Papers by Keyword: Ferrous Material

Abstract: Grinding experiments were carried out in wet, with MQL, in dry, with a spray of dry ice particles and various gases to examine influence of grinding atmospheres on the grinding performance in the combination surface grinding of steel and WC with a diamond wheel. From the experimental results, it was found that the grinding with inert gas injection which reduces an oxygen concentration at the grinding point would proceed a processing at more stable grinding force, resulting in less wear of the diamond abrasives.

Abstract: A polyimide resin-bonded cubic boron nitride (cBN) wheel was designed and manufactured for precision grinding ferrous materials. Firstly, the curing reaction of the resin, which including chain and cross-linking polymerization stages with the exothermic peaks of 140°C and 235°C, respectively, was analyzed by DSC-TG. Based on thermal analysis, a hot press forming process and a post thermal treatment were employed for manufacturing the wheel. Grinding experiment results showed that the transient normal grinding forces vary from 9 to 12 N and fluctuate slightly with 1~2 N when grinding hardened steel 45#. The grinding ratio of 775 and the surface roughness of 0.19 μm were obtained.

Abstract: A phenolic resin-bonded cubic boron nitride (CBN) wheel was designed and manufactured for precision grinding ferrous materials. The resin was determined to be a linear phenolic resin pre-polymer added with hexamethylenetetramine by infrared spectrum and the curing reaction, which characterized by an exothermic peak at about 180°C with release of NH₃, was analyzed by differential scanning calorimeter and thermogravimetry. Based on thermal analysis, a hot press forming process and a post thermal treatment were employed for fabricating the resin-bonded CBN wheel. Grinding experiment results showed that normal grinding forces vary from 7 to 11 N and fluctuate slightly with 1~2 N. The grinding ratio of 585 and the surface roughness of 0.18 μm were obtained under an appropriate grinding condition.

Abstract: Through analyzing and inspecting the raw materials conditions and process conditions that affect ferrous material reduction in the thermal reserve zone, the article indicates that for the three commonly used ferrous material of blast furnace, sinter, pellets and lump ore, sinter is easiest to reduce and lump ore is most difficult to reduce. And increasing of the size of ferrous material promote the reduction of the ferrous material slightly. With the increase of batch weight, weight loss of ore and coke decrease at first and then increase. With the increase of the ratio of coke/ore, the extent of reduction of ferrous material had not significantly improved.

Abstract: The dependence of composition and sintering temperature on physical properties of ALA was investigated. Mechanism of black discoloration(sometimes called black core) usually found in the interior cores of artificial lightweight aggregate was also investigated by the optical observations. As a result, the primary cause of black discoloration in the interior of the lightweight aggregate body resulting from incomplete burn-out of carbonaceous impurities and iron-containing materials.In the cross-sectional morphology of ALA, bloating phenomena as well as formation of large pores were found in the samples containing ferrous materials. By increasing content of ferrous materials, both specific gravity and water absorption have been decreased.

Abstract: Warm compacting and sintering behaviors of pre-mixed Fe-2Ni-2Cu-1Mo-1C powders were studied. Results showed that green density increased with compacting temperature and then fell slightly; the maximum green density was obtained at about 120°C. Green compact density and spring back effect of the pre-mixed powder increased gradually as the compacting pressure increased. Sintered density first increased and then fell as the temperatures went up under different sintering temperatures for 50 minutes, but the trends of sintering dilatation were first reduced and then increased. Sintered density first reduced and then increased with the prolonged sintering time at 1300°C, but the trends of dimension change after sintering were the very reverse. Tensile strength, elongation and hardness of the warm compacted Fe-2Ni-2Cu-1Mo-1C materials generally increased as sintering temperature and sintering time went up.