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LI Chenglao SHEN Lian LIU Junhai Xi''''an Jiaotong University Xi''''an China 《金属学报(英文版)》1992,5(1):13-15
The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us-ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted-resolidified layer has been examined by optical microscopy and transmission electronmicroscopy(TEM).It was characteristic of extremely fine dendrite in the laser melted-resolidified layer and δ-ferrite in bulk form in the center of dendrite.The predominant twinmartensite and a little dislocation martensite existed in the dendrite.The thin plate-likeM_(213)C_6 carbide precipitated coherently on the twin martensites along their twin plane.Therewere both austenite rich in W,V and Cr and M_6C carbide in the interdendritic regions. 相似文献
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离心铸造轧辊用高速钢的热处理 总被引:1,自引:0,他引:1
采用差式扫描量热法(DSC)及热膨胀法测定了离心铸造轧辊用高速钢的相变点,根据高速钢的临界转变温度,进行了退火、淬火和回火实验.着重研究了热处理过程中碳化物演变对轧辊用高速钢性能的影响.结果表明:退火温度需高于630℃,才能使铸态高速钢得到软化,硬度降低,便于切削加工.热处理前后,MC型一次共晶碳化物的成分、形态和数量基本没有变化;随着淬火温度的升高,处于亚稳状态的M2C型共晶碳化物的分解数量越来越多.高速钢最终硬度受回火温度影响较大,研究了回火温度与二次硬化之间的关系,确定了二次硬化峰值温度,研究了二次碳化物的溶解与析出对高速钢基体组织与力学性能的影响规律. 相似文献
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YU Xuejie Shanghai Iron Steel Research Institute Shanghai China ZHOU Tianjian Anhui Institute of Technology Hefei China YU Xuejie Senior Engineer Shanghai Iron Steel Research Institute Taihe Road Wusong Shanghai China 《金属学报(英文版)》1990,3(2):99-103
The mechanical properties and structure of bainite and martensite after tempering m 6-5-4-2high speed steel have been investigated.It was found that the secondary hardening effect andresistance to heat softening as well as impact toughness are higher in the bainite than in themartensite.TEM observations show that the(Fe,M)_3C precipitated in the martensite aftertempering at temperature near the peak of hardness-tempering temperature curve.However,no(Fe,M)_3C but the dispersive MC and M_2C precipitated in the ferrite and austenite ofbainite after tempering at the same temperature.This indicates that the diffusion of alloy ele-ments forming carbide might exist during the process of bainite growing. 相似文献
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研究了6-5-4-2高速钢中贝氏体和马氏体回火后的力学性能和组织结构。结果表明,贝氏体比马氏体具有更高的二次硬化效应以及抗回火稳定性和冲击韧性。透射电镜观察发现,马氏体在二次硬化峰温度范围回火时,有Fe_3C析出,而贝氏体铁素体和奥氏体中只析出弥散的MC和M_2C合金碳化物。这表明在贝氏体长大过程中存在合金元素的扩散。 相似文献
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Q. F. Wang J. H. Liu Z. Y. Li P. H. Li G. F. Zhou X. Chen Huazhong University of Sci. & Tech. Wuhan China ) Technology Center of WISCO Wuhan China) 《金属学报(英文版)》2000,13(1):151-156
1.IntroductionbeerbeamweldingilasbeenwidelyusedasanimportantprocessinsheetsteelstrUcture.WiththedevelOPmentofhighpowerlaseranditsincreasingsuccessfalaPPlicationsinindustry,itisbecomingObViousthatthatlaserweldingwillalsohaveanimportantimpactonthemediumandheaVysectionindusalintheneaxfutUre.Theleadingindustryforinboducinghighpowerlaserweldingistheshipbuilding['j.ULCBanisalatelydevelopedsteelinWuhanSteelwithultra--lowcarboncontentanddondnativendcrostructureOfbainite,whichwillbewidelyusedinsh… 相似文献
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利用轴流CO2激光加工机对45钢在轴流基模条件下进行激光相变硬化处理,并研究了其激光相变硬化组织及性能.结果表明,改性层微观组织由表层至基体依次为:表面熔凝区为片状马氏体,均匀相变硬化区为隐晶马氏体,过渡区为混合马氏体、屈氏体和部分未熔的铁素体;激光相变硬化改性层的硬度与基体相比有大幅度提高;最高硬度(约为基体的3倍)出现在次表层;激光相变硬化处理后耐蚀性有所提高,随扫描速度增加,耐蚀性增强. 相似文献
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高速钢中马氏体二次硬化的TEM研究 总被引:5,自引:0,他引:5
