Hot-dip Aluminizing Research Articles

Laboratory hot-dip aluminizing of sheet steels

It is a matter of common knowledge that in laboratory hot-dip aluminizing, great difficulties are often encountered in preparing specimens that are free of surface oxides and other ubiquitous contaminants such as oils, grease and dust. Inadequate preparation of specimens will inevitably lead to the prevention of alloy layer growth during hot dipping and poor coatings following withdrawal. This paper describes a method for the production on a laboratory scale of hot-dipped type 1 aluminized sheet- steel specimens of commercial quality.

SUS316ステンレス鋼への溶融アルミニウムめっき時に形成される合金層の構造

SUS316ステンレス鋼への溶融アルミニウムめっき時に形成される合金層の構造

On the influence of silicon on the growth of the alloy layer during hot dip aluminizing

The reactions between a low alloyed steel and a pure as well as a 2% silicon containing aluminium melt where studied at 780 and 792‡ C, respectively. The velocity of the iron enrichment was the same for both cases, whereas the alloy layer growth was much faster in the case of the pure aluminium melt. After hot dip aluminizing in the 2% silicon containing aluminium melt silicon was found to be incorporated in the alloy layer. From that it is clear that silicon acts on the solid state side, when reducing the alloy layer thickness during hot dip aluminizing.

高耐熱性溶融アルミニウムめつき鋼板の開発

高耐熱性溶融アルミニウムめつき鋼板の開発

Interface Morphology Between the Aluminide Layer and Iron Substrate in the Hot-Dip Aluminizing Process

AbstractThe morphology of the interface developed in the hot-dip aluminizing process between the aluminide layer and the iron substrate was investigated by metallography.A serrated interface was generally found between the aluminide layer and the iron substrate. However, a planar interface was produced by the addition of carbon and silicon in the iron substrate or the addition of silicon in the aluminum bath. This interesting phenomenon is explained on the basis of the nucleation of each aluminide grain at the contact interface. The serrated interface is believed to result from preferential nucleation of aluminide crystallites on certain crystallographic planes of the iron substrate, whereas the planar interface results from uniform nucleation at all sites. It was also determined that the structure of the iron substrate has no effecton interface morphology, and that the aluminide layer has a preferred orientation of (002). Resume La morphologie de l'interface qui se developpe dans le procede d'aluminage p...

Kinetic interactions between aluminiumliquidand iron/steelsolidfor conditions applicable to hot-dip aluminizing

AbstractHot-dip aluminizing of Remko iron, 0.05%C steel, and 0.17%C steel substrates has been carried out in the temperature range 673°-286° Cfor times from 5 to 300 s. Thickening of the iron-aluminium intermetallic layer obeys a parabolic time relationship at all temperatures except for the 0.17% C steel aluminized at 826°C. The temperature dependence of intermetallic layer thickening is exponential with an activation energy of the order of 170-180 kj/mol. This value is higher than that obtained in previous studies, and reasonsfor this discrepancy are given in terms of simultaneous growth and spalling of the intermetallic layer for dipping times in excess of 60 s.

The use of transmission57Fe M�ssbauer spctroscopy to study the kinetics of hotdip aluminizing of iron

The use of transmission57Fe M�ssbauer spctroscopy to study the kinetics of hotdip aluminizing of iron

Studies on the Fatigue Strength of Aluminum Coated Steel : 1st Report, The Effect of Aluminum Coating Method on the Fatigue Strength

Rotating bending fatigue tests were performed on three kinds of aluminum coated steels. The effect of three aluminum coating methods, namely electroplating, hot dip, and spraying on the fatigue strength of the steels were studied. The results obtained are as follows. (1) The effect of electroplating on the fatigue strength of the steel is not recognized at all. But a little effect of the spraying on the fatigue strength is observed. (2) In hot dip aluminum coating of the steels, a decrease of the fatigue strength is observed. This is considered to be due to the formation of cracks in a brittle alloy layer. Such cracks act as shape notches on the surface of steel base. Moreover, the formation of cracks decreases the effective area of specimen whic supports the alternating stress. (3) The addition of 1% beryllium to molten aluminum bath markedly improves the fatigue strength of hot dip materials.

