Double Cold Rolling Research Articles

Dislocation Strengthening and Texture Evolution of Non-Oriented Fe-3.3 wt% Si Steel in Double Cold Rolling

Dislocation Strengthening and Texture Evolution of Non-Oriented Fe-3.3 wt% Si Steel in Double Cold Rolling

Formation Mechanism and Influence Factors of Roll Surface Oil Film Thickness in the Double Cold Reduction Mill

In the double cold rolling process, the emulsion entering the roll gap during the double cold rolling process has the characteristics of high concentration and small flow rate so that the roll surface oil film thickness will affect roll gap oil film thickness, which in turn affects the rolling friction coefficient. This paper analyzes the formation mechanism and evolution process of the roll surface oil film thickness by considering the equipment and process characteristics of the emulsion direct injection application lubrication system. Then, based on the principle of fluid dynamics, the roll surface oil film thickness model in the double cold rolling process is established, and the prediction of the roll surface oil film thickness during the double cold rolling process is realized. Subsequently, the effects of five factors, such as rolling speed, work roll roughness, maximum contact stress between rolls, emulsion initial dynamic viscosity, and emulsion pressure viscosity coefficient, on the roll surface oil film thickness are quantitatively analyzed, and the corresponding influence laws are given. Finally, the relevant model and software that are applied to the 1220 double cold reduction mill have achieved good results.

Comprehensive Optimization Control Technology of Rolling Energy and Oil Consumption in Double Cold Rolling

Comprehensive Optimization Control Technology of Rolling Energy and Oil Consumption in Double Cold Rolling

Model and influence factors of oil film thickness in the deformation zone of double cold reduction mill

ABSTRACT In the double cold rolling process, oil film thickness in the deformation zone is a key parameter for evaluating rolling lubricity. This study investigated the formation and variation mechanism of oil film thickness on the strip and work roll surface in double cold reduction mill. Subsequently, a calculation model of oil film thickness in the deformation zone of double cold reduction mill was established by combining of the plate out theory and hydrodynamic lubrication principle. Moreover, the influence of emulsion flow, emulsion concentration, emulsion plate out distance, rolling speed, bite angle, entry deformation resistance, back tension, oil initial kinetic viscosity, and oil pressure viscosity coefficient on the oil film thickness were quantitatively analysed. The oil film thickness was achieved with an accuracy greater than 90% through a field application of this calculation model, which provides theoretical foundation for the lubricity control of double cold reduction rolling.

Microstructure Evolution Behavior of 22MnB5 Pickling Plate during Double Cold Reduction and Rapid Heating Process

The microstructure evolution during rapid induction heating process of 22MnB5 steel after double cold rolling was investigated, and the effects of deformation, heating temperature and heating rate on austenitic grain size and micro-hardness of quenched samples were discussed. The results show that the austenite begins to when heated to 850 °C and the austenite grains grow significantly when heated to 950 °C during rapid induction heating process. With the deformation increasing, the austenite grain size decreases, and the austenite grain refinement weakened when the deformation increases to a certain extent; but the influence of cold rolling on micro-hardness after quenching is not significant. In addition, there is little effect of heating rate on the 22MnB5 steel austenite with large cold deformation and a certain effect on the micro-hardness after quenching.

Structure and Texture Formation During Single and Double Cold Rolling and Annealing Processes for Nb+Ti Added Interstitial-Free Steels

The structure and texture formation for single cold rolling (SCR) with annealing and double cold rolling (DCR) with annealing were investigated based on optical microscope and X-ray diffraction (XRD) with a Nb + Ti bearing interstitial free (IF) steel. The results indicated that DCR recrystallization grain was smaller than that of SCR sample and double cold rolling process resulted in better mechanical properties than those resulted from single cold rolling process with the same total reduction conducted. The plastic strain ratio increases from 2. 23 for single cold rolling process to 3. 2 for double rolling process. The fish-bone structure was observed in all SCR and DCR samples. DCR annealed sample is made up of equiaxed grains of almost uniform size, whereas SCR annealed sample shows a duplex grain structure, consisting of both large and small-sized grains. (Ti+Nb) C and Fe(Ti+Nb) P type precipitates were very rarely observed in SCR annealed and DCR annealed steels. The intensity of {111} // ND for the DCR annealing was higher than that for SCR annealing.

Mechanical performance and texture characteristic of an IF steel containing Nb and Ti by double cold rolling

Single cold rolling and double cold rolling were applied to hot rolled strips with different reduction ratios. The evolutions of {100}, {111} and Goss face texture during double rolling were investigated by comparing the orientation distribution function (ODF) of the double rolled sample with that of the single rolled one. The double cold rolling texture is characterized by a higher γ-texture and a lower α-texture, and the {111}<112> component is improved remarkably. Based on the TEM observation and mechanical properties test, it is found that the reduction ratio assignment significantly affects the texture variation, as-annealing microstructures, and properties of the double cold rolled samples. These results may provide a theoretical guide for the industrial production of double cold rolled IF steel.

