Adhesion of iron coatings with steel and cast iron

The iron-plating process in methyl sulfate chloride electrolytes was investigated. The conditions of iron plating ensuring the coating adherence with steel and pig iron required in the technological processes of reconditioning and strengthening of machine pieces are determined. Process conditions ensuring the high coating adherence with steels 45, 15HGT, 40H, and grey and high-strength pig iron are found; they include steps: powering on of the polarizing current with the initial density of 0.15–0.5 kA/m² immediately after insertion of pieces in the electrolyte and raising of the current density up to the working level with a rate of 4–5 A/m² s. Metallographic, polarizing, and other research show the influence of the initial electrolysis conditions on the formation of the first layers of coverings and the process of iron electrocrystallization on structural phases of tempered steel and grey and high-strength pig iron.     

Compacted graphite iron: Cast iron makes a comeback

Although compacted graphite iron has been known for more than four decades, the absence of a reliable mass-production technique has resulted in relatively little effort to exploit its operational benefits. However, a proven on-line process control technology developed by SinterCast allows for series production of complex components in high-quality CGI. The improved mechanical properties of compacted graphite iron relative to conventional gray iron allow for substantial weight reduction in gasoline and diesel engines or substantial increases in horsepower, or an optimal combination of both. Concurrent with these primary benefits, CGI also provides significant emissions and fuel efficiency benefits allowing automakers to meet legislated performance standards. The operational and environmental benefits of compacted graphite iron together with its low cost and recyclability reinforce cast iron as a prime engineering material for the future.     

铝合金用铁添加剂中铁的快速测定法

研究了铁添加剂中铁量的快速测定方法,介绍了其原理,确定了试验条件,该方法简便,快捷、准确。     

Austempering and austempered ductile iron microstructure in copper alloyed ductile iron

The variation in the austempered microstructure, the volume fraction of retained austenite, X_λ, the average carbon content of retained austenite, C_λ, their product X_λC_λ and the size of bainitic ferrite needles with austempering temperature for 0.6% Cu alloyed ductile iron have been investigated for three austempering temperatures of 270, 330, and 380 °C for 60 min at each temperature after austenitization at 850 °C for 120 min. The austempering temperature not only affects the morphology of bainitic ferrite but also that of retained austenite. There is an increase in the amount of retained austenite, its carbon content, and size of bainitic ferrite needles with the rise in austempering temperature. The influence of austempering time on the structure has been studied on the samples austempered at 330 °C. The increase in the austempering time increases the amount of retained austenite and its carbon content, which ultimately reaches a plateau.     

铸铁焊条在大直径铸铁阀门修补上的应用

我公司在阀门安装过程中,由于紧固时用力不均,导致与循环冷水泵出口相连的Dg500 PN1．6单向铸铁阀门的出口法兰根部沿周向出现裂纹,经检查发现裂纹长度有圆周长度的三分之二还多,裂纹深度基本上是贯穿性的,部分裂到法兰密封面上(图1中粗黑线),还有部分裂穿法兰螺栓孔之间(图1中虚黑线)．针对     

High resolution electron microscopy characterization of nitrides of iron and iron alloys

A study of nitride-phase formation in alloys nitrided by glow discharge plasma nitriding was performed by high-resolution electron microscopy. The iron and steel samples were nitrided above and below the eutectoid transformation point (590 ‡C). After nitriding, the samples were annealed for several treatment times at 400 ‡C. The microstructure and identification of the iron nitrided phases formed by nitriding and annealing were investigated by x-ray diffraction (XRD), optical microscopy (OM) and mainly high resolution electron microscopy (HREM) in a JEOL-4000EX high resolution microscope at 400 kV. The results of the characterization show a surface ε compact nitride layer, which is transformed into ε + γ during cooling. The tempering process affects the surface hardness of the samples. After an initial increase relative to the untreated sample, the microhardness diminishes after long treatment times. This behavior is correlated with the αt’’ phase appearance, growth, and transformation.     

Properties of high-purity iron

Conclusions It was found that high-purity iron with total O, N, C, S, and P equal to 6 at. ppm and total nonferrous impurities less than 6 at. ppm has an ultimate strength of 5 kg/mm² and yield strength of 2.1 kg/mm².Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 2–8, December, 1974.     

Unconventional iron smelting processes

In this day of ever-widening interest in improvement of iron and steel making processes, it is of interest to look back and see what history reveals. Journal of Metals here presents that story, as told by the authors of Blast Furnace USA.     

Direct iron ore reduction

Why are we reversing previous conclusions as to the impracticability of direct reduction? The answers appear to be largely economic: rising scrap costs and the high cost of new capital equipment. Another factor stems from the increasing availability of lower grade ores and the necessity for treating fines; this means higher capital and operating costs associated with the classical blast furnace.