Abstract: A safety armor for protection against gunfire, comprising a shield composed of an alloy steel which has a base carbon content of less than 0.3% by mass of carbon and has been enriched in strength-increasing elements including at least one of carbon and nitrogen by means of a thermochemical treatment in a surface zone extending from at least one outer surface of the shield, with the steel of the surface zone having an increased surface hardness as a result of a thermal treatment including at least one of hardening and tempering carried out after the thermochemical treatment, the steel is enriched to at least 0.5% by mass of carbon in the surface zone and has a minimum hardness of 55 HRC on the outer surface with the presence of carbides in the surface zone, with the shield having a silicon content of not more than 0.4% by mass both in the surface zone and in a lower hardness region adjoining the surface zone which has a carbon content and hardness less than the surface zone.

Abstract: A low-cost, thermomechanical method for manufacturing [001] textured FeGa alloys is described. The method includes hot rolling a FeGa cast ingot to break down the cast structure, a two-stage warm rolling with an intermediate anneal, and then a final texture anneal that resulted in recrystallization and a recrystallization-induced texture. The FeGa ingot contains a grain growth agent that was used to restrain grain growth of the FeGa material in the undesired crystallographic direction. A protective steel sheath can be placed around the FeGa material during processing to avoid direct contact of the FeGa and the rolls during the hot and warm rolling process steps and also avoid oxidation of the alloy ingot. FeGa alloys with a very strong [001] texture and a large magnetostriction along [001] crystallographic direction were obtained using this method. FeGaBe alloys and new methods for making them are also described.

Abstract: A clutch member and a process for manufacturing the same. In the clutch member, a steel sheet has an initial composition of 0.32 to 0.38% of C, 0.15% or less of Si, 0.3 to 0.5% of Mn, and 0.16 to 0.60% of Cr, by mass; and has an initial uniformly dispersed structure of carbide with an average particle diameter of 0.1 to 1.2 ?m; and is subjected to punch and subsequent heat treatment for the main body to have a tensile strength of 1307 to 1633 MPa, hardness of 400 to 500 HV, impact value of 70 J/cm2 or more, and degree of flatness of 0.15% or less which is obtained by a formula of F=d/D where d is camber of the flat portion and D is a diameter of a circumscribed circle of the main body.

Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.

Abstract: Welded 36% Ni—Fe alloy steel and a method of making such welded steel for use in storage tanks, pipelines, and other equipment associated with cryogenic substances is disclosed. The welded steel has a similar coefficient of thermal expansion in both the weld and base steel.

Abstract: A rolling, sliding part is made from a bearing steel, and the rolling, sliding surface thereof has a surface layer portion which is 56 to 64 in Rockwell C hardness, up to 12 vol. % in retained austenite content and 4 to 6 degrees in the X-ray half value width of martensite. Even if made from a common bearing steel, the rolling, sliding part is reduced in the likelihood of developing a WEA or like fatigue structure, consequently exhibiting a prolonged rolling, sliding life for use under severe conditions involving a high temperature, high speed, high load or high vibration.

Abstract: The present invention provides a high strength welded steel pipe superior in weld zone embrittlement crack characteristics and a method of production of the same, that is, a method of production of a welded steel pipe superior in hydrogen embrittlement cracking resistance of weld metal characterized by seam welding from the inner and outer surfaces by a tensile strength of 850 MPa or more, then expanding or reducing the size of the pipe for correction, which method of production of welded steel pipe characterized in that the hydrogen concentration of the preceding weld metal is 0.2 cc or less per 100 g at ordinary temperature.

Abstract: Strain-hardened steel alloys having a high tensile strength are prepared by cold working of alloys whose microstructure includes grains in which laths of martensite alternate with thin films of stabilized austenite. Due to the high dislocation density of this microstructure and the tendency of the strains to move between the martensite and austenite phases, the strains created by cold working provide the microstructure with unique mechanical properties including a high tensile strength. Surprisingly, this is achieved without the need for intermediate heat treatments (patenting, in the case of steel wire) of the steel between cold working reductions.

