Rolling Practice Research Articles

Influence of Hot Rolling Practice and Furnace Residence Time on the Strength and Toughness of Normalised Nb-Ti-V Structural Steel Plate

The influence of moderate thermomechanical rolling and heat treatment time on the microstructure and mechanical properties of normalised Ni-containing Nb-Ti-V microalloyed plate steels was investigated. Conventional rolling (CR) and low austenitic temperature rolling (TM) schedules were applied to 25 and 55mm thick plates. Predicted plate thermal profiles were used to simulate normalising of 25 and 55mm thick plates at the mid-thickness. As expected, the microstructure after TM rolling was finer due to austenite sub-structure development below the no-recrystallisation temperature which increases the amount of ferrite nucleation sites. The tensile strength of the CR plates was generally higher due to a larger pearlite volume fraction resulting from slow cooling from a relatively coarse austenite. In 25mm plate, the presence of acicular ferrite after CR resulted in a higher yield strength than that obtained after TM rolling. Furnace residence times of 0.75min/mm and longer allowed for plates to be completely normalised – characterised by continuous, well-defined polygonal ferrite grain boundaries. Short furnace residence times restricted the plate temperature to below the end of the ferrite-to-austenite transformation (Ac3), where untransformed ferrite is retained from the as-rolled microstructure and is characterized by poorly defined grain boundaries. Rolling practice and normalising residence time had little to no effect on impact toughness, but significantly influenced the normalised yield strength of thicker plate.

Optimization of hot rolling parameters of CRNO steel with the aid of hot compression test and deformation map

Abstract Cold-rolled non-oriented (CRNO) electrical steels find a wide variety of applications in the core of electrical machines due to low core loss and high magnetic permeability. Stringent market conditions not only require CRNO steel with superior magnetic properties but also demand excellent surface conditions. CRNO steel is cold rolled to 0.5 mm in reversing mill. High hot rolled input thickness (>2.6 mm) increases the number of passes during cold rolling and adversely affects the mill productivity. It also results in surface defects such as buckling and coil break. The flow stress of this steel varies differently compared to conventional rolled steel. Thus, it becomes difficult to optimize the reduction schedule and hence safe hot rolling practice is adopted to restrict roll force within permissible limit resulting in higher thickness. A hot compression test was carried out in a Gleeble–3500 to evaluate the flow stress behaviour of this steel and a deformation map was developed to optimize the hot rolling window. The input from the hot compression test and deformation map was used to develop a mill setup model to accurately predict the roll force and optimize the reduction schedule of CRNO steel in the finishing stands of HSM. The final thickness of hot-rolled coils during industrial trials with an optimized reduction schedule was found to be in the range of 2.4–2.6 mm compared to 2.7–3.0 mm during conventional rolling. These coils were further cold rolled and finished in 4–5 passes compared to 6–7 passes with conventional rolling. Reduction in the number of passes has resulted in increased productivity during cold rolling as well as improved surface finish.

Acute Effect of Foam Roller Practice on Isokinetic Parameters

We aimed to examine the differences in knee strength, range of motion, and fatigue characteristics during high vs. low-speed isokinetic testing following FR practice on hamstring muscles and changes in the ROM on the knee extension and parameters during isokinetic fatigue testing. In total, 35 participants (20 men, 15 women) were recruited in this study. Of these 35 participants, 20 (12 men, 8 women) randomly underwent FR practice and the other 15 received no treatment (NFR). Pre-to-posttest body composition and high (180 o/sec) and low (60 o/sec) speed neuromuscular performance were performed with 24-h intervals. Follow-up screening showed significant decreases in knee extension and flexion parameters in the NFR group. Posttest percent knee extension and flexion torque deficit during fatigue testing protocol was significantly higher, while knee extension torque and ROM parameters were found significantly lower in the NFR group. FR group showed higher mean absolute torque and ROM values and lower percent knee extension and flexion torque deficit during fatigue resistance testing compared to baseline screenings. Positive significant correlations occurred between the ROM and knee extension (r=0.61) and flexion (r=0.52) peak torque and Hcon:Qcon (r=0.385) parameters during posttest screenings. The results of the current study suggest that the practice of high vs. low-speed isokinetic testing following foam rolling practice on hamstring muscles after strenuous exercise increased ROM without a decrease in peak and mean extension and flexion moments and helps to enhance an accelerated recovery.

