Enhancement of bending strength of heat-resistant steel by ion carbonitriding

The heat-resistant steel 20Kh3MVF-Sh is used for toothed gears employed in pumps of turbojet engines. In service, the working surface of the gears is subjected to intensive wear. Using gas-phase carburizing to case-harden such gears has proven to be insufficiently effective. In this work we have investigated the structure, the chemical composition, and the wear resistance of 20Kh3MVF-Sh steel after ion carbonitriding. We have obtained regression equations relating the wear resistance characteristics to the carbon and nitrogen concentration and the hardness of the diffusion layer. We have developed a combination process for ion carbonitriding which increases the wear resistance or steel 20Kh3MVF-Sh.N. É. Bauman State Technical University, Moscow. MAKB TEMP. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 9–13, June, 1994.     

电阻法测控碳氮共渗炉气碳氮势的可行性研究

对采用电阻法测控碳氮共渗过程炉气碳、氮势的可行性进行了研究,结果表明,炉气碳势、氮势与热丝电阻值仍存在着线性关系,这使采用电阻法测控滴注式气体碳氮共渗过程成为可能。通过试验,建立了碳、氮原子对热丝电阻值的测控数学模型,即:R=26.089+1.27C_p+1.75N_p。     

TA1纯钛离子碳氮共渗改性层耐磨性能研究

对TA1纯钛进行了离子碳氮共渗。用扫描电镜对离子碳氮共渗的TA1纯钛改性层进行了观察。用X射线衍射仪测定了改性层的物相。用能谱仪对改性层作成分分析。用显微硬度计测定改性层的硬度。用SRV摩擦磨损试验机测定摩擦系数，在往复式磨损试验机上进行，磨损试验。结果表明，经离子碳氮共渗的TA1纯钛表面获得了金黄色、均匀的Ti2N／TiN改性层，显微硬度为840HV0．01。碳氮共渗表面改性层能明显提高纯钛TA1的耐磨性。     

甲酰胺＋苯胺渗剂对碳氮共渗炉气气氛的影响

对以往常用的碳氮共渗剂的各方面性质了进行了分析，认为目前工厂中采用的渗剂含氮量低（＜０．２％Ｎ）且不易调节控制得到所需的氮含量，在分析了甲酰胺在碳氮共渗过程中所提供的碳势，氮势的能力之后，提供了能满足工件表层要求且可调节炉气氛的甲酰胺＋苯胺碳氮共渗剂。     

电阻法微机控制气体碳氮共渗

分析了电阻法控制气氛碳氮总势的原理;介绍了电阻法碳氮总势控制仪和电阻法微机控制气体碳氮共渗系统的硬件原理结构、组成、功能特点、软件流程框图、有关数学模型以及生产应用情况。结果表明,电阻法控制气氛碳氮总势是成功的,可以实现“低氮势”下的气体碳氮共渗工艺过程的自动控制,由此可大大提高产品的质量、降低能耗。     

TA2钛合金真空感应碳氮共渗组织及耐磨损和耐腐蚀性能

通过真空感应碳氮共渗技术对纯钛合金(TA2)在900 ℃下进行表面改性处理,并研究了经过碳氮共渗处理后TA2钛合金表面强化层的组织结构、耐磨损及腐蚀性能。结果表明:经900 ℃碳氮共渗处理后,TA2钛合金表面生成了一层以C_0.3N_0.7Ti为主的复合层;表层的显微硬度高达2236 HV0.25,相较于未经碳氮共渗处理的试样提高了约4.4倍;碳氮共渗后试样表现出典型的氧化轻微磨损特征。在模拟体液(SBF)溶液中,碳氮共渗TA2钛合金试样的腐蚀电位向正移动,自腐蚀电流密度明显降低,耐蚀性提高。     

Carbonitriding metals and alloys in nontoxic liquid media

Modern machine building and tool industries sometimes use toxic liquid media based on cyanic salts for saturating the surface of various parts with carbon and nitrogen. Green vitriol used for neutralizing the worked-out salts does not provide a full cleaning of the waste waters. For this reason the search for nontoxic liquid media for carbonitriding remains an urgent problem. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, p. 9, July, 1998.     

