Influence of Holding Time After Deformation on Bainite Transformation in Niobium Microalloyed Steel

  Using Gleeble 1500 system, the influence of holding time on bainite transformation in deformed niobium microalloyed steel during continuous cooling was analyzed, and the carbides in upper bainite were also systematically researched. The results show that the occurrence of the static recrystallization decreases the amount of bainite with an increase in the holding time and the emergence of retained austenite (RA) with the longer holding time. Two types of carbides were observed in upper bainite with regard to their precipitation sites. They either existed between the bainite ferrite laths or co existed with RA. The formation mechanism of two kinds of carbides was analyzed by combining TEM micrographs with the model.     

Influence of Mn Content and Hot Deformation on Transformation Behavior of CMn Steels

The hot deformation behaviors and the microstructural evolution of plain CMn steels with similar contents of C and Si but different contents of Mn have been investigated by compressive processing using Gleeble1500 mechanical simulator. Influence of Mn and hot deformation on continuous cooling transformation of steels has been studied. The experimental results showed that deformation in austenite region accelerated transformation process, and the extent is dependent on the hot deformation and cooling conditions. The hot deformation would promote transformation process, but the increase of transformation temperature is dependent on Mn contents. The results have also shown that the effect of deformation on ferrite transformation becomes more obvious with the increase of Mn content at relatively low cooling rate.     

Dynamic and Static Recrystallization Behavior of Low Carbon High Niobium Microalloyed Steel

 The recrystallization behavior of a low carbon high Nb microalloyed steel was investigated using Continuous and interrupted hot compression tests. The results showed that the onset of dynamic recrystallization (DRX) could be detected from inflection in the plot of the strain hardening rate θ against stress σ regardless of whether the stress peak appears or not. According to Zener-Hollomon parameter the activity energy of DRX (Qdef) was obtained, and a new modified expression calculating Qdef was proposed in consideration of the chemical composition of experimental steel. Applying the 2% offset method the static softening fraction was determined. The graphic representation of the softening fraction vs. interrupt time gave the information of the non-static recrystallization temperature (about 1000℃)and the relationship of precipitation-time-temperature. Static recrystallization kinetics follow Avrami’s law in high deformation temperature, and different values of the exponent n were given to illustrate the different effects of Nb element on static recrystallization at different deformation temperature.     

Study on the removal of MIBK from aqueous solution by vacuum membrane distillation

Ｖａｃｕｕｍｍｅｍｂｒａｎｅｄｉｓｔｉｌｌａｔｉｏｎ(ＶＭＤ)ｉｓａｐｒｏｍｉｓｉｎｇｓｅｐａｒａｔｉｏｎｔｅｃｈｎｉｑｕｅｆｏｒｔｈｅｐｕｒｉｆｉｃａｔｉｏｎｏｆｄｉｌｕｔｅａｑｕｅｏｕｓｓｏｌｕｔｉｏｎｓ,ｓｕｃｈａｓｓｅｐａｒａｔｉｏｎｏｆｇａｓｅｓｆｒｏｍａｑｕｅｏｕｓｓｏｌｕ ｔｉｏｎｓａｎｄｒｅｍｏｖａｌｏｆｖｏｌａｔｉｌｅｏｒｇａｎｉｃｃｏｍｐｏｎｅｎｔｓ(ＶＯＣ)ｆｒｏｍｄｉｌｕｔｅａｑｕｅｏｕｓｓｏｌｕｔｉｏｎｓ .Ｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｔｈｅｒｅｍｏ ｖａｌｏｆＶＯＣｆｒｏｍｄ…     

Study on removing zinc from nickel electrolyte by ion-exchange

Ｔｈｅｃｏｎｔｅｎｔｏｆｉｍｐｕｒｉｔｙｚｉｎｃｉｎｔｈｅｅｌｅｃｔｒｏｌｙｔｅｉｓｌｉ ｍｉｔｅｄｓｔｒｉｃｔｌｙｉｎｔｈｅｎｉｃｋｅｌｐｒｏｄｕｃｔｉｏｎｂｙｄｉａｐｈｒａｇｍｅｌｅｃ ｔｒｏｌｙｓｉｓ .Ｆｏｒｅｘａｍｐｌｅ ,ｉｎｔｈｅｐｒｏｃｅｓｓｏｆｐｒｏｄｕｃｉｎｇｎｉｃｋｅｌｏｆｚｅｒｏ ｇｒａｄｅ (Ｃｈｉｎａｓｔａｎｄａｒｄ) ,ｚｉｎｃｃｏｎｔｅｎｔｉｎｔｈｅｅｌｅｃ ｔｒｏｌｙｔｅｉｓｒｅｑｕｉｒｅｄｔｏｂｅｌｏｗｅｒｔｈａｎ 0 .0 0 0 3ｇ/Ｌ .Ｆｏｒｚｉｎｃ ｒｅｍｏｖｉｎｇｆｒｏｍｎ…     

Transformation Behavior of Low Carbon Steels Containing Two Different Si Contents

 Continuous cooling transformation behaviors of low carbon steels with two Si contents (050% and 135%) were investigated under undeformed and deformed conditions. Effects of Si contents, deformation, and cooling rates on γ transformation start temperature (Ar3), phase microstructures, and hardness were studied. The results show that, in the case of the deformation with the true strain of 04, the length of bainitic ferrite laths is significantly decreased in low Si steel, whereas, the M/A constituent becomes more uniform in high Si steel. An increase in cooling rates lowers the Ar3 greatly. The steel with higher level of Si exhibits higher Ar3, and higher hardness both under undeformed and deformed conditions compared with the steel with a lower Si content. Especially, the influence of Si on Ar3 is dependent on deformation. Such effects are more significant under the undeformed condition. The hardness of both steels increases with the increase of cooling rates, whereas, the deformation involved in both steels reduces the hardness.     

应用硝黄铁矫治山渣树缺铁黄叶病

山楂是营养价值很高的果品,富含维生素C、黄酮类成分以及铁、钙等元素,有助消化、降低血脂、软化血管等功效,是为人们喜爱的保健和医疗食品。由于其经济价值高,山楂栽培面积扩大很快,由山区扩到平原。平原地区种植山楂,由于缺铁,经常出现缺铁失绿症,影响果树的生长发育,尤其在幼树时期。在河北有的果园,山楂树黄叶病病株率高达50％左右,严重影响果树生长。     

Effect of Chromium on CCT Diagrams of Novel AirCooled Bainite Steels Analyzed by Neural Network

The quantitative effects of chromium content on continuous cooling transformation (CCT) diagrams of novel aircooled bainite steels were analyzed using artificial neural network models. The results showed that the chromium may retard the high and mediumtemperature martensite transformation.