Hot Deformation Behavior of C-Mn Steel with Incomplete Recrystallization during Roughing Phase with and without Nb Addition

The objective of the study is to improve understanding of the practical role of niobium (Nb) in the case of industrial inconsistent rolling processes such as the rolling of heavy gauge plates where a lower stored energy rolling practice will result in a less stable and less repeatable static recrystallization (SRX) activation that prevents complete recrystallization. In the current study, these variabilities are validated by comparing the mean flow stress (MFS) indirectly determined from the rolling force measured on a reverse four-high rolling mill stand. The material resistance to deformation and grain size evolution of a C-Mn steel during hot rolling was observed and validated with and without Nb addition. The pre-defined rolling schedule was predicted to exhibit incomplete recrystallization in the roughing phase due to the limited stored energy of deformation that resulted from low rolling loads and a higher number of rolling passes. The prior austenite grain size (PAGS) distribution was predicted and compared to the measured effective ferrite grain (FG) size distribution after the completion of hot rolling and phase transformation achieved using natural air plate cooling. Both the predicted PAG and measured FG distributions revealed the presence of multimodality, and both distributions were used for grain size reduction factor determination for γ → α transformation for the current study with 1.96 for 0 Nb and 1.70 for 240 Nb. The results presented in this paper are not only limited to the rolling schedule used in this paper because instabilities resulting in incomplete austenite conditioning are also observed when evaluating the cross-sections of other heavy plates and various steel grades utilizing different processing routes with comparable compositions such as modern lean abrasion-resistant steels, regular line pipe steels, and other similar grades.

Assessment of the effects of land rolling on wind erosion and crop growth in soybean production in the Red River Valley, Canada

Land rolling has become a popular practice in soybean and pulse production in the Northern Great Plains. The practice of land rolling is simply pulling a large-scale cylindrical roller over a cultivated field to push down stones and improve seed-to-soil contact. Many soybean farms in Manitoba are routinely rolled either immediately after seeding or at the very early stages of crop development. There has been considerable concern regarding the potential effects of land rolling on wind-induced soil loss, soil properties, and plant growth in soybean production. To address this concern, an on-farm research project was conducted at eight different field sites in the Red River Valley of southern Manitoba, Canada, in 2018 and 2019. Trials were established with rolled and non-rolled treatments arranged using a randomized complete block design. To examine the environmental and agronomic impacts of land rolling, data was collected to characterize wind-transported sediment (passive uni-directional samplers), soil properties (e.g., surface roughness and moisture content), yield, and plant growth parameters. Despite the land rolling reducing surface roughness the results showed no significant difference in the amount of collected wind-transported sediment between the two treatments. In addition, the particle size of the wind-transported sediment ranged between 0.002 and 0.1 mm suggesting that this size fraction is the most susceptible to wind erosion. Furthermore, there was a small, but significant, increase in soybean yield in the non-rolled treatment, despite having significantly lower volumetric soil moisture content. Overall, while land rolling reduced soil surface roughness and increased the wind erosion risk, it did not result in an increase in the amount of wind-transported soil loss. Lastly, within the Red River Valley the practice of land rolling to support higher soybean yield was not supported; however, the exact reasons for the small yield reduction is not fully understood.

ATLAS 5005

Abstract Atlas 5005 is a non-heat-treatable, aluminum-magnesium alloy. This alloy has been widely adopted for anodized architectural panels. With correct rolling practices and composition controls, Atlas 5005 architectural sheet provides exceptionally high-quality surfaces after anodizing. The architectural products produced from this alloy are used on many high-end building projects to meet customer specifications for uniformity and color match. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-482. Producer or source: Atlas Steels.

Role of hot rolling procedure and solution treatment process on microstructure, strength and cryogenic toughness of high manganese austenitic steel

Abstract In this study, the relationship between mechanical properties and microstructure of high manganese steels processed by different rolling practice and solution temperatures were systematically studied in terms of strength and toughness using optical microscopy (OM), scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM) techniques. The experimental results suggested that the solution treatment is an effective method to improve Charpy impact toughness at −196 °C from ~68 J to ~120 J, while the strength decreases. The grain size coarsened with the increase of solution temperature. However, the change in strength and toughness was small. The role of grain coarsening on strength and toughness was weak. The stability of austenite at low temperature was high as the microstructure only consisted of austenite. The fracture mode during low-temperature impact process was ductile and the main deformation mechanism was mechanical twinning

Identifying Challenges to the Commercial Viability of Direct Powder Rolled Titanium: A Systematic Review and Market Analysis

