Ti微合金化400 MPa级光伏支架用钢的开发

详细介绍了山西建龙1500生产线试制400 MPa级光伏支架用热轧钢带的成分设计、工艺路线以及产品质量情况。生产实践表明,按照设计的成分和工艺生产的光伏支架用热轧带钢的组织为铁素体+少量珠光体,拉伸性能和冷弯性能优异,能够满足用户的使用要求。

Thermomechanical controlled processing of hot-rolled multiphase steel containing Nb

Influence of thermo-mechanical controlled processing(TMCP),including two-stage rolling with laminar cooling,air cooling and ultra-fast cooling,on the microstructure and mechanical properties of three kinds of Nb-microalloeyed steels was investigated by hot-rolling experiment.Effect of chemistry compositions and microstructure on mechanical properties and the relationship between the multiphase microstructure' s formation with TMCP were analyzed.The results showed that the mixed microstructure containing ferrite,bainite,martensite and a small amount of retained austenite can be obtained by thermo-mechanical controlled processing.Size, quantity and distribution of the constituents(ferrite grain,bainite packet and M-A islands) significantly affect the mechanical properties of three kinds of Nb-microalloyed steels.Under the condition of similar TMCP parameters, there is a gradually decreasing tendency in tensile strength from high silicon Nb steel,high silicon Nb-Ti steel to low silicon Nb-Ti steel,and an opposite tendency in total elongation and product of tensile strength and ductility. Total elongation and product of tensile strength and ductility reach the maximum values(41%and 25256 MPa% respectively) for low silicon Nb-Ti steel.

热轧冷却工艺对Nb-Ti微合金双相钢组织和性能的影响

研究了热轧后空冷(800-850℃→750℃)+水冷(750℃→300～180℃)的两段式和水冷(782℃→760℃)+空冷(760℃→713℃)+水冷(713℃→414℃)三段式冷却方式对双相钢(％:0.08C、1.02Mn、0.22Si、0.02Nb、0.01Ti)组织和机械性能的影响。结果表明,采用两段式冷却方式可得到铁素体+分散的板条马氏体组织,并使铁素体尺寸达5.5μm,钢的屈服强度为345～365 MPa,抗拉强度为565～575 MPa、屈强比为0.60～0.65,优于三段式冷却方式轧制的双相钢。

Nb-Ti微合金化热轧多相钢的组织和性能

通过两阶段控轧和随后的三段冷却,获得了14mm厚的Nb-Ti微合金化热轧多相钢板.利用光学显微镜、扫描电镜、透射电镜、X射线衍射(XRD)、电子背散射衍射(EBSD)和力学性能测试等手段对其组织和性能进行了研究.结果表明,试验钢的显微组织由铁素体、贝氏体和少量马氏体组成;其平均屈服强度为518MPa,抗拉强度为616MPa,延伸率高达41%;组织中大量的铁素体大角度晶界、近似等轴状铁素体晶粒和较小尺寸贝氏体束的存在,大大提高了试验钢的塑性;铁素体和贝氏体组织的细化,细小的(Nb,Ti)C粒子以及铁素体晶粒和贝氏体板条内的位错提高了试验钢的强度.

热轧温度参数对Nb-Ti和Nb-V微合金钢力学性能的影响

设计了650 MPa级的Nb-Ti和Nb-V微合金钢的化学成分。采用正交实验方法考察了加热温度、终轧温度和终冷温度对这2种钢力学性能的影响。实验结果表明,加热温度和终冷温度是影响Nb-Ti和Nb-V钢力学性能的主要因素。2种钢的伸长率与屈服强度以及屈强比与屈服强度之间都具有明显的相关关系。

薄板坯连铸连轧工艺生产的Nb、Ti复合微合金化热轧带钢的强化机制

对具有高、低屈服强度的薄板坯连铸连轧工艺生产的Nb、Ti复合微合金化钢的热轧板进行了组织分析,研究了强化机制.组织分析表明,板卷均为铁素体组织.但具有高屈服强度的板卷铁素体呈现出非多边形特征,位错密度较高,晶粒明显小于低屈服强度的板卷.两类板卷中的复合型星形析出物较多,平均尺寸140—150 nm,消耗了钢中50%的Nb.强化机制研究表明,铁素体晶粒细化强化是主要强化机制,占总屈服强度的(43—46)%;两类板卷的析出强化效果微弱,只占总屈服强度的(4—6)%.位错强化与晶粒细化强化是板卷具有高屈服强度的原因.

