Fatigue life of multilayer hard-faced specimens

Specimens and the method for experimental evaluation of the fatigue life of multilayer hard-faced metal subjected to cyclic mechanical loading are described. The tests were carried out by three-point bending with cyclic non-zero loading in the centre of the specimen, which reproduces, with certain assumptions, the force loading characteristics of rolling rolls, the rolls of continuous casting installations and other tools and equipment for deformation of metals and alloys which are subjected in service to the simultaneous effect of cyclic mechanical and thermal loads. The proposed method is then used to investigate the durability of the specimens of 40Kh steel, hard faced with PP-Np-25Kh5FMS flux-cored wire with and without a ductile sublayer. The sublayer was deposited using Sv-08A solid wire or the PP-Np-25Kh5MF flux-cored wire. The experimental results show that the deposition of the ductile sublayer with Sv-08A and PP-Np-25Kh5MF wires increases the fatigue life of the deposited specimens 1.3 and 1.6 times, respectively. PP-Np-123Kh1MF wire, which produces a deposited metal with higher mechanical properties in comparison with the Sv-08A wire, results in a higher fatigue life of multilayer hard-faced specimens.     

元素V对奥氏体焊缝金属晶间腐蚀敏感性的影响

采用透射电镜(TEM)分析技术研究了1Cr19Ni23N焊条熔敷金属中钒含量对组织及对熔敷金属抗晶间腐蚀性能的影响.结果表明,低钒含量焊条熔敷金属组织中沿奥氏体晶界析出M23C6型富铬碳化物,在晶界附近形成贫铬层,导致晶间腐蚀的发生;高钒含量焊条熔敷金属组织中,V优先于Cr与C形成细小弥散的碳化钒分布在晶粒内部,使得该焊条在保持原较高碳含量的基础上,通过改变碳化物形态和分布达到了保持高强度和改善晶间腐蚀敏感性的目的.     

Effect of aqueous LiBr solutions on the corrosion resistance and galvanic corrosion of an austenitic stainless steel in its welded and non-welded condition

The corrosion resistance and galvanic behaviour of a highly alloyed austenitic stainless steel (UNS N08031) and a nickel-base alloy (UNS N06059) in its welded (GTAW) and non-welded condition were analysed in LiBr solutions by means of electrochemical measurements. Samples microstructure was studied by SEM and EDX analysis. The alloys considered showed passive behaviour and they were able to repassivate after the breakdown of the passive film. The pitting resistance of the materials increased as the LiBr concentration decreased. With regard to galvanic corrosion, the welded metal was always the anodic element of the UNS N08031-welded metal pair.     

Inconel 625熔敷金属抗Cl?腐蚀行为分析

为了分析Inconel 625熔敷金属在Cl?腐蚀液中的腐蚀行为,采用静态浸没腐蚀和慢应变速率拉伸的方法,研究了不同温度下熔敷金属浸没在熔盐中的腐蚀行为以及室温应力腐蚀开裂行为. 通过X-ray diffractiong(XRD),S-3400N扫描电子显微镜系统地研究了熔敷金属的腐蚀产物物相组成、腐蚀形貌和元素分布. 结果表明,在静态浸没腐蚀时,两种温度下熔敷金属腐蚀失重均呈现出递增的变化趋势,但是不同时间区间的增加幅度有所不同. 前10 h熔敷金属的腐蚀失重缓慢增加,10 ~ 60 h腐蚀失重激增,可以发现10 h是腐蚀行为的分界点. 700 ℃下熔敷金属的耐蚀性优于900 ℃,其原因在于700 ℃时熔敷金属表面出现致密MgO壳层,能够阻碍腐蚀反应进行;而900 ℃时,由于CrCl₃的存在,出现“破壳效应”,破坏MgO壳层,使其耐蚀性下降. 对于慢应变速率拉伸而言,腐蚀介质中试样的抗拉强度比在空气介质中降低22.97%,应力腐蚀开裂敏感性指数为30.39%,说明腐蚀介质中的Cl?会增大试样的应力腐蚀开裂敏感性.     

稀土对奥氏体焊缝金属晶间腐蚀敏感性的影响

采用扫描电镜(SEM)和透射电镜(TEM)等分析技术研究了加入 稀土前后1Cr19Ni23N焊条熔敷金属组织变化,讨论了稀土对奥氏体焊缝金属抗晶间腐蚀性能 的影响.结果表明,稀土的存在改善了焊条熔敷金属组织,强烈影响碳化物的数量、形态和 分布;与不加稀土时相比,焊缝中沿晶界析出碳化物的尺寸减小、数量减少、析出形态由网 状析出变为不连续的颗粒状,抗晶间腐蚀能力得到提高.     

Steel 08Kh17N6T for compressor blades

Steel 08Kh17N6T in recent years has become widely used for manufacturing parts for pumps and gas turbines in connection with its better mechanical properties and corrosion resistance, compared with the chromium steel 20Kh13 used previously for this purpose. In this paper, we present the results of an investigation of the longterm and fatigue strength and the corrosion resistance of steel 08Kh17N6T, and also data on the effectiveness of using it to manufacture compressors.I. I. Polzunov Central Scientific Research, Planning, and Design Institute of Boilers and Turbines (Scientific-Industrial Association). Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 25–26, November 1994.     

