High-speed steel rolls used for cold rolling

During cold rolled production of steel,each change of rolls causes a halt in production and affects the roll’s grinding maintenance and consumption.Consequently,rolls are very critical to the costs of steel production. Besides the rolling accidents,surface quality problems,including inhomogeneous wear and a decrease of the surface roughness of the rolls are other main reasons for outage and a change of the rolls.Therefore,safe rolls,with superior wear resistance and roughness retentivity will be a future trend in the cold rolling steel industry.In this study,the property characteristics and in-service performance of high-speed steel(HSS)cold rolling work rolls at Baosteel are discussed.The results of this study indicate that in-service performance of HSS cold work rolls has an improvement over conventional rolls.Implementation of HSS work rolls will prolong the rolling campaign and improve the rolling stability,thus,the cost of cold rolling production can be better controlled.     

Methods for increasing the service durability of cold rolling mill rolls

Various conditions of heat treatment of low-alloy pearlitic steels, medium-alloy martensitic and pearlitic-martensitic steels, and high-alloy ledeburitic roll steels are studied. Practical recommendations for increasing the quality of roll tools are developed. They consist of the application of cyclic heat treatment, including cyclic subzero treatment. The increase in the service durability of rolls after the implementation of these recommendations under industrial conditions is analyzed.     

轧制高强钢用新型冷轧工作辊的开发及其应用

针对高强钢、超高强钢的轧制生产需求,通过合金成分设计和制造工艺开发,研制出轧制高强钢用新型冷轧工作辊,工作层的耐磨性能以及辊体的强韧性得到显著改善。现场使用结果表明：单周期平均轧制吨位提高了约40%,单次下机磨削量降低了约7%,使用性能优于进口的同类型冷轧工作辊。新型冷轧工作辊适用于汽车用高强钢的轧制生产,硅钢、不锈钢及其他难轧板材等也有广泛的应用前景。     

Improving emulsion odor in cold rolling production

This paper describes the formation mechanism and mode of the emulsion odor of the cold rolling process, and introduces the relevant environmental regulations and methods used to measure the emulsion odor.Studies were conducted with respect to these issues.The technical measures used to minimize the emulsion odor, particularly the adjustment of the chemical formula of the cold rolling emulsion, are illustrated in detail.The study results have been successfully applied in cold rolling production, and a significant reduction in the emulsion odor is achieved.     

多参数耦合下冷轧铝带工作辊分段冷却调节特性

为得到多参数耦合下冷轧铝带工作辊分段冷却调节特性,建立了工作辊和轧件的一体化耦合传热模型.耦合传热建模过程包含工作辊和轧件导热微分方程的建立、轧件变形热和摩擦热的求解、换热边界条件的确立、工作辊热辊形的计算及采用二维交替差分对微分方程进行求解.仿真结果表明,同一轧制参数下工作辊分段冷却正负方向调节能力近似相等,但单向调节幅度受轧制参数影响较大,轧制长度、喷射梁工作压力和摩擦系数的增加对分段冷却调控能力具有促进作用,轧制速度的作用则相反.     

Retained austenite in the cracking process of steel on the working rolls of the cold sheet rolling mill

It was proved that the volume fraction of retained austenite (RA) in the quenched samples of the 0.80%C, 1.80%Cr, 0.23%Mo, 0.17%V steel on the working rolls of cold sheet rolling mills depends on their sizes. During tempering of this steel at 160°C the RA is stabilized so strongly that it is transformed neither by means of stresses nor strains. It was computed that in this steel, every 1% by volume of RA increases its fracture toughness (K_lc) by about 5%. Under conditions of dynamic loading the power of effect of RA is increased to about 7%.     

六辊冷连轧机中间辊横移过程辊间接触压力分析

 为了使轧机板形控制性能适应带钢规格材质变化,用于连续轧制高档冷轧薄带钢的六辊冷连轧机大都采取中间辊可横移技术。但是,中间辊横移必定使辊间接触压力分布更不均匀,导致出现接触压力尖峰。在中间辊横移过程中,辊间接触压力和横移阻力都会随横移速度的变化而发生改变,并可能导致辊间接触压力在轧辊端部形成更大的压力尖峰,从而造成轧辊磨损不均匀并缩短轧辊的使用周期。通过建立有限元仿真模型,以仿真模拟获得中间辊横移过程中辊间接触压力的变化规律后,优化设计轧辊辊形,并且提出使用非对称弯辊力的方法,实现了辊间接触压力的分布均匀化,降低了辊间接触压力尖峰值,并延长了轧辊的使用寿命。