Abstract: The testing results, etc. of surface flaws such as cracks formed in or just below a surface of a body to be detected are displayed using colors within different color regions in the color space when displaying, on the basis of a preset threshold value, the test signal ranging in magnitude from zero to the threshold value and the test signal falling in magnitude beyond the threshold value while changing the color and/or the depth of color little by little within each of the color regions according to the magnitude of the test signal. This enables small flaw signals, etc. to be displayed without exception, thereby preventing small flaws, etc. from being overlooked.

Abstract: A method and apparatus for ultrasonic flaw detection of line focus type suitable for detection of flaws in nonmetallic materials included in an object. Ultrasonic transmitter and receiver elements of line focus type are opposed at a distance (L) with an object under test placed between them, and a maximum ultrasonic echo is obtained at a distance Lp expressed by: Lp=0.75(FT+FR)−{(CS/CW)−1}t where FT (mm) is the focal length in the medium of the ultrasonic transmitter element of line focus type, FR (mm) is the focal length in the medium of the ultrasonic receiver element line focus type, CS (m/sec) is the speed of ultrasound in an object under test, CW (m/sec) is the speed of ultrasound in the medium, and t (mm) is the thickness of the object under test.

Abstract: An ultrasonic testing method uses surface waves to prevent false detection of primary cracks, to lower the level of structural noises from grain boundaries, and to improve the detectability in the ultrasonic testing by surface wave testing of hot rolling rolls. A surface wave probe 10 capable of transmitting and receiving a surface wave is provided with a piezoelectric element 10A, a resin wedge 10C disposed on the front surface of the piezoelectric element 10A and a damping block 10B disposed on the back surface. The surface wave probe 10 is driven to produce a short pulse having a pulse length being at most 2.5 times the wavelength of the surface wave to be produced. A coupling liquid medium is supplied to the probe 10 in accordance with the peripheral speed of the roll to be tested. Depending on the height of the reflected waves measured, the grinding allowance of the roll is determined, and the roll is ground according to the thus-determined grinding allowance.

Abstract: The present invention provides a composite roll for cold rolling capable of rolling a cold-rolled steel strip having little edge drop, a cold-rolled stainless steel strip or a bright finish steel strip having excellent surface brightness or a silicon steel strip excellent in magnetic properties without causing breakage of roll, which is a roll in which a sleeve is fitted at a surrounding of a shaft portion with the shaft portion as a central axis and its fabrication method, in which the sleeve is constituted by previously integrating a plurality of pieces of mold members divided by a face intersecting with the central axis of the roll. Further, this is a fit roll in which a sleeve member of an outermost layer is made of WC—Co series hard alloys having Young's modulus of 35000 kgf/mm or more and Co content of 12-50 weight % and is provided with a wall thickness of 3% or more of roll radius and a ratio L/D of a length L of a barrel of the sleeve to a diameter D of the roll falls in a range of 2-10.

Abstract: An ultrasonic testing method uses surface waves to prevent false detection of primary cracks, to lower the level of structural noises from grain boundaries, and to improve the detectability in the ultrasonic testing by surface wave testing of hot rolling rolls. A surface wave probe 10 capable of transmitting and receiving a surface wave is provided with a piezoelectric element 10A, a resin wedge 10C disposed on the front surface of the piezoelectric element 10A and a damping block 10B disposed on the back surface. The surface wave probe 10 is driven to produce a short pulse having a pulse length being at most 2.5 times the wavelength of the surface wave to be produced. A coupling liquid medium is supplied to the probe 10 in accordance with the peripheral speed of the roll to be tested. Depending on the height of the reflected waves measured, the grinding allowance of the roll is determined, and the roll is ground according to the thus-determined grinding allowance.

Abstract: It is possible, in a rolling method of a strip shifting one-side-tapered work rolls in the axial direction and causing the upper and the lower work rolls to cross each other, to appropriately set a quantity of shift and a crossing angle and to improve an edge drop satisfactorily, by utilizing the relationship of the three factors including the quantity of shift and the crossing angle for determining quantities of operation necessary to correcting an edge drop of the strip and the quantity of correction of edge drop corresponding to these quantities of operation in the form of the relationship between the roll gap between the upper and the lower work rolls and the quantity of correction of edge drop, by providing an effective roll gap reference position apart from the strip edge by a prescribed distance.

Abstract: In a six high rolling mill comprising each pair of upper and lower work rolls, intermediate rolls and backup rolls, at least the intermediate rolls of the work and intermediate rolls being adapted for shifting in axial directions thereof, each of the intermediate rolls has a barrel length longer than that of the backup roll such that barrel ends of the intermediate roll extend beyond barrel ends of the-backup roll at maximum and minimum shifted positions of the intermediate roll, thereby providing a six high rolling mill having a high mill rigidity.

Abstract: Herein disclosed is an endless hot rolling method using a hot strip mill substantially composed of a roughing mill and a finishing mill having a roll bender and a roll shifter to continuously roll sequentially joined different rolling materials. The method comprises the steps of: calculating a roll shift range in an axial direction for each rolling material so as to provide a desired crown; determining a rolling sequence so as to obtain a common roll shift range for each pair of neighboring rolling materials; connecting a preceding material at the tail end thereof to the head end of the succeeding material, between the roughing mill and the finishing mill; shifting the rolls during transition from the preceding material to the succeeding material so that the roll position corresponding to the joint of the two materials is within a common roll shift range for the materials; and changing the roll bending load in accordance with the roll shift pattern so as to achieve the desired crown of each material.

