为提高5154铝镁合金线材的综合性能,采取不同铸造冷却方式对5154铝合金线材进行试验研究,采用扫描电子显微镜、拉伸力学测试仪及电阻测试仪对合金材料的组织和性能进行研究,结果表明:采用新型双面冷却工艺生产的5154铝镁合金晶粒细小且均匀,合金晶粒得到了细化;其制备的∅8 mm铝镁合金铸杆抗拉强度高达242 MPa,断裂伸长率为22％,导电率为36％IACS,比传统单面冷却方法所制备的样品指标分别提高了7.1％、21.1％和 4.3％.
To cope with the production control difficulties of gear steel 17CrNiMo6 such as narrow hardenability range, high purity, fine grain and high strength and toughness, chemical composition was optimized, 30 t EAF-LF-VD smelting route was adopted with argon stirring,white slag reduction, vacuum refining and argon protection, and process parameters of deoxidation,impurity removal,alloying element addition,casting temperature and speed and cooling were better controlled. With these measures,main elements like C,Mn,Cr,Mo and Ni reach inner target,gas and non-metallic inclusions are effectively controlled that S≤0.003%, P≤0.005%,[O]≤0.0016%,[N]≤0.0075% and[H]≤0.000 13%. Hardenability is controlled to be within1-3HRC and the hardness meets customers’ requirement. No dot-like phase or visually inspected defect is found for macro-structure. And after forging heat treatment, the product structure gets uniform,inherent gain size reaches level 8 and mixed crystal is no more than 10%. The strength and hardness value meet the requirement, the toughness is good at room temperature and-40 ℃, and the strength and toughness match well.
In this paper, the current situation and influencing factors of flue gas waste heat utilization of ring cooling system of Liugang No. 1 360 m2sintering machine are analyzed and elaborated. And targeted by adopting energy-saving and environmental protection upgrading and upgrading of ring cooling equipment,exploring the potential of waste heat recovery of ring cooling system, rationally allocating the air volume relationship of each section of ring cooling machine,and so on.The hot air system of the ring cooling system of 1#360 m2sintering machine was optimized,and the heat resource waste issue of the ring cooling system was effectively solved.The heat energy utilization rate of the ring cooling machine was greatly improved, the waste heat generation and reheating temperature of the production line were increased by 9.59 kWh/t and 42 ℃ respectively,and the waste heat utilization efficiency was increased by 34.27%, and remarkable economic benefits were obtained.
In this paper,through the experiment of Canadian Tacora iron ore concentrates in the sintering process,the influence of different proportion of Tacora concentrate on the technical and economic indicators of the sintering production process is discussed.The industrial test results show that Canadian Tacora iron ore concentrate is high in iron content, low in silicon and aluminum content which is conductive to increase iron content and decrease silicon and aluminum content in sinter, and with the increase of Tacora concentrate ratio, the manganese content in sinter also increases,and the sinter reducibility and the sinter softening and thawing properties are improved;meanwhile, the increase of Tacora concentrate ratio has little effect on low-temperature pulverization of sinter.Canada Tacora concentrate is bad for pelletizing, and the pelletizing effect will be affected after the proportion is increased.Based on the comprehensive industrial test results,it is recommended that the amount of Tacora concentrate used in sintering production should not exceed 15%.
The metallographic structure, bake-hardening properties, texture and second phase particles of bake-hardening steel HC180BD + Z during natural aging were studied by multifunctional metallographic microscope, material universal testing machine, field emission scanning electron microscope, electron backscatterer and transmission electron microscope. The results show that after 3 months,6 months,9 months and 12 months of natural aging period,the average grain size of HC180BD+Z steel gradually increases,and the increase of grain size reduces the {111} favorable texture. In the aging process,there are MnS,CuS,AlN,Ti（C,N）,NbC and other second-phase particles precipitation, and Ti（C,N）and NbC always appear in the form of accompanying precipitation,which gradually decreases after six months of aging. And the grade has excellent bake-hardening properties within the 6-month aging period.
