绝热层对钢包热行为的影响

建立了基于有限元法的钢包二维传热模型,运用Ansys软件对钢包在不同绝热层厚度情况下的热状态及保温性能分别进行了模拟计算.有绝热层的钢包可以明显地提高自身的保温性能,且随着绝热层厚度的增加,保温效果愈加突显,但幅度越来越小.与无绝热层的钢包相比,在绝热层厚度达到20 mm时,钢包预热时间缩短约1 h,节约煤气消耗1000 m3,降低钢水温降约6℃.在热饱和阶段,钢包外壁温度平均降低了100℃,包壁散热减小,1h可以节能1255680kJ,折合标准煤43kg.最后利用现场实测数据进行了验证,结果表明模拟结果正确可信.      

热损失一定时双层保温材料的合理选择与使用

得出热损失一定的情况下合理选择内、外层保温材料的依据和双层保温可比单层保温的保温费用低的结论，导出了保温费用最低时双层保温材料各层厚度的计算公式。     

孔隙度对烧结不锈钢纤维多孔材料压缩性能的影响

采用丝径为100μm的不锈钢纤维经松装烧结工艺制备了孔隙度在70%～95%之间的金属纤维多孔板材.在MTS858材料试验机上检测压缩性能,结果表明:孔隙度在82.8%以下的试件的面内应力应变曲线大致分为三个阶段,应变很低情况下的线性弹性区、屈服平台区和应力急剧增大情况下的致密化区,其中屈服平台区较长,说明该材料具有较强的能量吸收能力;随着孔隙度的增加,不锈钢纤维多孔材料的卸载模量、屈服强度减小,其中孔隙度为70%的烧结不锈钢纤维多孔材料的平均卸载模量为5.2GPa,平均屈服强度达到了23MPa;孔隙度大于90.1%的试件屈服强度很低,能量吸收能力很小.     

铜基高通量换热管内多孔层的制备及性能研究

烧结型高通量换热管是通过在普通换热管内表面烧结一定厚度的多孔金属层达到强化沸腾传热的效果,多孔层的烧结温度对基管性能不能有损伤,同时要求多孔层本身孔隙连通,与基管结合较好,且耐蚀性与基管相当。本文设计了一种适用于铁白铜基管（BFe10-1-1）的管内多孔层烧结合金粉末Cu-10% Ni-20% Zn-2% Sn（质量分数）,该粉末成分耐蚀性优于基管。烧结实验结果表明,该合金粉末在940℃下烧结时对基管性能无损伤,烧结后与基管结合良好,同时粉末多孔层内部孔隙均匀联通;进一步的应用实验也证明,该多孔层合金粉末具有非常好的传热效果。     

武钢CSP加热炉内衬的优化设计

武钢CSP加热炉炉衬较薄,使用全纤维模块砌筑,其隔热性能好,但使用寿命较短。在保证炉衬厚度不增加、隔热效果不降低的前提下,通过传热计算对炉衬材料进行了优化设计。耐火层选用浇注料延长使用寿命,分析了隔热层分别采用纤维毡、纳米隔热板、超级憎水隔热板等不同隔热材料对外表温度与散热量的影响,确定了合理的材料组成,达到了既能延长使用寿命,又能降低成本的目的。     

钢包引流砂烧结与钢包自动开浇率提升研究进展

为了提升钢包自动开浇率,总结了钢包引流砂烧结的研究与工业实践成果,阐述了引流砂的烧结性能、钢包自动开浇的影响因素及提升措施,重点关注了不同材质引流砂的烧结机理和钢液对引流砂烧结的作用机制.不同材质引流砂的烧结结构类似,一般分为烧结层(包括部分烧结层)和未烧结层.引流砂的实际烧结层很薄,而且绝大多数引流砂会呈现未烧结的状...     

取向硅钢表面涂层结构对其性能的影响

通过扫描电镜观察取向硅钢截面涂层结构,分析其对取向硅钢绝缘性能、附着性、铁损的影响。研究结果表明:取向硅钢底层的钉扎、硅酸镁涂层、磷酸盐涂层共同作用影响着取向硅钢的性能;取向硅钢底层质量差会导致其绝缘性能和磁性能差;底层钉扎对铁损影响较大,钉扎厚度为3μm时,取向硅钢的铁损低且附着性好;硅酸镁涂层越致密均匀,取向硅钢的附着性越优良;钢板的底层厚度与磷酸盐涂层厚度同时影响着取向硅钢的绝缘性能,在相同的底层厚度下,提高磷酸盐涂层的厚度有利于提高钢板的层间电阻。     

The effect of iron oxide as an inhibition layer on iron-zinc reactions during Hot-Dip galvanizing

