A composite armor plate is disclosed. The composite armor plate includes a first layer made from an ultra-high hardness, high strength alloy that is bonded to a second layer made from a high fracture toughness alloy that also may have high strength. The composite armor plate according to the present provides a gradient of strength, hardness, and toughness. The composite armor plate according to the invention may also include third and fourth layers of different alloys that provide combinations of hardness, strength, and fracture toughness that are intermediate of the hardness, strength, and fracture toughness provided by the first and second steel layers. A method of making the composite armor plate is also disclosed.

A fastener for connecting a first housing part of a steam or gas turbine to a second housing part of the turbine which is made of a parent metal with a high degree of stress relaxation.

A precipitation hardenable, martensitic stainless steel is disclosed. The alloy has the following broad composition in weight percent.

TABLE-US-00001 Ni 10.5-12.5 Co 1.0-6.0 Mo 1.0-4.0 Ti 1.5-2.0 Cr  8.5-11.5 Al Up to 0.5 Mn  1.0 max. Si 0.75 max. B 0.01 max.

The balance of the alloy is iron and the usual impurities found in commercial grades of precipitation hardenable martensitic stainless steels as known to those skilled in the state of the art in melting practice for such steels. A method of making parts from the alloy and an article of manufacture made from the alloy are also described.

There is provided a centrifugally cast composite roll for rolling having excellent wear resistance and surface deterioration resistance at levels of a high-speed steel cast iron roll and having rolling incident resistance at a level of a high alloy grain cast iron roll. A centrifugally cast composite roll for rolling having an outer layer and an inner layer, the outer layer including chemical components by mass ratio: C: 1.0 to 3.0%; Si: 0.3 to 3.0%; Mn: 0.1 to 3.0%; Ni: 0.1 to 6.0%; Cr: 0.5 to 6.0%; Mo: 0.5 to 6.0%; V: 3.0 to 7.0%; Nb: 0.1 to 3.0%; B: 0.001 to 0.1%; N: 0.005 to 0.070%; and the balance being Fe and inevitable impurities, wherein: the chemical composition of the outer layer satisfies following Formula (1), has a crystallization and precipitation amount of graphite suppressed to less than 0.3% by area ratio, and has 1 to 15% of MC carbide by area ratio; and the centrifugally cast composite roll for rolling does not have a cast defect having a diameter of ϕ4 mm or more at a boundary between the outer layer and the inner layer,

50×N+V<9.0  (1).

A high-strength steel sheet comprises: a chemical composition containing C, Si, Mn, P, S, Al, N, Mo, Cr, Ca, and Sb with a balance consisting of Fe and inevitable impurities, wherein [% Si], [% Mn], [% P], [% Mo], and [% Cr] satisfy a predetermined relationship; a steel microstructure that contains ferrite, hard phase, and retained austenite and in which a carbon concentration in the retained austenite is 0.55% or more and 1.10% or less, an amount of diffusible hydrogen in the steel sheet is 0.80 mass ppm or less, a surface layer softening thickness is 5 μm or more and 150 μm or less, and a corresponding grain boundary frequency in a surface layer of the steel sheet after a high-temperature tensile test is 0.45 or less; and a tensile strength of 980 MPa or more.

A steel sheet including a steel micro-structure containing, in volume fraction, tempered martensite: 85% or more, retained austenite: 5% or more to less than 15%, and ferrite, pearlite, bainite, and as-quenched martensite being less than 10% in total, when contents of Mn and C in the retained austenite are denoted by Mn.sub.A and C.sub.A, and when contents of Mn and C in a matrix are denoted by Mn.sub.M and C.sub.M, respectively, following Formulas (1) to (3) are satisfied, and the number of carbides having an equivalent circle radius of 0.1 μm or more is 100 or less in a region measuring 20000 μm.sup.2, and the steel sheet has a tensile strength of 1100 MPa or more. The steel sheet is excellent in crash resistance and formability.

Mn.sub.A/Mn.sub.M≥1.2  (1)

C.sub.A/C.sub.M≤5.0  (2)

C.sub.A≤1.0  (3)

A bearing component composed of a chromium-molybdenum-vanadium alloyed tool steel is produced by a process that includes: (i) performing a first preheating within a temperature range of 600-650° C., (ii) performing a second preheating within a temperature range of 850-900° C., (iii) austenitizing in vacuum at 1000-1180° C. for 20-40 min, (iv) gas quenching at a minimum of 4-5 bar overpressure, and (v) tempering by performing either a double temper at 520-560° C. for 1.5-2.5 hours in each temper, or a triple temper at 520-560° C. for 0.5-1.5 hours in each temper. The steel alloy may be composed (in mass percent) of 1.32-1.45 C, 0.32-0.50 Si, 0.26-0.48 Mn, 4.0-4.85 Cr, 3.35-3.55 Mo, 3.55-3.85 V, 0-0.13 W, 0-0.20 Ni, 0-0.15 Cu, 0-0.8 Co, 0-0.03 P, and 0-0.03 S, the balance being iron and unavoidable impurities. Mo may be replaced with W or vice versa in a replacement ratio Mo:W of 1:2.

Provided is a ferritic stainless steel having excellent brazability and excellent corrosion resistance to condensed water in an environment in which the ferritic stainless steel is used for an exhaust heat recovery device or an EGR cooler. The ferritic stainless steel has a composition containing, in mass %, C: 0.025% or less, Si: 0.01% or more and less than 0.40%, Mn: 0.05 to 1.5%, P: 0.05% or less, S: 0.01% or less, Cr: 17.0 to 30.0%, Mo: 1.10 to 3.0%, Ni: more than 0.80% and 3.0% or less, Nb: 0.20 to 0.80%, Al: 0.001 to 0.10%, and N: 0.025% or less, with the balance being Fe and incidental impurities, and satisfying the following expression (1) and expression (2):
C+N≤0.030%  (1)
Cr+Mo≥19.0%  (2) where C, N, Cr, and Mo in expression (1) and expression (2) represent the contents (mass %) of the corresponding elements.

A ferritic stainless steel sheet for an automobile brake disc rotor includes: 0.001 to 0.05 mass % of C; 0.001 to 0.05 mass % of N; 0.3 to 4.0 mass % of Si; 0.01 to 2.0 mass % of Mn; 0.01 to 0.05 mass % of P; 0.0001 to 0.02 mass % of S; 10 to 20 mass % of Cr; one or both of 0.001 to 0.5 mass % of Ti and 0.01 to 0.8 mass % of Nb; and a balance consisting of Fe and impurities. After a hot stamping treatment, a crystal grain size is in a range from 100 to 200 μm, and precipitates each having a grain size of 500 nm or less are present at a density of 0.01 to 20 pieces per square micrometer.

A stainless steel seamless pipe having high strength, excellent low-temperature toughness and corrosion resistance, and a composition including, in mass %, C: 0.06% or less, Si: 1.0% or less, Mn: 0.01% or more and 1.0% or less, P: 0.05% or less, S: 0.005% or less, Cr: 14.0% or more and 17.0% or less, Mo: more than 3.80% and 6.0% or less, Cu: more than 1.03% and 3.5% or less, Ni: 3.5% or more and 6.0% or less, Al: 0.10% or less, N: 0.10% or less, O: 0.010% or less, and the balance is Fe and incidental impurities. Elements C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfy a predetermined relationship. The stainless steel seamless pipe has a yield strength of 862 MPa or more and has a microstructure that contains at least 40% martensitic phase, at most 60% ferrite phase, and at most 30% retained austenite phase by volume.