钛合金双层辉光离子无氢碳氮共渗摩擦性能研究

利用双层辉光离子渗金属原理改善钛合金Ti6Al4V的耐摩擦性。使用蜂窝状高纯度固体石墨作为源极，钛合金Ti6Al4V做阴极，一定比例的氩气、氮气作为载气。依靠辉光放电空心阴极效应，溅射出原子、离子状的碳元素，碳、氮元素混合形成等离子体，靠阴极负偏压把碳、氮吸引到Ti6Al4V的表面，依靠轰击和扩散在Ti6Al4V材料表面形成具有特殊物理、化学性能的合金层。X射线衍射检测显示渗层内形成了包含TiC，TiN的硬度相；辉光放电光谱（GDS）检测结果显示，在渗层内碳、氮元素分们呈梯度形式；硬度测试显示渗层硬度由表及里呈现梯度下降，表面硬度提高两倍以上；摩擦磨损检测表明Ti6Al4V材料经无氢碳氮共渗处理后，其粘着现象明显降低，摩擦系数降低一半多，耐磨性大大提高。     

An investigation on the microstructure, tribological and corrosion performance of AISI 321 stainless steel carbonitrided by RF plasma process

An anticorrosive and wear-resistant superficial top layer was distinctly produced in AISI 321 austenitic stainless steel by rf plasma carbonitriding. Details about the elemental distribution profiles and the microstructure of the carbonitrided samples, as a function of treatment temperature, were characterized by glow discharge optical spectroscopy (GDOS), grazing incidence X-ray diffraction (GIXRD) and optical microscopy (OM). The tribological behavior was investigated using a ball-on-disc tribometer. Further the corrosion performance of the treated samples compared to the untreated one was examined using electrochemical tests with potentiodynamic anodic polarization curves. Glow discharge optical spectroscopy indicated that, the nitrogen and carbon contents diffused into the surface during carbonitriding were found to be treatment temperature dependent. The lowest friction coefficient and superior wear resistance in the presence of excellent corrosion resistance were observed for the samples carbonitrided at treatment temperature of 818-863 K. According to Arrhenius plot analysis, the activation energy was 4 eV/atom while the effective diffusion coefficient was found to be 199.3 × 10² μm²/h.     

Raising the Operating Properties of Die Steel 5Kh2GF by Creating Carbonitride Layers by Thermochemical Treatment

The effect of carbonitriding of nickel-free die steel 5Kh2GF in a highly active environment based on amorphous carbon and potassium ferricyanide is studied. The temperature of the carbonitriding process is varied within 800 – 900°C, and the duration is varied from 3 to 8 h. The structure and the hardness of the steel are determined. The wear resistance of the steel after the carbonitriding increases by a factor of 4 – 6.     

18─8型不锈钢固体法氮碳共渗的研究

研究了18-8型不锈钢固体法氮碳共渗渗剂的组成、工艺、渗层显微组织、渗层深度、硬度以及耐磨性。     

20CrMnTi钢压辊深层稀土硼碳氮共渗

对20CrMnTi钢深层稀土硼碳氮共渗工艺进行了研究，并对其共渗层的组织、硬度及耐磨性和耐腐蚀性能进行了测试与分析。结果表明，与碳氮共渗工艺相比，深层稀土硼碳氮共渗层的硬度、耐磨性和耐蚀性明显提高。将其应用于20CrMnTi钢粮机压辊，模具寿命提高了40％，取得了较好的经济效益。     

自保护碳氮共渗膏剂的工艺特性研究

研究了一种自保护碳氮共渗膏剂，探讨了该膏剂的自保护机理、碳热变化和碳扩散距离，测定了碳氮共渗层的成分、相组成、显微组织及性能。试验表明，经该膏剂碳氮共渗处理试样的表面硬度、耐磨性及渗速均优于气体碳氮共渗，该工艺适用于工件的局部碳氮共渗。     

Laser boriding of titanium alloys

The low wear resistance of titanium and its alloys limits their use in machine building. Methods for the surface hardening of titanium and its alloys, which tend to enhance their antifriction properties. are of significant interest in this respect. Laser alloying is one of the most promising methods of improving the strength of the surface. In this study. we investigated the characteristic features of the structural formation of the surface layers of titanium alloy VT3-1 during laser alloying from dross coatings containing a mixture of boron carbide B₄C and chromium.Perm State Technical University. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 14–15, January, 1994.     

