| Iron radicel sinter is the most productivity and the most popular sinter in powder metallurgy industry. Like other ordinary steely material, the performance of iron radicel sinter is mainly due to chemistry element species of alloy, sinter density, microstructure and so on. For extending the applying of sludge iron powder in Panzhihua Group Iron & Steel, ltd.(PGIS) and increasing its industrial subjoin, the prealloy composite iron powder coated with copper could be obtained by modificating iron powder surface with chemical replacing copperize method, while the physical and chemical performances of iron powder could be promoted. Some parameters like granularity ,density and fluidity could be mensurated and compared. It is discovered that the density be debased to some extant, but the fluidity is increased. Some globose and snow copper crystal on the surface of original powder could be observed by scanning electron microscope and some stone-hull coated structure could be formed. The composite powders are pressed and produced flan in 200Mpa pressure, then it is heat concretion treated in vacuum furnace. Agglomerated samples are observed by metallography before and after eroding, and it is found that fractional cropper has been diffused to iron adicel system. The study adopted pure iron powder for applying in powder metallurgy industry is extracted by magnetic sedimentation method and deoxidization technics from PGIS converter sludge. Some parameters are: the total iron content is more than 98%, the average granularity is 236 μm, the density is 1.98g/ cm~3 and the fluidity is 36s/50g.Under experimental condition, the best technics condition of extracting iron powder coated with copper from PGIS converter sludge is: 20g 300-granularity iron powder, using 20ml 1% hydrochloric acid to abstering powder for 3min , 0.4 mol / L bluestone solution 100ml , and the mixing speed is slow or midvelocity. The factors touching coated powder are arraied from better to ebb: the concentration of bluestone solution, the ratio of solid to liquid (the ratio of powder quantity to bluestone solution capacity), powder granularity, mixing speed. The study is indicated that the two coated powders treated by heat concretion are both composed of ferrolites and pure copper, and the structures are asymmetry. When preparing powder metallurgy hardware with iron coated by copper, the sinter technics should be selected between copper powder sinter and iron powder sinter, that is, the soaking time and sinter time ought to be higher than copper sinter and lower than iron sinter. The ampliative experiment of industrial manufacture to coated powder is carried out, and the indexes of compositive Cu / Fe powder are: the copper content in FeCu20 powder is 19%-21%, the copper content in FeCu30 powder is 29%-31%, the density is 2.4-3.0g/cm3, the fluidity is not more than 35Sec/50g, the granularity is not more than 154 μm and the rate of sinter contraction is 0.32%-1.00%.On the other hand,as iron powder surface modification method, The copperized replacement technics is simple, low cost, fast sediment speed and has little environmental pollution. Adopting this technics,not noly environment protection can be observed, but also can bring upper ecnomic benefits. A technical valuable method is provided for recycling converter sludge efficiently.
|
PDF Full Text Request