The aim of this work is to study the effect of various quenching media on the microstructural evolution and properties enhancement of AISI 4135 alloy steel. The formation of dual microstructures and their effect on mechanical and wear properties are investigated in this work. An attempt is made to correlate the microstructure-properties relation based on the quenching method used. Steel is heated above the austenitic temperatures (A₃) and subsequently cooled down through various quenching media to obtain the variations in microstructures and related properties. The heat treated samples were investigated for microstructural evolution through optical microscopy and scanning electron microscope; mechanical characterization through microhardness study, tensile testing and impact testing; and wear characterization through pin on disc tribometer. It was observed that increased cooling rates increased the volume fraction of martensitic structures whereas oil quenching enhanced fine pearlite and bainite formation. The air cooling led to the formation of fine pearlite along with ferrite structures. Strength, hardness and wear resistance is favored with martensite formation but toughness decreases.

这项工作的目的是研究各种淬火介质对AISI 4135合金钢的组织演变和性能增强的影响。在这项工作中研究了双微结构的形成及其对机械和磨损性能的影响。尝试基于所使用的淬灭方法来关联微结构-性能关系。钢被加热到奥氏体温度以上（A ₃），然后通过各种淬火介质冷却，以获得微观结构和相关性能的变化。通过光学显微镜和扫描电子显微镜研究了热处理过的样品的微观结构。通过显微硬度研究，拉伸测试和冲击测试进行机械表征；通过盘式摩擦计上的销钉进行磨损表征。观察到增加的冷却速率增加了马氏体结构的体积分数，而油淬处理则增加了细小的珠光体和贝氏体的形成。空气冷却导致形成细小的珠光体以及铁素体结构。马氏体的形成有利于强度，硬度和耐磨性，但韧性降低。