JY6607 PAG淬火介质应用研究

介绍了JY6607PAG淬火介质特性,测定了不同浓度了JY6607PAG冷却特性曲线。选择不同浓度的JY6607PAG淬火介质及传统水或油淬火介质对45钢、30CrMo和1Cr13试棒进行淬火,分析了拉伸性能、淬透性、淬火硬度均匀性及淬火开裂倾向。结果表明,45钢采用5％--10％JY6607PAG淬火、30CrMo钢采用10％--15％JY6607PAG淬火可以获得比传统淬火介质水或油更好的综合性能。试验所采用的所有浓度的JY6607PAG淬火介质都能淬透1Cr13不锈钢,但是,浓度低于20％时,出现了淬火开裂。因此,使用时建议采用高于30％的浓度。     

Application of polymeric quenchant in heat treatment of crack-sensitive steel mechanical parts: Modeling and experiments

Success or failure of a quenching process is determined by selecting an appropriate quenchant. In this work, the quenching process of the automobile tie rods in different media including water, oil, and a polymeric solution was investigated. The microstructures and mechanical properties of the rods were predicted by a finite element simulation model. Several specimens were cut from the tie rods and heat treated by quenching in five different quenching media including water, oil, and PAG aqueous solutions with polymer concentrations of 10, 20, and 30%. The hardness tests and metallographic analyses were performed on the specimens. Considering the results of the simulations and the experiments, the optimum quenchant was selected and the tie rods were heat treated using this quenchant. The results showed that the use of Poly Alkylene Glycol (PAG) solution quenchants, with respect to its unique cooling mechanism, outperformed water and oil quenchants. The distortion and cracking was reduced compared to water quenching and, on the other hand, the mechanical properties which were not achievable by oil quenching were resulted using polymer-based quenching medium.     

A comparative analysis of outcome of carbide-tool holder quenching in various liquids upon induction brazing

The paper provides some results of prediction of hardness and hardened layer thickness of a 35KhGSA steel holder of carbide tool upon quenching in aqueous solution of salts and bases, in water, and in oils at various quenchant temperatures. Thermokinetic cooling paths of the holder surface points are shown to differ quantitatively and qualitatively between the first two quenchants and oils at room temperature. Numerical investigation of quenching in water at 100°C has revealed an abrupt increase, by a factor of 2–3, in the holder surface cooling rate as soon as the cooling curve enters the austenite-to-bainite phase transformation region. For the case of quenching in an aqueous solution of salts and bases a functional relation has been found between the thickness of the holder surface layer quenched to maximum hardness and the quenchant temperature.     

Computer modeling of the formation of a differential of mechanical properties on the holder surface of carbide-tipped tool bit through quenching upon induction brazing

A scheme of intensive cooling of a portion of the steel holder of a carbide-tipped tool bit during its quenching after induction brazing is put forward. The scheme implies that the cooling of various portions of the holder working surface is carried out in such a way that they should have different martensite content, resulting in a differential of mechanical properties. The scheme is illustrated by some examples of computer modeling of the mechanical properties differential for a 35KhGSA steel holder of a carbide-tipped tool bit in the cases of quenching in aqueous solutions of Na-KMTs polymer and in quenching oil I-20. It is demonstrated that by choosing an appropriate quenchant and cooling scheme one can impart high hardness to the major-wear portion of the holder and high impact toughness to the zone of the tool bit fixing in a milling cutter.     

硼对刃具钢组织与性能的影响

为研制开发适合水淬的新型刃具钢,采用显微组织观察、力学性能测试、热处理试验和磨粒磨损试验等技术手段,对比研究了含硼中碳钢与不含硼的65Mn钢热轧后与热处理后的显微组织和应用性能.结果表明:热轧态中碳含硼钢中存在较多铁素体相,强硬性更低,韧塑性更好;中碳含硼钢水淬回火后组织为回火马氏体,硬度可达50 HRC以上,高于油淬回火的65Mn钢,韧塑性和耐磨性也明显好于65Mn钢.中碳含硼钢完全适合水淬工艺,减少了工业污染,符合环保要求.     