A systematic review of factors affecting the viability of direct powder rolling (DPR) as a process route for producing low-cost titanium metal strips was conducted by consolidating performance and process data from published research. Included is a market analysis that was performed by sourcing price points from powder and wrought product suppliers. As a result of the typical oxygen levels (>0.2 wt %) in low-cost powders, the performance of the DPR product is estimated at best to be comparable to ASTM grade 3 and 4 wrought products. Furthermore, evidence supporting chlorine levels >0.02 wt % in low-cost (non-melt) commercially available powders suggest poor weldability, which restricts the application of DPR titanium strips. A comparison of price points for powder and wrought products showed that the potential for commercial viability is likely to exist only for thin gauge strips of <1 mm thickness, as the cost advantage diminishes as the strip thickness increases. Based on the DPR product profile identified in this study (thin gauge, non-weldable, grade 3 or 4), the potential product applications are severely limited. The inability to reliably meet the properties of grade 2 metal strips excludes many uses of titanium metal strips. Consequently, it is emphasized that efforts need to be directed at improving the quality of low-cost powders and developing rolling practices to produce thicker gauge metal strips with desirable properties.

Combinations of rolling, mineral oil, sulfur, and phosphorous acid affect Microdochium patch severity

AbstractMicrodochium patch is a turfgrass disease that occurs in cool, humid regions caused by the fungal pathogen Microdochium nivale (Fr.) Samuels &amp; Hallett [Teleomorph = Monographella nivalis (Schaffnit) E. Müll]. Fungicide applications are the predominant method of control; however, pesticide restrictions have generated concern regarding the use of traditional chemicals to manage turfgrass pests. The objective of this research was to evaluate the effects of the cultural practice of rolling in combination with applications of mineral oil, S, and/or phosphorous acid (H3PO3) on the suppression of Microdochium patch on an annual bluegrass (Poa annua L.) putting green. A 2‐yr field trial took place from September 2013 to June 2014 and was repeated from September 2014 to June 2015 on a sand‐based annual bluegrass putting green in Corvallis, OR. Experimental design was a 2 × 4 × 2 × 2 randomized complete split‐plot design with four replications. Factors included rolling, the fertility products S and H3PO3 applied alone and in combination, mineral oil treatment, and year. Mineral oil suppressed Microdochium patch although applications led to turfgrass thinning. The combination of S and H3PO3 provided greater Microdochium patch disease suppression compared to applying either alone. Rolling also suppressed Microdochium patch in the second year of this study. Further research to determine how to best utilize these combined cultural practices to manage Microdochium patch is warranted.

Characterization and Modelling of High Temperature Flow Behaviour of V Modified 2.25Cr-1Mo Heat Resistant Steel Plate

In order to study the high temperature flow behaviour of the V modified 2.25Cr-1Mo steel plate to guide the industrial rolling practice, the hot compression tests were carried out at the temperatures from 900 °C to 1150 °C and the strain rates from 0.01 s−1 to 1 s−1 on Thermecmastor-Z equipment. Based on the experimental data of the hot compression tests, a kind of Arrhenius-type constitutive equation was developed. The equation can accurately show the relationship between the flow stress and the deformation temperature, the strain and the strain rate. The measured true stress-true strain curves exhibit two kinds of flow stress curves. Moreover, the forming mechanisms of these two types curves were explained by softening, wok hardening theory as well as metallographic and hardness experimental results. The accuracy of the developed Arrheniustype constitutive equation was identified by three kinds of statistic parameters and also by comparison of the measured and predicted data. The reasonable value of the three types of statistic parameters and the good agreement between the experimental and predicted data can confirm the validity of the developed Arrheniustype constitutive equation for V modified 2.25Cr-1Mo heat resistant steel plate.

Magnitogorsk Rolling Practice 2019: the benchmark for young scientists from around the world

Magnitogorsk Rolling Practice 2019: the benchmark for young scientists from around the world

It\u2019s not all about price: factors associated with roll-your-own tobacco use among young people -\xa0a qualitative study

BackgroundSmoking prevalence in Ireland is falling in all age groups, but the prevalence of roll-your-own (RYO) tobacco use is rising among young people. This qualitative study aims to explore and understand the factors associated with young people’s use of RYO products.MethodsSemi-structured individual and focus group interviews were conducted with young people aged 16–22 years. Participants were recruited from a higher education institution and youth organisations working with early school leavers across Dublin. In total, there were 62 participants in the study, consisting of 22 individual interviews and eight focus group interviews with 40 participants. Categoric and thematic data analysis was used to generate the findings.ResultsWe identified two broad themes, incentivising and disincentivising factors. The lower cost of RYO products compared to pre-manufactured cigarettes was the most important incentive for users. However, other product characteristics, such as the artisanal factors associated with RYO products were also found. Social and environmental influences were apparent, in which certain groups and environments facilitated and normalised RYO practices. Amenities and facilities often provided smokers with normalised spaces which could be dedicated to the enactment of rolling practices and to the creation and maintenance of social bonds with other users. Disincentives included negative features related to the product itself, adverse health effects, and the effects of tobacco denormalisation.ConclusionsWhile the lower cost of RYO products is very important for young smokers, other product characteristics and influences also incentivise and disincentivise use. A more comprehensive understanding of the multi-dimensional appeal of these products will assist policymakers to target strategies to reduce the attractiveness to young smokers of these products.