The Evolution of Texture and Stored Energy during Recrystallization of IF High Strength Steel Investigated by Means of Orientation Imaging Microscopy

The evolution of texture and stored energy was studied for Ti bearing and Ti-Nb bearing IF high strength steel undergoing a double cold rolling and annealing treatment by using Orientation Imaging Microscopy. Ti bearing IF high strength steel showed a similar texture evolution of the α and γ fiber components to that of IF steel. On the contrary, Ti-Nb bearing IF high strength steel displayed a different texture evolution from the one observed in the former steels. The difference in texture and stored energy evolution between both high strength steels seemed to be affected by the segregation behavior of solute alloying elements such as P.

Attaining deep drawability and non-earing properties in Ti + Nb interstitial-free steels through double cold rolling and annealing

The intensity and uniformity of the γ-fibre improve very significantly in a Ti + Nb interstitial-free steel after the cold rolled and annealed sample is subjected to a second cold rolling and annealing treatment. A uniform grain size as well as a balance between the two major components of the γ-fibre, namely {1 1 1}〈1 1 2〉 and {1 1 1}〈1 1 0〉, are expected to make the material highly deep-drawable and free from earing during processing.

Effect of Initial Texture on the Evolution of Texture and Stored Energy during Recrystallization of Interstitial Free Steel

By applying a double cold rolling and annealing treatment, the evolution of the α and γ fiber components differed from the ones observed in conventional processing. This is attributed to the difference of the initial texture. An increased reduction of stored energy of the {111}&lt;112&gt; component was found by monitoring the change of the stored energy during annealing, indicating that the onset of the nucleation stage of recrystallization by relaxation and annihilation of dislocations occurred mainly on the {111}&lt;112&gt; component with its higher stored energy. The detailed texture evolution of the double cold rolled specimen during 2nd annealing is described by coupling the theory of oriented nucleation and orientation pinning, which is experimentally confirmed by OIM scan.

Evolution of textures in interstitial free steel during multiple cold rolling and annealing

A Ti bearing interstitial free (IF) steel was finish rolled in the ferrite zone and the texture evolution during double cold rolling (DCR) and double annealing technology was investigated by orientation distribution function (ODF). The γ-fibre texture of DCR has been compared with traditional single cold rolling (SCR) and annealing. The SCR annealing texture component {1 1 1} 〈1 1 2〉 remained after DCR and it improves the formation of {1 1 1} 〈1 1 0〉 during DCR annealing. During rolling process the gliding planes will usually rotate towards rolling plane. The rotation could not be achieved totally due to the deforming resistance from crystal defects. The result is that {1 1 1} turn to parallel the sheet plane and form. The in-grain shear bands observed after DCR play a major role on the rotation and improve the γ-fibre texture indirectly. The mean plastic strain ratio ( r-value) of DCR is much higher than that of SCR. The work hardening coefficient ( n-value) less relies on the rolling and annealing technology.

Influence of heat treatment on the properties of cold-rolled precision carbon strip

1. The optimum properties of masks may be obtained with tann=770–820°C, and regardless of chemical analysis of the steel and the conditions of preliminary cold rolling the minimum tensile strength and coercive force, the maximum ferritic grain size, and the sharpest crystallographic structure, providing good formability of the strip, are provided. 2. A reduction in carbon content from 0.05 to 0.004% under otherwise similar conditions leads to a reduction in tensile strength of 7–10 N/mm2, in coercive force of 20–25 A/m, and in microhardness of 3–5 N and an increase in the P(111)/P(100) ratio of 2–3 relative units with a reduction in elongation on the area of flow of 2–3%. 3. The use in production of the strip of double cold rolling with an intermediate anneal in the production line with a second rolling with e=29% has a significant influence on the properties of the finished masks. In comparison with single rolling the tensile strength drops by 50 N/mm2, the coercive force by 50 A/m, and the microhardness by 5–8 N while the average grain size increases by not less than twice and the P(111)/P(100) ratio by five to six times. 4. Use of double cold rolling of strip and annealing of the masks at 770–820°C but not above the Ac3 provides an approximately 20% reduction in scrap for nonuniform transparency and tear defects in spherization.

2回冷延2回焼鈍工程による18クロムステンレス鋼板の深絞り性

The drawability of 18Cr stainless steel sheets is strongly affected by the crystallographic orientation and not by the grain size. The drawability of 18Cr stainless steel sheets produced by a single cold rolling and annealing process is very poor, because a considerable amount of the {100} component parallel to the sheet plane, which is mainly composed of {100}〈011〉 inherited from the hot rolled condition, is retained and the increase of the {111} component can hardly be anticipated in the process.In general, 18Cr stainless steel thin sheets are produced by a double cold rolling and annealing process. It is well known that the drawability of mild steel sheets of greatly improved drawability can be processed in the “double” process. So it has been tried to improve the drawability of 18Cr stainless steel sheets by the application of the “double” process.Consequently, it is found that the drawability of 18Cr stainless steel sheets is greatly improved by a proper combination of cold rolling reduction in each stage.