A study was conducted on the effect of a uniform oxide layer on the galvanizing reaction in 0.20 wt pct Al-Zn and pure Zn baths at 450 °C. In the 0.20 wt pct Al-Zn bath, poor wettability of the oxide layer was observed. No significant liquid Zn penetration of the oxide occurred and, therefore, attack of the steel substrate to form localized Fe-Zn growth did not occur. It was found that the iron oxide acted as a physical barrier or inhibition layer in the pure Zn bath, similar to the Fe₂Al₅ inhibition layer that forms at the steel interface in Al-Zn baths. The inhibition effect of the oxide in the pure Zn bath was temporary, since cracks and other macrodefects in the oxide acted as fast diffusion paths for Zn. Localized Fe-Zn growth (outbursts) formed at the steel/coating interface, and the number of outbursts was generally inversely proportional to the oxide layer thickness at constant immersion times. Increased immersion time for a constant oxide layer thickness led to an increase in the number of outbursts. These results simulate the diffusion short circuit mechanisms for Fe₂Al₅ inhibition layer breakdown in Al-containing Zn baths.     

Development of the steel AISI 4145HM for senior petroleum drill of BX Steel

The Steel AISI 4145HM for senior petroleum drill of BX Steel was produced by the follow sheet: hot metal pretreatment→converter→LF→RH→caster 350 mm×470 mm rectangular billet→hot delivery→reheating→800 mill rolling→insulation→straightening→anneal→grinding→inspection→packaging and pay into treasury→shipment.Selected BX Steel particular hor metal,adopted hot metal desulphurization pretreatment technology.The LF refining making the white slag,and keep a certain time.The RH treatment must make sure the vacuum degree and refining time,more importantly controlling argon blowing process.In addition,must design proper technology data continuous casting similar superheat,casting speed,and specific water flow rate.Depend on technological measures,the product been had series of the qualities:homogeneity of chemical composition,low content of harmful elements,high purity,compact organization.Adopted the process of casting billet hot delivery and hot charging,used stepping heating furnace,and designing reasonable thermal parameters.Two -high reversing mill rough rolls preparation square billet,short - stress - path rolling mill rolls round bar.Steel products bad holding and controlling soaking time and temperature. Steel products bad annealed,and annealing process must been controlled for ensuring steel hardness uniform. For avoiding residual stress,steel been straightened before anneal.The test results and using effect shows that the producing with uniform annealing hardness and nice processing properties,nice overall mechanical properties,were recognized by users.     

Porous sintered fire supressors for the localization of acetylene-oxygen and hydrogen-oxygen flames

Summary A study was made of porous sintered tubular elements from nonspherical Kh17N2 stainless steel powders under critical conditions of gas flame processes. The critical values of the Peckle number were calculated; it was found that, for the acetylene-oxygen flame, the values of Pe_cr differ only little from a mean value of 65, while Pe_cr for the hydrogen-oxygen flame is 60.It is shown that sintered tubular elements from nonspherical stainless steel powders may be employed as fire supressors for quenching the acetylene-oxygen and hydrogen-oxygen flames in order to decrease hazards inherent in processes of gas flame treatment of metals.Translated from Poroshkovaya Metallurgiya, No. 9 (57), pp. 18–22, September, 1967.     

复合型碱性中间包覆盖剂的研制及其冶金效果

针对15t小型中间包(无上盖)的特殊性开发的复合型碱性中间包覆盖剂YKL-3,在碱性预熔料、膨胀石墨质量达到原料要求指标的条件下,能在中间包中形成上层疏松多孔状保温层,下层碱性液渣层。其中碱性预熔料与碱性包衬的相容性、吸附Al₂O₃能力均优于酸性中间包覆盖剂,膨胀石墨在铺展性和保温效果方面也优于酸性覆盖剂,连铸≤0.15%C的A32、A36钢时,无增碳现象。     

链箅机布料系统的均匀布料

 根据链箅机-回转窑球团采用成品生球带式输送机+摆动皮带+宽皮带+辊式布料器+溜料板组成的布料系统,介绍其布料原理。实际生产中,链箅机布料存在布料不均、影响箅板使用寿命等问题,分析摆动皮带、宽皮带、辊式布料器、溜料板引起布料不均的原因。对均匀布料进行研究,实现布料设备紧凑组合、降低工程投资。阐述摆动皮带的工作原理,得出摆动皮带的摆动结构自身不对称是造成链箅机箅床左右料层不均的根本原因。针对摆动皮带自身结构引起的布料不对称问题展开算法研究,设计合理的摆动皮带运行轨迹。正确选择溜料板的合理角度和分离点,实现均匀布料。     

Application of insulation padding in a heavy turbine guide vane casting

To replace metal padding by insulation padding for castings can save the melt and reduce cleaning work of castings.The design of insulation padding was investigated.The equation of the modulus extension factor for insulation padding and the ratio of its thickness over the modulus of a casting were improved to deter-mine the thickness of insulation padding.The insulation padding was designed for a turbine guide vane casting weighing 3.5 t.A sound casting was obtained with 750 kg steel saved.On the other side, the cast-ing obviously expanded at the interface with the insulation padding, which is perhaps the reason that the use of insulation padding has been suspended for many years.To avoid the expansion of insulation pad-ding, a shielding layer made of a kind of material of good fire resistance was adopted to prevent the insula-tion layer from touching the melt.The shielding layer serves as a cushion of heat and expansion during so-lidification process so as to resist the expansion of castings and guarantee the feeding effect at the same time.Furthermore, insulation padding can be placed by a certain offset into the mold cavity so as to coun-teract the expansion of castings.     