Head curvature of pure titanium sheet influenced by process parameters and controlling in hot rolling process

We investigated the influences of process parameters on the head curvature of pure titanium sheet in hot rolling process and proposed the controlling means. First, the thermal simulation experiments for pure titanium TA1 were carried out to investigate the hot deformation behaviors of pure titanium in the temperature range of 700-800 °C with strain rate range of 1-20 S-1, and the processing map was established to determine optimized deformation parameters. Then, the finite element model has been constructed and used to analyze the effect of process parameters on the direction and severity of head curvature of pure titanium sheet. The process parameters considered in the present study include workpiece temperature, work roll diameter, pass reduction, oxide scale thickness of workpiece surface, and interface friction coefficient. The simulation results show that the workpiece temperature and the interface friction coefficient are the two main factors. The proposed controlling means was carried out on a hot rolling production line and solved the head curvature problem effectively. The rolling practices indicate that the rolling yield is improved greatly.

Prevalence of bronchial asthma among school-going children in Mangalore, South India

Background: Asthma in childhood is a major public health issue. Objective: To estimate prevalence and associated housing environment factors of asthma among school children. Material &amp; Methods: We conducted a cross sectional study among school children aged six to fifteen years. Standard ISAAC (International Study of Asthma and Allergies in Children) Core Questionnaire for Asthma was used for determining the prevalence of wheezing and asthma. Demographic, housing and indoor pollution factors were collected. Data were analyzed by SPSS version 15. Results: Prevalence of ‘wheeze ever’ and ‘current wheezers’ was 10% and 9% respectively. Physician diagnosed asthma was seen in 6.3 %. Severe asthma was noted in 28.6% of current wheezerswith 84.6% and 8.8% having one to two and four to 12 wheezing attacks per year respectively. Wheezing was present post exercise in 5.4%, nocturnal cough in 6.1%, sleep disturbance less than one night/week (40.7%), one or more nights/week (3.3%) and wheezing limiting speech to few words between breaths (20.9%). Prevalence was greater among boys (9.8%) than girls (7.5%) and maximal in age group eight to nine years. On multiple logistic regression presence of overcrowding and absence of smoke outlet were significantly associated with current wheeze. Socio-economic status, beedi rolling practices and absence of separate kitchen was statistically significant with severe asthma. Conclusions: Current wheezer prevalence was9% and more in boys. Adoption of improved housing conditions and avoiding environmental tobacco exposure may aid in reducing childhood asthma attacks in this developing city.

Improving Thin Strip Profile Using Work Roll Cross and Work Roll Shifting Methods in Cold Strip Rolling

The optimization of rolling parameters in order to achieve better strip shape and to reduce rolling force is a challenge in rolling practice. In this paper, thin strip asymmetrical rolling of aluminum at various speed ratios under lubricated condition has been investigated at various combinations of work rolls cross (WRC) angles and work rolls shifting (WRS) values. The effects of strip width, reduction, and rolling speed on strip shape taking WRC and WRS into consideration are discussed. Results show that strip profile improves significantly when the WRC angle is increased from 0° to 1°, with an associated reduction in rolling force. Increasing WRS value from 0 to 8 mm improves the strip profile as well but not as significantly as when WRC angle is increased. No significant improvement was found in strip shape when the strip width was increased. At higher reduction, the strip shape was improved; a decrease in the rolling force was also observed. A higher speed ratio was found to be effective only at a higher WRC angle. The effect of lubrication on the strip profile was significant. Results indicate that an optimum combination of WRC, WRS, reduction, width, and speed ratio under lubricated conditions can ensure an improved exit strip profile, reduce rolling force, and obtain a better quality strip.

