简介QPT超高强度钢课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,简介,Q-P-T,超高强度钢,徐祖耀,上海交通大学材料科学与工程学院,徐祖耀，我国应尽早发展高强度钢。中国工程院化工、冶金与材料学部第六届学术会议论文集。薛群基主编，化学工业出版社，,2007, 403-406.,为改善环保、节能和节约原材料（包括铁矿石），急宜将器件轻量化、提高钢的强度（,15002000MPa,或以上）、降低钢产量。,超高强度钢发展简史,20,世纪,60,年代以来，发展出马氏体时效钢，如,0.013C-18Ni-0.4Mo,钢,(,Floreen,S., Physical metallurgy of,maraging,steels. Metall. Rev., 1968, 13B:115-128.),经马氏体相变及中间相,(Ni,3,Mo,、,Ni,3,Ti,、,Fe,2,Mo),沉淀强化,马氏体二次时效钢：马氏体强化及碳化物沉淀强化,(,Machmeier,P. M., Little C. D., Horowitz M. H., Oates R. P. Development of a strong,martensitic,steel having good fracture toughness. Met. Technol., 1979: 291-296.,Ayer,Raghavan,Machmeier,P. M.,Microstructural,basis for the effect of chromium on the strength and toughness of AF1410-based high performance steels. Metall. Mater. Trans., 1996, 27A: 2510-2518. ),如,0.16C-10Ni-2Cr-1Mo-14Co,钢，,0.24C-11Ni-3Cr-1.2Mo-13.4Co,钢，,AF1410,，,AerMet100,钢,:,抗拉强度,1500MPa,以上，接近甚至超过,2000MPa,韧性,60J,。,含高合金元素、冶炼、加工要求较复杂，成本较高。,Bhadeshia,等研发的很强大件钢：,含,0.78-0.98wt%C,及,Si,、,Mn,、,Cr,（,V,、,Co,、,Al,）等合金元素。抗拉强度高达,2.5GPa,，硬度超过,600HV,，断裂韧度大于,30-40MPam,1/2,(Caballero F. G.,Bhadeshia,H. K. D. H.,Mowella,J. A., Jones D. G., Brown P. Very strong low temperature,bainite,. Mater. Sci. Technol., 2002, 78: 279-284.,Caballero F. G.,Bhadeshia,H. K. D. H., Very strong,bainite,. Current opinion in solid state and mater. Sci., 2004, 8: 251-257.,Bhadeshia,H. K. D. H. Large chunks of very strong steel. Mater. Sci. Technol., 2005, 21: 1293-1302.,Bhadeshia,H. K. D. H.,Bainitic,balk,nanocrystalline,steel. Proc. the 3rd Inter Conf: Advanced Structural Steels (ICASS),Gyeongju, Korea, 2006: 3340. ),等温时间较长（,2-60,天，加入,Co,或,Al,后缩短至半小时），含碳量过高，易形成,Fe,3,C,，潜在脆性。,范长刚等提出在,4340,钢的基础上提高碳含量至,0.5wt%,，即,0.37%Si,钢中含碳量比,4340,提高,0.10%,，,1.75%Si,钢中碳含量比,300M,提高,0.07%,，其他成分相近，经真空电弧电渣重熔，控制,S0.005%,，,P0.01%,及气体含量，经,900,淬火,:,*0.37%Si,钢经,200,回火得：条状马氏体，,碳化物及,2%,的残余奥氏体，,R,m,=2205MPa, K,IC,=61.5MPam,1/2,*1.75%Si,钢经,270,回火得：条状马氏体，,碳化物及,0.5%,，会有潜在脆性危险。,(,范长刚，董瀚，时捷，刘燕林，雍岐龙，惠卫军，王毛球，翁宇庆。