Abstract: A sleeve 10 for introduction of a pressurized fluid, which is attached to a rockbolt main body 1, comprises a cylindrical projecting part 11 of a large diameter and a bearing-plate-holding part 12 of a diameter smaller than an aperture of a bearing plate 6. The projecting part 11 and the bearing-plate-holding part 12 preferably has the same inner diameter. When the rockbolt main body 1 is embedded in a bedrock or ground, the bearing plate 6 locates on an edge of a rockbolt-setting hole of the bedrock or ground, and the bearing-plate-holding part 12 extends through the bearing plate 6 into the rockbolt-setting hole. Since the projecting part 11 and the bearing plate 6 are disposed on a sprayed concrete layer, a projection height of the rockbolt is remarkably decreased. Consequently, lining concrete 8 is applied onto the sprayed concrete layer with ease, and the bedrock or ground is reinforced with high reliability.

Abstract: A high-strength steel pipe rockbolt has an expansive rockbolt main body prepared by processing a high-strength steel sheet of 1.8-2.3 mm in thickness with a tensile strength of 490-640 N/mm2 and an elongation of 20% or more into a welded pipe and roll-forming the welded pipe into a shaped pipe having one or more concavities extending along an axial direction. Use of the high-strength steel sheet ensures sufficient strength of the shaped pipe regardless of a decrease in thickness. The thin welded pipe is also advantageous in resistance to cracking caused by accumulation of strains introduced during roll-forming, swaging both ends of the welded pipe and hydraulic expansion. Moreover, expansive deformation of the shaped pipe is initiated by injection of a pressurized fluid at a low pressure, so that the expansive deformation is completed in a short time period with an improved working efficiency.

Abstract: A lock bolt of a high strength steel pipe, wherein an expansion type lock bolt body is formed of a deformed pipe manufactured by using, as a raw material, a high tension steel plate having a tensile strength of 490 to 640 N/mm2, an elongation of 20% or more, and a plate thickness of 1.8 to 2.3 mm and having a single or a plurality of recessed parts extending in the axial direction of the deformed pipe. Since the high tension steel plate is used in the lock bolt, sufficient strength can be secured for the lock bolt though the steel plate is thin, and cracking due to stains introduced in a molding process, a both end shrinkage process, and a pressurizing/expanding process can be suppressed. Since an expansion start pressure when a pressurized fluid is press-fitted and inflated is also low, a time in which the expansion/deformation is completed can be shortened and workability can also be improved.

Abstract: A sleeve 10 for introduction of a pressurized fluid, which is attached to a rockbolt main body 1, comprises a cylindrical projecting part 11 of a large diameter and a bearing-plate-holding part 12 of a diameter smaller than an aperture of a bearing plate 6. The projecting part 11 and the bearing-plate-holding part 12 preferably has the same inner diameter. When the rockbolt main body 1 is embedded in a bedrock or ground, the bearing plate 6 locates on an edge of a rockbolt-setting hole of the bedrock or ground, and the bearing-plate-holding part 12 extends through the bearing plate 6 into the rockbolt-setting hole. Since the projecting part 11 and the bearing plate 6 are disposed on a sprayed concrete layer, a projection height of the rockbolt is remarkably decreased. Consequently, lining concrete 8 is applied onto the sprayed concrete layer with ease, and the bedrock or ground is reinforced with high reliability.

Abstract: A hot-dip Zn—Al—Mg plated steel sheet good in corrosion resistance and surface appearance that is a hot-dip Zn-base plated steel sheet obtained by forming on a surface of a steel sheet a hot-dip Zn—Al—Mg plating layer composed of Al: 4.0-10 wt. %, Mg: 1.0-4.0 wt. % and the balance of Zn and unavoidable impurities, the plating layer having a metallic structure including a primary crystal Al phase or a primary crystal Al phase and a Zn single phase in a matrix of Al/Zn/Zn2Mg ternary eutectic structure. To obtain a plating layer possessing this metallic structure, the cooling rate of the plating layer adhering to a steel strip extracted from a plating bath and the plating bath temperature are appropriately controlled in a continuous hot-dip plating machine and/or appropriate amounts of Ti and B are added to the bath.

Abstract: A hot-dip Zn—Al—Mg plated steel sheet good in corrosion resistance and surface appearance that is a hot-dip Zn-base plated steel sheet obtained by forming on a surface of a steel sheet a hot-dip Zn—Al—Mg plating layer composed of Al: 4.0-10 wt. %, Mg: 1.0-4.0 wt. % and the balance of Zn and unavoidable impurities, the plating layer having a metallic structure including a primary crystal Al phase or a primary crystal Al phase and a Zn single phase in a matrix of Al/Zn/Zn2Mg ternary eutectic structure. To obtain a plating layer possessing this metallic structure, the cooling rate of the plating layer adhering to a steel strip extracted from a plating bath and the plating bath temperature are appropriately controlled in a continuous hot-dip plating machine and/or appropriate amounts of Ti and B are added to the bath.

