Effect of nitrogen on the properties of low-carbon ferritic steel with 25% Cr

Conclusion To improve the working capacity of steels of the 000Kh25 type the nitrogen content must be limited to 0.01%.Central Scientific-Research Institute of Heavy Machine Construction. Kiev Polytechnical Institute. All-Union Scientific-Research and Planning-Technological Institute of Chemical Machine Construction. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 50–52, September, 1975.     

Effect of thermomechanical treatment on the heat resistance of modified steel with 12% Cr

Conclusion The heat resistance of modified chromium steels (12% Cr) can be improved at operating temperatures up to 550° by means of HTMT, but at 600° (after tempering at 650°) the heat resistance is lower than after the standard heat treatment.Czechoslovakia. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 27–29, November, 1977.     

Nitrogen alloying of the 12% Cr martensitic-ferritic steel

The influence of the nitrogen content on the structure and mechanical properties of heat and corrosion resistant 12% Cr martensitic-ferritic steel developed at the Central Research Institute of Structural Materials Prometey has been studied. Steel containing 0.061 wt % nitrogen possesses a high level of mechanical properties. The decrease in the nitrogen content to 0.017 wt % leads to an increase of structurally free ferrite fraction in the steel, a decrease in the density of dislocations, a decrease of structural dispersity and the absence of finely dispersed precipitates of niobium and vanadium nitrides and carbides. As a result, there is a decrease in the strength properties, especially in the heat resistance.     

热处理工艺对12Cr钢组织与性能的影响

利用金相检测、室温拉伸、硬度和冲击检测等方法,研究了不同热处理工艺对12Cr钢组织及性能的影响。结果表明,淬火温度对12Cr钢热处理后的晶粒度影响显著,随淬火温度的升高,12Cr钢的晶粒逐渐长大,而其冲击性能明显改善,硬度也明显提高;随回火温度的上升,12Cr钢的强度逐渐降低。当淬火温度上升到1160 ℃时,晶粒度粗达3级;当回火温度超过700 ℃时,12Cr钢的短时持久性能明显恶化;在1100 ℃淬火,680 ℃回火时,获得均匀的板条状马氏体组织,短时持久性能最佳。     

Effect of aluminizing treatment on the oxidation properties of 12Cr heat resisting steel

In order to investigate the effect of aluminization on the oxidation properties of 12Cr martensitic heat resisting steel, a specimen was prepared by forging after centrifugal casting. After aluminizing treatment under various conditions, scanning electron microscopy observation, and hardness, line profile and x-ray diffraction analysis of the alloy layer were performed. The results confirmed that the thickness of the layer of Al₁₃Fe₄, with a Vickers hardness of over 880, increased with increasing aluminizing temperature and time. Moreover, it was concluded from the results of the oxidation experiment that the oxidation properties of the aluminized specimen were improved by up to approximately 30 %.     

深冷处理对Cr12MoV钢力学性能的影响

对经不同深冷处理后的Cr12MoV钢进行了力学性能检测和摩擦磨损试验。试验结果表明,深冷处理可以明显提高Cr12MoV钢的硬度,最高增量达到228 HV0.2。深冷处理可减少Cr12MoV钢的残留奥氏体并提高其耐磨性,经深冷处理3×1 h＋180℃×1.5 h回火处理后,耐磨性提高最为显著,其磨损失重率下降37.1%;而残留奥氏体量则由未冷处理的34.36%降至2.58%,降幅达92.5%。     

成分波动对AMS 6308钢力学性能的影响

采用力学性能测试以及金相分析、TEM等微观结构分析,研究了传统热处理工艺(915℃×0.5h油冷+(-80)℃×1h+205℃×2h空冷)下成分波动对AMS 6308钢力学性能和微观组织的影响.结果表明,1号试验钢(wt％:0.1C,1.0Cr,1.97Ni,3.25Mo,2.0Cu,0.08V,0.83Si,余量Fe)的塑性和韧性最优,且强度和硬度也保持在较高的水平,其综合力学性能最佳(Rm=1135 MPa,Rp0.2 =880 MPa,A=16％,Z =63％,KV2=125 J,35 HRC).     