,2200MPa,超高强度低合金钢的组织和力学性能,.,兵器材料科学与工程, 2006, 29(2): 31-35.),(,K,rauss G. Deformation and fracture in,martensitic,carbon steelstempered at low temperatures. Metall. Trans., 2001, 32B: 205-221.),Fracture response, under conditions of tensile loading, as a function of tempering temperature and steel carbon content in carbon and low-alloy steels quenched from austenite to,martensite,淬火钢中残余奥氏体的作用,改善钢的塑性和韧性，如：,*条状马氏体被几纳米厚的残奥所包围，增加了韧性。,(,徐祖耀,.,马氏体相变与马氏体,(,第二版，第三章,).,北京,:,科学出饭社,1999.,Lai G.Y., Wood W. E., Clark R. A.,Zackay,V. F., Parker E. R. The effect of,austenization,temperature on the microstructure and mechanical properties of as-quenched 4340 steel. Metall. Trans.,1974, 5: 1663-1670.),*,奥氏体的热稳定化现象使工具钢无变形淬火和高速钢的无变形回火。,(Gordon P., Cohen M., Rose R. S. Effect of quenching-bath temperature on the tempering of high speed,steel. Trans. ASM, 1944, 33: 411-454.,徐祖耀，奥氏体稳定化及其对热处理的作用。北京钢铁工业学院学报，,1957(4) : 26-33,。,徐祖耀，周济源。,9XC,钢工具的等温淬火,(,无变形淬火,),。北京钢铁工业学院学报，,1957(4) : 34-41,。,徐祖耀，周济源。,P18,钢杆形工具的等温淬火。北京钢铁工业学院学报，,1957(4) : 42-44,。,徐祖耀，周济源。工具钢的无变形淬火。机械工程学报，,1957(5): 249-255,。,徐祖耀，张万祯。奥氏体在回火时的催化作用和稳定化现象。科学记录，,1957,，,1(3): 59-63,。,Hsu Tzu-,yao,(,徐祖耀,), Chang Wan-,chen,(,张万祯,). The conditioning and stabilization of austenite during tempering. Science Record, New Series,1957, 1(3): 65-70.,徐祖耀，张万祯。高速钢在回火时奥氏体稳定化现象。北京钢铁工业学院学报，,1958(6) : 85-91,。,徐祖耀。高速钢的回火。金属学报，,1965(8) : 443-454,。,Hsu Tzu-,yao,(,徐祖耀,). The tempering of high speed steel.,Scientia,Sinica, 1965, 14: 1509-1522.,徐祖耀。高速钢工具的无变形回火。机械工程学报，,1958(6): 203-206,。,徐祖耀，嵇铃，杨嘉韦华。高速钢回火新工艺。首届中国热处理学会年会论文选集。北京,:,机械工业出版社，,1966: 196-202,。,),*氢脆裂纹受阻于奥氏体,:,300M,钢（含残奥约,3%,）对比,4340,钢（残奥,2%,），同样析出,碳化物，,但应力腐蚀速度慢一个数量级。,(,Ritchic,R.,Cedeno,M. H. C.,Zackay,V. F., Parker E. R. Effects of silicon additions and retained austenite on stress corrosion cracking in ultra-high strength steels. Metall. Trans., 1978, 9A: 35-40.),*,低碳钢中残余奥氏体的重要作用。,(,徐祖耀。低碳钢中的残余奥氏体。,上海金属，,1995,，,17(1): 1-6,。,),Thomas,等在,1979,及,1981,年由高分辨电镜及场离子显微镜原子探针揭示：含,0.27wt%C,钢经淬火后，低碳条状马氏体为,1.04wt% C,残余奥氏体所包围。,(,Rao,B. V., Thomas G. Transmission electron microscopy characterization of dislocated “lath”,martensite,. Proc Inter Conf: MartensiticTransformations-79, MIT, 1979: 12-16.,Sarikaya,M., Thomas G. Lath,martensites,in carbon steels are they,bainitic,. Proc Inter Conf: Solid to Solid Phase Transformations. Ed. Aaronson H. I., Laughlin D. E.,Sekerka,R. E.,Wayman,C. M.,，,1981. TMS-AIME, 1982: 999-1004.),他们认为淬火时碳由马氏体分配,(,不同相间的扩散,),至奥氏体所致。