Material Ratio Curve Research Articles

Imprinting of Dull Roll Surface Texture to Carbon Steel Strips in Temper Rolling by Dry Condition

One of the important qualities of a cold-rolled steel sheet is the surface texture, which is obtained by imprinting a dull-roll surface texture. It is controlled by actual operation data and experiences, because the mechanism of the surface imprinting has not been clarified because of the complexity of elastic-plastic deformation of the rolled sheet in temper rolling. In this paper, surface imprinting is investigated in temper rolling as dry rolling of a 4-high rolling mill. Temper rolling experiments for as-annealed low-carbon steel strips and as-annealed high-carbon steel strips were conducted in the range of 1 to 11 % reductions. Electric-discharged dull rolls and shot-dull rolls were employed. Surface microstructures of temper rolled strips were observed directly, as well as surface textures in terms of the arithmetical mean deviation of the assessed profile (Ra), material ratio curves, and probability densities applied to compare the surface imprinting. As a result, the electric-discharged dull roll shows better surface imprinting than the shot-dull roll. The peak part of the roll surface is more easily imprinted on the steel sheet to form the valley part when the electric-discharged dull roll is used than when the shot-dull roll is used.

The Effect of Soluble Lubricant on Surface Imprinting in Temper Rolling by 4 Hi Rolling Mill

The surface roughness of carbon steel sheets is controlled by dull roll surface imprinting by temper rolling. In most cases, temper rolling is performed using a lubricant or under a dry condition. However, the oil film of the lubricant and its lubricating ability have not been clarified. In this study, the effect of a lubricant on surface imprinting by temper rolling was investigated under the following three lubrication states: a dry condition (no lubricant), with a water-soluble lubricant and with a mineral oil. Temper rolling experiments for as-annealed low-carbon steel strips and as-annealed high-carbon steel strips were conducted in the reduction range of 1 to 3 %, using the 4-high rolling mill. A shot-dull roll and an electric-discharged dull roll were employed as work rolls. The surface texture of temper rolled strips was observed directly, and surface textures in terms of the mean roughness (Ra), three-dimensional texture, cross-sectional profile, material ratio curve and probability density in order to compare the effect of the lubrication states. As a result, for high-carbon steel, the use of the water-soluble lubricant leads to better surface imprinting than the dry condition and the use of the mineral oil. The use of the mineral oil results in the least surface imprinting. For the low-carbon steel, the use of the water-soluble lubricant and the dry condition lead to better surface imprinting than the use of the mineral oil.

The Effect of Lubricant on Microwear of Dull Rolls in Temper Rolling by 4 Hi Rolling Mill

The surface roughness of a roll is imprinted on a carbon steel sheet by temper rolling. It is important to reduce roll microwear; since the roll surface causes microwear, the roughness of the rolled sheet could not be controlled. In most cases, temper rolling is performed using lubricants or under a dry condition. However, the influence of lubricant on roll microwear has not been clarified. In this study, roll microwear has been evaluated under three lubrication states, using a 4-high rolling mill. Temper rolling experiments for as-annealed low-carbon steel strips and as-annealed high-carbon steel strips have been conducted in the reduction range of 1 to 3%. The experiments were performed under three lubrication states: a dry condition, with a water-soluble lubricant, and with a mineral oil. A shot-dull roll (SD roll) and an electric-discharged dull roll (ED roll) were employed. Surface textures of the rolls have been observed directly with a laser microscope by identifying the exact locations using markers to acquire three-dimensional microgeometry before and after rolling. Surface textures in terms of the mean surface roughness (Ra), three-dimensional texture, cross-sectional profile and material ratio curve were applied to compare the microwear of dull rolls. As a result, roll microwear was found to occur when a total contact length between roll and strip reaches 80 m. The ED roll shows greater roll microwear than the SD roll under the dry condition. The use of the water-soluble lubricant and the mineral oil decreases the roll microwear of the ED roll.