V-Ti微合金钢热变形过程中复合微合金析出相的形成机制

通过对V-Ti微合金钢平衡析出相的微合金含量的热力学预测以及对热变形过程中析出相的电镜观察和能谱分析,研究了热变形过程中微合金析出相的组成及其形成机制。结果表明,奥氏体热变形过程中的微合金析出相自从基体中沉淀出来,就是复合析出相(Ti,V)(C,N),并且随形变温度的降低,复合析出相(Ti,V)(C,N)中Ti含量减少而V含量增多,析出相的成分存在一定差异。

Nb-Ti微合金化对热轧0.5~0.7Cr铲斗刀板型钢组织和性能的影响

试验0.5~0.7Cr铲斗刀板型钢（/%：0.22~0.30C,0.25~0.45Si,0.95~1.20Mn,0.006~0.009P,0.008~0.010S,0.5~0.7Cr,0.015~0.065Nb,0~0.040Ti）由50 kg真空感应炉熔炼,热轧成16 mm厚板,终轧温度850~900℃,空冷。通过光学显微镜、扫描、透射电镜和力学性能测试研究了Nb-Ti含量（0.015Nb,0.035Nb-0.010Ti,0.065Nb-0.040Ti）对热轧态铲斗刀板钢组织和力学性能的影响。结果表明,试验钢组织为F＋P,随Nb-Ti含量增加,钢板的晶粒细化,珠光体片层间距降低,（Nb,Ti）C和（Nb,Ti）（C,N）析出物增多,强度增加,0.065Nb-0.040Ti钢板的力学性能为屈服强度632 MPa,抗拉强度916 MPa,延伸率17.7%,K_（AV）40 J,HB硬度值234。

Development of Ti–V–Mo Complex Microalloyed Hot-Rolled 900-MPa-Grade High-Strength Steel

A new Ti-V-Mo complex microalloyed hot-rolled high-strength steel sheet was developed by controlling a thermo-mechanical controlled processing （TMCP） schedule, in particular with variants in coiling temperature. The effects of coiling temperature （CT） on various hardening mechanisms and mechanical properties of Ti-V-Mo complex mi- croalloyed high-strength low-alloy steels were investigated. The results revealed that the steels are mainly strengthened by a combined effect of ferrite grain refinement hardening and precipitation hardening. The variation in simulated coiling temperature causes a significant difference in strength, which is mainly attributed to different precipitation hardening increment contributions. When the CT is 600 ℃, the experimental steel has the best mechanical properties： ultimate tensile strength （UTS） 1000 MPa, yield strength （YS） 955 MPa and elongation （EL） 17%. Moreover, about 82 wt% of the total precipitates are nano-sized carbide particles with diameter of 1-10 nm, which is randomly dispersed in the ferrite matrix. The nano-sized carbide particles led to a strong precipitation hardening increment up to 310 MPa.

