摘  要：本论文主要是研究热处理工艺对低合金高强钢组织性能的影响。通过控制变量的方法对试样进行不同方式的热处理。其一是对试样进行不同温度的淬火，温度为850°C～1000°C且隔30°C一个，保温30分钟取出水淬，然后进行650°C统一回火60分钟。其二对试样进行相同温度淬火，温度为880°C且保温30分钟。取出水淬，然后进行不同温度和时间的回火，从而有横向和纵向的对比，温度为400°C保温60m分钟，500°C保温60分钟，550°C保温时间分别为30、60、120分钟。对不同温度淬火和回火处理过后的试样进行了力学性能检测和组织结构观察。实验结果表明：随着淬火温度的升高试验钢的强度是先升高后降低，且在880°C达到最大，840°C以下淬火后，组织中存在未溶铁素体，组织为铁素体和板条马氏体；880°C以上淬火后，组织为板条马氏体；随着回火温度的升高，试验钢的强度下降，塑、韧性提高，当回火温度达到450°C以上时，组织转变为回火索氏体，韧性大幅提高；较优的热理工艺为880°C淬火后再550°C回火。81032

毕业论文关键词：低合金高强钢；热处理；显微组织；力学性能

Effect of Heat Treatment Process on Microstructure and Properties of Low Alloy High Strength Steel

Abstract:This paper mainly studies the effect of heat treatment on the thermal properties of low alloy high strength steel。 The samples were subjected to different methods of heat treatment by means of variable control。 One is to subject the sample to a different temperature of quenching at a temperature of 850°C to 1000°C and at intervals of 30°C for 30 minutes to remove the water and then to temper at 650°C for 60 minutes。 The two samples were subjected to the same temperature quenching, the temperature was 880°C and the temperature was 30 min。 The water was removed and then subjected to tempering at different temperatures and times, with horizontal and longitudinal contrast, temperature of 400°C for 60 m, 500°C for 60 minutes and 550°C for 30, 60, and 120 minutes, respectively。 The mechanical properties of the samples after quenching and tempering were measured and the structure was observed。 The experimental results show that the strength of the test steel increases first and then decreases with the increase of the quenching temperature, and reaches the maximum at 880°C。 After quenching at 840 C, there is insoluble ferrite in the organization, Body and lath martensite; 880°C above quenching, the organization of lath martensite; with the tempered temperature increases, the test steel strength decreased plastic and toughness increased when the tempering temperature reached 450°C, the organization changed to tempered sorbite, the toughness increased significantly; the superior heat process was 910°C quenched at 550°C after tempering。

Key words: low alloy high strength steel; heat treatment; microstructure;       mechanical properties

目录

1  绪论 1

1。1 选题背景 1

1。2 低合金高强钢简介和分类 1

1。2。1低合金高强钢的简介 1

1。2。2低合金高强钢的分类 1

1。2。3合金高强钢中合金元素的作用 2

1。3 低合金高强钢在国内外工程的应用 3

1。4国内外研究概况 4

1。4。1 国外低合金高强钢的发展概况 4

1。4。2 国内低合金高强钢的发展概况