共查询到18条相似文献,搜索用时 187 毫秒
1.
2.
3.
氮是提高不锈钢强度、耐腐蚀性和奥氏体稳定性的最有效元素之一。目前对用加压工艺,诸如加压电渣重熔、加压感应熔炼等方法生产的高氮奥氏体不锈钢进行了许多研究。 相似文献
4.
加压技术在高品质特殊钢冶炼和凝固方面的研究主要集中在含氮不锈钢,尤其是高氮钢的冶炼制备技术;综述了加压技术在高品质特殊钢制备过程中的作用,如增大易挥发元素(氮、钙、镁等)溶解度及改善凝固组织等作用,并以高氮钢(22Cr-21Ni-7.5Mo-0.6N)为试验钢种,结合Thermo-Calc热力学计算软件探讨了压力对凝固相变过程的影响规律,计算结果表明,当加压至100 MPa后,固液相线温度分别提高了6.60和5.98 K,且改变了奥氏体形成区域大小,增加了固液相变驱动力,减小了临界形核半径,增大了形核速率。随着对易挥发元素作用认识的不断深入,加压技术将在高品质特殊钢的研发和制备过程中发挥至关重要的作用。 相似文献
5.
6.
7.
采用MgO坩埚高频真空/加压感应炉在氮气压力04~10 MPa、温度1 570~1 640 ℃下,对加压感应熔炼Fe Cr V系高氮不锈钢进行了实验研究。结果表明,在30CaO 45Al2O3 25SiO2渣覆盖的情况下,氮在Fe 15Cr 10V、Fe 18Cr 10V、Fe 18Cr 15V和Fe 20Cr 20V液态合金中的溶解度分别为0595%、0736%、0776%和1020%,溶解度与氮分压的关系基本符合Sievert定律。渣对钢液吸氮和铝脱氧都起重要的作用,1 873 K、10 MPa氮气氛中,在30CaO 45Al2O3 25SiO2、40CaO 40Al2O3 20SiO2、40CaO 50Al2O3 10SiO2三种不同渣系作用下氮在液态Fe 18Cr 15V中的浓度分别是0776%、0849%和0884%。 相似文献
8.
本文论述了优化电炉配料、选用优质石灰、精选萤石、电炉出钢换渣工艺;电渣重熔采用四元渣系,选用提纯萤石,重熔过程全程氩气保护铝粒脱氧等工艺措施,生产出低碳、低硅、低氮及残余、五害元素符合要求的自耗电极及电渣锭,经轧制成材检验低倍组织及非金属夹杂物符合技术协议要求。 相似文献
9.
轴承钢电渣重熔过程中氧的控制及作用研究 总被引:8,自引:0,他引:8
研究了不同氧含量((5~40)×10-6)的自耗电极及重熔渣系对轴承钢氧含量、夹杂物和疲劳性能的影响,结果表明:①无论用高氧含量(>30×10-6)自耗电极还是低氧含量(<10×10-6)自耗电极重熔,电渣钢中氧含量都保持在(15~30)×10-6;②影响电渣钢中氧含量的决定因素是渣中的aFeO值,自耗电极中的原始氧含量影响较小;③电渣重熔过程中,自耗电极中原始夹杂可基本去除,重熔钢中的夹杂主要是金属熔池冷却结晶过程中新生成的。 相似文献
10.
11.
Cr‐Mn steel grades with high nitrogen contents are becoming increasingly important in the field of austenitic stainless steels. Industrial production facilities allow to use two different strategies to reach a high nitrogen content. The first involves taking advantage of the pressurised‐electroslag remelting process, which is operated at elevated nitrogen partial pressure; the second consists of adding elements which increase the nitrogen solubility of the melt so that high nitrogen contents can be achieved at atmospheric pressure. This paper focuses on nitrogen solubility and austenite stability. These have been observed as important and in some cases restricting for the successful implementation and production of high alloyed Cr‐Mn austenitic steels. The precondition for a stable austenitic microstructure can be predicted with the help of equations using chromium and nickel equivalents. Different formulae were tested and their results compared to the microstructure of the alloys. The nitrogen solubility in the melt is particularly important for the steel grades cast under atmospheric conditions. It has been found feasible to produce steel grades up to 0.9 mass percent nitrogen at atmospheric pressure on an industrial scale. Several theoretical approaches for calculating the nitrogen solubility in the melt were tested for atmospheric conditions and compared to the chemical analyses of conventionally cast Cr‐Mn steel grades. 相似文献
12.
13.
A simple and feasible method for the production of high nitrogen austenitic stainless steels involves nitrogen gas alloying and adding nitrided ferroalloys under normal atmospheric conditions. Alloying by nitrogen gas bubbling in Fe Cr Mn Mo series alloys was carried out in MoSi2 resistance furnace and air induction furnace under normal atmospheric conditions. The results showed that nitrogen alloying could be accelerated by increasing nitrogen gas flow rate, prolonging residence time of bubbles, increasing gas/molten steel interfaces, and decreasing the sulphur and oxygen contents in molten steel. Nitrogen content of 069% in 18Cr18Mn was obtained using air induction furnace by bubbling of nitrogen gas from porous plug. In addition, the nickel free, high nitrogen austenitic stainless steels with sound and compact macrostructure had been produced in the laboratory using vacuum induction furnace and electroslag remelting furnace under nitrogen atmosphere by the addition of nitrided alloy with the maximum nitrogen content of 081%. Pores were observed in the ingots obtained by melting and casting in vacuum induction furnace with the addition of nitrided ferroalloys and under nitrogen atmosphere. After electroslag remelting of the cast ingots, they were all sound and were free of pores. The yield of nitrogen increased with the decrease of melting rate in the ESR process. Due to electroslag remelting under nitrogen atmosphere and the consequential addition of aluminum as deoxidizer to the slag, the loss of manganese decreased obviously. There existed mainly irregular Al2O3 inclusions and MnS inclusions in ESR ingots, and the size of most of the inclusions was less than 5 μm. After homogenization of the hot rolled plate at 1 150 ℃×1 h followed by water quenching, the microstructure consisted of homogeneous austenite. 相似文献
14.
15.
高氮不锈钢的开发进展 总被引:2,自引:0,他引:2
加压冶炼高氮不锈钢是材料研究的一个新领域。介绍了高氮不锈钢的生产工艺及高压冶炼高氮不锈钢的主要设备。综述了欧美、日本等研发的高氮不锈钢的成分、力学性能及应用现状。由于受试验装备的限制,国内高氮不锈钢的研究与国外相比还有差距。针对高氮不锈钢具有多种优良性能,以及氮应用于对人体无害的生物、医疗材料方面前景广阔,提出医疗用高氮不锈钢将成为理想的生态材料。 相似文献
16.
综述了高氮钢制备及焊接过程中氮的溶解与释放规律;论讨了不同制备及焊接工艺下钢中氮溶解度的计算公式、适用条件及影响因素等;指出大气压力下的GTA焊接过程是一个非平衡过程,焊缝处的氮含量与保护气体中的氮分压之间不满足Sievert定律,焊缝处的氮含量主要取决于钢中平衡氮含量和Cr的含量;选择GTA焊接时,在较低的氮分压下,便可对焊缝氮含量进行控制,但由于氮的吸收和释放较快,采用GTA焊接时焊缝氮含量不能精确控制;采用(CO2,YAG)激光焊接时需要考虑焊缝氮的释放;氮质量分数大于1.0%的高氮钢焊接方法亟待开发. 相似文献
17.