珠光体耐热钢顶杆焊接工艺研究

12CrMoV珠光体耐热钢顶杆在制作过程中,采用V型坡口焊条电弧焊、水平固定全位置对接接头焊接,焊接性差,焊接难度大,通过规范焊接工艺和焊接质量控制,有效避免了未焊透、夹渣、裂纹等缺陷,保证了焊接质量.     

595℃长期时效对M152马氏体耐热钢力学性能的影响

采用力学性能测试、金相分析及TEM微观结构分析,研究了M152马氏体耐热钢在595℃长期时效过程中的力学性能和结构变化,并探讨了时效脆化机制。结果表明:在595℃时效过程中,发生了显著的回复,位错密度下降,且原始组织中弥散分布的M2C和M7C3碳化物逐渐转变成M23C6碳化物,并聚集长大,导致强度逐渐降低;时效脆化的主要原因是杂质元素的非平衡晶界偏聚和碳化物的晶界析出共同作用,时效初期的脆化主要是由于M2C碳化物沿马氏体板条界的连续析出造成的。     

620℃长期时效对新型铁素体耐热钢1Cr11Co3W3MoVNbNB组织和力学性能的影响

采用X射线衍射、光学显微镜、扫描电镜和透射电镜研究了620℃长期时效对1 100℃油淬+720℃高温回火的新型铁素体耐热钢1Cr11Co3W3MoVNbNB(%:0.10C、11.08Cr、3.20Co、2.54W、0.52Ni、0.15Mo、0.09Nb、0.021N、0.014B)的显微组织和力学性能的影响。结果表明,620℃2 000 h时效下,时效时间对室温及620℃力学性能影响不大,时效过程中主要有M_(23)C_6、Nb(CN)和M_3B_2三类析出相,板条亚结构没有明显的变化,显微组织稳定;固溶的Mo、W、V主要在时效过程中"脱溶"进入析出相,Nb、B主要在高温回火以及时效初期"脱溶"。     

25-12型耐热钢高温性能研究

设计熔炼了25-12型耐热钢,对其高温抗氧化性能和高温力学性能进行了测试分析,并与奥氏体不锈钢1Cr18Ni9Ti作了对比。结果表明,在1150℃恒温氧化条件下,平均氧化速度25-12耐热钢为0.943g(/m2·h),而1Cr18Ni9Ti钢为9.208g(/m2·h),25-12耐热钢表现出更好的抗氧化性,且其抗压缩变形能力略高于1Cr18Ni9Ti。     

12Cr1MoV钢高温时效中组织结构变化的原子扩散分析

试验了成分(％)为：0．095C-1．00Cr-0．31Mo-0．22V的12Cr1MoV珠光体耐热钢在650～750℃ 1．42～873h时效时钢中合金元素的扩散、位错亚结构以及碳化物大小、数量和分布。并运用原子扩散无规行走理论计算了在对应不同Larson-Miller指数P值的不同温度和时间下时效时钢中合金元素的扩散距离。结果表明，扩散分析的结果与试验材料成分和各种结构单元特征尺寸范围内组织结构的变化相一致；而且12Cr1MoV钢在500℃以上时效时，铬、钼原子的扩散与迁移距离显著，为10～38μm，远大于迁移距离约为0．5μm的钒原子。这从动力学角度说明钒是通过弥散强化提高12Cr1MoV钢热强性的主要元素之一。     

耐热钢臁高温合金的开发与研究

叙述了我公司生产耐热钢和高温合金的装备和现状，详细了阐述了近年来我公司在耐热钢和高温合金领域的研究与开发。     

高温长期时效对钴高温合金GH605组织与性能的影响

研究了长期时效处理对钴基高温合金ＧＨ６０５组织与性能的影响。结果表明,８１５℃长期时效过程中,随时效时间的延长,析出碳化物（主要是Ｍ６Ｃ）逐渐增多,而且时效５００ｈ后发现有少量针状或棒状Ｌａｖｅｓ相析出。高温塑性,尤其是室温塑性的下降与碳化物过分粗化以及脆性Ｌａｖｅｓ相的析出并增多有关,但这两个因素对于室温拉伸强度及高温持久寿命的影响较小。为了使合金塑性得到恢复,可以采用重新固溶处理的措施。     

耐热钢及高温合金的开发与研究

叙述了我公司生产耐热钢和高温合金的装备和现状 ,详细阐述了近年来我公司在耐热钢和高温合金领域的研究与开发。     

时效温度对贝氏体型冷作强化非调质钢力学性能的影响

 研究了时效温度对一种低碳Mn-B-Ti系贝氏体型冷作强化非调质钢力学性能的影响。结果表明：试验料的强度随时效温度的升高先是增加,并在250℃时存在一个峰值,随后强度又随时效温度的升高而降低,当温度升高到400℃以上时强度明显降低;试验料的塑性和屈强比则随时效温度的升高逐渐增加,其中后者增加的幅度更显著。与未充氢试样相比,试验料拉拔并充氢后的延迟断裂性能显著降低。随着时效温度的升高,充氢试样中的氢含量降低,缺口抗拉强度RBN和延迟断裂强度比R缓慢增加,当时效温度大于200℃时,RBN和R则明显增加。因此,在满足保载永久伸长变形量及强度和塑性要求的前提下,应选择合适的时效温度,以保证材料的延迟断裂性能。     

冷却速度对X12CrMoWVNbN10-1-1耐热钢的力学性能影响

采用力学性能测试、金相分析以及TEM微观结构分析,研究了淬火和回火冷却速度对X12CrMoWVNbN10-1-1耐热钢力学性能的影响,并探讨了脆化机制,结果表明:在相同的回火工艺下,随淬火冷却速度的降低,强度降低,塑性变化不大,但冲击值增加,其主要原因是缓冷降低了马氏体基体的再结晶温度,导致基体的回复与再结晶程度增加;...     