离子硬化工艺在316L不锈钢阀内件中的应用

对316L奥氏体不锈钢进行离子渗氮(PN)和离子碳氮共渗(PNC)处理,利用光学显微镜、显微硬度计、电化学工作站、粗糙度检测仪和三坐标测量仪对试样渗层厚度、显微硬度、耐腐蚀性、表面粗糙度和变形量进行讨论分析。结果表明:316L钢经离子碳氮共渗处理后的渗层硬度分布较好,可提高耐腐蚀性能。离子碳氮共渗技术可应用于阀内件(包括球芯和阀座)的表面硬化处理,在保证零件尺寸配合公差的条件下,大幅提高阀内件的表面硬度。     

Carbonitriding of porous materials based on iron

Conclusions Carbonitriding of sintered materials should provide a high level of impregnation with nitrogen; the level of carbon impregnation is of secondary importance and in order to provide minimum deformation it should be low. In order to obtain high mechanical properties and operating characteristics for equipment the following carbonitriding schedule is suitable; carbon potential 0.4–0.5% C, nitrogen potential 0.7–0.8% N, temperature 860°C, duration 1 h.Production Association AvtoZIL. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 31–33, May, 1990.     

Structure of the diffusion layer after low-temperature carbonitriding

Conclusions The formation of pores results from the large metastability of -phase in which the pressure of molecular nitrogen in equilibrium with the nitrogen dissolved in the lattice of -phase reaches several hundred thousand atmospheres.Pores are evidently nucleated on dislocations and the nuclei of pores form when nitrogen atoms in the center of the dislocation combine to form a molecule of larger volume, dissociation of which does not occur, since the internal pressure of molecular nitrogen exceeds the local compressive stress induced by distortion of the crystal lattice.The growth of pores occurs by slip under the influence of the internal pressure of molecular nitrogen.Nitrogen, active in pores under high pressure, tends to leave the metal. With a high density of pores the bridges between individual pores collapse and channels are created in the pores for diffusion of biatomic gases. If air acting on the diffusion layer at high temperatures oxidizes the inner surface of the pores then the pores will be filled to a greater or lesser extent with iron oxide.Studies of the theory and laws of the phenomenon considered make it possible to determine the optimal conditions for carbonitriding to guarantee strict limitation of the pore density and the depth of the zone in which pores are formed.State Scientific-Research Institute of Materials, Czechoslovakia. Translated from Metallovedenie Termicheskaya Obrabotka Metallov, No. 10, pp. 2–6, October, 1974.     

真空离子碳氮共渗工艺在采煤机双联齿轮上的应用

采煤机双联齿轮采用真空离子碳氮共渗处理 ,能避免齿面氧化脱碳 ,减少变形 ,完全满足双联齿轮技术要求。     

氰化层表面微脉冲电阻堆焊试验研究

运用微脉冲电阻堆焊新技术经层表面的修复进行了研究,采用Ｎｉ３５、Ｎｉ６０、Ｆ５０５等粉材作为补材,氰化的２０Ｃｒ２Ｎｉ４Ａ钢作基体,进行了微脉冲电阻堆焊工艺试验。分析了堆焊层与基体之间的结合特点,测定了其硬度分析布及热影响区大小。研究表明,采用Ｆ５０５作为打底材料,能明显地减少Ｎｉ６０合金粉末微脉冲电阻堆焊焊补层中的裂纹,使氰化层表面堆焊高硬度覆层成为可能。     

Hydrogen effects on the passive film formation and pitting susceptibility of nitrogen containing type 316L stainless steels

The effects of hydrogen on the passivity and pitting susceptibility of type 316L stainless steels have been investigated with alloys containing different nitrogen contents (0.015, 0.198 and 0.556 wt.% N). The study revealed that electrochemically pre-charged hydrogen significantly reduced the pitting resistance of alloys conatining 0.015 and 0.198 wt.% nitrogen contents. In alloy with highest nitrogen content (0.556 wt.% N), an increase in the passive film current density with hydrogen was observed without affecting breakdown potential. Auger electron spectroscopy (AES) analysis of the passive film indicated the presence of nitrogen in the passive film. On other hand, for hydrogen charged samples, nitrogen was found to be significantly less in the passive film. In Electrochemical impedance spectroscopy (EIS) measurement, the decrease in semi-circle radius of Nyquist plot, and the polarization resistance, R_P associated with the resistance of the passive film was observed with hydrogen, indicating that hydrogen decreased the stability of the passive film. The present investigation indicated that precharged hydrogen deteriorated the passive film stability and pitting corrosion resistance in these alloys, and the increase in nitrogen content of the alloy offsets the deleterious effect of precharged hydrogen.