アルミニウム被覆されたステンレス鋼の合金層について

アルミニウム被覆されたステンレス鋼の合金層について

わが国の溶融アルミニウム・メッキ技術の現状

わが国の溶融アルミニウム・メッキ技術の現状

溶融アルミニウムメッキの付着量測定法について

溶融アルミニウムメッキの付着量測定法について

アルミニウムメッキによる高張力鋼および高クロム鋼の応力腐食割レ防止について

The main stress corrosion crackings occurring on steels are chloride corrosion cracking on 18-8 stainless steel and sulfide corrosion cracking on high tension steels. In the previous paper (Part 1), the authors reported on the method of prevention of chloride corrosion cracking by means of hot dip aluminizing. Subsequently, they made experiments on sufide corrosion cracking of high tension steels by using H2S solution.The results obtained were as follows:1) As the results of stress corrosion tests of the specimens, the crack sensitivity of SCM-21 steel to sulfide corrosion was most remarkable at 1, 400ppm of H2S concentration, and its apparent threshold stress was about 22.0kg/mm2. In the tests of SUS-24B steel, a large number of etching pits were found, though no rupture was seen. The formation of these pits was thoroughly prevented by aluminum coating.2) The sulfide corrosion cracking was perfectly prevented by aluminum coating on the whole surface of the specimen. However, it was not satisfactorily prevented by partial coating of aluminum.3) The above facts would be due to the idea that the current density between the parent metal (SCM-21) and coated aluminum in H2S solution was not large enough for preventing the steels from occurrence of cracks.

1020. A pulse source of large electron currents of small duration: S P Bugaev et al, Izv VUZ Fiz11 (1), 1968, 145–147 ( in Russian).

The electrochemical behaviour of hot dip aluminium–silicon coatings on steel is studied in relation to the in-depth structure and composition, determined by SEM/EDX and EBSD. Progressive GDOES sputtering was used for electrochemical analysis using a micro-capillary three-electrode microcell in craters positioned in the various sublayers. Additionally, cross-sections were analyzed with SKPFM. Results show that the outer free aluminium layer of the coating is able to cathodically protect the underlying layers and substrate. Conversely, the interdiffusion layers are nobler than the steel. The galvanic series implies that cathodic protection will depend on the nature of the defect and the corrosion environment.

1024. Kinetics of the dehydration of calcium sulphate dihydrate in vacuo: B Molony and M J Ridge, Aus J Chem, 21, April 1968, 1063–1065.

The electrochemical behaviour of hot dip aluminium–silicon coatings on steel is studied in relation to the in-depth structure and composition, determined by SEM/EDX and EBSD. Progressive GDOES sputtering was used for electrochemical analysis using a micro-capillary three-electrode microcell in craters positioned in the various sublayers. Additionally, cross-sections were analyzed with SKPFM. Results show that the outer free aluminium layer of the coating is able to cathodically protect the underlying layers and substrate. Conversely, the interdiffusion layers are nobler than the steel. The galvanic series implies that cathodic protection will depend on the nature of the defect and the corrosion environment.

Gas and gettering problems in colour television tubes

The electrochemical behaviour of hot dip aluminium–silicon coatings on steel is studied in relation to the in-depth structure and composition, determined by SEM/EDX and EBSD. Progressive GDOES sputtering was used for electrochemical analysis using a micro-capillary three-electrode microcell in craters positioned in the various sublayers. Additionally, cross-sections were analyzed with SKPFM. Results show that the outer free aluminium layer of the coating is able to cathodically protect the underlying layers and substrate. Conversely, the interdiffusion layers are nobler than the steel. The galvanic series implies that cathodic protection will depend on the nature of the defect and the corrosion environment.