含Ti和含V低碳结构用微合金钢轧制工艺特点的比较

分析了影响微合金钢组织性能的主要物理冶金因素 ;比较了含Ti和含V的低碳结构用微合金钢在轧前加热、热轧过程、轧后冷却及冷轧退火方面工艺特点的差别。

Effect of Cooling Patterns on Microstructure and Mechanical Properties of Hot-Rolled Nb Microalloyed Multiphase Steel Plates

The effect of the run-out table cooling patterns on the microstructure and mechanical properties of Nb microalloyed steel plates was investigated by hot rolling experiment. The results showed that the mixed microstrueture containing ferrite, bainite and significant amounts of retained austenite can be obtained through three kinds of cooling patterns on the run-out table under the same hot rolling condition. Three kinds of cooling patterns possess different austenite transformation kinetics, which leads to variations in microconstituent characteristics. The yield strength increases, the tensile strength decreases and the total elongation tends to increase as the cooling patterns Ⅰ , Ⅱ and Ⅲ were applied respectively. The yield strength, the total elongation and the product of tensile strength and ductility reach the maximum values （547 MPa, 37. 2% and 28 384 MPa% respectively） for the steel plate processed by cooling pattern Ⅲ.

500MPa级Nb-Ti微合金化方矩形管用钢的开发及其强化机制

采用光学显微镜和透射电子显微镜等对500MPa级Nh—Ti微合金化方矩形管用钢的组织与性能进行了分析，研究了其强化机制。结果表明，终轧温度和卷取温度对试验钢的组织和力学性能有显著影响，当卷取温度不变时，随着终轧温度的下降，屈服强度、抗拉强度和断后伸长率均升高；当终轧温度不变时，随着卷取温度逐渐下降，屈服强度和抗拉强度呈现出先上升后下降的规律，而断后伸长率呈现出单调上升的规律；试验钢在终轧温度为840℃和卷取温度为570℃时可获得最优的综合力学性能，其屈服强度和抗拉强度分别为537，578MPa，断后伸长率为33．5％；细晶强化是试验钢最主要的强化机制，由晶粒细化引起的强度增量占总强度的49％～51％，由固溶强化引起的强度增量次之，占总强度的23％～27％，由析出强化引起的强度增量较小，仅占总强度的3．8％～8．2％。

Q420C角钢钒钛微合金化工艺研究

采用不同V系、V-Ti系微合金化成分设计的Q420C级电力角钢进行工业试制,并进行力学性能检验、金相分析、JMatPro以及电解化学相分析。结果表明,V-Ti微合金系,Ti元素全部析出,Ti先与N结合生成TiN,钢中剩余的N含量较少,降低了V的析出驱动力,导致V元素析出率较低,析出率仅约30%;Ti的加入改变了V的析出形式,部分V在TiN上形核长大,粗化了析出相尺寸,析出物尺寸大多大于20 nm,其析出物基本上不起析出强化作用,V-Ti系角钢的析出强化效果不及V系角钢。通过研究和构建角钢多元纳米相的层次化析出与竞争析出理论基础,为电力角钢成分设计及工艺控制提供理论依据。

Microstructure and mechanical properties of hot-rolled low-carbon steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ

The effect of inclusion-induced nucleation on hot-rolled steel base metal was evaluated in comparison with welding heataffected zone(HAZ).Microstructure and mechanical properties of hot-rolled low-carbon steel containing Ti–Ca oxide particles were studied.The results showed that inclusions in Ti–Ca deoxidized steel distributed dispersely and were effective for intragranular acicular ferrite nucleation.Under hot rolling and controlled cooling conditions,microstructure in steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite,which exhibited higher strength and excellent toughness.The microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain,intragranular bainite packets formed between interlocking acicular ferrite plates,and the remaining austenite decomposed into fine polygonal ferrite grains.The resultant complex microstructure improved the impact toughness significantly.By comparison,in HAZ microstructure,laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

热浸镀锌对Nb-Ti微合金化S550GD+Z钢力学性能的影响

采用TEM、EBSD、物理化学相分析等技术分别对Nb-Ti微合金化S550GD+Z钢热轧板及热浸镀锌板的显微组织、析出相和强化机理进行分析,研究了微合金钢板镀锌后强度提升的机理。结果表明:拉伸测试得出镀锌板较热轧板的屈服强度提升约34.6 MPa,其中锌层强度增量贡献约15 MPa;通过计算得出镀锌板较热轧板的固溶强化增量、细晶强化增量、位错强化增量、析出强化增量、锌层强度增量提供的综合强度提升约47.8 MPa。锌层强度增量是Nb-Ti微合金化S550GD+Z钢板镀锌后强度提升的主要原因。

