轴承套圈的淬火畸变

轴承套圈的淬火畸变有尺寸变化和几何形状变化两种类型。对SUJ2钢制6200型轴承套圈进行了试验,分析了轴承套圈的淬火畸变量,如膨胀量、椭圆度和圆柱度与套圈尺寸、淬火油温、残留奥氏体量、淬火冷却均匀性之间的关系,提出了改进措施。     

淬火温度对H13钢性能的影响

Ｈ１３钢常规淬火温度为１０５０℃，提高淬火温度到１１００℃，可使Ｈ１３钢的σｂ、σ０．２（室温、５００℃）及热疲劳性能提高，有利于延长Ｈ１３钢热作模具的使用寿命。     

冶金因素对SAE52100长圆柱体淬火畸变的影响

钢件淬火会导致其产生复杂且难以预测的尺寸和形状改变(畸变)。甚至用同一块坯料不同部位的材料制作的零件,其淬火过程中发生的畸变行为也大不相同。这是由于若干引起畸变的潜在因素(如合金元素、偏析、残余应力和相组成等)不均匀分布所造成的,而这些潜在因素作用的累积贯穿于零件制造的全过程。本文研究了合金元素的分布和偏析对淬火畸变的影响。研究用试棒为用直径45 mm的SAE 52100钢棒料加工成的不同直径圆柱体,并将其编号,以便分辨其在原棒料上的确切位置。然后将试棒装入通氮气保护的井式炉加热奥氏体化,随后进行喷气淬火。测量结果表明,试棒在淬火过程中的尺寸变化与其在坯料中的取样位置密切相关,而试棒的弯曲程度和方向与取样位置和直径之间没有显著的关联。     

25MnV钢矿用高强度圆环链的中频感应加热淬火

研究了25MnV钢矿用高强度圆环链在中频感应淬火加热时链环的温度分布、淬火后链环顶部的金相组织以及不同淬火温度下链环晶粒度的变化规律。结果表明，25MnV钢矿用高强度圆环链在中频感应淬火加热时，链环直臂温度比顶部温度低。链环顶部加热温度达到970～993℃时(直臂温度为895～917℃)，淬火组织为板条马氏体，晶粒度为10～10．5级，圆环链有最佳强韧性配合。当顶部加热温度达1017℃时，淬火组织及晶粒度明显粗化，导致力学性能恶化。     

淬火后清洗工艺对GCr15钢残留奥氏体含量的影响

通过对GCr15轴承钢淬火后采用不同的清洗方式及清洗温度,研究其对残留奥氏体含量的影响。研究表明,淬火冷却至室温后停留时间过长,残留奥氏体含量将增多;随着清洗温度的升高,残留奥氏体含量在一定程度上亦增多。     

热处理工艺参数对高碳低合金贝氏体抗磨钢组织与性能的影响

通过调整热处理工艺参数,探讨对高碳低合金贝氏体钢的组织形态、力学性能及耐磨性的影响。分析认为,奥氏体化温度、等温温度及时间对试验钢的性能均有不同程度的影响,可以根据工件使用工况要求,适当调整热处理工艺参数,获得所需组织及性能。     

超高强Q&P钢淬火温度对组织和性能的影响

研究了淬火温度对Q&P钢微观组织和力学性能的影响,并通过经验公式及CCE平衡的计算,确定出理论的最佳淬火温度,并与实验结果相对比.结果表明,随淬火温度升高马氏体量降低、奥氏体量升高,使得钢的强度降低,塑性升高,在250℃时能取得较好的强塑积,与计算值较为吻合.     

奥氏体晶粒度对汽车齿轮钢热处理畸变的影响

采用由化学成分与20Cr钢近似的2种汽车齿轮钢制备了尺寸为外径70 mm、内径40 mm、厚25 mm的试样,研究了奥氏体晶粒度对其热处理畸变的影响以及轧制工艺对奥氏体晶粒度的影响。结果表明,奥氏体晶粒较细的试样,其淬火畸变比奥氏体晶粒较粗的试样小;提高轧制温度有助于试样获得细小的奥氏体晶粒,从而减小其淬火畸变。     

Nanocrystalline Surface Layer on AISI 52100 Steel Induced by Supersonic Fine Particles Bombarding

Surface treatment of AISI 52100 steel by supersonic fine particles bombarding (SFPB) was studied in this article. The surface topography, morphology of the surface layer, and microhardness distribution of the surface layer have been investigated using a surface profiler system, a scanning electron microscopy (SEM), and a microvickers hardness tester. The microstructure, phase composition, and residual stress distribution of the surface layer in AISI 52100 steel after the SFBP treatment have been characterized by means of x-ray diffraction, SEM, and transmission electron microscopy. The results showed that a nanocrystalline surface (NS) layer was formed on the top surface of the SFBP-treated AISI 52100 steel samples. The NS layer is about 2 μm in thickness with a surface roughness of R _a = 1.2 μm, R _y = 6.7 μm, R _z = 6.0 μm. Phase transitions occurred in the surface of the SFBP-treated samples. Residual compressive stress is obtained at the surface of the SFBP-treated samples. The maximum value of compressive stress appears at the outermost of the surface, and the affection region of the whole surface is about 60 μm in thickness. A hardened surface layer has been fabricated in the AISI 52100 steel. The thickness of the hardened surface layer is about 70 μm. The maximum value of hardness occurs at the depth of 20 μm from the outermost surface.     

