共查询到17条相似文献,搜索用时 796 毫秒
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利用Lagrange两相流模型定量研究了吹氩板坯结晶器内双循环流形成条件,并用水模型检验了数值模拟结果.在此基础上考察了吹氩量、钢流量,结晶器宽度、水口浸入深度以及下倾角度对双循环流形成的影响规律.结果表明:选择与其它工艺参数匹配的吹氩量是保证双循环流型的重要条件,且维持此流型的临界吹氩量随钢流量的增加而增加.当钢液质量流量较大(qm>2.5 t/min)时,减小结晶器宽度和增加水口浸入深度均有助于扩大临界吹氩量范围,而水口下倾角度对其影响较小;当钢液质量流量较小(qm≤2.5 t/min)时,以上工艺参数的影响均不明显. 相似文献
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采用数值模拟方法研究了水口内钢水流场形态及各种因素对水口沉积速率的影响.模拟结果表明:滑板附近处以及水口底部的沉积比其它地方更为明显;吹氩量对水口内的压力存在较大的影响,压力在滑动水口处存在突降;滑动水口开度为66.45%时,浇铸速度为1.2m/min的情况下,要防止吸气,最小吹氩量必须大于10L/min.Al2O3的沉积速率与其浓度成线性增加关系;随着浇铸速度的提高,沉积速率也逐步增大.在吹氩量合适的范围内,吹氩能够降低沉积速率.对于同一拉速,5和30L/min的吹氩量对降低沉积速率的效果相近. 相似文献
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莱芜钢铁股份有限公司炼钢厂为了保证钢水成分合格率及均匀性,一直采用钢包底吹氩技术。包底单透气砖吹氩虽对提高钢质有很大贡献,但常常发现包内钢液搅拌不均匀,吹氩存在死区,造成成分偏析、钢温不均,影响轧材质量。为此莱钢目前已改进吹氩工艺,采用钢包底部双透气砖吹氩新工艺,取得了良好的效果。 相似文献
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用同一炉钢的铸件和锻件对比研究了在水介质中的应力腐蚀性能。结果表明:铸钢和锻钢应力腐蚀裂纹扩展的激活能相同,均为Q=5540cal/mol,且和氢渗透测出的表观扩散激活能一致。无论是阳极极化还是阴极极化,均使铸钢和锻钢的da/dt升高,但阴极极化较为明显。氢渗透测量表明:不论阳极极化或阴极极化,随着电流增大,饱和氢渗透量明显增加,极化对da/dt和氢渗透通量的影响相似。 试验温度对K_(ISCC)的影响极小,但铸钢的K_(ISCC)明显地比锻钢高。氢渗透测试结果发现锻钢的饱和氢渗透通量约比铸钢大一倍。这与断口观察一致,由此可以解释K_(ISCC)的差异。尽管断口形貌明显依赖开裂时的K_I值,但在K_(ISCC)附近锻钢全是沿品断口,而铸钢则以准解理为主。 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):760-765
AbstractThe aim of this study was to investigate the influence of three shielding gases (argon and argon–hydrogen and argon–helium mixtures) and two activating fluxes (a commercial flux and a TiO2 based flux) on the geometry of welds produced by the tungsten inert gas (TIG) welding process on several casts of austenitic stainless steel AISI 316, using currents ranging from 100 to 300 A. Penetration depth increases with increasing current for all shielding gases, but weld depth to width ratio is higher for argon than for argon–hydrogen shielded welds. Both activating fluxes produce a substantial increase in penetration depth and in depth to width ratio of the welds. No correlation was found between penetration depth and oxygen content in the melted material. Some interaction exists between activating fluxes and shielding gases, which can affect the weld geometry and/or the defect formation in the welds. 相似文献
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应用正交试验法对奥氏体不锈钢TIG焊用活性剂配方进行了试验研究.采用所研制的活性剂,在不开坡口的情况下,当热输入E=1.01kJ/mm时,可一次焊透5 mm厚奥氏体不锈钢板;当E=1.95 kJ/mm时,可一次焊透8 mm厚奥氏体不锈钢板,焊接过程中电弧稳定,焊缝成形良好.活性剂对焊接过程中合金元素的烧损有一定的抑制作用,所得焊缝中Cr、Ni元素的含量与母材的相比只略有下降.A-TIG焊缝的显微组织结构与TIG焊缝的相比几乎没有差别,但前者的硬度高于后者. 相似文献
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板坯连铸结晶器内钢液过热消除过程的数值模拟 总被引:1,自引:0,他引:1
利用数值模拟方法研究了连铸结晶器内钢液的三维温度分布和传热,分析了水口浸入深度、水口侧孔倾角、结晶器宽度、拉速、钢液过热度、吹Ar、电磁制动及吹Ar量和电流强度等对结晶器内过热钢液的温度分布和传热的影响.结果表明,凝固坯壳前沿的最大热量传入处出现在结晶器窄面的钢液冲击点附近,钢液的大部分过热耗散发生在这一区域附近;过热钢液传递到凝固坯壳表面的热流量与拉速和过热度的增加成正比;吹Ar导致结晶器窄面冲击区域和宽面上部区域的热流密度增加;电磁制动有利于提高结晶器上部区域的温度,但对热流密度分布没有明显影响;吹Ar和电磁制动的双重作用使结晶器上部区域的宽面热流密度提高,冲击区域的热流密度分布没有明显变化. 相似文献
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Abrasion wear resistance of arc-sprayed stainless steel and composite stainless steel coatings 总被引:1,自引:0,他引:1
The abrasion wear resistance of stainless steel and composite stainless steel/titanium boride coatings arc sprayed with air
and argon was evaluated. Stainless steel coatings arc sprayed with air were found to be slightly more resistant than bulk
stainless steel, whereas those sprayed with argon were slightly less resistant. The wear resistance of composite stainless
steel/titanium diboride coatings was from two to four times greater than that of bulk stainless steel, depending on the cored
wire constitution and the type of gas used for spraying. Microstructural analysis, microhardness measurements, and optical
profilometry were used to characterize the coatings and wear damage. By considering both the wire constitution and the spraying
conditions, it was possible to fabricate composite stainless steel coatings that showed a 400 % increase in wear resistance
over bulk stainless steel. 相似文献