淬火温度对含铜5Cr15MoV马氏体不锈钢性能的影响

将含铜5Cr15MoV马氏体不锈钢在不同温度热处理并使用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)、硬度测试和电化学测试等手段对其表征,研究了淬火温度对其组织、硬度以及耐蚀性能的影响。结果表明,铜元素的添加提高了材料中残余奥氏体的体积分数,而使其硬度降低。淬火后钢中的未溶碳化物为fcc结构的富铬M₂₃C₆型碳化物,铜元素的添加对5Cr15MoV马氏体不锈钢中碳化物的尺寸和形貌没有明显的影响,但是使其耐蚀性能略微降低。随着淬火温度从1000℃提高到1100℃,未溶碳化物逐渐减少,耐蚀性提高。残余奥氏体的含量也随着淬火温度的提高而增多,碳化物与残余奥氏体的共同作用使淬火后钢的硬度曲线呈抛物线状并在1050℃达到最大值。     

真空分级淬火对8Cr4Mo4V钢组织和性能的影响

在真空条件下对航空轴承用8Cr4Mo4V钢进行不同温度的分级淬火并采用扫描电镜观察其微观组织、用XRD谱进行相分析并测试洛氏硬度、冲击性能和旋转弯曲疲劳性能,研究了真空分级淬火对其微观组织和力学性能的影响。结果表明,真空分级淬火后的8Cr4Mo4V钢其微观组织由下贝氏体、马氏体/残余奥氏体和碳化物组成;随着分级淬火温度的提高,淬火和回火态钢中析出碳化物的数量增加,残余奥氏体的含量降低。分级淬火温度为580℃时淬火态钢中贝氏体的含量最高(达到13.87%),残余奥氏体的含量为28.59%。回火后析出碳化物的含量和洛氏硬度均为所有分级温度中的最大值,分别为4.37%和62.38HRC。真空分级淬火能提高8Cr4Mo4V钢的综合力学性能。与未分级真空淬火相比,进行580℃×10 min真空分级淬火的8Cr4Mo4V钢的冲击韧性提高了23.3%,旋转弯曲疲劳极限提高了110 MPa。     

Prediction of surface hardening of a carbide-tool holder due to quenching upon induction brazing

The paper presents some results of numerical prediction of the possibility of hardening a working surface of a steel holder of a carbide tool through quenching in aqueous solutions of salts and bases upon the insert-to-holder induction brazing. The investigation is performed using a previously developed computer model of a temperature field in a carbide tool during its induction brazing, air cooling as it is carried from the induction heater to a quenchant, and cooling in the quenchant. Predictive estimates of the hardened surface layer thickness and the hardness of the holder working surface are made for various quenching conditions.     

Characterization of cryogenic heat treated Vanadis 4 PM cold work tool steel

The amount of retained austenite in the quenched cold work tool steel sample is 17.7%, in the condition of sub-zero heat treated and double tempered samples following by quenching is 1.9% determined by XRD analysis. The types of carbides (MC, M₇C₃, M₂₃C₆) present in the structure was determined by XRD and SEM-EDS analysis. The hardness of test samples were 865 HV(0.1) for quenched sample and 785 HV(0.1) forth sample subjected to sub-zero treatment and double tempered after the quenching.     

Tuning austenite stability in a medium Mn steel and relationship to structure and mechanical properties

We study here the underlying factors that govern the stability of austenite in a medium Mn (Fe–0.18C–11Mn–3.8Al) (wt-%) steel. In this regard, a novel heat treatment involving intercritical quenching and tempering was designed to obtain high total elongation (TEL) and high ultimate tensile strength (UTS) in the cold-rolled steel. And the UTS and TEL approached 920–1150?MPa and 35–65%, respectively. The product of TEL and UTS (PSE) exceeded 40?GPa%, with a maximum value of 60?GPa%. A detailed analysis of microstructure before and after tensile deformation revealed that the TRIP effect occurred and the stability of austenite was predominantly governed by the grain sizes of austenite rather than the orientation of austenite grains. The theoretical analysis of work hardening data suggested that the superior elongation of medium Mn TRIP steel is related to the high stability of austenite and the cooperative deformation of ferrite.     