取向硅钢产品表面质量检测对比分析

检测了3家不同企业取向硅钢成品板表征表面质量的指标,同时对表面层采用扫描电镜和能谱仪进行微观结构和化学成分组成进行检测。对比不同企业的成品板表面质量指标和微观结构发现：不同企业的取向硅钢表面层质量有差异,A产品表面绝缘电阻高于B和C产品且后者表面绝缘电阻相当,B和C产品涂层附着性和耐蚀性优于A产品。从微观形貌和成分分析上可以得出,A产品绝缘层厚是表面绝缘电阻大的原因之一,B、C产品附着性级别好是由于钉扎在基体的颗粒大或是距离硅酸镁较近,A产品表面有裂纹导致耐蚀性下降。     

High-porous materials of carbon steel fibers and their mechanical properties

A base porous material made of pressed and sintered St.10 steel fibers is carburized, hardened, and tempered to produce new porous materials of 60 and U8 hardened steel fibers. Comparing the mechanical properties of porous materials made of St.10, 60, and U8 steel fibers shows the following. In compression tests, the hardened 60 steel material with 70 and 80% porosity has yield stress higher by a factor of 10 and 8, respectively, than that of the base material. In tension tests, the hardened U8 steel material with a porosity of 60–90% has three to six times higher yield stress and tensile strength than those of the base material.     

SOME MECHANICAL PROPERTIES OF SAE 1045 STEEL JOINTS BONDED WITH SINTERED COMPACTS

Abstract

The physical and mechanical properties of plain steel (SAE 1045) butt joints, bonded with a sintered alloy as a filler material, are described. Sintered alloys were made from two types of iron powders–electrolytic and Swedish sponge– with various additions ranging from 7 to 20 wt.-% of an electrolytic copper powder, a prealloyed bronze powder (90% Cu+ 10% Sn), and a mechanically mixed elemental bronze powder.

The results showed that the tensile strength was not reduced as drastically as that of the copper-brazed joints, when the thickness of the bonding material (sintered alloy) was increased. The highest bond strength in tensile and fatigue testing was obtained with the sintered alloys comprising iron powder and 10 wt.-% pre alloyed bronze powder. The results indicate that there is a practical possibility of brazing steel using sintered compact as a filler material under a neutral or a reducing atmosphere.     

钢包复合反射绝热涂层试验

文章介绍了炼钢厂钢包复合反射涂层的研制及应用情况,通过钢包复合反射涂层的应用,解决了钢水散热损失,保证了连铸生产顺利进行。对于降低出钢温度及减少精炼提温补偿取得了令人满意的效果。     

铜包覆石墨烯增强316L奥氏体不锈钢力学性能研究

采用分子水平混合和低速球磨的方法制备铜包裹石墨烯/316 L不锈钢复合粉体,通过放电等离子烧结制备石墨烯增强316 L奥氏体不锈钢复合材料,研究铜及石墨烯对复合材料密度、硬度和拉伸性能的影响,并对拉伸断口形貌进行了分析.结果表明:通过分子混合和球磨混合可制备铜包裹石墨烯与不锈钢均匀混合的复合粉体.烧结过程石墨烯结构保持完整.铜包裹石墨烯增强体可明显改善烧结不锈钢复合材料的密度、硬度、抗拉强度和屈服强度,使其分别提高3.6%、17.4%、35.8%和34.5%.     

粉末形状与松装密度对不锈钢烧结多孔材料制备工艺及其性能的影响

通过选用气雾化及水雾化两种工艺方法制备的不锈钢粉末来制取粉末烧结多孔材料。探讨了粉末形状及松装密度对不锈钢粉末烧结多孔材料制造工艺中的成形压力和烧结温度等工艺参数的影响;研究了原料粉末松装密度对不锈钢粉末烧结多孔材料的透气性、拉伸强度的影响。结果表明:成形压力、烧结温度和制品的透气性受粉末松装密度影响显著。粒度范围为0.18～0.90mm时,气雾化粉末的成形压力比水雾化粉末要高近1倍;当粉末的粒度相同时,采用松装密度大的球形粉末所需的烧结温度比松装密度小的不规则粉末的高60～70℃;粒度为0.45～0.60mm时,选用松装密度为4.13 g/cm3粉末所制备的多孔制品的透气性为3.16×10-10m2,而选用松装密度为2.67 g/cm3的粉末所制备的多孔制品的透气性仅为8.8×10-11m2。不锈钢多孔材料的强度受原料粉末的松装密度影响显著;粒度相同,制备工艺相同时,采用较低松装密度的粉末的制品,能够得到较高的强度。