in this review include vacuum process chambers for manufacturing semiconductor and liquid crystal devices, wear-resistant ceramics used for steel-making, optical lens forming and cutting tools, refractory tubes for casting aluminum alloys, and automotive applications.

Oxidation of Molten Steel by the Air Permeated through a Refractory Tube.

Refractory tubes such as a shrouding nozzle and a submerged entry nozzle are employed for molten steel transferring from a ladle to a tundish, and a tundish to a mold, respectively, to prevent molten steel from being oxidized. When the cross-sectional area in the molten steel flow channel is suddenly contracted and subsequently enlarged, a negative pressure is generated at the area. Thereby air is permeated into the molten steel flow through the refractory tube and oxidizes the molten steel. The permeability of a submerged entry nozzle was predicted from measurement of the gas permeated through the refractory tube by a dipping test. Using the predicted permeability and the pressure analysis in fluid flow, we calculated the oxidation rate by the permeated air during molten steel transferring. As a result, the concentration decrease rate of aluminum in molten steel is estimated 0.35 ppm per hour and this oxidation formed by the permeated air does not attribute to alumina build-up in the submerged entry nozzle.

Effects of Operating Parameters on Desulfurization of Molten Iron with Magnesium Vapor Produced In-situ by Aluminothermic Reduction of Magnesium Oxide

The effects of operating parameters on desulfurization of molten iron with magnesium vapor produced in-situ by the aluminothermic reduction of magnesium oxide have been studied. To promote the reduction of magnesium oxide and to make use of the heat of the molten iron, a refractory tube charged with the pellets that were made of the mixture of magnesia and aluminum powders, was immersed into the melt. The produced magnesium vapor was injected directly into the melt with Ar or N2 carrier gas to react with sulfur in it.Compared with using Ar, using of N2 as the carrier gas resulted in lower desulfurization efficiency due to a part of aluminum reacting with N2 to form AlN. Increasing the pellet forming pressure promoted the reduction of magnesium oxide, and hence improved the desulfurization efficiency. The use of a porous Al2O3 or MgO tube decreased the desulfurization rate as compared with that of a dense graphite tube. In the case of the porous Al2O3 tube, the magnesium vapor reacted and/or was adsorbed with the porous Al2O3 tube in the initial stage of the experiment. The reverse reaction and/or the desorption took place to produce magnesium vapor in the later stage of the experiment. In the case of the porous MgO tube, the magnesium vapor was adsorbed and desorbed by the tube during the experiment. When the dense Al2O3 tube was used, a horizontal nozzle was installed to improve the desulfurization efficiency. It is possible to enhance the desulfurization efficiency of pellet by dividing pellet charging into two portions. As the oxygen partial pressure in the atmosphere was increased, the desulfurization efficiency became low and the resulfurization reaction became more noticeable in the later stage of the experiment.