Characterization of cryogenic heat treated Vanadis 4 PM cold work tool steel

The amount of retained austenite in the quenched cold work tool steel sample is 17.7%, in the condition of sub-zero heat treated and double tempered samples following by quenching is 1.9% determined by XRD analysis. The types of carbides (MC, M₇C₃, M₂₃C₆) present in the structure was determined by XRD and SEM-EDS analysis. The hardness of test samples were 865 HV(0.1) for quenched sample and 785 HV(0.1) forth sample subjected to sub-zero treatment and double tempered after the quenching.     

Distortion in quenching an AISI 4140 C-ring – Predictions and experiments

Heat treatment processes are used to enhance the material properties of a wide range of mechanical steel components, according to their final application. Quenching is a common step in these heat treatments, involving the fast cooling of previously austenitized parts and leading to a phase transformation from austenite to hard martensite in the material. Quenching commonly causes a geometric distortion in the parts, associated with the thermal contraction and with the change in the mechanical and geometrical properties of austenite and martensite. It is of importance to predict these distortions, so that one can design corrective post-heat treatment shape corrections or include them in the pre-heat treatment part dimensions, thus leading to a final part with adequate shape and dimensions. This study presents the results of a finite element (FE) simulation of the quenching of an AISI 4140 steel C-ring in oil, covering the analysis of the distortion caused by both thermal contraction and phase transformation. Furthermore, the distortion behavior during the cooling stage is analyzed, as well as the hardness and martensite volume fractions. Experiments were also conducted in order to obtain the geometric distortion, the microstructures and hardness of the C-rings. The FE modeling results are in good agreement with the experimental values and, to the knowledge of the authors, this is the first time that such an agreement has been obtained for the distortion caused by quenching of C-rings. The design of new products and quenching processes should consider the studied aspects, and may also be assisted by the methodology applied to this work.     

Copper bearing microalloyed ultrahigh strength steel on a pilot scale: Microstructure and properties

In the present study, copper bearing low carbon microalloyed ultrahigh strength steel has been produced on a pilot scale. Transformation of the aforesaid steel during continuous cooling has been evaluated. The steel sample has been thermomechanically processed followed by either air cooling or water quenching. Variation in microstructure and mechanical properties at different finish rolling temperatures has been studied. A mixture of granular bainite, bainitic ferrite and precipitation of nano-sized (Ti, Nb)C particles is the characteristic microstructural feature of air cooled steel. On the other hand, predominantly lath martensitic structure along with the similar type of microalloying precipitates of air cooled steels and Cu precipitates are obtained in case of water quenched steel. The best combination of strength (1364-1403 MPa) and ductility (11-14%) has been achieved for the selected range of finish rolling temperature of water quenched steel.     

薄板坯连铸连轧生产65Mn钢的CCT曲线和淬透性

利用Formaster热膨胀仪和金相法,测定了薄板坯连铸连轧工艺(CSP)生产的高碳高强度65Mn钢的CCT曲线,测得临界点为AC1=719℃,AC3=747℃,Ms=267℃,临界冷却速率为35℃/s。使用扫描电镜和硬度仪分析表明,薄板坯连铸连轧工艺生产的65Mn钢的淬火组织细小均匀,硬度高,比传统工艺生产的65Mn钢的淬透性好。     

