奥氏体未再结晶区变形对06Mn2SiCrB热轧双相钢CCT曲线的影响

通过模拟４ｍｍ热轧板的最后４道精轧工序，测定了０６Ｍｎ２ＳｉＣｒＢ热轧双相钢的动、静态ＣＣＴ曲线，对比得出：Ｄ 未再结晶区变形，将产生明显的形变诱导作用，使ＣＣＴ曲线中铁素体析出线向左上方移动，珠光体析出线向右上方移动，贝氏体析出终了线左移，钢的ＣＣＴ曲线上铁素体、马氏体二相分离型相变的冷却速度范围变宽。     

低碳钢奥氏体未再结晶临界温度Tnr的实验测量

根据国内外研究成果，用先进的Ｇｌｅｅｂｌｅ－２０００热模拟试验机测量了低碳钢奥氏体未再结晶临界温度Ｔｎｒ。实验结果表明，经验计算得出的Ｔｎｒ与实测值相当吻合，可推广应用到其它低合金钢或微合金钢的研究中，对马钢控轧控冷的理论的应用和推广具有重要意义。     

奥氏体未再结晶区变形对连续冷却时相变影响的预测

以热力学软件Thermo-Calc所得到的热力学参数为基础，编制了一个对奥氏体连续冷却时的相变进行分析的程序。这一程序可以用于预测奥氏体非再结晶区变形并以不同速率冷却时的转变过程及最终组织。实验计算所得到的静态、动态CCT曲线与实验数据比较吻合。     

形变量对含Nb钢奥氏体未再结晶临界温度的影响

利用热模拟试验机的多道次压缩变形测量含Nb微舍金化钢的应力应变，研究了含Nb微合金化钢在不同温度下的平均流变应力的变化规律，确定了含Nb微舍金化钢的未再结晶临界温度Tnr，分析了多道次变形过程中道次应变量对Tnr的影响。试验结果表明：当道次应变量为0．2～0．4时，含Nb微舍金化钢的Tnr在978．8℃～998．9℃，Tnr随道次应变量的增加而降低。     

热变形参数对含铌钢奥氏体未再结晶区变形相变的影响

利用Thermecomastor-Z热模拟试验机,研究了铌质量分数为0.128%的微合金低碳钢在奥氏体未再结晶区变形及连续冷却过程的相变,分析了变形温度、变形速率、变形量等热变形参数对相变的影响规律.研究表明,在连续冷却条件下,随着冷却速度的增加,相转变开始点降低,当冷却速率大于5℃/s时,90%以上的组织为粒状贝氏体.变形温度的升高、变形量及变形速率的增加对相变有促进作用.     

C-Mn超级钢的工业化生产和应用

以屈服强度为200 MPa级的普碳钢为基本成分,采用成分微调与控轧控冷工艺相结合的技术路线,可将屈服强度提高到400～500MPa,同时保证良好的综合性能.产品应用于汽车、建筑等行业,取得了用户降低成本,生产厂多获效益的双赢效果.介绍了G-Mn钢轧制过程组织变化、超级钢生产和应用等方面取得的研究成果.     

未再结晶区控轧工艺对HQ60钢的显微组织与力学性能的影响

研究了未再结晶区的不同压下率对含Ｎｂ－Ｖｉ的ＨＱ６０低合金钢的组织和性能的影响。结果表明，当未再结晶区的累计压下率由４０％提高到７０％时，ＨＱ６０钢的晶粒由４．８５μｍ细化到２．７７μｍ，强度和韧性都有较大提高，使得这种由铁素体、贝氏体和珠光体等复相组织组成的钢的强韧性得到了改善。     

采用包晶区以上含碳量在薄板坯连铸连轧生产线上开发CCSB船板钢

介绍了CCSB开发过程中如何充分利用薄板坯连铸连轧工艺和设备优势,通过化学成分和控轧控冷工艺的合理设计,来保证产品的性能,特别是低温韧性。同时通过对产品的组织和性能的分析及介绍,表明本钢开发的CCSB完全满足船用钢板的使用要求,并获得了中国船级社的工厂认可。     

奥氏体未再结晶区变形对铁素体晶粒尺寸影响的数值计算

以软件Thermo-Calc所得到的热力学参数为基础，并考虑变形存储能的影响，编制了一个奥氏体连续冷却却相变分析程序，它可用于预制奥氏体非体结晶区变形和以不同冷却速度冷却时的转变过程中及最终组织，利用这一程序的计算结果与实验数据比较吻合。     

采用控轧控冷工艺生产车轮用轮辐钢板

通过1700 mm热连轧机组对轮辐钢(%:0.09C、0.12Si、0.98Mn、0.010P、0.005S、0.010Nb、0.04Als)进行830～890℃终轧温度和620～680℃卷取温度的轧制试验。结果表明,板坯加热温度1230～1250℃、终轧温度(870±15)℃、卷取温度(660±15)℃生产的车轮用轮辐钢板的组织为细铁素体加少量的珠光体,屈服强度335～380 MPa,抗拉强度430～485 MPa,伸长率26%～31%,每卷带钢的纵向强度差为13～37 MPa,在车轮制作过程中冲压成型良好,冲废率小于0.3%。     

宝钢特殊钢分公司长型材轧钢生产线的新工艺和新技术

不锈钢长型材生产线是宝钢特殊钢分公司调整产品结构、淘汰落后工艺的标志工程,是集中当代先进工艺流程和装备水平的不锈钢、特殊钢专业生产线.文章介绍了轧钢生产线工艺流程、特点和新工艺、新技术应用.     