Abstract: An iron-based compact having a high density and also an iron-based sintered body having a high strength and a high density are manufactured with a high productivity by pre-compacting an iron-based mixed powder prepared by mixing an iron-based metal powder and a graphite powder; pre-sintering the resulting pre-compacted iron-based mixed powder at a temperature higher than 1000° C. but not higher than 1300° C. to produce a sintered iron-based powder preform containing C: 0.10 to 0.50 mass %, O: 0.3 mass % or less, and N: 0.010 mass % or less and having a density of 7.2 Mg/m3 or more; and subjecting the sintered iron-based powder preform to high-velocity compaction at a compaction energy density of 1.8 MJ/m2 or more (1.4 MJ/m2 or more for a sintered pure-iron based powder preform).

Abstract: Steel sheet, the composition of the steel of which comprises, the contents being expressed by weight: 0.08%?C?0.23%, 1%?Mn?2%, 1?Si?2%, Al?0.030%, 0.1%?V?0.25%, Ti?0.010%, S?0.015%, P?0.1%, 0.004%?N?0.012%, and, optionally, one or more elements chosen from: Nb?0.1%, Mo?0.5%, Cr?0.3%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting.

Abstract: A method of forming gray iron components includes applying a substantially uniform magnetic field to gray iron. The method also includes heat-treating the gray iron while the gray iron is within the magnetic field.

Abstract: An article is presented where the article comprises an alloy having a minor phase dispersed within a matrix phase and a plurality of substantially equiaxed grains. The article further comprises a continuous gradient in grain size from a first grain size at an outer surface of the article to a second grain size at an inner portion of the article, wherein the first grain size is less than the second grain size. Methods for forming the article using high deformation processing are also presented, where the processing includes extruding the feedstock material through a die having a twist channel configured to apply a torsional strain to the feedstock material as it passes through the die to form an extruded billet.

Abstract: The method of making a hardened steel part or component includes making a semi-finished article of air-hardened steel; cold-forming the semi-finished article into a finished-shape part or component with a desired or predetermined finished shape and then hardening the finished-shape part or component with the finished shape by a heat treating process. The air-hardened steel particularly preferably contains about 0.67% by weight carbon, about 1.50 % by weight silicon, about 1.50% by weight manganese, about 1.00% by weight chromium, about 0.10% by weight nickel, about 0.25% by weight molybdenum, and a balance or remaining portion of iron with standard impurities.

Abstract: A vehicle is armored the steps of sequentially making a steel plate with a thickness of 4 mm to 15 mm of by weight 0.2 to 0.4% carbon, 0.3 to 0.8% silicon, 1.0 to 2.5% manganese, max. 0.02% phosphorous, max. 0.02% sulfur, max. 0.05% aluminum, max. 2% copper, 0.1 to 0.5% chromium, max. 2% nickel 0.1 to 1% molybdenum, 0.001 to 0.01% boron, 0.01 to 1% tungsten, max. 0.05% nitrogen, and balance iron and impurities. This plate is heated to above the AC3 temperature and deformed without cooling in a press. While still in the press, the steel plate is cooled and cured. Then the deformed and cured steel plate is taken out of the press and mounted on the motor vehicle without significant further working or shaping.

Abstract: Methods are provided for forming a plurality of permanent magnets with two different north-south magnetic pole alignments for use in microelectromechanical (MEM) devices. These methods are based on initially magnetizing the permanent magnets all in the same direction, and then utilizing a combination of heating and a magnetic field to switch the polarity of a portion of the permanent magnets while not switching the remaining permanent magnets. The permanent magnets, in some instances, can all have the same rare-earth composition (e.g. NdFeB) or can be formed of two different rare-earth materials (e.g. NdFeB and SmCo). The methods can be used to form a plurality of permanent magnets side-by-side on or within a substrate with an alternating polarity, or to form a two-dimensional array of permanent magnets in which the polarity of every other row of the array is alternated.

Abstract: The present invention relates to the use of a pre-coating process, which utilizes metallic plating as a surface pre-treatment for a ferrous-alloy precursor prior to applying a corrosion-inhibiting coating to improve the overall corrosion protection of the pre-treated and pre-coated component. Preferably the ferrous-alloy precursor is a heat-treatable, precipitation-hardenable stainless-steel material and the pre-treatment is a cadmium or a zinc-nickel alloy plating without a subsequent chromate or phosphate seal finish.

