P_2钢的热处理工艺性和机械性能

<正> 目前国内生产的汽轮机高、中压整锻转子的材料,基本上采用P_2钢。但是通过多年的生产实践,各方面对这种钢作出了不同的评价,力图研制出新钢种来代替P_2钢。为了给研究新钢种的人们提供一些参考资料,特将苏联对P_2钢的热处理工艺性和机械性能的研究资料摘编于下。     

AN INVESTIGATION ON A Cr-Mn-N AUSTENITIC HEAT-RESISTING STEEL

研究了钼、钨、钒和硼诸元素对Fe-Cr-Mn-N合金系各种性能的影响,发展出一种完全不含镍的臭氏体钢种。用电弧炉进行了生产试制。新钢种的冶炼、锻轧性能均良好。系统的试验结果指出:与动力工业上常用的铬镍奥氏体钢257T(Cr14 Ni14 W2 MoTi)相比较,新钢种除了长期时效韧性较逊外,其他室温和高温力学性能均与之相当,或者较优,因而新钢种有可能用作动力工业上的耐热材料。     

鉻-錳-氮奥氏体耐热鋼的研究

研究了钼、钨、钒和硼诸元素对Fe-Cr-Mn-N合金系各种性能的影响,发展出一种完全不含镍的臭氏体钢种。用电弧炉进行了生产试制。新钢种的冶炼、锻轧性能均良好。系统的试验结果指出:与动力工业上常用的铬镍奥氏体钢257T(Cr14 Ni14 W2 MoTi)相比较,新钢种除了长期时效韧性较逊外,其他室温和高温力学性能均与之相当,或者较优,因而新钢种有可能用作动力工业上的耐热材料。     

汽车用微合金非调质钢的应用现状及发展

叙述了我国汽车用非调质钢的应用现状,生产过程中出现的问题以及解决措施。探讨了控锻—控冷技术在发展非调质钢种的重要作用,并对非调质钢的应用发展提出建议。     

K系列固定焊机顶锻系统改造及顶锻工艺

顶锻是钢轨闪光焊接的关键阶段,K系列焊机具有加热宽度窄、加热温度场陡等特点,但顶锻力和顶锻速度等顶锻性能参数相比于GAAS80类固定焊机有所欠缺,从K1000固定式焊机顶锻控制程序和顶锻油路结构两个方面进行改造,以提高顶锻速度和保压能力,提高带电顶锻阶段功能为目的。结果表明:经过硬件方面的调整和优化,满足了顶锻工艺参数的调整范围,提高了钢轨焊头质量,特别针对U75V类钢轨和耐蚀轨等高合金钢种,有着积极的效果。     

预热闪光焊与脉动闪光焊工艺比较

对现阶段国内采用的预热闪光焊工艺和脉动焊工艺从加热方式、烧化过程的控制原理、顶锻过程的控制方式等方面进行比较,并阐述两类焊接工艺对不同钢种焊接性能差异,在实际工艺参数调试过程中易出现的焊接缺陷,以及对应焊接性较差钢种的参数调整措施。结果表明:代表预热闪光焊工艺的GAAS80焊机焊接U75V钢种具有很强的焊接性;但经过合理调试工艺参数,典型脉动焊接工艺的K1000焊机针对难焊的U75V钢种也可以得到良好的接头质量。     

1Mn18Cr18N钢无磁性护环锻件的试制

1Mn18Cr18N钢系无磁性高锰奥氏体不锈钢,该钢种合金含量高,可锻温度区间窄,在锻造过程中易出现表面裂纹。采用电炉冶炼、电渣重熔工艺获得优质钢锭。锻造加热温度为1190~1210℃,终锻温度在900℃以上。多火次,小压下量锻造,把表面裂纹减轻到最低程度。固溶处理后生产出了满足用户需求的护环锻件。     

提高大规格冷作模具钢D2探伤合格率的锻造工艺研究

对宝钢集团特殊钢分公司大量生产的大规格D2模具钢出现探伤报废的原因进行了分析,认为主要是锻造比不足,共晶碳化物未能有效地破碎所致.据此研究了提高该钢种探伤合格率的锻造工艺,创新地提出了大锭型镦粗加径锻联合锻造的新工艺,使特殊钢分公司目前生产的大规格D2钢探伤合格率提高了近50%.     