,(,Sarikaya,M., Thomas G., Steeds J. W.,，,Barnal,S. I., Smith G. D. W. Solute element partitioning and austenite stabilization in steels. Proc. Inter. Conf: Solid to Solid Phase Transformations, 1981. Ed. Aaronson H. I., Laughlin D. E.,Sekerka,R. E.,Wayman,C. M.,，,1981. TMS-AIME, 1982: 1421-1425.),徐祖耀等于,1983,年发表碳分配计算结果，称：在淬火过程中碳分配使残余奥氏体增碳能基本、或稍迟后完成。,(,徐祖耀，李学敏。低碳马氏体形成时碳的扩散,.,金属学报，,1983,，,19 : A83-88,。,徐祖耀，李学敏。低碳马氏体形成时碳的扩散,(,续,),。金属学报，,1983,，,19 A: 505-510,。,Hsu T. Y. (,Xu,Zuyao,), Li,Xuemin,. Diffusion of,carbon during the formation of low-carbon,martensite,.,Scripta,Metall., 1983, 17: 1285-,1288.),在上世纪，已发现,Si,钢中贝氏体相变时碳会向奥氏体扩散，形成“无碳化物贝氏体”。,(,Bhadeshia,H. K. D. H.,Bainite,in steels. London: The Inst. Materials, Cambridge Press, 2001: 373; 385.),含较高,Si,钢经室冷形成无碳化物贝氏体。,(,Matlock D. K., Krauss G., Speer J. G. Microstructures and properties of direct-cooled forging steels, Materials Processing Technology, 2001, 117: 324-328.),Mn,-Si Trip,钢在中间退火时，碳由铁素体向奥氏体分配。,(,Decooman,B. C. Ed. Proc. Inter Conf on TRIP-aided high strength ferrous alloys.,Gardracht,Redaktions,and,Industrie,Press Service, Bad,Harzberg, Germany, 2002.),淬火,-,分配（,Q-P,）工艺和淬火,-,分配,-,回火（,Q-P-T,）工艺：,Speer,等提出,Q-P,工艺，即将含硅钢,(,如他们开始试用的,0.35 C-1. 3,Mn,- 0. 74 Si,钢,),淬火至,M,s,一,M,f,间，并再在一定温度等温使碳由马氏体分配至残余奥氏体，将一定量奥氏体富碳稳定至室温，以保证钢的塑性和韧性。,(,Speer J. G., Matlock D. K.,DeCooman,B. C.,Schroch,J. G. Carbon partitioning austenite after,martensite,transformation.,Acta,Mater., 2003, 51: 2611-2622),上文中,Q-P,热力学和动力学部分并不成功，但分配功效显著。,Q-P,工艺对发展超高强度钢卓有功绩。,Q-P-T,热处理工艺,为进一步提高钢的强度，在,Q-P,工艺基础上，提出淬火一碳分配一回火,(Q-P-T),工艺。即除碳分配外，在含一定量,Si,的钢中有意识地加入复杂碳化物形成元素，使在一定温度等温时，析出复杂碳化物或在低碳等温（均属回火）析出,碳化物，除分配至残余奥氏体韧化外，还增加沉淀强化。,淬火,-,碳分配,-,回火（,Q-P-T,）工艺示意图,（,AT, QT, PT, TT,和,RT,分别表示奥氏体化温度，淬火温度，碳分配温度，回火温度和室温）,Schematic Quenching-Partitioning-Tempering (Q-P-T) process,(AT,、,QT,、,PT,、,TT and RT are,austenitizing, quenching, partitioning, tempering and room temperatures respectively),（徐祖耀。钢热处理的新工艺。第九次全国热处理大会论文集。中国机械工程学会热处理学会,大连, 2007: 1-12,。徐祖耀。钢热处理的新工艺。热处理, 2007, 22(1): 1-11,。