Abstract: A billet for a thixocasting process and a thixocasting process using the billet allows casting using a thixocasting process to be realized at low production cost without permeation of an oxide film to the inside of the billet in injection molding. In a billet used for a thixocasting process continuously cast by intermittently drawing out, the interval of the oscillation marks is 10 mm or less and the maximum tilt angle of the oscillation marks relative to a cross section which is at a right angle to the drawing out direction is 45° or less.

Abstract: A process is disclosed for the continuous thermochemical treatment of metal strip. It is useful with steel strip, of the oxidation-reduction type, in which the strip moves through a furnace in a protective atmosphere. The strip passes through at least one partial or total isolation device positioned within one or more sections of the furnace. The strip is heated in this isolation device in atmospheres having a dew point tailored to each strip according to the specific composition of the steel so that the atmosphere is oxidizing in the case of certain addition elements, but remains reducing in the case of iron.

Abstract: The present invention relates to a method for the manufacture of galvannealed metal sheet, wherein a hot strip is produced from an IF steel containing 0.01 to 0.1 wt. % silicon, wherein the hot strip is coiled at a coiler temperature no lower than 700° C. and no higher than 750° C., wherein a cold strip is rolled from the coiled hot strip, wherein the cold strip is recrystallization-annealed in an annealing furnace in an annealing gas atmosphere, wherein the cold strip thus annealed is provided with a zinc coating in a zinc bath, and wherein the coated cold strip is post-annealed at a galvannealing temperature no lower than 500° C. and no higher than 540° C. The invention also relates to a galvannealed metal sheet which possesses improved adhesion of the coating layer to the base material and proposes a method which is suited for the manufacture of metal sheet having such properties.

Abstract: High pressure cylinders comprising backing steel cylinders and tool steel liners are disclosed. An annealed tool steel liner is inserted into the backing steel cylinder, followed by heat treating to harden the tool steel liner. The tool steel liner may be provided as a single continuous tube, thereby avoiding problems associated with segmented liners. The high-pressure cylinders are suitable for use as plastic and rubber extruders injection molding cylinders and the like.

Abstract: A steel wire, 0.10-0.40 mm in diameter, obtained by subjecting a high-carbon (0.70-0.90 wt. %) steel wire material to heat treatment and wire drawing, wherein its tensile strength and test values of special repeated torsional tests satisfy a predetermined relation; and a method of manufacturing the same. A high strength steel wire which has so high a ductility as to substantially prevent the wire from being broken even during wire twisting, and which rarely encounters a decrease in the ductility even after the wire has been subjected to age hardening by heating, is obtained, and a method of manufacturing the same is economical.

Abstract: A steel composition, in which, Si content is regulated to a given range and Nb and Cu or Ni, Mo are compositively added, and a recrystallization annealing is carried out to form an internal oxide layer just beneath a surface of a steel sheet and a surface oxide simultaneously formed on the surface of the steel sheet is removed by pickling. As a result, the formation of oxides of Si, Mn and the like is considerably decreased on the surface of the steel sheet in a subsequent heating before plating because the above internal oxide layer acts as a diffusion barrier. Thus, there can be obtained high tensile strength hot-dipped steel sheets having a considerably excellent plating property.

Abstract: A hot-working steel article, e.g., tool, comprising a material which comprises, in % by weight, 0.451 to 0.598 C, 0.11 to 0.29 Si, 0.11 to 0.39 Mn, 4.2 to 4.98 Cr, 2.81 to 3.29 Mo, 0.41 to 0.69 V, with the balance iron, contaminants and accompanying elements, as well as an alloy and a process for making said article.

Abstract: A method using of a magnetic field to affect residual stress relief or phase transformations in a metallic material is disclosed. In a first aspect of the method, residual stress relief of a material is achieved at ambient temperatures by placing the material in a magnetic field. In a second aspect of the method, retained austenite stabilization is reversed in a ferrous alloy by applying a magnetic field to the alloy at ambient temperatures.

Abstract: A weldable structural steel product having fine complex precipitates of TiN and CuS is provided which contains, in terms of percent by weight, 0.03 to 0.17%C, 0.01 to 0.05% Si, 0.4 to 2.0% Mn, 0.005 to 0.2% Ti, 0.0005 to 0.1% Al, 0.008 to 0.030% N, 0.0003 to 0.01% B, 0.001 to 0.2% W, 0.1 to 1.5% Cu, at most 0.03% P, 0.003 to 0.05% S, at most 0.005% O, and balance Fe and incidental impurities while satisfying conditions of 1.2≦Ti/N≦2.5, 10≦N/B≦40, 2.5≦Al/N≦7, 6.5≦(Ti+2Al+4B)/N≦14, and 10≦Cu/S≦90, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 &mgr;m or less.