Simulation of cylinder ‘zero-wear’ process

The tendencies of cylinder surface topography changes during “zero-wear” process are mentioned. It is proved that the assessment of amplitude parameter of worn cylinder surface is sufficient to monitor the shape of the amplitude distribution (material ratio curve). The information that the standard deviation height of fine part resulted from wear process is proportional to maximum height of worn surface is very important. It is possible to obtain simulated worn surface profiles when the horizontal parameters of their fine parts are known. The presented above technique can be extended into worn cylinder surfaces measured in three dimensions. The last part of paper is devoted to prediction of the local cylinder linear wear, determined as change of amplitude parameter. This procedure is based on the linear dependence between volumetric wear and initial material volume of the cylinder surface topography. The new models were successfully used for a large number of cylinder liners after ‘zero-wear’ process in internal combustion engines.

The method of truncation parameters measurement from material ratio curve

Abstract This paper presents the method of determination of truncation parameters during abrasive machining process and “zero-wear” without knowing the profile before abrasion. This method, based on the material ratio (Abbott) curve is very easy. Because truncation parameters proposed in the literature are interconnected, the other pair of parameters was recommended. The model of profile of Gaussian ordinate distribution truncation was extended into profiles of various initial shapes. A local linear wear measurement method for some types of engineering surfaces was also developed based only on measured worn surface. To use the presented methods, the measured area must be representative, the surface profile must preserve sufficient amounts of the original profile and initial shape of the truncated profile must be known.

無潤滑下の調質圧延における表面粗さ転写

One of the important qualities of a cold-rolled steel sheet is the surface texture, which is obtained by imprinting a dull-roll surface texture. It is controlled by actual operation data and experiences, because the mechanism of the surface imprinting has not been clarified because of the complexity of elastic-plastic deformation of the rolled sheet in temper rolling. In this paper, surface imprinting is investigated in temper rolling as dry rolling of a 4-high rolling mill. Temper rolling experiments for as-annealed low-carbon steel strips and as-annealed high-carbon steel strips were conducted in the range of 1 to 11 % reductions. Electric-discharged dull rolls and shot-dull rolls were employed. Surface microstructures of temper rolled strips were observed directly, as well as surface textures in terms of the arithmetical mean deviation of the assessed profile (Ra), material ratio curves, and probability densities applied to compare the surface imprinting. As a result, the electric-discharged dull roll shows better surface imprinting than the shot-dull roll. The peak part of the roll surface is more easily imprinted on the steel sheet to form the valley part when the electric-discharged dull roll is used than when the shot-dull roll is used.

調質圧延時のロール表面粗さ摩耗に対する調質圧延油剤の効果

A roll surface texture is imprinted on a carbon steel sheet in temper rolling. It is important to reduce the roll microwear; since the roll surface causes the microwear, the value of the surface imprinting could not be provided. In most cases, dry condition or a lubricant was applied as lubrication states in temper rolling. However, the influence of lubricant with respect to the roll microwear has not been clarified. In this work, roll microwear has been evaluated in three lubrication states by the 4Hi rolling mill. Temper rolling experiments for as-annealed low carbon steel strips and as-annealed high carbon steel strips have been conducted in the range of 1 to 3% in reduction. Non lubricant (dry condition), water soluble lubricant and mineral oil were utilized as lubrication states. A shot dull roll (SDR) and an electric-discharged dull roll (EDR) were employed. Surface textures of the rolls have been observed directly. Surface textures in terms of mean surface roughness (Ra), three dimensional textures, cross section profiles and material ratio curves were applied to compare the dull rolls microwear. As a result, roll microwear is caused during 80 m rolling length making contact with the back up roll and steel strips; this because stable afterwards. The electric-discharged dull roll shows larger roll microwear than the shot dull roll with dry lubrication. The water soluble lubricant and the mineral oil both decrease the roll microwear of the electric-discharged dull roll.

調質圧延におけるロール表面テクスチャーの転写

The surface texture of thin steel sheet provides considerable effect on sheet press formability and image clarity after coating for automotive body parts and beverage can uses. However, the transcription mechanism of surface texture, such as surface roughness, from roll onto deformed sheet has not been clarified, because of the complexity of elastic–plastic deformation of the rolled sheet in temper rolling. Temper rolling experiments for as-annealed low- and high-carbon steel sheets have been conducted in the reduction range from 1.0 to 8.0% using a laboratory-scale rolling mill. Bright rolls, shot dull rolls and electric-discharged rolls were employed. Dry, soluble oil and mineral oil were applied as lubrication states in the rolling experiments. The surface microstructures of temper-rolled sheets were observed. Three-dimensional (3D) surface textures of the rolled sheets were measured, in terms of 3D mean roughness (SRa), 3D maximum profile peak height (SRp), 3D minimum profile valley depth (SRv) and 3D material ratio (Rmr) curves. The probability densities of surface roughness were analyzed from the Rmr curves for both rolls and deformed sheets. From the results, the transcription of roll surface textures onto the temper-rolled sheets was discussed.