Effect of Deep Cryogenic Treatment on Formation of Reversed Austenite in Super Martensitic Stainless Steel

The effect of deep cryogenic treatment on the formation of reversed austenite(RA)in super martensitic stainless steel was investigated.RA was found to form in steels without(A)and with(B)deep cryogenic treatment.The volume fraction of RA initially increased and then decreased with increasing tempering temperature over 550-750 ℃for the two steels,which were quenched at 1 050 ℃.In addition,for both with and without deep cryogenic treatment,the RA content reached a maximum value at 650 ℃ although the RA content in steel B was greater than that in steel A over the entire range of tempering temperatures.Furthermore,the hardness(HRC)of steel B was greater than that of steel A at tempering temperatures of 550-750 ℃.From these results,the basic mechanism for the formation of RA in steels A and B was determined to be Ni diffusion.However,there were more Ni-enriched points,a lower degree of enrichment,and a shorter diffusion path in steel B.It needed to be noted that the shapes of the RA consisted of blocks and stripes in both steels.These shapes resulted because the RA redissolved and transformed to martensite along the martensitic lath boundaries when the tempering temperature was 650-750 ℃,and a portion of RA in the martensitic lath divided the originally wider martensitic laths into a number of thinner ones.Interestingly,the RA redissolved more rapidly in steel B and consequently resulted in a stronger refining effect.     

Formation of Reversed Austenite in High Temperature Tempering Process and its Effect on Mechanical Properties of Cr15 Super Martensitic Stainless Steel Alloyed with Copper

Formation mechanism of the reversed austenite of Cr15 super martensitic stainless steel (SMSS) alloyed with copper after high temperature tempering was investigated by means of thermo‐calc software, transmission electron microscope (TEM), and X‐ray diffraction (XRD). The mechanical properties of the SMSS were also tested. The experimental results show that the reversed austenite with low dislocation density is formed at high temperature tempering processing. The transformation of the martensite to reversed austenite is a diffused phase transformation, and the growth of the reversed austenite is closely related to the diffusion process of Ni. The bulk reversed austenite with large amount of stacking faults is formed with the increase of the tempering temperature. The volume fraction of reversed austenite increases at first and then decreases with increasing tempering temperature, and the maximum amount of the reversed austenite is obtained at 650°C. The reversed austenite is unstable at the tempering temperature above 650°C and the martensitic phase transformation will occur at the following cooling process. The mechanical properties of Cr15 super martensitic stainless steel are significantly influenced by the volume fraction of reversed austenite.     

Q345钢在直轧过程中二相粒子析出对奥氏体晶粒的影响

通过热模拟轧制技术,研究了不同工艺条件下二相粒子析出物对奥氏体再结晶的影响,并对Q345钢直接轧制工艺中C,N化物的析出对组织性能的影响进行了深入探讨.结果表明,利用二相粒子析出可以细化奥氏体晶粒组织,从而改善钢的内部组织和材料的力学性能.     

Effect of Heat Treatment on Reversed Austenite in Cr15 Super Martensitic Stainless Steel

 The effect of different heat treatments on the reversed austenite in Cr15 super martensitic stainless steel was investigated. The experimental results indicate that the microstructure of the steel is composed of tempered martensite and diffused reversed austenite after quenching at 1050 ℃ and tempering from 550 to 750 ℃. The volume fraction and size of reversed austenite increase with increasing tempering temperature and both of them reach the maximum value at 700 ℃. The volume fraction and size of reversed austenite decrease when the temperature is above 700 ℃. The transmission electron microscope (TEM) results indicate that the orientation relationship between tempered martensite and reversed austenite belongs to Kurdjmov-Sach (K-S) relationship.     

耐候钢变形奥氏体的连续冷却转变

采用膨胀法结合金相分析建立了耐候钢变形和未变形奥氏体的连续冷却转变曲线（CCT曲线）.试验钢变形奥氏体的CCT曲线具有较宽的铁素体析出区,即有较宽的＂速度窗口＂;铁素体区与贝氏体区之间有60～80 ℃的奥氏体稳定区,可作为＂卷取窗口＂;贝氏体转变区的右侧端部封口等.所有这些特征为热轧生产双相钢提供了基本条件.     

热轧船板钢时奥氏体相变的规律

通过对现场轧制工艺的模拟,借助热加工模拟试验机研究了变形量、变形温度及变形后的冷却速度,对一般强度船板钢变形奥氏体向铁素体和珠光体转变的影响。实验结果表明:增加变形量,降低变形温度,减缓冷却速度可在不同程度上促进奥氏体向铁素体和珠光体的转变。     

FTSR线铁素体轧制低碳钢板的组织性能分析

对FTSR线采用铁素体轧制工艺生产的3.0 mm低碳钢板进行了微观组织分析和力学性能测定.结果表明,FTSR薄板坯连铸连轧生产线可以实现用铁素体轧制工艺生产低碳钢板,运用此工艺生产的3.0 mm低碳钢板组织为不均匀的铁素体,平均晶粒尺寸约29μm,铁素体晶粒的边界存在少量片层间距约几十纳米的珠光体组织;钢板的屈服强度为215～240 MPa,抗拉强度为305～335 MPa,伸长率为33%～41%,比采用奥氏体轧制工艺生产的钢板强度低且延伸性好;室温下钢板的冷弯性能、成形性能及冲击韧性等都较为优良.