研究了含4%Co的M42基体钢在250—700℃回火区间的析出相低温回火有M_3C(M以Fe为主)碳化物析出,400℃以上回火,数量逐渐减少.500—560℃观察到一个衍射芒线的演化过程.在580℃回火时观察到面心立方M_2C(M以Mo为主),700℃时面心立方M_2C全部转变成六方M_2C,还有VC和Cr_(23)C_6。衍射芒线是由于合金元素Mo,W与碳元素在{100}_(α′)面上的偏聚造成的,是由复合偏聚区向过渡相(面心立方M_2C)的演变.这一演变使M42基体钢回火出现二次硬化现象。 相似文献
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LIU Ning CUI Kun Huazhong University of Science Technology Wuhan.China DENG Zonggang Hefei University of Technology Hefei China CHENG Benpei KONG Jie Institute of Solid State Physics Academia Sinica Hefei China Doctorate student Department of Mechanical Engineering No. Huazhong University of Science Technology Wuhan China 《金属学报(英文版)》1993,6(1):36-39
Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites grow into the melt and then the fine equiaxed cellularstructure appears in upper melt region nearly surface.The substructure of cellular grains anddendrites was observed to consist of martensite and retained austenile,while the carbides asM_6C_■ Cr_7C_3 and MC distributed at their boundaries.It is believed that the highermicrohardness up to HV_(0.1)=865—960 of the laser fused structure of the alloy is due to the oc-currence of martensite. 相似文献
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借助扫描电镜、透射电镜及X射线衍射仪研究了W6Mo5Cr4V2(M2)高速钢激光熔凝后的显微组织,结果表明,熔化区最深处的显微组织细小,其形态类似于铸锭凝固的激冷区。较狭窄的激冷区形成后,长柱状晶向熔体内生长;最后,靠近表面的熔化区上部是细致的等轴细胞状组织,其中细胞晶及柱状晶内部由马氏体和残余奥氏体组成,而合金碳化物M_6C,Cr_7C_3及MC分布在胞晶和柱状晶的界面上.由于存在马氏体组织,因此激光熔凝组织具有HV_(0.1)865—960的高硬度。 相似文献
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微量Mg在M2高速钢中的作用 总被引:2,自引:0,他引:2
研究了Mg对M2高速钢凝固组织和共晶碳化物高温球化的影响,试验表明:加入适量的Mg可以使M2高速钢通常的片状M2C型共晶碳化物转变成鱼骨状的M6C和块状的MC型碳化物,Mg还阻碍鱼骨状共晶碳化物的高温球化。 相似文献
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THE TEMPERING OF HIGH SPEED STEEL 总被引:2,自引:0,他引:2
论述了高速钢回火时奥氏体的催化作用和稳定化现象的工作,以及根据研究结果所拟定的回火新工艺.奥氏体催化作用的效果以冷却过程中残余奥氏体转变为马氏体的温度M′来表示.催化作用的效果决定于回火的溫度和时间. 先经高溫保溫又在较低溫度(但在一定溫度T_c以上)保溫(分级回火),则催化作用不但具有迭加性,或和高溫同样时间的效果相等,而且有时超过高溫保溫的效果.高溫保溫有时还能促使低溫时的催化作用.经适当分级回火后(例如先经560℃保温又在550℃保溫),残余奥氏体转变为马氏体的数量能和多次回火后相比拟,但所需总时间却能大为缩短. M′溫度随钢內残余奥氏体量的增加而降低,并随奥氏体內含碳量而改变. 在T-c溫度以下、M′溫度以上停留,奥氏体的稳定化作用(M′值的降低)极为显著.稳定化的程度(△M′)因停留时间的增长而增加,一直达到一定的饱和值.最大稳定化的程度以及稳定化开始的速度因保溫溫度的升高而减小.在M′溫度以下保溫,其最大的奥氏体稳定量因保溫溫度的升高而增加.回火时奥氏体的稳定化现象可能主要由应力的减小所引起的,这些应力在冷却时有助于马氏体核胚的扩展. 催化作用可认为是稳定化的可逆过程,它应该包括下列过程:无序分布位错的重新排列,α-γ相交界面位错 相似文献
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采用额定功率为5KW连续可调的CO2横流激光器,研究了激光的输出功率和焊接地2mm厚1r18Ni9Ti奥氏体不锈钢的力学性能指标(抗拉经度σb,屈服强度σ0.65)的影响规律;并且通过分析得到了激光焊接1Cr18Ni9Ti薄板的最佳工艺参数。 相似文献
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Cr12MoV钢激光熔凝层的显微组织SCIEI 总被引:1,自引:0,他引:1
用透射电镜和X射线衍射仪,分析了Cr12MoV钢激光熔凝层的显微组织为奥氏体的树枝晶,其晶间还有共晶碳化物和少量二次碳化物,没有观察到马氏体相变,因此激光熔凝处理后,钢的表面硬度降低。 相似文献
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VARIATION OF SUBSTRUCTURES OF PEARLITIC HEAT RESISTANT STEEL AFTER HIGH TEMPERATURE AGING 总被引:2,自引:0,他引:2
R.C.Yang K.Chen H.X.Feng H.Wang 《金属学报(英文版)》2004,17(4):477-481
The observations of dislocations, substructures and other-microstructural details were conducted mainly by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) for 12Cr1MoV pearlitic heat-resistant steel. It is shown that during the high temperature long-term aging, the disordered and jumbled phasetransformed dislocations caused by normalized cooling are recovered and rearranged into cell substructures, and then the dislocation density is reduced gradually. Finally a low density linear dislocation configuration and a stabler dislocation network are formed and ferritic grains grow considerably. 相似文献