Controlled Rolling and Cooling Process for Low Carbon Cold Forging Steel

Effect of controlled rolling and cooling process on the mechanical properties of low carbon cold forging steel was investigated for different processing parameters of a laboratory hot rolling mill. The results show that the specimens with fast cooling after hot rolling exhibit very good mechanical properties, and the improvement of the mechanical properties can be attributed mainly to the ferrite-grain refinement. The mechanical properties increase with decreasing final cooling temperature within the range from 670 ℃ to 570 ℃ due to the finer interlamellar spacing of pearlite colony. The specimen with fast cooling after low temperature rolling shows the highest values of the mechanical properties. The effect of the ferrite grain size on the mechanical properties was greater than that of pearlite morphology in the present study. The mechanical properties of specimens by controlled rolling and cooling process without thermal treatment were greatly superior to that of the same specimens by the conventional rolling, and their tensile strength reached 490 MPa grade even in the case of low temperature rolling without controlled rolling. It might be expected to realize the substitution medium-carbon by low-carbon for 490 MPa grade cold forging steel with controlled rolling and cooling process.

EFFECT OF THE CONTROLLED ROLLING CONTROLLED COOLING ON STRENGTH AND DUCTILITY OF THE BAINITE MICRO ALLOYED ENGINEERING STEEL

The continuous cooling transformation of hot deformation austenite austenite of test steel and the effect of different processing schedules of controlled rolling and controlled cooling on the strength and ductility have been studied. The theory and the experiment base are presented for controlled rolling and controlled cooling of the SBL micro alloyed engineering steel.

Influence of Controlled Rolling and Cooling Process on the Mechanical Properties of Low Carbon Cold Forging Steel

In the present paper,controlled rolling and cooling processing was conducted by using a laboratory hot rolling mill.The influence of different processing parameters on the mechanical properties of low carbon cold forging steel was investigated.The results show that the faster cooling after the deformation (especially in low temperature rolling conditions) leads to the refinement of the ferrite grain.The specimen exhibits very good mechanical properties owing to the finer ferrite grains.The pearlite morphologies can also affect the mechanical properties of low carbon cold forging steel.The mechanical properties increase with decreasing final cooling temperature within the range from 650℃ to 570 ℃ due to the finer interlamellar spacing of pearlite colony.The mechanical properties of the specimens with fast cooling after the conventional rolling are not only better than those of the specimens with slow cooling after low temperature rolling,but also almost similar to those of the specimens with fast cooling after low temperature rolling.It is suggested that fast cooling after high temperature rolling (the conventional rolling) process would be of important industrial value.

Effect of controlled rolling/controlled cooling parameters on microstructure and mechanical properties of the novel pipeline steel

The study of controlled rolling/controlled cooling process parameters which affect the microstructure and mechanical properties of a novel pipeline steel has been optimized by the orthogonal experiment with four factors and three levels in this paper. However, the parameters of thermo-mechanical control process （TMCP） optimized by the Gleeble-3500 hot simulator could not satisfy performance requirements of the X100 pipeline steel. In order to improve the performance of this steel, the influence of finish cooling temperature （FCT） on the microstructure and property is studied in detail. It is found that, as this steel is thermo-mechanically treated by this set of parameters （the start heating temperature, finish rolling temperature （FRT）, FCT and cooling rate of 1,180 ℃, 810 ℃, 350 ℃ and 35 ℃/s, respectively）, the micro- structures are mainly composed of granular bainite （GB） and acicular ferrite （AF）. The effective grain sizes are below 20 μm; the steel reaches the optimal balance between the strength and the toughness; the yield strength is 695 MPa; the tensile strength is 768 MPa; the elongation is 16.6 %; the impact energy is 262 J at room temperature. All indexes could meet the requirements of X100 pipeline steel.

以TPCP工艺开发690MPa级超低碳贝氏体钢

采用Mn-Ni-Cu -B系合金 ,在 4 2 0 0mm轧机上实行Ⅲ型控轧 ,以ACC装置进行轧后冷却 ,开发出超低碳贝氏体钢 (ULCB) 5 0mm厚板。其抗拉强度达到 70kg级 ,低温冲击性能优良。这为开发

Research on TMCP technology for the manufacture of SUS 304 L austenitic stainless steel plates

Two thermo-mechanical controlled processes （TMCP） including controlled rolling and accelerated cooling are proposed for the production of heavy gauge SUS 304 L austenitic stainless steel plates with different strengths and other characteristics. Based on the recrystallization mechanism and carbide precipitation behavior of SUS 304 L austenitic stainless steel ,TMCP provides a powerful means to control the microstructure and precipitation of the hot rolled steel plate by the controlled rolling and accelerated cooling process. The dislocation density and grain size are the main factors in determining the strength of the stainless steel plates. Therefore ,it is necessary to strictly control the hot rolling parameters, including parameters such as the finish hot rolling temperature in the recrystallization temperature region and the total reduction in the non-recrystallization region. Furthermore, in order to avoid carbide precipitation and guarantee the intergranular corrosion resistance of TMCP SUS 304 L austenitic stainless steel, a critical cooling rate after rolling is determined.