Abstract: According to the method of the present invention, the ball plug is press fit into the counterbored passage of a fuel injector nozzle assembly prior to hardening of the fuel injector nozzle assembly. A core hardening and gas nitriding process is then applied to the assembly, causing the ball plug to expand and the passage diameter to shrink. This results in a greatly increased seal between the ball plug and the passage, and substantial elimination of the gaps experienced therebetween in prior art fuel injector nozzle assemblies.

Abstract: Method of reheating metallurgical products, in which solid products, especially steel products, are reheated so as to bring them from a temperature substantially below 400° C. to a temperature of at least about 1000° C. by passing them through a furnace having an upstream zone in which the said products are preheated and a downstream zone in which the said products are brought to their final temperature on leaving the furnace, the downstream zone of the furnace being fitted with burners, at least some of which operate with an oxidizer which is air, the smoke (flue gases) generated by these burners flowing as a countercurrent to the products and preheating these products in the upstream preheating zone. According to the invention, at least one burner is placed in the upstream preheating zone of the furnace, this burner being fed with a mixture of oxidizer and fuel, the oxidizer containing more than 21 vol % and preferably more than 30 vol % oxygen.

Abstract: A method for manufacturing a seamless steel tube, wherein a tubing material for the seamless steel tube is produced by a hot working process from a material having less workability, such as a high Cr-high Ni-high C alloy steel including Cr at a content not less than 15 weight % and Ni at a content not less than 20 weight % or a ferritic stainless steel including Cr at a content not less than 16 weight %, and then cold drawn at a reduction rate of not less than 15% and further cold rolled after applying an appropriate heat treatment, so that a round or an inner grooved steel tube is obtained. It is preferable that the hot extrusion process is employed for the hot working process and a cold Pilger mill is employed for the cold rolling process. In the cold rolling process, the crackings or damage resulting from the reduced toughness of the tubing material as well as the breakage of a mandrel in producing the round or the inner grooved tube can be suppressed.

Abstract: The method for manufacturing steel sheet comprises the steps of: rough-rolling to form a sheet bar; finish-rolling the sheet bar to form a steel strip; applying primary cooling and secondary cooling to the finish-rolled steel strip; and coiling the secondary-cooled steel strip. The primary cooling is conducted at cooling speeds of 120° C./sec or more down to the temperatures of from 500 to 800° C. The secondary cooling is conducted at cooling speeds of less than 60° C./sec.

Abstract: A wire rod steel superior in straightness, after being subjected to cold drawing. This wire rod steel comprises: C: 0.15 mass % or less (not including 0 mass %), Si: 0.05 mass % or less (including 0 mass %), Mn: 0.3-2 mass %, P: 0.2 mass % or less (including 0 mass %), S: 0.08-0.5 mass %, Al: 0.05 mass % or less (including 0 mass %), N: 0.01 mass % or less (not including 0 mass %), inevitable impurities and Fe as the balance. Its ferrite grain size number of the wire rod steel is No. 11 or less according to ISO 643.

Abstract: The present invention includes bainitic steel doctor blades, bainitic steel coating blades, bainitic steel creping blades and bainitic steel rule die knives used in gravure printing, flexographic printing, paper making, die cutting of materials including paper, plastic, foam, leather, etc. Other uses include printing processes such as pad printing and electrostatic printing. The invention also includes an improved method for producing bainitic steel strip. The present invention is accomplished by using bainitic steel components that exhibit superior straightness and wear properties and are bendable around small radii.

Abstract: A method for cold forming a flattened, end-threaded rod into a U-bolt answers the need for high-strength steel rods that can be bent into flattened U-bolts by spring and suspension repair facilities or the like. By controlling the amount of work put into the end-threaded flattened rod during bending, it is possible to manufacture a flattened, end-threaded rod from a high-strength steel that can be successfully cold bent into a U-bolt. The amount or degree of flattening and the radius of the U-bolt are variables which applicant controls to successfully cold bend a high-strength steel flattened rod into a U-bolt. Therefore, the spring and suspension repair facility avoids the need to heat the flattened rods for warm forming and, instead, can maintain an inventory of end-threaded and flattened rods for cold forming into flattened U-bolt comply with OEM designs when modifying or repairing vehicles.