加热温度和冷却速度对70S6非调质钢组织及硬度的影响

通过研究加热温度和冷却速度对 70 S6非调质钢组织和性能的影响 ,得出该钢种的临界晶粒长大温度约12 0 0℃左右 ,其锻后冷却方式应为单件空冷或弱风冷却     

高性能高速钢W_8Mo_2Cr_4V_2NAl

本文介绍了高性能高速钢W_8Mo_2Cr_4V_2NAl的性能特点。该钢种立足国内资源,通过较佳的合金化以较低的合金总量,达到了淬、回火硬度HR_c67左右、600℃红硬性HR_c64以上,韧性超过W_18Cr_4V而与W_6Mo_5Cr_4V_2相当。它具有锻、轧、扭热塑性良好的工艺性能,可满足冶金生产和工具制造的需要。由其制造的钻头、车刀、滚刀和锯片等切削刀具的使用寿命高于W_18Cr_4V和W_6Mo_5Cr_4V_230％以上,其中锥柄钻荣获国家金质奖。文中还列举试验数据初步探讨了N、Al等合金元素的作用。研制钢种已通过鉴定,并获得上海市新产品奖。     

The tempering parameter for evaluating softening of hot and warm forging die steels

The tempering characteristics of three different hot and warm forging die steels (FX, 2714, and WF) were systematically studied over a range of temperatures (316–677 °C) and a range of times (1–300 h). The softening rate for each steel was determined by the change in room temperature hardness. In this study, the hardness data are quantitatively related to the tempering parameter via regression analysis. The tempering parameter (also known as the Hollomon–Jaffe parameter or the Larson–Miller parameter) accounts for the effects of both tempering time and tempering temperature. Room temperature hardness is a measure of the microstructural change that occurs during the tempering process. Results from this study show a bilinear softening as a function of the tempering parameter. For hot and warm forging application the second portion of the curve is more applicable, since these die steels are tempered to some extent before initial use. The slope of the curve can be used as a measure of softening, which is one of the contributing factors on how well the die steel will perform in actual forging operations. These results indicate that WF has the highest resistance to softening during use, FX is somewhat less resistance to softening, and 2714 is the least resistant of the three die steels studied.     

不锈钢锻造用玻璃防护润滑剂

玻璃防护润滑剂是降低锻压过程中锻件与模具的摩擦、防止锻件表面氧化和合金元素贫化、同时隔离锻件与模具之间热传导的独特工艺材料.本文采用复合玻璃的设计思想,研制出了在850～1180℃温度范围内不锈钢锻造用玻璃防护润滑剂.采用试烧法研究了复合玻璃润滑剂随温度的变化规律;根据不锈钢材料锻造加热条件,测试了玻璃润滑剂在金属坯料表面的防护性能,并对复合玻璃润滑在不锈钢锻造变形时的润滑机理进行了分析.     

4Cr3Mo2MnVNbB模具钢的应用

外科手术器械产品大都采用Cr13型马氏体不锈钢锻造成型。但由于马氏体不锈钢坯件基体硬度较高,热变形性能差,所以锻模寿命通常不高,已成为影响产品生产成本的主要因素之一。试验证明,采用4Cr3Mo2MnVNbB(Y4)钢替代3Cr2W 8V钢制造手术器械锻模,模具的使用寿命显著提高,已成功用于生产。     

用高氮钢制造复杂高强度零件(英文)

High performance components, e.g., fasteners, nowadays are usually made out of cold forged and heat treated steels like steel 1.5525 (20MnB4). To overcome the problems of heat treatment, e.g., low surface quality, new workpiece materials for cold forging should be found to achieve the needlessness of heat treatment after cold forging. One possible material is given by high nitrogen steels like steel 1.3815 (X8CrMnN19-19). Due to the high strain hardening of these materials the process and tool design for an industrial batch process are challenging and should be conducted by FE-simulation. The numerical results show that, high strength tool materials, like PM-steels or cemented carbides, in most cases, are inevitable. Additionally to the selection of suitable tool materials, the tool layout should be developed further to achieve a high loadability of the tools. The FE-models, used for process and tool design, are validated with respect to the materials’ flow and occurring forming force to assure a proper design process. Also the comparison of strength of components made out of steel 1.5525 in quenched and tempered conditions and steel 1.3815 in strain hardened condition is done. The results show that the component made of steel 1.3815 has a significantly higher strength than the component made of steel 1.5525. This shows that by the use of high nitrogen steels a high performance component can be manufactured by cold forging.     