Abstract: A system for making an on-line determination of the degree of alloying in galvannealed steel sheets are provided, which includes an X-ray tube for generating X-ray, detectors for detecting the X-ray diffraction intensity of the .zeta. phase and .GAMMA. phase of Fe--Zn intermetallic compounds phases of the galvannealed steel sheet and a detector for detecting the background intensity, all of the detectors being located same plane on the surface of the galvannealed steel sheets, and further includes an arithmetic unit for receiving the outputs of the detectors to compute the X-ray diffraction intensities. Preferably, this system includes a detector for detecting the X-ray diffraction intensity of the .delta..sub.1 phase.

Abstract: A method for estimating the press formability of galvannealed steel sheets provided, wherein: the values found by: ##EQU1## wherein I(.gamma.)=the total X-ray diffraction intensity of the .gamma. phase,I(.GAMMA.)=the total X-ray diffraction intensity of the .GAMMA. phase,I.sub.B (.gamma.)=the background X-ray diffraction intensity of the .gamma. phase,I(.gamma.)-I.sub.B (.gamma.)=the true X-ray diffraction intensity of the .gamma. phase,I(.GAMMA.)-I.sub.B (.GAMMA.)=the true X-ray diffraction intensity of the .GAMMA. phase,.GAMMA.=the .GAMMA. phase of an Fe-Zn intermetallic compound in coating of galvannealed steel sheet, and.gamma.=the .gamma. phase of the intermetallic compound, are used as an index to determine the press formability.

Abstract: For vacuum deposition plating steel strip, a vacuum deposition plating apparatus is used including an inlet-side vacuum sealing device provided in front of a vacuum deposition plating chamber, with an inlet-side inactive gas replacement chamber provided between the inlet-side vacuum sealing device and an annealing furnace. An outlet-side vacuum sealing device is provided at the rear of the vacuum deposition plating chamber, with an outlet-side inactive gas replacement chamber provided between the outlet-side vacuum sealing device and the atmosphere. An inactive gas circulating/purifying device circulates an inactive gas from vacuum chambers of both the vacuum sealing devices to atmospheric pressure chambers of both the vacuum sealing devices and removes water, oil and oxygen from the inactive gas. Oxygen and hydrogen in the inactive gas are regulated to provide 60 ppm or less of oxygen and 0.2 to 2.0% of hydrogen, and also to regulate the dew point of the inactive gas to -50.degree. C. or less.

Abstract: A vacuum deposition plating apparatus having an inlet-side vacuum sealing device provided in front of a vacuum deposition plating chamber, an inlet-side inactive gas replacement chamber provided between the inlet-side vacuum sealing device and an annealing furnace, an outlet-side vacuum sealing device provided in the rear of the vacuum deposition plating chamber, an outlet-side inactive gas replacement chamber provided between the outlet-side vacuum sealing device and the atmosphere, and an inactive gas circulating/purifying device for circulating an inactive gas from vacuum chambers of both the vacuum sealing devices to atmospheric pressure chambers of both the vacuum sealing devices and for removing water, oil and oxygen from the inactive gas; a pressure gauge provided on the annealing furnace; a pressure gauge, a control valve, an automatic valve, a hydrogen concentration detector and a discharge valve provided on the inlet-side inactive gas replacement chamber; a pressure gauge and an automatic valve prov

Abstract: A continuous vacuum deposition apparatus for coating a metal strip in which a control means for changing the width of the metal vapor channel so that strips of various widths can be deposition-coated with transversally uniform thickness distribution is disclosed.

Abstract: A vacuum evaporation equipment for continuous vacuum evaporation of a metal onto a band or strip of product including at least one vacuum sealing station, provision of ducts that are disposed surrounding the band product and extending from the point of vapor deposition where the band product is subjected to a vacuum evaporation process an a chamber held at a reduced pressure or vacuum state to the extent that substantially no reevaporation of once deposited metal is effectively prevented from occurring. The ducts are adapted to be heated to a temperature substantially higher than the temperature of the steel band product. In addition, there is provided at least one vacuum sealing station with rolls rotatably mounted in the interior of a casing and a complementary sealing bar mounted in a complementary engagement relationship with the rolls having a close gap therebetween.

Abstract: Disclosed is a combined continuous plating apparatus for hot-dip plating and vacuum deposition plating characterized in that the outlet of the gas reduction annealing furnace of a conventional continuous hot-dip plating apparatus and the inlet of the seal roll chamber of a known continuous vacuum deposition plating apparatus are connected through a pressurized chamber in order to prevent invasion of hydrogen-containing reduction gas into the vacuum deposition chamber, whereby is prevented the possibility of the hydrogen-containing gas causing an explosion should air leak into the vacuum deposition chamber.

Abstract: In a continuous vacuum deposition plating of a metal strip, thinner coating at the edges can be prevented by maintaining the pressure of the deposition chamber in which an evaporation chamber is housed at a properly higher level than the pressure of the evaporation chamber.

Abstract: In the continuous vapor deposition coating of a metal strip, the coating amount can be rapidly changed by keeping the vapor flow at acoustic velocity and changing the cross-sectional area of the vapor path.