Abstract: A method for processing a hot formed, high-tensile-strength steel having an ultimate tensile strength (UTS) of at least about 730 MPa (105 ksi) and excellent toughness to retain essentially all the strength and toughness is provided. This processing is needed for the fabrication of high strength fittings that are used in the construction of linepipe for transport of natural gas, crude oil, as well as other applications. Furthermore, the hot formed high strength steel may be weldable with a Pcm of less than or equal to 0.35.

Abstract: Ferrous articles are austenitized, then converted to at least 60% bainite, and the balance substantially converted to martensite; the articles are then cold worked, preferably by both compression and tensile deformation to at least 60% yield strength. The articles have improved serviceability, particularly fatigue life.

Abstract: Ferrous articles are austenitized, then converted to at least 60% bainite, and the balance substantially converted to martensite by quenching; the articles are then cold worked, preferably by both compression and tensile deformation to at least 60% yield strength. The articles have improved serviceability, particularly fatigue life.

Abstract: A process is disclosed for the continuous thermochemical treatment of metal strip. It is useful with steel strip, of the oxidation-reduction type, in which the strip moves through a furnace in a protective atmosphere. The strip passes through at least one partial or total isolation device positioned within one or more sections of the furnace. The strip is heated in this isolation device in atmospheres having a dew point tailored to each strip according to the specific composition of the steel so that the atmosphere is oxidizing in the case of certain addition elements, but remains reducing in the case of iron.

Abstract: A novel shape memory alloy of Fe—Mn—Si system containing at least Fe, Mn, and Si wherein the alloy contains niobium carbide in the structure and is improved in that a sufficiently satisfactory shape memory effect is provided without carrying out a special treatment termed training.

Abstract: Improved targets for use in DC magnetron sputtering of nickel or like ferromagnetic face-centered cubic (FCC) metals are disclosed for forming metallization films having effective edge-to-edge deposition uniformity of 5%(3&sgr;) or better. Such targets may be characterized as having: (a) a homogeneous texture mix that is at least 20% of a <200> texture content and less than 50% of a <111> texture content, (b) an initial pass-through flux factor (LPTF) of about 30% or greater; and (c) a homogeneous grain size of about 200 &mgr;m or less.

Abstract: After heat treatment for hardening the outer peripheral surface of the input shaft 15 is enforced, a straightening operation for straightening the bent portions of the input shaft 15 caused by the heat treatment is carried out prior to formation of the through holes 17, 17. After then, the input shaft 15 is machined using electric sparks to thereby form the through holes 17, 17 in the input shaft 15. In the present working method, there is eliminated the possibility that, during the straightening operation, stresses can concentrate in the through holes 17, 17 portions of the input shaft 15, thereby being able to attain the above object.

Abstract: A process for the production of a metal sheet having a multi-layered structure and a fine composite structure, which process comprises stacking at least two kinds of thin sheets selected from thin sheets of pure metals and thin sheets of alloys alternately so as to have multiple layers in total, integrating the stacked sheets by circumferential welding or placing the stacked sheets in a steel or stainless steel box to integrate these, and then, bonding all the layers of the integrated sheets metallically by hot rolling, and a metal sheet obtained thereby.

Abstract: A bulk amorphous metal magnetic component has a plurality of layers of amorphous metal strips laminated together to form a generally three-dimensional part having the shape of a polyhedron. The bulk amorphous metal magnetic component may include an arcuate surface, and preferably includes two arcuate surfaces that are disposed opposite each other. The magnetic component is operable at frequencies ranging from between approximately 50 Hz and 20,000 Hz. When the component is excited at an excitation frequency “f” to a peak induction level Bmax, it exhibits a core-loss less than “L” wherein L is given by the formula L=0.0074 f (Bmax)1.3+0.000282 f1.5 (Bmax)2.4, said core loss, said excitation frequency and said peak induction level being measured in watts per kilogram, hertz, and teslas, respectively.

Abstract: The method for manufacturing cold-rolled steel sheet comprises the steps of: rough-rolling a slab using a rough-rolling unit; finish-rolling the sheet bar using a continuous hot finishing-rolling mill; cooling the hot-rolled steel strip on a runout table; coiling thus cooled hot-rolled steel strip; and applying picking, cold-rolling the hot-rolled steel strip, and final annealing to the cold-rolled steel strip.