L360N无缝管线钢管的控轧控冷生产工艺开发

某PQF连轧管机组生产Ф273 mm×8 mm规格L360N无缝管线钢管时,采用常规热轧、控制轧制、控制轧制+控制冷却三种方式组织生产,分析了这三种工艺生产的无缝钢管的性能与组织差别。工业试验表明,控制轧制+控制冷却可以明显细化晶粒,在提高钢管拉伸性能的同时,可大幅提高钢管的冲击韧性,合理的控轧控冷工艺可使钢管稳定满足-30℃冲击值的要求。

Effect of Rolling Process on Microstructure and Properties of 95CrMo Drill Steel

In order to improve the strength and toughness of 95CrMo steel and explore a short flow process, a direct rolling process was employed, and the effect of finishing rolling process on microstructure and mechanical properties was investigated. The results show that, with the decrease of finishing rolling temperature, inter-lamellar spacing in- creases, the strength as well as hardness has a general increase, and secondary cementite is distributed uniformly but represents a remarkable decrease in size. Based on Hall-Petch type equation, an effective relationship of yield strength and pearlite structure parameters was established. The correlation coefficients between the measured and calculated strength were more than 0.95, which indicated a high reliability of the relationship. By analyzing the individual strength contributions of pearlite structures, yield strength was found to have a more great dependence on pearlite inter-lamellar spacing than colony size.

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。

非调质27CrMn2VS钢的开发及工业生产实践

非调质钢由于市场的需要而在机械、汽车、风电等领域得到广泛应用,在欧美和日本等发达国家的非调质钢生产水平成熟且应用普及率较高,但在中国发展较晚、应用率偏低且进口率高。通过对化学成分、生产工艺流程(80 t转炉→LF精炼→VD真空→连铸)的设计,得到了一种工程机械用非调质27CrMn2VS钢(/%:0.22~0.35 C,0.20~0.40 Si,1.50~2.50 Mn,0.035~0.065 S,0.35~0.65 Cr,0.05~0.15 V)。工业生产通过使用P≤0.15%,S≤0.35%的铁水、LF精炼3批次喂S线,连铸过程采用电磁搅拌+轻压下的工艺,终轧后轧材入缓冷坑缓冷,获得的显微组织为贝氏体(占比78~88%)+珠光体+铁素体,非金属夹杂物级别A细≤2.5级、A粗≤2.0级、B细≤1.0级、B粗≤1.5级、C类≤0.5级、D类≤0.5级、Ds≤0.5级,屈服强度1020~1050 MPa、抗拉强度820~850 MPa。连续生产5炉的化学成分稳定、洁净度高、内部质量和表面质量极好,可用于替代部分传统'调质钢。

农用收割机滚筒用440MPa冷轧钢带的研发与制备

针对农用收割机滚筒制造用钢提出的母材均质化、高强度、易成型的质量提级需求,采用低碳、低硅、高锰,加铌、钛的微合金化成分设计,配合控轧控冷及罩式退火工艺,成功研制开发了农用收割机滚筒用440MPa冷轧钢带。所得冷轧退火钢带组织以铁素体+点状(部分球状)渗碳体为主,屈服强度≥350MPa,抗拉强度≥450MPa,断后伸长率≥27%,钢带综合性能较好,保证强韧性的基础上,兼顾较好的折弯成型及焊接性,实现了低成本、高性能农用车制造专用钢带的批量制备,满足农用收割机滚筒制造加工要求。

65钢热轧盘条脱碳分析与控制

基于JMatPro软件计算65钢的相变点Ac_(1)、Ac_(3)及其奥氏体化温度,研究铸坯脱碳、加热工艺和控轧控冷工艺对热轧盘条的影响,通过测定铸坯脱碳层深度并绘制连续冷却转变曲线(CCT),确定最优工艺参数。结果表明,65钢坯修磨深度应控制在1 mm以内,加热温度应控制在950~1050℃,除鳞压力应控制在18 MPa以上,终轧温度应控制在800~830℃,吐丝温度应控制在800~850℃,风冷线辊道速度应控制在0.7~0.8 m/s,经轧制后∅5.5 mm成品盘条未见全脱碳,且总脱碳层深度为0.03 mm,满足产品的脱碳要求(总脱碳≤0.044 mm)。