焊后热处理对12Cr1MoVG/12Cr2MoWVTiB钢焊接接头组织性能的影响

对12Cr1MoVG/12Cr2MoWVTiB异种钢焊接接头焊态及不同热处理温度下(720～770℃)的接头组织、硬度及拉伸、冷弯性能进行了测定.结果表明,随着热处理温度的提高,焊缝组织由回火马氏体+少量颗粒状贝氏体逐步转变为粒状贝氏体+索氏体组织,两侧焊缝硬度差异缩小,组织均匀化程度提高,晶粒有长大倾向.接头强度呈下降趋势,740℃强度下降趋缓,这是由于焊接残余应力得到大幅度释放,同时沉淀相的弥散强化作用增强所致.试验表明,730～770℃保持1 h焊后热处理制度均可满足使用性能要求,以740～760℃保持1 h热处理制度为佳.     

化学成分及热处理对槽帮铸钢力学性能的影响

为满足刮板运输机中部槽槽帮材料的强韧性要求,研究了添加Cr、Mo、V等合金元素的低合金高强度铸钢经不同的调质处理后的力学性能。结果表明,合金元素的添加对铸钢的强度有一定的强化作用,但使其塑性和韧性相对有所降低。ZG26SiMnMoV铸钢在920 ℃水淬条件下可获得良好的力学性能,强度基本保持在1000 MPa以上,硬度保持在300~350 HB范围,经580 ℃回火后综合力学性能最优,伸长率达18.5%,室温冲击吸收能量达40 J以上,适合用作中部槽槽帮材料。     

Effect of heat treatment and neutron irradiation on magnetic properties of ferritic-martensitic steels containing 12% Cr

The magnetic properties (magnetization, coercive force) of ferritic-martensitic steels EK-181 (low-activation, Fe-12Cr-2W-V-Ta) and ChS-139 (Fe-12Cr-2W-V-Ta-Mo-Nb-Ni) have been studied. The steel samples were subjected to different heat treatments and irradiation with neutron fluences of up to 5 × 10¹⁹ cm^?2 (E _n ≥ 0.1 MeV) in an IVV-2M nuclear reactor at a temperature no higher than 70°C. Within the limits of the experimental error (～1%), the heat treatment and neutron irradiation have almost no effect on the magnitude of the magnetization of these steels. Neutron irradiation leads to an increase in the coercive force of steels up to ～50% depending on the regimes of heat treatment and neutron fluence.     

回火工艺对1Cr12Ni3MoVN钢组织和性能的影响

通过显微组织分析、室温拉伸试验、冲击试验、硬度试验,研究不同回火制度下1Cr12Ni3MoVN钢的显微组织与力学性能。结果表明,随着回火温度的增加,1Cr12Ni3MoVN钢析出相数量不断增加,对材料的强度、冲击性能具有增强效果;碳化物聚集长大,基体组织逐渐由马氏体向回火索氏体转变,杂质元素在晶界处偏聚而降低了材料的断裂抗性,冲击韧性降低,回火温度应取较低温度;随565 ℃回火时间的延长,1Cr12Ni3MoVN钢抗拉强度、屈服强度、硬度下降,塑性变化不大,冲击吸收能量略有增加,回火保温时间不宜过长;随回火冷却速度的降低,1Cr12Ni3MoVN钢强度先升后降,塑性变化不大,冲击吸收能量显著下降,硬度变化不大,建议以空冷方式进行回火冷却。最佳的回火热处理工艺为565 ℃保温2 h,空冷。     

电脉冲渗硼工艺对Cr12MoV钢渗层组织与性能的影响

Cr12MoV钢采用电脉冲辅助渗硼,并对其渗硼层厚度及其性能进行了表征和分析。结果表明,电脉冲降低了渗硼温度且提高了渗硼层深度,脉冲电场的电致迁移阻碍了Fe2B向FeB的转变,渗硼区Fe2B/FeB相组成比例增大,耐磨性比传统渗硼提高5倍。     

Conversion of MX nitrides to Z-phase in a martensitic 12% Cr steel

A 12% Cr model steel was designed with the purpose of studying the nucleation and growth of modified Z-phase, Cr(V,Nb)N. The model alloy develops Z-phase after relatively short ageing times and contains only nitrides of Cr, V and Nb. Interferences from the presence of carbides and the development of Laves phase were avoided by keeping the C, W and Mo contents as low as possible. Transmission electron microscopy and X-ray diffraction analysis of extracted particles were used to follow the evolutions of phase composition, phase morphology and phase fraction, particularly of the precipitation of Z-phase, during ageing at 600, 650 and 700 °C for up to 10³ h. The development of Z-phase appears to be accomplished by the diffusion of Cr atoms into (V,Nb)N particles and their subsequent conversion into cubic or tetragonal Z-phase. Studies at various temperatures indicate that Z-phase development proceeds fastest at 650 °C and that Z-phase forms faster at prior austenite grain boundaries.