共查询到17条相似文献,搜索用时 500 毫秒
1.
常压下氮在钢中的溶解度遵循Sieverts定律,溶解度较低(通常低于0.3%),因此,在高氮钢的冶炼中,如何提高氮含量成为了研究的焦点。本文介绍了氮在高氮奥氏体钢中的作用,分析了氮在高氮钢中析出和溶解的热力学原理,为增压提高氮含量的措施提供了理论基础;同时分析了其动力学原理,探讨了钢液吸氮和脱氮的限制性环节。此外,本文还从微观角度,即从形核机理阐述了高氮奥氏体钢氮析出和溶解的新的研究方向。 相似文献
2.
3.
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
4.
采用当量法对高氮钢钢液中的氮含量进行了推导,并用304不锈钢和316不锈钢的有关试验数据进行了验证,确定当量法可以进行高氮钢液氮溶解度的估算。随着合金含量的提高,氮在钢液中的溶解度会逐渐偏离Sieverts定律。通过热力学分析,得出了6Cr21Mn10MoVNbN气阀钢钢液中氮溶解度的估算公式。 相似文献
5.
6.
7.
对某厂230 t VD处理过程的氮含量控制进行了研究。分别从真空度、底吹强度、真空处理时间等工艺参数及硫、氧等钢液成分对VD脱氮的影响进行了分析。分析表明:降低钢液初始氮含量,严格控制钢中的硫、氧含量,增强底吹强度,延长高真空保持时间对生产低氮钢有利;对VD破真空后钢液增氮的原因进行了分析,并提出:适当改变破真空操作制度、调整软吹流量,可以减少钢液增氮。 相似文献
8.
9.
10.
11.
12.
13.
14.
15.
16.
Effect of Grain Size on Mechanical Properties of Nickel-Free High Nitrogen Austenitic Stainless Steel 总被引:1,自引:0,他引:1
The fine grained structures of nickel-free high nitrogen austenitic stainless steels had been obtained by means of cold rolling and subsequent annealing.The relationship between microstructure and mechanical properties and gain size of nickel-free high nitrogen austenitic stainless steels was examined.High strength and good ductility of the steel were found.In the grain size range,the Hall-Petch dependency for yield stress,tensile strength,and hardness was valid for grain size ranges for the nickel-free high nitrogen austenitic stainless steel.In the present study,the ductility of cold rolled nickel-free high nitrogen austenitic stainless steel decreased with annealing time when the grain size was refined.The fracture surfaces of the tensile specimens in the grain size range were covered with dimples as usually seen in a ductile fracture mode. 相似文献
17.
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