激光淬火功率对45~#钢抗植物磨料磨损性能的影响

本文以苜蓿草粉为典型植物磨料,系统研究了激光淬火功率对45~#钢抗植物磨料磨损性能的影响。试验结果表明:在实验条件下,材料表面硬度最大值可达679HV,材料硬度最大值在距表面0.2~0.4mm之间;激光淬火后的45~#钢抗植物磨料磨损性能远高于未经激光处理的试件。激光功率对材料硬度和耐磨性的影响趋势并不完全一致,耐磨性最好的试件硬度并非最高;植物磨料对激光淬火后的45~#钢的磨损机理主要为显微切削,与未经激光淬火的试件相比,激光淬火后的45~#钢表面犁削深度明显浅而窄,但当激光功率降至1750W时,塑变疲劳和碳化物剥落明显增加。研究结论可为农业机械金属材料的耐磨性设计提供依据。     

Effects of alloying elements and cooling rates on the high-strength pearlite steels

The effects of the alloying elements of Cr, Mn and the cooling rates after hot deformation on the microstructures and mechanical properties of pearlite steels were studied. Results show that increasing Cr and decreasing Mn significantly increase the eutectoid transformation temperature of steel. The grain sizes of prior austenite of the steels after hot deformation are ～12?µm. However, the high-Cr–low-Mn steel exhibits a finer interlamellar spacing and some better mechanical properties than that of the high-Mn–low-Cr steel. A full pearlite microstructure with an interlamellar spacing of 97?nm was obtained on the former steel, which exhibits a hardness of HRC49, a tensile strength of 1700?MPa and an elongation of 19%.     

Effects of Plastic Deformation and Stresses on Dilatation during the Martensitic Transformation in a B-bearing Steel

To provide data for improved modelling of the behaviour of steel components in a simultaneous forming and quenching process, the effects of plastic deformation and stresses on dilatation during the martensitic transformation in a B-bearing steel were investigated. It was found that plastic deformation of austenite at high temperatures enhances ferrite formation significantly, and consequently the dilatation decreases markedly even at a cooling rate of 280 degreesC/s. The created ferritic-martensitic microstructure possesses clearly lower hardness and strength than the martensitic structure. Elastic stresses cause the preferred orientation in martensite to be formed so that diametric dilatation can increase by nearly 200% under axial compression.     

Si对中锰钢淬火配分组织和性能的影响

将20Mn5钢和20Mn5Si2钢进行淬火和配分(Q&P)工艺处理,用扫描电镜观测其微观组织,用X射线法测量残余奥氏体量,研究了Si对其微观组织和力学性能的影响.结果表明,试验钢中的奥氏体含量明显高于传统的TRIP钢和Q&P 工艺处理钢;在相同Q＆P工艺条件下,20Mn5Si2钢比20Mn5有较多的残余奥氏体,析出物数...     

Evaluation of apparatus for assessing effect of forced convection on quenching characteristics

Abstract

Two systems for the generation of controlled convection conditions in quenching baths for laboratory tests are presented that differ significantly in complexity of design. The cooling of cylindrical samples heated to temperatures considerably above the boiling point of the quenchant is determined from the effect of convection on the kinematics of wetting. It was found from experiments carried out using aqueous polymer solutions that in general surface active substances have a stabilising effect on film boiling. Using pure water and two concentrations of an aqueous polymer solution as sample fluids, it was also found that data obtained in a simplified convection system may satisfactorily reflect the influence of the intensity of convection on the cooling process. The cooling results to be expected in commercial quenching applications employing forced convection can be predicted from the experimentally ascertained influence of convection on the cooling performance of quenching baths.

MST/801     

65Mn钢奥氏体连续冷却转变曲线(CCT图)

利用膨胀法结合金相--硬度法,在Gleeble-1500热模拟机上测定了65Mn钢的临界点Ar1、Ar3、Ac1和Ac3以及Ms;测定了该钢在不同冷却速度下连续冷却时的膨胀曲线,获得了该钢的连续冷却转变曲线(CCT曲线);研究了65Mn钢连续冷却过程中奥氏体转变过程及转变产物的组织和性能,大致确定了避免网状铁素体、贝氏体以及魏氏组织铁素体的冷却速度,找出了生产65Mn钢盘条的控冷速度范围,为生产实践和新工艺的制定提供了参考依据.