アルミニウムメッキによる18-8オーステナイト系ステンレス鋼の応力腐食割レ防止について

アルミニウムメッキによる18-8オーステナイト系ステンレス鋼の応力腐食割レ防止について

Continuous Hot-Dip Aluminizing of Steel Strip

SummaryThe design of a plant for the large-scale continuous aluminizing of steel strip by hot-dipping is discussed. The processes through which the strip passes include heating, pickling, oxide reduction, hot-dipping and rapid cooling, and the equipment used for these stages is described. Consideration is given in more detail to the formation of the alloy layer and to the effect of alloying additions to the aluminium bath. The properties of the coating are then reviewed, together with the corrosion resistance that it provides. In conclusion, some notes are presented on suitable applications for aluminized steel.

アルミニウム被覆鋼の溶接に適する溶接棒 (電気) の研究

It is difficult to find out such a suitable rod for either gas or electric welding of two “Alumers (hot-dipped aluminum coated steel)”, as not to cause any cut-off defect in the Al-Fe alloy layer around the welded border line.Therefore, V-shape cut off is usually made first along the welding line of two Alumers, which, then, can be welded with ordinary welding rod, and this welded line is finished, if necessary, by covering with thin layer of special steel welding rod. In Fig. 1, the cut-off defect can clearly be seen in the Al-Fe alloy layer, which has been one of the gravest defects of Alumer, unsolved since it turned up in the Japanese industry.A series of experiments, therefore, was carried out to find out a suitable rod especially for electric welding of “Alumer”, and the result was as follows:(1) By using the suitable flux, it is possible to weld Alumers together with the Al or Al-alloy welding rod, and stable Al-Fe alloy layer can be obtained.(2) With the fluxes of main ingredients of KCl, NaCl, and AlE3, and addition of small amount of K2SO4 and NH4Cl as ionization medium, the weldability is much improved.(3) With the rods of Al-Si (Si 11%) alloy as core metal, more stable layer is obtained, and the weldability also becomes better.(4) It is necessary to use D. C. welding of reversed polarity arc.(5) Comparing high temperature oxidation resistivity, the welding with Al-Si rod is superior to that with the stainless steel rod.

Evaluation of Some Materials and Coatings for Utility Pole Line Hardware

Abstract Examines some factors dictating manufacturers' choice of hardware materials and coatings for utility pole hardware. These factors are corrosion resistance, cost, adaptability and compatibility. Discusses use of aluminum, stainless steel and high strength, low alloy steels as materials for corrosion resistance. Also discusses corrosion resistant coatings: hot dip aluminum on steel, zinc filled coatings, spray metal coatings and fluidized bed process. Comparisons are made of cost of materials and coatings. 7.10, 6.4.2, 6.2.1, 5.3.4, 1.2.2

ディーゼル機関用予燃焼室への溶融アルミメッキの応用

The precombustion chamber of diesel engine of tractor requires heat resistance like that of the hot dip aluminium coating on steel.Though the precombustion chamber does not participate in any mechanical movement, it must stand, with its limited space, the combustion of low grade fuel containing much sulphor and other impurities, and its inside must be exposed directly to high temperature of 500-800°C.The hot dip aluminium coating may be said to be most suitable for the above requirements.The application of the process for the precombustion chamber was investigated as follows:A. Necessary conditions1) Temperature2) Ignition products of fuel3) Inside surface area of precombustion chamber4) Weight5) Necessary mechanical properties6) Surface finishing precision degree7) WeldabilityB. Adherence of AluminiumAfter the above mentioned investigation, the process was actually applied to the mild steel and heat-resistant steel (SEH-3) precombustion chambers.Then the engine with this chamber was run for test, the result of which was so satisfactory that the application of the hot dip aluminium coating to the mild steel precombustion chamber was recognized to be practicable.