Abstract: An apparatus for pre-processing a stainless steel to be cold-rolled comprising: annealing and pickling means having a mechanical descaling device and a pickling device; rolling means consisting of rolls arranged to be two or more stages; and means capable of applying liquid lubricant at a thin thickness to a work roll of the rolling means.

Abstract: A method for controlling edge drop in a cold rolling operation adaptable to tandem cold rolling mill stands by shifting a pair of vertically disposed single-end-tapered work rolls along the widthwise direction of a steel strip. The work rolls have tapered end portions that are disposed on the two widthwise ends of the steel strip.

Abstract: A multi-roll cluster rolling apparatus has a pair of work rolls, and a plurality of first intermediate rolls, a plurality of second intermediate rolls and a plurality of backup rolls arranged successively in the mentioned order behind each the work roll. A roll crown presented by unidirectinally tapering one end of a roll is imparted to at least a pair of rolls, e.g., the work rolls, selected from a roll group consisting of the work rolls, first intermediate rolls and the second intermediate rolls. A roll crown approximated by at least one-pitch portion of a waveform is imparted to at least one other pair of rolls, e.g., pairs of the first intermediate rolls. A roll crown approximated by at least two-pitch portion of a waveform is imparted to at least one of the remainder pairs of rolls, e.g., selected pairs of the second intermediate rolls. The rolls of each pair having the same roll crown arranged arranged in opposite axial directions and are axially shiftably mounted on a mill housing.

Abstract: A wet skin-pass rolling method for rolling a steel sheet by a mill while adjusting the hardness of said steel sheet through control of the rolling reduction. The method comprises determining an allowable range of reduction ratio from a predetermined desired range of hardness of the product, determining a command delivery-side sheet thickness to be obtained at the delivery side of the mill on the basis of the sheet thickness measured at the entry side of the mill, and adjusting the sheet thickness control in accordance with the command delivery-side sheet thickness.

Abstract: A method of pre-processing a stainless steel strip to be cold-processed comprising the steps of: annealing and pickling the stainless steel strip after completing hot rolling; applying liquid lubricant with a thickness of 1 .mu.m or less to the surfaces of rolls before the rolls come into contact with the stainless steel strip; and rolling the stainless steel strip at a reduction ratio exceeding 5%. An apparatus for pre-processing a stainless steel to be cold-rolled comprising: annealing and picking means having a mechanical descaling device and a pickling device; rolling means consisting of rolls arranged in two or more stages; and means capable of applying liquid lubricant in a thin layer to a work roll of the rolling means.

Abstract: A method of manufacturing a steel sheet having excellent deep-drawability. A steel blank is rolled into a steel sheet having a predetermined thickness. The steel contains C: not more than 0.008 wt %, Si: not more than 0.5 wt %, Mn: not more than 1.0 wt %, P: not more than 0.15 wt %, S: not more than 0.02 wt %, Al: 0.010 to 0.10 wt %, N: not more than 0.008 wt %, and at least one element selected from the group consisting of Ti and Nb which is contained in an amount satisfying the relationship of 1.2 (C/12+N/14).ltoreq.(Ti/48+Nb/93). In at least one pass, rolling is conducted within a temperatures range lower than the Ar3 transformation point but not lower than 500.degree. C., in such a manner that the roll radius R (mm) and the blank thickness t (mm) before rolling by rolls satisfy the relationships of R.ltoreq.200 and R.sup.2 .times..sqroot.t.ltoreq.100000, and the total rolling reduction at temperature lower than the Ar3 transformation point is not lower than 60%.

Abstract: A process and an equipment for micro-pattern forming on the surface of a rolling roll, and a metallic thin sheet and preparation thereof by transferring a micro-pattern on the surface by use of the roll are provided. Such a rolling roll can be attained by a method wherein resin film mixed with optical absorbing agent is formed on the surface, a Q switch YAG laser having an output of 5 to 100W is applied to make a marking on this resin film, a part of the coated film is removed in strict accordance with the pattern, then an etching process is applied to the roll surface. The metallic thin sheet skin pass rolled by this roll is used as a car panel and is superior in pressworkability and sharpness of reflections.

Abstract: A rolling mill comprises a pair of crown work rolls each having, at both ends of a drum, tapered ends ground at different taper angles, respectively. The work rolls are located one above the other with one tapered end of one work roll being in opposition to one tapered end having a different taper angle of the other work roll. The work rolls are movable in axial directions, such that edges of the plates are rolled by one tapered end of one work roll and a drum of the other work roll, and between tapered ends of both the work rolls. The method and rolling mills are capable of controlling the crown and edge drop reduction and simultaneously preventing local protrusions such as high spots and edge built-up to produce flat rolled plates having no difference in thickness and further capable of controlling the crown and the edge drop according to the material, thickness and width of the plates.