Corrosion resistance of a cast steel overpack for high-level radioactive waste disposal in Japan

The corrosion rate and stress corrosion cracking (SCC) susceptibility of a cast steel are studied for its application to metal containers (namely overpacks) for geological disposal of high-level radioactive waste. Specimens for corrosion tests are cut from a prototype overpack manufactured by full-scale casting. Casting defects are widely distributed in the prototype overpack; however, the flat-bottom hole equivalent diameters for all defects detected by an ultrasonic test are 3.6 mm or less, which is relatively small. Forged steels and rolled steels are also tested for comparison of their corrosion properties with the cast steel. The corrosion rates are obtained by immersion tests in bentonite saturated with synthetic seawater under anaerobic conditions at 80°C for up to 1 year. The corrosion rate for the cast steel calculated by the weight loss during the experiments is close to that for the forged steels and rolled steels. The SCC susceptibility is examined using slow strain rate tests in a 1.5-mol L⁻¹ carbonate–bicarbonate solution, in which the occurrence of high-pH SCC is often reported for carbon steels. The SCC susceptibility increased with the increase in the carbon content of the products; however, there are no clear differences between casting and forging.     

4Cr2MoWVNi与H11模具钢离子渗氮耐磨性能研究

对4Cr2MoWVNi和H11模具钢进行了对比磨损试验,研究了渗氮对两钢种耐磨性的影响.结果表明,无论试样渗氮与否,4Cr2MoWVNi钢的热耐磨性均优于H11钢.4Cr2MoWVNi钢连杆热锻模寿命优于H11钢.模具正常失效形式均为热磨损.     

Electrochemical synthesis of ferritic stainless steels alloyed with 1 wt-%Ti,V and Nb in sulphuric acid solution

Abstract

Corrosion behaviours of stainless steel alloys containing corrosion resistant elements were investigated. Ferritic stainless steel electrodes were synthesised by the application of a scan rate of 1 mV s^–1. Stainless steels were unalloyed and alloyed with approximate 1 wt-% Ti, V and Nb elements. The samples were obtained from casting and forging. The steels were exposed to different heat treatments. Heat treatment was not applied to the first group of samples. The second and the third group of samples were rapidly cooled after annealing at 1100°C for 30 and 180 min respectively. The corrosion performances of ferritic stainless steels were investigated in 0·1 M H₂SO₄ solution, by use of electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) investigations were performed. Scanning electron microscopy micrographs showed generalised pitting on the surface. Corrosion resistance was calculated by Stearn-Geary equation. It was determined that titanium has the best effect on the corrosion resistance of ferritic stainless steels homogenised for 180 min.     

Effect of Overheating on the Mechanical Properties of Roll-Foundry and Die Steels

The effect of overheating on the properties and structure of roll steels 9Kh2, 9Kh2MF, and 9Kh2SVF and steel 5KhNV used for the production of heavy-duty forging dies is studied. It is shown that the elevation of the heating temperature changes the fracture behavior of roll steels. The temperature of overheating of roll steels is established. It is shown that the consequences of the overheating can be removed by means of subsequent quenching from conventional temperatures (860 – 890°C). The overheating is shown to have a weak effect on the properties of steel 5KhNV, which can be removed by single heating to a temperature of 890°C.     

除砂器装置用30CrMoA钢锻件的研制

通过对炼钢、锻造、热处理每个环节严格控制,特别是热处理时采用亚温淬火、回火的工艺方法,全面满足了材料的力学性能要求。钢中P、S含量控制在0.007%以下,钢材纯净度高,探伤合格率达100%。     

PHYSICAL SIMULATION OF INTERFACIAL CONDITIONS IN HOT FORMING OF STEELS

1.~nonNUInericalmodellingbythefiniteelement(FE)methodhasbecomeaneffectiveandeconomyicmeansforsimulatingmetalfoeingprocesses.However,accuratemodellingdemandsthecorrectdefinitionandinputsofthedataforthethermalandphysicalpIDPertiesoftheworkpieceandtoolmaterials,theboUndaryconditionsattheworkpiece--toolinterfaceandinotherareas,inadditiontoappropriatemeshgenerationandnumericalsolutions.Althoughmostofthematerialdataareavailable,thedataforinterfacialheattransferandfrictionconditions,Whichhavesubst…