电磁成形耐热不锈钢的试验研究

介绍了一种新型无接触金属熔体电磁近终成形技术及其原理,并利用20kHz电源中小尺寸耐热不锈钢的电磁成形工艺进行了系统研究,结果表明,采用斜边感应器和下屏蔽罩能够达到电磁场和温度场的动态耦合,有利于获得侧表面垂直且状态稳定的钢液柱,在大量试验研究的基础上,获得了表面质量较好的圆形和椭圆形截面不锈钢构件。     

In Situ Synthesis of Heat Resistant Gradient Composite on Steel Surface

 A heat resistant gradient composite was synthesized in situ on steel with the self propagating high temperature synthesis (SHS) reaction of 3Ni Al Ti C system during casting. The phases, microstructure, and composition of the composite were analyzed by using an X ray diffractometer (XRD), and a scanning electron microscope (SEM) coupled with an energy dispersive X ray spectroscope (EDS). The formation mechanism of the composite is also discussed. TiC/Ni3Al/steel gradient composite is achieved by forming the gradient distributions of Fe, Ni, and Al, accompanied with the gradient variation of the microstructure from TiC/Ni3Al, to TiC/Ni3Al/steel, and to steel. The composite is in situ synthesized through whole reaction of 3Ni Al Ti C system in liquid steel and densification procedure, and the liquid steel infiltrates into pores in the SHS product and forces liquid Ni3Al to form self compaction further.     

Microstructure Evolution and Mechanical Properties of HR3C Steel during Long-term Aging at High Temperature

Microstructure evolution and the changes in mechanical properties of HR3 Csteel during long-term aging at650,700 and 750℃ were investigated.The precipitated phases of the aging steel included M23C6 carbides,Z-phase and a trace amount of Nb(C,N).The M23C6 carbides were distributed mainly at the grain boundary,while Z-phase was mainly inside the grains.Amounts of both M23C6 carbides and Z-phase during the aging process increased with increasing aging period and temperature.Coarsening of M23C6 carbides was influenced significantly by aging time and temperature,while the size of the Z-phase was relatively less affected by the aging time and temperature,which had a steady strengthening effect.Coarsening of the M23C6 carbides was the main reason for the decline in high temperature yield strength during long-term aging at 750℃.The M23C6 carbides were linked into a continuous chain along the grain boundary which accounted for the decrease of toughness during aging.     

40CrMnSiMoV弹簧钢热处理工艺与力学性能研究

通过端淬试验及经各种工艺热处理试验,对弹簧钢40CrMnSiMoV的淬透性及热处理工艺与力学性能进行了试验研究.试验结果表明:此钢种不仅淬透性良好,而且力学性能强、韧性水平高.     

热处理工艺对30MnSi PC钢棒力学性能的影响

针对30MnSi 预应力混凝土用钢棒(简称PC钢棒)在实际生产中抗延迟断裂性能差、力学性能不稳、屈强比高等问题,从生产PC钢棒的技术关键热处理制度入手, 通过调质处理得到回火屈(索)氏体组织,分别绘出了淬火温度、回火温度与抗拉强度、伸长率、屈强比的关系曲线.系统地研究了热处理工艺参数对钢棒的组织及强韧性的影响规律并进行了理论分析.摸索出了生产30MnSi PC钢棒的合理工艺制度:当加热时间一定时,淬火温度920～960 ℃,回火温度控制在390～430 ℃时,能获得较好的综合力学性能.     

新型铁素体耐热钢抗氧化性研究

本文对一种新型铁素体耐热钢进行了抗氧化实验研究和实际使用条件下的模拟实验研究，证明了实验钢具有优异的抗氧化性。并可以作为在１０００￣１０５０℃空气介质条件下长期服役的构件。     

Influence of Lamellar Direction in Pearlitic Steel Wire on Mechanical Properties and Microstructure Evolution

During cold drawing of pearlitic steel wire,the lamellar structure becomes gradually aligned with the draw-ing axis,which contributes to the ultra-high strength.A direct simulation about the mechanical behaviors and micro-structural evolution of pearlitic lamellae was presented.A representative volume element (RVE)containing one pearlitic colony was established based on the real transmission electron microscope (TEM)observation.The deform-ation of pearlitic colony during tension,shear and wire drawing were successfully simulated.The numerical results show that this metallographic texture leads to a strong anisotropy.The colony has higher yielding stress when the la-mellar direction is parallel and perpendicular to the tensile direction.The lamellar evolution is strongly dependent on the initial direction and deformation mode.The formation of typical period shear bands is analyzed.In the wire draw-ing,the pearlitic colony at the sub-surface experiences a complex strain path:rotation,stretching along the die sur-face,and rotation back.     

Effect of Heat Treatment on Microstructure and Mechanical Properties of HB400 Grade High Strength Abrasion Resistant Steel

High strength abrasion resistant steel plates are widely used in mining,construction and agricultural machineries.The plates are,however,usually poor in impact toughness.An attempt is made to improve the impact toughness of HB400 grade abrasion resistant steel by controlling quenching and tempering of the plates.Optimized combination of the strength and the toughness has been achieved by choosing best fit set of quenching and tempering condition.Mechanism underlying the achievement has been investigated in terms of the microstructure consisting of tempered lath martensite,retained austenite and precipitated carbides.