浅谈皖西某钢厂中厚板生产线的特点

随着经济全球化的推进,中厚板在工业制造领域的应用越来越广泛。我国的中厚板生产线主要在2000年及以后投产,以生产普通中厚板为主,缺乏高性能中厚板产品。因此,皖西某钢铁集团为推动高端产品生产线的发展,采用国内某冶金设备工程公司的先进技术和设备,建设全新的3500 mm双机架中厚板生产线,为丰富国内钢铁产品种类和推动行业发展做出积极的贡献。

控轧控冷工艺对低碳铌微合金钢组织和性能的影响

用Gleeble-1500热模拟实验机测定了低碳铌微合金钢变形后的连续冷却转变曲线（CCT曲线），并在实验室对该实验钢采用不同的工艺进行了控制轧制和控制冷却的实验。研究了工艺参数对实验钢力学性能和微观组织的影响，分析了低碳铌微合金钢的强韧化机制。热模拟实验结果表明，实验钢在较宽的冷却速度范围（0．5～30℃／s）内可以获得贝氏体组织。控轧控冷的实验结果表明，实验钢的组织主要为铁素体和贝氏体。随着终轧温度的降低，组织得到细化，强度提高，但屈强比也随之增加；降低卷取温度使组织中的贝氏体含量略有增加，强度有所提高。初步探讨了贝氏体对实验钢性能的影响，为制定合适的生产工艺制度提供了依据。

X70管线钢控轧控冷工艺与组织性能的关系

X70管线钢中针状铁素体的比例随热变形后的冷却速度增加而提高,冷却速度为15 ℃/s时达到最大,冷却速度再增加,该比例变化不大.冷却速度较低时(2 ℃/s)和热变形后的终冷温度较高时(650 ℃)组织中出现珠光体.随着终冷温度的降低,试验钢的组织细化,在500～550 ℃终冷时组织较为理想.铁素体晶内弥散分布有尺寸为20 nm左右的析出相,析出相在位错处择优成核并与基体保持共格或半共格关系.

X80管线钢的研究进展

介绍X80管线钢的应用、化学成分特点、组织结构以及控轧控冷工艺在生产该钢种中的应用。还简述了X80管线钢对焊接的特殊要求。

控轧控冷生产中高碳钢高速线材组织和性能的预测模型

建立了高碳钢高速线材在控制轧制和控制冷却生产中组织转变和力学性能的预测模型。该模型分为再结晶、相变、组织和力学性能四部分 ,分别考虑了在控轧控冷过程中的各种冶金现象。该模型的预测结果与现场实际测量结果比较一致 。

控轧控冷工艺对Nb-V钢的组织性能析出行为的影响

采用光学、电子显微技术和力学分析等方法 ,系统地研究了不同控轧控冷条件对铌钒复合微合金化低碳热轧钢板的组织和性能的影响规律 ,提出了较佳的控轧控冷工艺参数 。

热轧H型钢的在线控冷

针对H型钢轧制中的一些问题,设计了H型钢在线控冷装置。此装置采用气雾冷却方式,着重对H型钢R部进行快速冷却,冷速达100℃/s以上。试验结果表明,产品表面状态改善,晶粒细化,屈服强度和抗拉强度均提高21 MPa以上且断面性能均匀。轧件上冷床温度降低,生产效率提高,年产量达到预定产能的2倍以上且节省原冷床上风机的消耗。

低碳钢热轧钢筋再结晶控制轧制与控制冷却实现晶粒细化

低碳钢低的再结晶温度使得其在钢筋的连续轧制过程中可以通过再结晶控制轧制及控制冷却工艺来实现晶粒细化。试验结果表明 ,成分为 0 .18C- 0 .2 2 Si- 0 .6 0 Mn的低碳碳素钢在 85 0℃或更低温度以较大的变形量变形时 ,可以获得 10～ 2 0μm的奥氏体晶粒尺寸 ;当加以 2 0℃ / s或更高的冷却速度冷却时 ,可以得到 4～ 6μm或更细小的铁素体晶粒尺寸。晶粒细化使得钢筋的力学性能明显提高。