低合金超高强度钢中的相变及组织控制

发布时间：2019-05-25 04:24

【摘要】：概述了低合金超高强度钢中所涉及的相变及组织控制方法。马氏体相变是低合金钢获得超高强度的最基本的途径,通过优化热处理或形变热处理工艺获得细化的马氏体板条是保证超高强度的关键。马氏体钢中足够的塑韧性通过适度回火来保障,回火过程中组织控制的关键是避免脆性渗碳体碳化物的析出。对低合金超高强钢起重要作用的贝氏体主要有两种,下贝氏体和无碳化物贝氏体,其中下贝氏体主要与马氏体一起形成复合组织,细化马氏体板条尺寸。无碳化物贝氏体通过得到超细亚结构或超细板条而获得超高强度,同时利用贝氏体转变的不完全性获得稳定的高碳残留奥氏体来保证塑韧性。残留奥氏体在低合金超高强钢韧性改善方面起着重要作用,Q-P(或Q-P-T)钢和TRIP钢中较多的残留奥氏体可赋予低合金超高强钢超乎寻常的高塑韧性。
[Abstract]:The phase transformation and microstructure control methods involved in low alloy ultra-high strength steel are summarized. Martensitic transformation is the most basic way to obtain ultra-high strength of low alloy steel. The key to ensure ultra-high strength is to obtain refined martensite lath by optimizing heat treatment or deformation heat treatment. Enough plastic toughness in maraging steel is guaranteed by moderate tempering. The key to microstructure control during tempering is to avoid the precipitation of brittle cementite carbides. There are two kinds of bainite which play an important role in low alloy ultra-high strength steel, lower bainite and carbide-free bainite, in which the lower bainite mainly forms composite microstructure with martensite and refines the lath size of martensite. Ultra-high strength is obtained by obtaining ultra-fine substructure or ultra-fine strip without carbide bainite, and stable high carbon retained Austenite is obtained by using the incompleteness of bainite transformation to ensure plastic toughness. Retained Austenite plays an important role in improving the toughness of low alloy ultra-high strength steel. More retained Austenite in Q / P (or Q-P-T) steel and TRIP steel can give low alloy ultra-high strength steel extraordinary high plastic toughness.
【作者单位】：天津大学材料科学与工程学院先进金属材料研究所;天津商业大学机械工程学院;
【基金】：国家杰出青年科学基金(51325401) 国际热核聚变试验堆(ITER)计划专项课题(2014GB125006) 国家重点基础研究发展计划(973计划)(2014CB046805) 国家自然科学基金(51474156)
【分类号】：TG142.33

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