铁素体珠光体型非调质钢连续冷却转变的研究

采用DIL805L淬火相变膨胀仪研究了铁素体珠光体型非调质钢的连续冷却相变组织变化规律,分析了冷却速率和合金元素对相变组织、显微硬度和CCT曲线的影响。结果表明,Mo有助于获得针状铁素体组织,进而提高韧性,Mn与微合金元素V有助于提高钢的综合力学性能;冷速增大至0.5 ℃/s时,开始出现针状铁素体;冷速小于1 ℃/s时,获得完全的铁素体+珠光体组织;随着冷速的增大,钢的硬度不断增大。     

低合金调质高强钢球罐的焊接质量控制

通过对WEL-TEN610CF钢的焊接性分析，制定了合理的焊接工艺，并对高压球罐现场焊接各环节进行严格的质量控制。从而使低合金调质高强钢球罐的焊接质量得到了保证。     

Structure and properties of thermally hardened 10KhSND pipe steel

VNITI (All-Union Scientific-Research Design-Technological Institute of Pipe Industry). Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 21–23, January, 1990.     

Structure levels of pearlite deformation in carbon steel of eutectoid composition

The structure of eutectoid steel 80 has been studied at various stages of producing high-strength large-diameter reinforcing bars using transmission and scanning electron microscopy. Peculiar features of structural state have been revealed by the scale factor. It has been demonstrated that the stage of intensive strengthening does not exist at the initial steps of drawing a large-diameter wire. Using EBSD it has been established that, in the course of drawing, within the limits of the former austenite grain, a conglomerate is formed that consists of pearlitic colonies with the single orientation of the ferrite constituent along the {100} cleavage plane, which causes the poor technological plasticity of the studied steel.     

油淬火回火刷用扁钢丝的硬度分析

将φ6.5 mm的60钢盘条拉拔成1.8 mm的钢丝,由三连轧机轧制成横截面尺寸为3.175 mm×0.70 mm的刷用扁钢丝,采用敞开式炉膛马弗炉,对其进行油淬火回火处理,用显微硬度计进行硬度测试,用统计与方差分析方法处理数据。结果表明:当淬火温度为890℃,回火温度为575~580℃时,钢丝的硬度为45.00~48.00 HRC,硬度差能控制在3 HRC范围内,比较稳定。     

Structure and mechanical behavior of heavily drawn pearlite and martensite in a high carbon steel

Neutron diffraction measurements have revealed that cementite peaks disappear in a pearlite steel with drawing and that the residual intergranular stresses are generated. The diffraction profiles in a heavily drawn specimen suggest the tetoragonality with a small c/a in the ferrite matrix. Although cementite was hardly observed in the heavily drawn specimen, its c/a value determined by neutron diffraction and mechanical behavior are quite different from those of as-quenched martensite. The changes in hardness and c/a with annealing or tempering were also different between heavily drawn pearlite and marteniste. Hence, most of carbon atoms do not exist inside the ferrite lattice in the drawn pearlite and multi-scaled heterogeneous plastic deformation in pearlite seems to affect the asymmetry in the diffraction profile. Fracture behavior and hardness change with tempering is different in the two microstructures.     

非调质钢推广应用中的强韧化工艺研究

非调质结构钢工件,由于控制锻造.控制冷却工艺及装备的不完善,常出现强度高而韧性低的倾向,从碳含量、钢中的微合金元素、控锻-控冷工艺等方面对非调质钢的组织及力学性能的影响进行了初步分析,并就锻后热处理工艺方法的创新进行探讨.     

回火态AerMet100钢的热物理性能

AerMet100钢是一种先进的二次硬化型Ni-Co-Cr系结构钢,通过试验获得了回火态AerMet100钢的密度、热应变、弹性模量、泊松比、热导率、流变应力随温度的变化情况,以及升温过程奥氏体转变Ac₁和Ac₃点,降温过程马氏体转变Ms点和马氏体转变系数K_m。最后基于获得的回火态AerMet100钢热物理性能数据,以齿轮淬火过程为例,采用SYSWELD有限元分析软件进行了仿真分析。结果表明,回火态AerMet100钢的室温组织为回火马氏体+残留奥氏体,在升温过程中奥氏体反应热焓为42 600 J/kg,其他热物理性能参数均在Ac₁~Ac₃范围内发生非线性变化,且测试状态和升温速度不同导致Ac₁和Ac₃存在差异,回火态AerMet100钢不同冷却速度下的Ms基本一致,约为213 ℃,马氏体转变系数K_m值为0.011 736。SYSWELD有限元仿真分析表明,试验获得的各项热物理性能数据可用于该钢的热处理模拟分析。     

Cryogenic treatment of case hardened steel

Abstract

The case for cold treating tools is clear-cut, but carburised components such as gears may not always benefit from cold treatment. The consequent reduction of retained austenite in high carbon carburised cases affects several properties of the component. Whether that change in properties is beneficial depends very much on the intended operating conditions of the component. This paper attempts to put the arguments for and against cold treatment for various operating conditions.     

热轧复合不锈钢-碳钢复合板界面特征

研究了热轧不锈钢-碳钢复合界面的组织形貌、成分、硬度变化及结构特征。结果表明热轧复合碳钢—不锈钢复合板的复合界面两侧存在一定厚度的扩散层。由于元素扩散及碳化物的生成,复合界面附近硬度升高。对于基层碳钢,靠近界面处显微硬度值最高,而对于复层不锈钢,在距界面处一定距离,显微硬度达到最高值。复合界面剥离后呈现等轴韧窝形貌,表明通过热轧复合的方法,不锈钢和碳钢之间能够实现良好的复合。     

珠光体钢与奥氏体钢异种钢焊接材料的选择与应用

分析了珠光体钢与奥氏体钢异种钢的焊接性,介绍了焊接材料的选用原则、材料种类、工艺及工程中的应用.结果表明：该类异种钢焊接材料的选择原则是,尽量选用接近或高于奥氏体钢的高合金成分,而不是接近珠光体钢的成分;尽量避免焊缝中马氏体组织形成,保证接头获得良好的使用性能和焊接性.可供该类异种钢选用的焊接材料种类较多,工艺方法各具特色.三个典型应用案例表明,这类异种钢焊接质量的有效控制,取决于焊接材料的合理选用及正确的工艺方法.新型、高效、自动化焊接材料是颇具推广应用前景的焊接新材料.