共查询到17条相似文献,搜索用时 62 毫秒
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通过成分设计、相变规律研究、工业规模试制,分别获得了(PF+B)双相组织及AF组织的管线钢钢板。二者的试验研究结果表明,当弛豫终止温度低于相变开始温度后,组织中将出现多边形铁素体(PF)。弛豫终止后以20℃/s左右的冷速加速冷却时,未转变的奥氏体转变为由粒状铁素体(GF)及贝氏体铁素体(BF)组成的贝氏体B组织。相比于AF组织管线钢,(PF+B)组织管线钢具有较低的屈强比及较高的伸长率。试验获得的(PF+B)组织管线钢的轧板厚度达30.8mm,强度级别达到X70级,拥有较低的屈强比和较高的伸长率,满足海底管线对抗变形性能的要求。 相似文献
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The CCT behaviors of two bearing Nb polygonal ferrite-bainite high strength and high-deformability pipeline steels were studied in undeformed condition, The static CCT curves were constructed. The static CCT curves, microstructures and microhardness of two experimental steels were compared. It was found that microstructures of these steels contain polygonal ferrite, pearlite, bainite as cooling rate from 0.0278 to 42.5�桤s-1; Addition of Nb in the steel retards polygonal ferrite and granular bainite transformation, suppresses ferrite growth and refine ferrite grain, makes transformation line of bainite right shift, narrows the range of cooling rate of ferrite transformation, raises start temperature of ferrite and banite transformation; ferrite transformation zone is narrowed and the bainite transformation zone is expanded with increasing of Nb. 相似文献
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利用扫描电镜,研究了工艺制度对X80级抗大变形管线钢组织和性能的影响。研究结果表明,随开始冷却温度的降低,先共析铁素体含量逐渐增加,贝氏体组织含量逐渐降低,钢板抗大变形性能参数提高。当开始冷却温度为720~740℃时,钢板具有最佳的综合力学性能,屈服强度Rt0.5为565 MPa,抗拉强度Rm为730 MPa,伸长率为42.7%,屈强比Rt0.5/Rm为0.75,Rt1.5/Rt0.5为1.161、Rt2.0/Rt1.0为1.116,均匀变形伸长率达到12.33%。 相似文献
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高级别管线钢的组织性能及变形抗力模型 总被引:1,自引:0,他引:1
以X80管线钢为例,对高级别管线钢的组织性能及变形抗力模型进行了研究.对实验室试制的X80级高级别管线钢的力学性能、显微组织进行了分析研究;利用Gleeble-1500热模拟试验机对高级别管线钢的变形抗力模及其影响因素型进行了研究.结果表明:此次实验室试制的厚度为11 mm的X80高级别管线钢力学性能优良,平均屈服强度为640 MPa,平均抗拉强度为730 MPa,屈强比为0.88,-20℃条件下平均冲击功为320J.通过对试验钢进行显微组织观察发现X80级高级别管线钢的显微组织主要为粒状贝氏体加针状铁素体组织. 相似文献
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《钢铁研究学报(英文版)》2011,(Z1):707-711
A low carbon Nb-microalloyed high deformability pipeline steel with X100 grade has been processed by TMCP and followed two-stage cooling process.The microstructure is characterized by ferrite/bainite multiphase.The effective grain size is 1.85μm in average.The volume of ferrite is about 10-15% and the grains sizes are mostly less than 5μm.The bainite consists of granular-bainite and lath-bainite,with M/A islands finely dispersed.The longitudinal tensile yield strength,uniform elongation,yield ratio are 647MPa,7.6% and 0.78,respectively.Ferrite/bainite multiphase have large strain hardenability that resulting high strength and high deformability combination.Precipitation of Nb also improves the strength and uniform deformability by precipitation strengthening and grain refinement. 相似文献
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Alloying Elements in High Speed Steels 总被引:2,自引:0,他引:2
Highspeedsteelsarestilldominatingcuttingtoolmaterials,whichwouldnotbechangedinthenearfuture,althoughothertypesoftoolmaterials,suchascementedcarbides,diamonds,ceramicma-terialsandcubicboronnitride,havebeenrapidlydeveloped,partlyduetocomplementaryofall… 相似文献
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Effect of Cooling Start Temperature on Microstructure and Mechanical Properties of X80 High Deformability Pipeline Steel 总被引:1,自引:0,他引:1
The effect of cooling (laminar cooling) start temperature on the phase constitution was analyzed by quantitative metallography. The martensite/austenite (M/A) island distribution was fixed by colour metallography. The strength and uniform elongation of the steels were tested with quasi-static tensile testing machine. The in-coordinate deformation of the soft and hard phases was analyzed using FEM. The results indicate that when the cooling start temperature is 690 ℃, the mechanical properties are the best, meeting the requirements of X80 high deformability pipeline steel. 相似文献
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The mechanical properties of heat affected zone (HAZ) of two commercial high-Nb X80 grade pipeline steels with different alloy elements were investigated using thermal simulation performed on a Gleeble-3500 thermal simulator. The results showed that the high-Nb steels have excellent weldability. Embrittlement regions appear in coarse grain heat affected zone (CGHAZ) and intercritically heat affected zone (ICHAZ); Softening region appears in fine-grain heat affected zone (FGHAZ), and the strength here was even lower than 555 MPa as required in the standard. Meanwhile, with the increase of heat input, the strength and the toughness of HAZ of steel with high Nb, C and lower alloy decrease notably. Therefore, take into account the welding procedure during manufacture of weld pipe, suitable amount of alloy elements, such as Cr, Ni, Cu, Mo and so on, is necessary for high Nb X80 heavy-thick steel plate. 相似文献
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大变形管线钢是一种管道在通过地质复杂地区(滑坡、地震、冻土等)时,为了降低地层移动对管道可能造成的变形损伤而开发出来的新型管道结构用材料。采用材料显微分析方法和力学性能测试等手段,对一种大变形X80管线钢在应变时效中的脆化规律进行了研究。结果表明,应变时效使试验钢产生脆化。随着应变时效温度的升高,强度和硬度增加,塑性和韧性下降。应变时效脆化形成的机制是管线钢间隙原子与位错的交互作用。与普通X80钢相比,大变形X80钢的应变时效倾向较小,这是因为双相组织中铁素体固溶的碳、氮原子少,位错密度低。 相似文献
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采用实验室热轧、显微分析及力学性能检测手段,对Nb-Mo及Nb微合金化X100管线钢在不同工艺条件下的组织特征及力学行为的变化规律进行了研究.分析结果表明:工艺参数对Nb-Mo复合成分试验钢影响较大,控轧控冷工艺条件下Nb-Mo及Nb微合金化X100管线钢力学性能均能达到API 5L中X100管线钢要求,但Nb-Mo复合成分力学性能富余量较大,性能较优.随冷却速度的增加及终冷温度的降低,试验钢强度增加,韧性及塑性恶化.板条马氏体与贝氏体复相组织较板条马氏体可大大提高试验钢的塑性及低温冲击韧性. 相似文献