表面织构对GCr15淬硬轴承钢切削过程影响分析

针对GCr15淬硬轴承钢切削过程中由于切削力大、切削温度高而导致的刀具磨损加剧问题,在工件表面预置织构,通过有限元仿真结合正交试验对切削过程进行模拟,并通过信噪比分析方法进行优化分析,利用极差分析、方差分析确定最优切削参数组合以及切削参数对于切削力以及温度的影响程度。切削仿真结果表明:切削速度120 m/min、进给量0.05 mm/r、切削深度0.1 mm为最优切削参数组合。在最优切削参数条件下,通过对表面织构GCr15轴承钢进行切削仿真模拟,得到切削力以及切削温度的仿真结果。将表面织构和无表面织构的切削仿真模拟结果进行对比,结果表明表面织构切削仿真的切削力及切削温度都得到有效降低,有利于减少刀具磨损,提高刀具寿命。     

Influence of oil and water media on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel

A series of fretting test were carried out using a DELTA PLINT testing system to study the influence of hydraulic oil and water on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel. The test result shows that media hydraulic oil and water have a distinct influence on fretting behaviour of the tested materials. Medium water can lead to shifting of the partial slip regime in the fretting map from a larger displacement amplitude toward a smaller one and enlargement of the mixed slip regime, in comparison with that in ambient atmosphere. While medium hydraulic oil can result in shifting of the partial slip regime from a smaller displacement amplitude toward a larger one. In the gross slip regime, hydraulic oil and water play a positive role as lubrication media. They can clearly decrease the fretting friction coefficient between AISI 52100 and AISI 1045. The test result also demonstrates that this lubrication effect will get better with increasing displacement amplitude and that hydraulic oil is better than water for lubrication. SEM observation of the wear scars displays that the fretting wear mainly results from abrasive wear and delamination of the fretted materials when using these two kinds of substances as lubrication media.     

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 滲碳轴承钢套圈工件检验时发现个别套圈存在开裂现象,采用金相显微镜,洛氏硬度等方法进行了分析,认为滲碳过程中产生的块状、网状碳化物在之后的一次淬火,二次淬火时形成淬火裂纹,并提出了相应的预防措施。     

纵向旋转切削加工对环形零件畸变的影响

通过旋转试验和有限元分析介绍了工件在切削加工过程中产生的畸变情况，分析了工件的装夹方式、切削速度、切削深度和进刀量对100Cr6钢环圆度的影响。通过去应力退火释放冷加工诱发的残余应力后工件的圆度与切削参数有关。另外测试了被试验环的表面残余应力，其表面残余应力与装夹方式有关。将测量的装夹力作为计算参数输入，通过有限元分析方法测试了装夹方式对工件变形的影响。协同测量结果示出了装夹方式影响工件变形的一个主要因素，表面残余应力与工件的径向变形有关，最大的拉伸应力位于夹口位置。旋转切削试验结果表明，提高切削速度圆度会稍有增加；随着切削深度的加大，圆度呈下降趋势，尽管切削力增加了；进给量的增加会导致更高的切削力，因此圆度值也增加；常规的去应力退火可使被加工环的圆度值增加。     

轴承钢磁控溅射TiN涂层工艺参数对其性能的影响

目的研究磁控溅射工艺参数,包括溅射功率、溅射时间,对TiN涂层轴承钢表面性能的影响。方法采用磁控溅射技术,固定其他工艺参数不变,分别以溅射功率和溅射时间为变量,在轴承钢GCr15表面镀制TiN膜层,并测定硬度,进行摩擦磨损试验。结果固定溅射功率为200 W,随镀膜时间的延长,硬度和耐磨性呈递减趋势,镀膜时间为5~10 min时,硬度值达345.23~353.88HV,摩擦磨损量为2.9~3.4 mg。固定镀膜时间为30 min,随着溅射功率从70 W增大至200 W,硬度与耐磨性也呈递减趋势,溅射功率为100 W时,硬度值可达577.91HV,摩擦磨损量为0.9 mg。结论溅射功率的影响占主导地位,且溅射功率不宜偏高。欲提升材料表面硬度和耐磨性能,溅射功率取100 W,镀膜时间取30 min最为适宜。     

Properties and Tribological Performance of Vanadium Carbide Coatings on AISI 52100 Steel Deposited by Thermoreactive Diffusion

Vanadium carbide coatings were formed on AISI 52100 steel specimens by thermoreactive diffusion and characterized using nanoindentation, x-ray diffraction, and chemical analysis. The deposition process formed a 4-µm coating of vanadium carbide (V₄C₃) with an average grain size of 33 nm and a [200] crystallographic texture. The hardness and elastic modulus of the coatings were determined to be 35 ± 7.5 GPa and 334 ± 67 GPa, respectively. Friction and wear of the coatings were examined in reciprocating sliding contact against tungsten carbide (WC) balls in dry and in an abrasive environment. It was determined that in the abrasive environment, the V₄C₃ coating provided wear protection comparable to WC.     

Mechanical Behavior and Microstructure Evolution of Bearing Steel 52100 During Warm Compression

High-performance bearing steel requires a fine and homogeneous structure of carbide particles. Direct deformation spheroidizing of bearing steel in a dual-phase zone can contribute to achieving this important structure. In this work, warm compression testing of 52100 bearing steel was performed at temperatures in the range of 650–850°C and at strain rates of 0.1–10.0 s^?1. The effect of deformation temperatures on mechanical behavior and microstructure evolution was investigated to determine the warm deformation temperature window. The effect of deformation rates on microstructure evolution and metal flow softening behavior of the warm compression was analyzed and discussed. Experimental results showed that the temperature range from 750°C to 800°C should be regarded as the critical range separating warm and hot deformation. Warm deformation at temperatures in the range of 650–750°C promoted carbide spheroidization, and this was determined to be the warm deformation temperature window. Metal flow softening during the warm deformation was caused by carbide spheroidization.