PSB785精轧螺纹钢控冷轧制工艺实践

为使PSB785精轧螺纹钢筋强度与塑性相匹配,采用以下工艺:(1)钢坯加热出炉温度为960～1 020℃,开轧温度为970℃;(2)轧件进精轧机温度为850～890℃,钢筋的终轧温度为930～1 000℃,自回火温度为680～700℃;(3)上冷床温度为560～600℃。采用设计工艺生产的25,32 mm PSB785精轧螺纹钢筋的抗拉强度为1 021～1 055MPa,延伸率为8.5%～9.6%,金相组织为珠光体+铁素体,晶粒度为9.0～9.5级,穿水层为回火索氏体,穿水层深度为1.24～1.46 mm,符合GB/T 20065—2006《预应力混凝土用螺纹钢筋》,可满足用户的使用要求。

水性高温阻锈剂在控冷轧制工艺中的应用

介绍了水性高温阻锈剂的原理与特性和在线穿液装置的设计原理、要点和结构特点,经工业化生产应用,证明有较强的阻锈效果,有广阔的应用前景。

控冷轧制对HRB400E热轧带肋钢筋性能的影响

生产钢筋混凝土用HRB400E热轧带肋抗震钢筋时,钒铁和锰铁合金用量占有较大比率对钢材成本的影响很大.为寻求一种可以减少合金元素的替代方法,以降低成本,进行了控冷轧制工艺生产HRB400E热轧带肋抗震钢筋性能试验研究.结果表明采用控冷轧制工艺可以提高钢筋的屈服强度70-100MPa,而且能够改善产品表面质量.在产品质量性能满足国家标准要求的情况下,试验的HRB400E热轧带肋抗震钢筋吨钢降低合金成本60元左右.

线材水冷过程优化控制模型

在分析了钢坯出炉后热过程特点的基础上 ,建立了线材控冷轧制热过程数学模型 ,提出了“前馈+反馈”的温度控制方式。实际运行结果表明 :该控制方式能够合理地控制水箱水流量 ,从而确保线材水箱出口处的温度满足工艺要求 ,大大提高线材成品的质量。

硬线钢盘条优化工艺生产实践

首钢水钢公司通过对硬线钢的成分及轧制工艺优化，减少了盘条性能波动，提高了塑性拉拔性能，产品各项性能指标全部满足用户拉拔制作钢丝及钢绳要求，提高了产品质量，增强了公司硬线钢产品的竞争力。

Dynamic characteristics of cold rolling mill and strip based on flatness and thickness control in rolling process

The dynamic model of cold rolling mill based on strip flatness and thickness integrated control was proposed,containing the following sub-models:the rolling process model,the dynamic model of rolls along axial direction,and the compensation model.Based on the rule of volume flow rate,the dynamic rolling process model was built.The work roll and backup roll were taken as elastic continuous bodies,the effect of shear and moment of inertia were taken into consideration,and then the dynamic model of rolls was built.The two models were coupled together,and the dynamic model of rolling mill was built.In the dynamic model,the thermal expansion of the rolls,the wear of the rolls and other related parameters can not be considered.In order to compensate the dynamic model,the coupled static model of rolls and strip was applied.Then,according to the inner relationship of these models,the dynamic model and the compensation model were coupled,and the dynamic model of rolling mill based on the strip flatness and thickness integrated control was built.The dynamic simulation of the rolling process was made,and the dynamic thickness and the dynamic flatness information were obtained.This model not only provides a theory basis for the virtual rolling,but also provides a platform for the application of advanced control theory.

Compound control for speed and tension multivariable coupling system of reversible cold strip mill

To weaken the nonlinear coupling influence among the variables in the speed and tension system of reversible cold strip mill, a compound control(CC) strategy based on invariance principle was proposed. Firstly, invariance principle was used to realize static decoupling between the speed and tension of reversible cold strip mill. Then, considering the influence caused by the time variation of steel coil radius and rotational inertia of the left and right coilers, as well as the uncertainties, a CC strategy that is composed of extended state observer(ESO) and global sliding mode control(GSMC) with backstepping adaptive was proposed,which further realized dynamic decoupling and coordination control for the speed and tension system. Theoretical analysis shows that the resulting closed-loop system is global bounded stable. Finally, the simulation was carried out on the speed and tension system of a 1422 mm reversible cold strip mill by using the actual data, and through the comparison of the other control strategies, validity of the proposed CC strategy was shown by the results.

Control and application of cooling path after rolling for hot strip based on ultra fast cooling

Hot rolled strip requires diverse and flexible control of cooling path in order to take full advantages of strengthening mechanisms such as fine grain strengthening, precipitation strengthening, and transformation strengthening, adapting to the development of advanced steel materials and the requirement of reduction-manufacturing. Ultra fast cooling can achieve a great range of cooling rate, which provides the means that the hardened austenite obtained in high temperature region can keep at different dynamic transformation temperatures. Meanwhile, through the rational allocation of the UFC （ultra fast cooling） and LFC （laminar flow cooling）, more flexible cooling path control and cooling strategy of hot rolled strip are obtained. Temperature distribution and control strategies under different cooling paths based on UFC are investigated. The process control temperature can be limited within 18 ℃, and the mechanical properties of the steels get a great leap forward due to the cooling paths and strategies, which can decrease costs and create great economic benefits for the iron and steel enterprises.

Numerical simulation and model of control-efficiency of thermal crown of work rolls in cold rolling

Aiming at accuracy control of the thermal crown of work rolls in cold rolling,new parameters such as regulation domain and control-efficiency factors were proposed and a numerical analysis model of the thermal crown of work rolls was established using finite difference method to study roll's thermal deformation.Based on simulation results,the influences of control-efficiency factors on thermal crown are presented and the thermal crown of work rolls is analyzed after taking sub-cooling of sprinkling beam into consideration.It has been found that the control-efficiency factor of any position on the roll's surface is linear function of the temperature and the control ability of water temperature is stronger than other control parameters.In addition,the verification of the model has been carried out based on the producing technology data in some factories and the numerical simulation results coincide well with the experimental data.Therefore,this work has important value for on-line control of roll's crown in cold rolling.