Abstract: A high strength phosphorus-containing steel having fine texture free from the problem of embrittlement by positively using the presence of P, which is a carbon steel having an average ferritic grain diameter of 3 &mgr;m or less and containing from 0.04 to 0.1% by mass of P, wherein the volume fraction of P segregated in the grain boundary accounts for 0.3 or less in case the grain boundary is covered by a P layer 1 nm in thickness.

Abstract: When an electrical potential is applied to a metal or a metallic solution or a metal that is close to the melting point or a metal that is molten the electric charges are either drawn off and the metal has a high positive potential or a surfeit of electric charges are added and the metal has a high negative potential. When the metal is heated and then cooled, under said potential, the internal structure of the metal is changed. The crystal structure can become nano crystaline and or amorphous dependent upon the alloying elements, the potential and the temperature. This process has applications in inductive electrical parts as well as metalic structual materials.

Abstract: To be able to satisfactorily bright-anneal metals having a high affinity to oxygen in a hood-type furnace or the like under a protective gas, a rather pure inert gas such as argon, neon or helium, which is mixed with not more than 50 vol-% of a reducing gas, for instance hydrogen, is used as protective gas in cooperation with an oxygen binder, preferably titanium.

Abstract: The invention relates to medium carbon steels and low alloy steels having a concentration of a machinability enhancing agent (“MEA”), i.e. tin and/or antimony, at its ferrite grain boundaries which enhances the steel's machinability and to processes for producing such steels. The invention encompasses medium carbon steels and low alloy steels characterized by having MEA bulk contents of from about 0.02 to about 0.09 weight percent, by having the sum of the MEA bulk content and the copper bulk content being no greater than about 0.10 weight percent, and by having a microstructure at the time of machining having a concentration of MEA at ferrite grain boundaries in an amount at least about five times the MEA bulk content of the steel.

Abstract: Disclosed herein is a method of coating a substrate with a zinc dialkyldithiophosphate (ZDDP) material, comprising the steps of selecting a substrate which is reactive with said ZDDP material; providing an atmosphere containing said ZDDP material at a predetermined concentration; exposing said substrate to said atmosphere for a sufficient period of time and at a sufficient temperature, so as to cause said ZDDP material to form a layered substrate having a layer of a ZDDP derivative material thereon; and annealing said layered substrate.

Abstract: A method of complete bainite hardening of steel for use in bearings and other load carrying components, wherein bainite transformation is performed at a temperature just above the martensite formation temperature, transforming 25%-99% of the austenite into bainite at said temperature, and then increasing the temperature to speed up the transformation of the remaining austenite into bainite.

Abstract: A thixocast casting material is formed of an Fe--C--Si based alloy in which an angle endothermic section due to the melting of a eutectic crystal exists in a latent heat distribution curve and has a eutectic crystal amount Ec in a range of 10% by weight <Ec<50% by weight. This composition comprises 1.8% by weight .ltoreq.C.ltoreq.2.5% by weight of carbon, 1.4% by weight .ltoreq.Si.ltoreq.3% by weight of silicon and a balance of Fe including inevitable impurities.

Abstract: This invention provides a ferritic heat-resistant steel suitable for a pressure-resistant member to be used at a temperature of 400 to 550.degree. C. The ferritic heat-resistant steel having an excellent high temperature strength contains, in terms of wt %, 0.05 to 0.15% of C, 0.10 to 0.08% of Si, 0.20 to 1.5% of Mn, 0.5 to 1.5% of Cr, 0.10 to 1.15% of Mo, 0.005 to 0.30% of V, 0.005 to 0.05% of Nb, 0.0002 to 0.0050% of B, and if necessary, 0.005 to 0.05% of Ti and 0.4 to 1.0% of W, either alone or in combination, and having a structure comprising not greater than 15% of pro-eutectoid ferrite, in terms of a metallic structural area ratio, and the balance of bainite. The present invention provides also a process for producing a ferritic heat-resistant steel having an excellent high temperature strength, comprising tempering the steel having the composition at a temperature within the range 950 to 1,010.degree. C., and conducting tempering while keeping a T.P. value within the range of 18.50.times.10.sup.