终轧温度和轧后冷却对含钛微合金钢屈服强度的影响

用ＴＨＥＲＭＥＣＭＡＳＴＯＲ－７试验机模拟热连轧生产，研究终轧温度和轧后冷却工艺对含钛微合金钢性能的影响。用轧后立即快冷工艺时，快冷中止温度和卷取温度影响钢的沉淀强化组分，而对晶界强化组分无影响；终轧温度、轧后延迟快冷开始温度对钢的沉淀强化组分和晶界强化组分都有影响。给出了相应的强化组分定量估计公式。

热轧含钒微合金钢在加速冷却条件下的强化因素

讨论了含钒微合金钢在热轧及加速冷却条件下终轧温度、终冷温度、冷却速度对钢的力学性能的影响。加速冷却含钒钢的显微组织为细小的多边形铁素体和粒状贝氏体组织，由此获得相变强化。钒引起的碳化物析出强化，在加速冷却条件下得到加强，这是由于生成了大量的弥散细小的析出物，并且析出强化效果在６００℃冷却条件下最大。

卷取温度对钛微合金化钢组织与性能的影响

与铌钒微合金化钢相比,钛微合金化钢有更低的成本,因此设计了一种低碳钛微合金化热轧高强钢,并利用扫描电镜(SEM)和透射电镜(TEM)等仪器研究了不同卷取温度对实验钢组织和性能的影响.结果表明:卷取温度对实验钢的组织与力学性能有较大的影响,300℃卷取时得到板条贝氏体和粒状贝氏体的混合组织,400和470℃卷取时得到粒状贝氏体组织;实验钢的屈服强度和抗拉强度均随卷取温度的升高呈现出先下降再上升的规律,延伸率呈现出先升高再下降的规律,分析认为力学性能的变化主要由相变强化、析出强化以及M-A岛的尺寸和形态共同决定;470℃卷取时实验钢有较好的综合力学性能,屈服强度和抗拉强度分别达到了700和865 MPa,延伸率达到了18.9%.

刮板输送机中锰钢中部槽的自强化抗磨机理及应用

针对煤矿刮板输送机中部槽的耐磨难题,研究了热轧中锰耐磨钢和马氏体耐磨钢的冲击磨损性能,分析了中锰钢的自强化耐磨机理,介绍了中锰耐磨钢在煤矿刮板输送机中部槽的应用实例。试验结果表明,热轧中锰钢比传统马氏体耐磨钢表现出更好的抗冲击磨料磨损性能,磨损表面硬化层厚度约1 000μm,最高显微硬度达531HV,对应的洛氏硬度达52HRC,表现出优良的耐磨强化效果。研究发现,中锰耐磨钢的耐磨强化机理随冲击功的不同而变化,由较低冲击功的马氏体相变、位错和层错复合强化机制,演变为较高冲击功时的马氏体相变、位错和形变孪晶复合强化机制。实际应用表明,热轧改性中锰耐磨钢的抗磨损性能优于Hardox450耐磨钢,可显著降低中部槽磨损,大幅度延长刮板输送机可靠运行寿命。

外加陶瓷颗粒细化低碳微合金钢晶粒

真空条件下,在低碳微合金钢中加入微米级ZrC陶瓷颗粒,使其成为钢在热轧时奥氏体的形变核心及其形变诱导铁素体的再结晶核心以细化晶粒.研究了添加不同体积分数ZrC粒子对低碳微合金钢组织和力学性能的影响.结果表明,通过本实验研究出的颗粒外加方式可使ZrC颗粒有效分散于钢中,对钢的组织产生明显的细化作用,可使钢的晶粒细化到5.5μm,钢的强度得到较大幅度的提高,钢的显微组织为铁素体.当加入ZrC颗粒的体积分数为1.1%时,可获得最佳综合力学性能.