Roughness of ground and hard-turned surfaces on the basis of 3D parameters

Recently, significant technological progress has been accomplished in the field of cutting processes, which still lasts nowadays. Namely, the processes requiring a significant amount of coolant are have been replaced by new processes requiring no coolant or demand minimal cooling. A typical example of this replacement is the change from grinding for hard turning. In the framework of the present research work, hardened bores of gears were machined by either wet grinding or dry turning. In order to compare the results, 3D roughness investigations were done on ground and hard-turned surfaces. It has been stated that 3D parameters provide more detailed and richer information than the 2D parameters that have been used for a long time. The aim of the investigation of these parameters is to prove that hard turning can securely guarantee the prescribed roughness parameters and does not present any disadvantage compared to grinding. However, besides this, more typical properties were observed on the turned texture, which significantly differ from grinding. The difference is reflected by the areal material ratio curve.

Relationship between roughness parameters based on material ratio curve and tactile roughness for sanded surfaces of two hardwoods

The roughness parameters on the material ratio curves were related to tactile roughness for samples of buna and mizunara. The surfaces of the samples were sanded using various grades of coated abrasives and the roughness parameters, reduced peak height (Rpk), core roughness depth (Rk), and reduced valley depth (Rvk), were estimated on the material ratio curves, which were obtained from roughness profiles determined using robust Gaussian regression filter. The values of Rpk and Rk were almost the same for buna and mizunara under the same sanding conditions and increased exponentially with tactile roughness. The coefficients of determination of those parameters and tactile roughness were higher than 0.79 at all cutoff wavelengths. On the other hand, the value of Rvk for mizunara was significantly larger than that for buna because of the deep local valleys. There was no relationship between Rvk and tactile roughness for both species.

Processing roughness of sanded wood surfaces

Any quantitative evaluation of a sanded surface requires that the data be filtered to remove form errors and waviness. Wood surfaces contain irregularities due to both the sanding process and the anatomy, so the anatomical roughness must be excluded from any measurement of the surface if the processing roughness is to be properly evaluated. The efficacy of a number of standard filters was examined to see if they were suitable for oak, beech and spruce surfaces sanded with P1000 grit. Filters in current standards introduced distortions, but a robust Gaussian filter, contained in a draft standard, appeared to give roughness profiles free of distortions. The processing roughness and anatomical roughness, contained in the filtered profile, were separated with an algorithm based on a threshold defined in the material ratio curve. Work is continuing to compare the properties of different grit size and species combinations.

The Use of 3-D Topographic Analysis to Determine the Microgeometric Transfer Characteristics of Textured Sheet Surfaces through Rolling

Abstract Traditionally, rolling mills were used for the purposes of flattening metal sheet, and reducing its thickness. However recently their use has been extended to provide a method for producing sheet with specified textures. The transfer characteristics of a textured roll to a she may be investigated qualitatively and quantitatively using a number of different approaches. Quantitative techniques include the use of t-dimensional profilometry which is obviously inherently limited in its ability to characterise a 3-dimensional (3-D) surface. Although 3-D surface topography measurement systems have been available for some time, 3-D characterisation techniques are still in their infancy (particularly with functional significance). The aim of this paper is to show how the use of 3-D characterisation techniques may be used to qualitatively and quantitatively analyse engineering surfaces. In this paper the texture transfer characteristics of sheet rolling is explored and the extent of transfer is determined. The technique employed shows how the integrity of topography transfer may be established with a limited basic set of 3-D parameters through the analysis of parameter variation. An area material ratio curve is also introduced and its usefulness m the comparison of the amplitude distributions of two surfaces is demonstrated.