Computer Model STAN 2000 and its Use in Practice of Steels Hot Rolling on Mill 2000 of Severstal

An integral computer model/program STAN 2000 for simulation of steels hot rolling on mill 2000 of SEVERSTAL was developed. The capacity of the model includes, for example, the following features:‒ control of power parameters and prediction of hot strip temperature for a given rolling and accelerated cooling regimes;‒ follow-up of the evolution of steel microstructure at all stages of strip production and prediction of ultimate mechanical properties (yield stress, ultimate tensile stress and relative elongation);‒ optimization of rolling regimes for existing steel grades and developing them for a new ones.The STAN 2000 program is written in С++ programming language and can work on all modern Microsoft Windows family operating systems. The program has a well-designed and user-friendly interface facilitating its practical use.The integral model was calibrated using an extensive data base on rolling regimes and forces, measured temperatures and final mechanical properties for a number of steel grades rolled on mill 2000 of SEVERSTAL with chemical compositions covering the following ranges of alloying elements content (mass.%): С(≤0.65); Mn(≤2.0); Si(≤1.0); Cr(≤0.9); Ni(≤0.6); Cu(≤0.5); Mo(≤0.4); Nb(≤0.05); V(≤0.065); Ti(≤0.06); B(≤0.003).Some results of calculations performed with STAN 2000 program for temperatures, rolling forces and mechanical properties are presented and compared with experimental data. Some examples of the program utilization in hot strip production on mill 2000 of SEVERSTAL are presented and discussed.

Influence of Thermomechanical Control Process on the Evolution of Austenite Grain Size in a Low-Carbon Nb-Ti-Bearing Bainitic Steel

On the basis of hot rolling practice, the effects of thermomechanical control process parameters on the evolution of austenite grain size before the deformation at non-recrystallization zone were investigated in detail. The inflections in the strain hardening rate versus true stress curves show that the dynamic recrystallization (DRX) has initiated for different deformation conditions studied in the present work. But the volume fractions of the equiaxed grains in the specimens which were immediately water quenched to room temperature after deformation are different from each other. Moreover, the main refinement mechanisms for different deformation conditions have been differentiated. It is interesting to note that the austenite grain size can be refined significantly with increasing the strain from 0.0 to 0.5 for different deformation temperatures. However, when the strain increases to 0.8, the austenite grain size cannot be further refined for the higher deformation temperature range, while the austenite grain size can be further refined for the lower deformation temperature range. In addition, the effect of strain rate on the austenite grain refinement is vigorous for the higher deformation temperatures. Moreover, the empirical equation to estimate the austenite grain size for different deformation parameters was established.

Research into the Flow Stress of Al-Mg-Si Alloy (AD-35) during the Abrupt Change of the Strain Rate at Elevated Temperatures

In industrial practice of rolling and hot forging, i.e. extrusion-type forging, abruptchanges in strain rate during the deformation of the material occur. For accurate numericalsimulation of a forging process, the experimental investigation of the effect of the transient changein strain rate on plastic flow behaviour is necessary. The present paper deals with the investigationof this effect on the flow stress of an AD-35 aluminium alloy during its deformation within thetemperature range of 350-450 °C. During continuous uniaxial compression loading of a cylindricalspecimen, the strain rate was either constant or abruptly increased or decreased from its initial valueat engineering strain of app. 26 %. The following strain-rate histories were applied: 1) constantstrain rate of 0.1, 1.0 and 10 s-1; 2) abrupt strain-rate increasing from 1.0 to 10.0 s-1; 3) abrupt strainratedecreasing from 10.0 to 1.0 s-1. The results of the experimental investigations corresponded tothe transient change in strain rate histories were used to verify the model of softening as well as themodel of hardening of the AD-35 alloy during the abrupt change of the strain rate. It allows todefine these models explicitly.

Microstructure analysis on IN 718 alloy round rod by FEM in the hot continuous rolling process

Based on physical metallurgy rules and experiential equations, models for microstructure analysis on IN 718 alloy in the round rod hot continuous rolling process has been developed using the finite element method (FEM) on the software ANSYS/LS-DYNA. The dynamic and metadynamic recrystallization models in and after deformation, the grain growth models in the compensated reheating process for IN 718 alloy are regressed, and corresponding processes are involved in these models. For a real rolling practice, the calculated central grain sizes were examined and are in good agreement with the measured ones. The element in the center of the workpiece is a typical one possessing the maximum of the effective strain, the temperature and the grain size in the rolling process. In the hot continuous rolling process, the relationship between the final grain size of the typical element and the inlet velocity of the first stand has been regressed by FE analysis, and the lower rolling speed is beneficial to the grain refinement.

Information Management Practice of Cold Rolling Progress Based on "High-Speed Management"

A unit of high-speed, large-scale, continuous, automated PCM, which is used for production process information management practice, is introduced in this paper. According to the practice of cold rolling equipment and "High-speed Management," advanced management methods and tools are embedded to process control, so as to achieve online control of "quality flow", real-time evaluation and improvement.