,Hsu T. Y. (,Xu,Zuyao,). Design of structure, composition and heat,treatmeat,process for high strength steel. Invited paper: Pacific Rim Inter. Conf. Advanced Materials and Processing, Korea, 2007. Phase Transformation Session. Mater. Sci. Forum, 2007, 561-565: 2283-2286.,徐祖耀。用于超高强度钢的淬火,-,碳分配,-,回火,(,沉淀,)(Q-P-T),工艺。热处理，,2008,，,23(2): 1-5,。,Hsu T. Y. (,Xu,Zuyao,). Quenching-partitioning-,tempering(Q,-P-T) process for ultra-high strength steel. International Heat Treatment and Surface Engineering, 2008, 2(2): 64-68.,徐祖耀。白主创新发展超高强度钢。上海金属，,2009,，,31(2): 1-6,。,徐祖耀。淬火,-,碳分配,-,回火,(Q-P-T),工艺浅介。金属热处理，,2009,，,34(6),：,1-8,。,),Q-P-T,钢的组织成分及热处理工艺设计,显微组织,:,具高位错密度的细条状（全部或部分纳米级条宽）马氏体；马氏体上析出复杂碳化物或,碳化物；避免析出,Fe,3,C,；马氏体条间含一定量,(,厚度,),、一定碳含量的残余奥氏体；原始奥氏体具细晶组织。,成分：,C0.5wt%,，以免脆性；,Si,或,Al,约,1-2wt%,，抑制,Fe,3,C,形成，稳定,(,),碳化物，保证碳分配；,Mn,或,Ni,等合金元素少量，作固溶强化，降低,Ms;,复杂碳化物形成元素，使,Ms,下降，并使呈沉淀强化。,热处理：,Q-P-T,处理，淬火温度（,QT,），分配温度（,PT,）以及回火（沉淀）温度的确立因所需钢的强、韧度而定。,Q-P-T,钢经热处理后的组织与力学性质示例,1. 0.485C-1.195Mn-1.185Si-0.98Ni-0.21Nb,钢：,850,奥氏体化,300s,，淬火至,95,盐浴，再经,400,分配，进行碳分配及回火后水淬至室温。,经,400,保温,10s,后，试样含残余奥氏体,4.1%,，,30s,后含量增至,6.4%,。,经,400,保温,10s,后，形成几十纳米宽的马氏体条，外包残余奥氏体，,Nb,复杂碳化物呈纳米级大小的弥散沉淀（经,40010s,的尺寸为,(52)nm,，,1800s,后为,(3510)nm,）。,(Wang X. D.,Zhong,N.,Rong,Y. H., Hsu T. Y. (,Xu,Zuyao,). Novel ultra-high,nano,-lath,martensitic,steel by quenching-partitioning-tempering process. J. Mater. Research, 2009, 24: 260-267.),含,0.48wt,C,超高强度钢显微组织,TEM,像,(a),淬火至,95,明场像,(b),淬火至,95,的暗场像象及选区衍射,(c)400,C,回火,10s,明场像,(d) 400,C,回火,10s,暗场像及选区衍射,TEM micrograph of an ultra-high strength steel containing 0.48wt%C,(a) quenched in 95,C, bright field image; (b) quenched in 95,C, dark field image;,(c) tempered at 400,C for 10s, bright field image; (d) tempered at 400,C for 10s, dark field image,含,0.48 wt,C,超高强度钢经,400,分配及回火,10s,后其中碳化物沉淀的,TEM,像,(a),明场像,(b),暗场像,TEM micrograph of carbide precipitation in an ultra-high strength steel containing 0.48wt%C after partitioning and tempering at 400,C for 10s,(a) bright field image; (b) dark field image,含,0.48 wt,C,超高强度钢经,400,分配及回火,1800s,后其中碳化物沉淀的,TEM,像,TEM micrograph of carbide precipitation in an ultra-high strength steel containing 0.48wt%C after partitioning and tempering at 400,C for 1800s,(a) bright field image; (b) dark field image,含,0.48wt%,超高强度钢经,400,保温不同时间后的抗拉强度和总延伸率,Ultimate tensile strength and elongation of 0.45wt%C ultra-high strength steel as function of duration at 400,C,2,0.2C-1.5Mn-1.5Si-0.O5Nb-0.13Mo,钢,：,920,奥氏体化,300s,，,淬火至,220,盐浴，,400,碳分配和回火（,10,，,20,，,40,，,180s,）,，水淬至室温。