Structural materials for atomic reactors with liquid metal heat-transfer agents in the form of lead or lead—Bismuth alloy

Natural safety nuclear reactors operate at a working temperature of the liquid-metal lead heat-transfer agent equal to 550°C, which intensifies the metal corrosion and is fraught with the danger of thermal embrittlement. It is shown that long-term operation of the equipment requires inhibition of the heat-transfer agent by oxygen and the use of silicon steels. However, alloying with silicon increases the susceptibility of the steel to thermal and radiative embrittlement. This makes it necessary to create new steels with a stable structure. The suggested composition of austenitic steel 04Kh15N11S3MT is designed for shell and internal structures, and steel 10Kh9NSMF is designed for the pipe system of the steam generator. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 20–24, September, 1999.     

Effect of the structure of weld metal on the pitting susceptibility of welded joints of ferritic-austenitic steel

The structure of welded joints of tubes from ferritic-austenitic steel 02Kh22N5AM3 is studied by methods of metallographic, x-ray diffraction, and electron microscopic analyses. Corrosion properties of welded joints are determined in pitting tests. The results of the study are used for developing a mode of welding and heat treatment that increases substantially the corrosion resistance of the weld metal. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 32–35, July, 2006.     

The corrosion of welded joints of 16GS + 08Kh13 bimetal, made of the specimens cut out from a column after the long-term operation

Corrosion-electrochemical investigations into bimetals are conventionally carried out on samples with the carrying layer preliminarily removed. In this work, the liability of welded joints to HSC without removal of the carrying layer is investigated, which has considerably enhanced the information content of the results. A possibility is demonstrated of the application of ANV-70B electrodes and Sv-07Kh25N13 welding wire, developed at the Paton Electric Welding Institute, in the process of welding in an Ar + O₂ gas mixture for repairing equipment manufactured from bimetal equipped with a cladding layer of 08Kh13 steel. It is established that the preliminary heating of the bimetal up to 350°C in the welding process with the application of both ANV-70B electrodes and Sv-07Kh25N13 welding wire enhances the resistance of the metal to hydrogen sulfide corrosion cracking. Original Russian Text ? V.A. Kachanov, Yu.B. Danilov, T.E. Shepil, E.K. Gvozdikova, V.Yu. Kozin, A.I. Kabashnyi, S.M. Ivanuna, K.A. Yushchenko, L.V. Chekotilo, A.V. Bulat, 2007, published in Korroziya: Materialy, Zashchita, 2007, No. 1, pp. 14–19.     

Effect of temperature on the galvanic corrosion of a high alloyed austenitic stainless steel in its welded and non-welded condition in LiBr solutions

Galvanic corrosion generated by the coupling between the austenitic stainless steel Alloy 926 (UNS N08926) and the welded Alloy 926 has been studied by means of electrochemical methods. The materials have been tested in highly concentrated LiBr solutions at different temperatures. The effect of Li₂CrO₄ as corrosion inhibitor has also been evaluated. Galvanic corrosion has been studied under open circuit conditions using a zero-resistance ammeter (ZRA). Results have demonstrated the poor severity of the coupling between the Alloy 926 and the welded metal in the studied conditions. The probability of localized corrosion increased with temperature and concentration, as the galvanic current density and galvanic potential data demonstrated.     

Influence of zirconium and nitrogen on the structure and properties of surfaced chromium metal

Conclusion With simultaneous microalloying with 0.013% Y, 0.05% Zr, and 0.075% N, the volume share of twinned martensite increases, the packets of dislocation martensite decrease, and a significant quantity of finely dispersed carbonitride particles is formed, which has a positive influence on the service properties of type 15Kh8N2M1FT surfaced metal.E. O. Paton Electric Welding Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 33–37, August, 1993.     

Effect of small compositional changes on marine immersion corrosion of low alloy steels

Small changes in the composition of mild and low alloy steels can effect their immersion corrosion behaviour. A number of comprehensive test programs for coupons immersed at different locations and recovered at different times have been reported. Comparison between them has also been attempted with modest success as well as leaving some apparent inconsistencies in the effect of some alloying elements.In this paper, a new comparative analysis of previously reported observations is reported. It employs a recently reported multi-phase phenomenological corrosion-time model, with different corrosion phases governing corrosion behaviour. Each phase is a function of time.The analysis shows that metal composition can influence the first, kinetically controlled corrosion phase and also the long-term anaerobic corrosion phases. However, during the phase controlled by oxygen diffusion through the corrosion product, metal composition is largely irrelevant, in agreement with theoretical predictions. It is shown that the several observations in the literature about the effect of particular alloys can be reconciled, including apparently conflicting observations about the effect of chromium content.     