,400,保温,10,，,20,，,40,，,80,和,180s,后的试样中的残余奥氏体量分别为,4.5%,，,7.0%,，,5.4%,，,5.2%,和,5.8 %,。,马氏体条宽：有小于,100nm,的，有大于,100nm,的。复杂碳化物呈纳米级大小。,(,Zhong,N., Wang X. D.,Rong,Y. H., Wang L. Enhancement of the mechanical properties of a,Nb,-,microalloyed,advanced high strength steel treated by quenching-partitioning-tempering process. Mater. Sci. Eng., 2009, 506A, 111-116.,0.2C QP-T,钢经,400,不同时间碳分配和回火后的抗拉强度和总延伸率,Ultimate tensile strength and elongation of 0.2C Q-P-T steel as a function of partitioning and tempering duration at 400,C,3. 0.1C-1.51Mn-1.48Si-0.02Nb-0.04V-0.015Ti-0.304 Mo,钢：,1000,奥氏体化，淬至,223,，,350,保温,30s,，水淬至室温，得残余奥氏体,(0.7wt%C),约,6%,；,保温,100 s,后残余奥氏体,(0.8wt% C),约,3.3%;,经,350120 s,后得屈服强度,700 MPa,，抗拉强度,900 MPa,；,20,吸收能量,100J,，,200,为,60J,。,(Seung Chan Hong, Jae Cheou Ahn, Saug Yong Nam, Kim Seog Ju,，,Yang Hee Choen, Speer John G., David K. Mechanical properties of high-Si plate steel produced by the quenching-partitioning-tempering process. Metals and Materials Inter., 2007, 13(6): 439.),4. 0.41C-1.27Si-1.30Mn-1.01Ni-0.56Cr,钢：,金学军等工作（待发表）显示,碳化物强化的,Q-P-T,钢。,820,奥氏体化,10min,，淬火至,180,盐浴，保温,30-10800s,，水淬至室温。马氏体强化及,碳化物析出强化，也属,Q-P-T,钢。,180,C,分配及回火对力学性质和,残余奥氏体体积分数的影响,Q-P-T,超高强度钢的综合力学性能优于双相钢、,Trip,钢、一般马氏体型钢、,Q-P,钢等等。,Q-P-T,钢的抗拉强度和总延伸率和双相（,DP,）钢、,TRIP,钢、一般马氏体型（,M,）钢、,Q-P,钢，以及含,Ni,钢经,Q-P,处理（、和）的性质作比较,Comparison of ultimate tensile strength and total elongation for dual phase (DP), TRIP,martensitic,(M), Q-P, Ni-containing Q-P (,、,and ) and Q-P-T steels,钢研总院结构材料研究所比较,Q-P-T,处理钢以及一般淬火,-,回火钢,(Q-P),的抗拉强度和伸长率，证明,Q-P-T,钢当荣胜一筹。,Q-P-T,钢与传统淬火回火钢,(Q-T),钢抗拉强度和延伸率的比较,发展,Q-P-T,钢待解决的问题,高强度钢的纯洁、均质等尤须冶炼、连铸和轧加工等环节重视。日前我国多数制造厂的技术水平尚需提高。,提高产品强度及减轻重量还需由机械设计师来倡试执行。,高强度钢，尤其是强度大于,2000MPa,的超高强度钢的加工和热处理设备、工艺和运行，尚待有关人士通力合作解决。,在保证足够韧性的条件下，减小马氏体条宽来提高强度尚有余地，应结合马氏体相变形核率研究做进一步深化。,Q-P-T,工艺还可试作渗碳，以减少污染、降低成本。,Q-P-T,钢中含,1-2%Si,会影响表面质量。以,Al,代替，当属上策。但连铸中会有结渣等问题，亟待解决。,谢谢！,