Ni-Cr-Mo系合金焊后熔敷金属耐蚀性研究

本文研究了适合于焊接Ni-Cr-Mo系合金的药芯焊丝（一种是金属型无渣药芯焊丝,另一种是造渣型的药芯焊丝）焊接后熔敷金属的耐蚀性。通过光学金相显微镜、扫描电镜和X射线衍射仪对熔敷金属的金相组织进行了研究,熔敷金属的组织主要由奥氏体基体和析出相组成,晶粒比较均匀,尺寸为20—50μm。在堆焊过程中．相当于对合金进行了敏化处理,很容易析出TCP（topologically close—packed）相,这就造成了晶界和基体的合金元素成分、结构的不均匀性,从而容易产生晶间腐蚀。通过ASTMG28晶间腐蚀试验,结果表明,熔敷金属的耐腐蚀性与母材Hastelloy C-276合金相当,对其晶间腐蚀行为进行了初步的探讨,表明在氧化性的腐蚀介质中,富含Mo的TCP相易被腐蚀。     

Corrosion of steels due to the action of microorganisms

The susceptibility of variously alloyed structural steels to microbiological corrosion in media enriched with hydrogen sulfide and favorable for reproduction of sulfate-reducing bacteria is studied. It is shown that stainless steels 05Kh17N4DB and especially nitrogen-alloyed steel 05Kh13A possess a higher anti-adhesive capacity with respect to corrosion-active microorganisms and resistance to microbe fouling and formation of corrosion-active biofilms than the conventional structural steel 38KhGM. It is assumed that the action of nitrogen can be connected with formation of biocide substances.     

2205型双相不锈钢带极电渣堆焊材料的研制

研制出2205型双相不锈钢带极电渣堆焊材料,H2205焊带及其匹配焊剂SJ26B,解决了工程上采用2209型双相不锈钢带极堆焊材料熔敷金属铁素体含量很难达到40％的难题。采用该套材料进行带极电渣堆焊试验,结果表明：堆焊工艺性能极佳,冶金性能优异,熔敷金属力学性能、耐蚀性能优良,熔敷金属铁素体含量为40％-60％,满足工程实际需要。     

Corrosion stability of austenitic steels 05Kh22AG15N8M2F and 12Kh18N10T in chloride-containing media

Protection of Metals and Physical Chemistry of Surfaces - Comparative corrosion tests are performed of doped stainless steels: conventional stainless steel 12Kh18N10T and new high-tension...     

Biological corrosion of construction materials at nuclear power engineering enterprises

The research data concerning the biological corrosion of construction materials for nuclear power plants (NPPs) are submitted in this article. The corrosion kinetic features of 08Kh18N10T and 20 steels in industrial neutral electrolyte are analyzed before and after the above steel types are contaminated with microorganisms. The effects of microorganisms and the products of their metabolism on the corrosion of biocide component-protected steels are evaluated.     

原油油船货油舱耐蚀钢配套药芯焊丝及焊接接头耐腐蚀性能研究

依据2013年2月中国船级社（CCS）标准《原油油船货油舱耐蚀钢检验指南》的规定,在模拟上甲板腐蚀工况试验条件下,对新研制的EH36级货油舱耐蚀钢配套药芯焊丝熔敷金属及焊接接头腐蚀性能进行了研究。试验结果表明：耐蚀钢配套药芯焊丝熔敷金属及焊接接头腐蚀性能满足CCS标准规定,药芯焊丝熔敷金属25年腐蚀损耗估算值为1．72182mm,焊缝金属与母材间腐蚀深度均小于标准规定（小于30μm）。研制开发的EH36级货油舱耐蚀钢配套药芯焊丝熔敷金属及焊接接头上甲板腐蚀性能合格。     

Investigation of the structure and impact-abrasive wear resistance of coatings of the Fe–C–Cr–Mn–Si system,additionally alloyed with nitrogen

Special features of the formation of the structure and properties of plasma-powder coatings of 250Kh15G20S are investigated. The effect of additional alloying of the coating with nitrogen by adding nitrided ferrochrome to the filler powder is considered. The effect of the deposition conditions and of the chemical composition of deposited metal on its hardness and impact-abrasive wear resistance is described.     

Acoustic detection of stress-corrosion cracking of nitrogen austenitic steels

Structural changes and resistance to the stress-corrosion cracking of the nitrogen-bearing austenitic steels 04Kh20N6G11M2AFB and 09Kh20N6G11M2AFB (with 0.04 and 0.09 wt % C, respectively) after different treatments, including thermomechanical action, quenching from 1200°C, and aging at 700°C for 2 and 10 h, have been studied. It has been shown that aging at 700°C of the air-melted austenitic steel 09Kh20N6G11M2AFB leads to a decrease in the strength of samples with an induced crack upon the cantilever bending in air and in a 3.5% aqueous solution of NaCl as compared to the strength of the steel 04Kh20N6G11M2AFB-EShP with a smaller carbon content after high-temperature mechanical treatment or quenching from 1200°C. The smallest resistance to stress-corrosion cracking is observed in the samples of 09Kh20N6G11M2AFB steel after 10 h of aging, which is accompanied by the most intense acoustic emission and by brittle intergranular fracture. This is explained by the high rate of the anodic dissolution of the metal near chromium-depleted grain boundaries due to the formation of continuous chains of grain-boundary chromium-containing precipitates of carbides and nitrides.