42results about How to "Improved delayed fracture resistance" patented technology

Provided are: a high-strength bolt that has a tensile strength of 1,000-1,400 MPa and a delayed fracture resistance that is on par with standard steel alloys even when Mo and Cr are omitted or reduced with respect to SCM steel or SCr steel; a steel wire for a bolt that is for producing the aforementioned high-strength bolt; and a useful method for producing the bolt and the steel wire for a bolt. The steel wire for a bolt satisfies a predetermined chemical composition. With regard to the boron content of the surface of the steel wire for a bolt, when the diameter of the steel wire for a bolt is denoted by D0 and the boron content of a D0 / 4 portion of the steel wire for a bolt is 100%, the average proportion of the boron content of the surface of the steel wire for a bolt is 75% or less and the difference between the maximum value and the minimum value of this proportion is 25% or less. The prior austenite grain size number in an area from the surface of the steel wire for a bolt to a depth of 100 [mu]m is no.8 or higher.

A cold rolled and annealed martensitic steel sheet is provided. The steel sheet includes by weight percent, 0.30 greater than or equal to C smaller than or equal to 0.5%, 0.2 greater than or equal to Mn smaller than or equal to 1.5%, 0.5 greater than or equal to Si smaller than or equal to 3.0%, 0.02 greater than or equal to Ti smaller than or equal to 0.05%, 0.001 greater than or equal to N smaller than or equal to 0.008%, 0.0010 greater than or equal to B smaller than or equal to 0.0030%, 0.0 greater than or equal to Nb smaller than or equal to 0.1%, 0.2 greater than or equal to Cr smaller than or equal to 2.0%, P smaller than or equal to 0.02%, S smaller than or equal to 0.005%, Al smaller than or equal to 1%, Mo smaller than or equal to 1% and Ni smaller than or equal to 0.5%. The remainder of the composition includes iron and unavoidable impurities resulting from melting. The microstructure is 100% martensitic and a prior austenite grain size is lower than 20(mu)m. The steel sheet has a delayed fracture resistance of at least 24 hours during an acid immersion U-bend test. A method, part, structural member and vehicle are also provided.

Systems, methods, apparatuses, and computer program products for time division duplex (TDD) uplink / downlink (UL / DL) configuration indication for TDD interference management and traffic adaptation (eIMTA) are provided. One method includes providing, by a network node, a time division duplex (TDD) uplink / downlink (UL / DL) configuration indication pattern. The TDD UL / DL configuration indication pattern may be used to indicate multiple TDD UL / DL configurations in DCI format C associated with the certain configured carriers andthe concrete fixed downlink subframe index.

Provided are a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet having at least 980 MPa, and having excellent plating properties, workability in terms of bendability, hole expandability, and balance between strength and ductility, and delayed fracture resistance. This high-strength plated steel sheet is a plated steel sheet having a plating layer on the surface of a base material steel sheet, includes predetermined steel components, and comprises, in order from the interface between the base material steel sheet and the plating layer toward the base material steel sheet side: a soft layer having a Vickers hardness that is 90% or less of the Vickers hardness at a t / 4 position of the base material steel sheet, where t is the thickness of the base material steel sheet; and a hard layer including martensite, bainite, and ferrite in predetermined ranges. The average depth D of the soft layer is 20 [mu]m or greater, and the average depth d of an inner oxide layer is 4 [mu]m or greater and less than D.

The invention belongs to the field of alloy steel smelting of iron and steel industries, and particularly provides an extra large high strength steel for a fastening part and a production method. The steel for the fastening part comprises, by mass, 0.43-0.47% of C, no more than 0.10% of Si, 0.60-0.90% of Mn, no more than 0.020% of P, no more than 0.010% of S, 0.02-0.06% of Als, 0.90-1.20% of Cr, 0.30-0.60% of Mo, 0.20-0.50% of V, 0.02-0.06% of Nb, 0.001-0.003% of B, and the balance Fe and unavoidable impurities. The production method of the steel comprises the following steps of molten iron desulfurization, converter smelting, deoxidation alloying, argon blowing, LF furnace treatment, continuous casting, casting blank heating, high line or bar rolling and stelmor control cooling. Steel inclusion produced through the method is low in grade, the extra large high strength steel is uniform in texture, good in cold heading property and hardenability and good in delayed fracture resistance, the tensile strength of wire rods reaches above 850 MPa, the depth of hardening layers of produced products reaches above 10 mm, the problem that the diameter of the large-scale fastening part needs to be increased to meet the tolerance requirements is solved to a certain extent, and the method is suitable for manufacturing the large-scale high strength fastening part.

The invention discloses a 14.9-grade steel wire rod for high-strength fasteners and a preparation method thereof. Its chemical composition contains: C: 0.44-0.48%, Si: ≤0.20%, Mn: 0.40-0.80% in mass percentage , P: ≤0.015%, S: ≤0.010%, Cr: 1.0‑1.5%, Mo: 0.6‑0.8%, Nb: 0.03‑0.06%, V: 0.2‑0.5%, Ti: 0.03‑0.06%, Ni: ≤0.20%, Cu: ≤0.20%, Alt: 0.010‑0.050%, N: 0.0080‑0.0160%, H: ≤0.00015%, O: ≤0.0015%, the balance is Fe and impurities; the steel wire rod can improve the finished product The tensile strength of the bolt is high, and it has excellent resistance to delayed fracture.

A bolt according to the present invention has such a chemical composition in which 0.50 to 0.65% by mass inclusive of carbon (C), 1.5 to 2.5% by mass inclusive of silicon (Si), 1.0 to 2.0% by mass inclusive of chromium (Cr), 0.2 to 1.0% by mass inclusive of manganese (Mn) and 1.5 to 5.0% by mass inclusive of molybdenum (Mo) are contained, the total amount of phosphorus (P) and sulfur (S) which areimpurities is 0.03% by mass or less and the remainder is made up from iron (Fe), and the bolt has, formed on the surface thereof, an iron-based oxide film having a thickness of 3 to 20 [mu]m inclusive, has excellent delayed fracture resistance, and can achieve a stable tightening axial force.

The invention discloses a high-strength heat-treated steel bar and a manufacturing method thereof. The steel bar is processed through an induction heating process. During cooling, the steel bar is first annealed to a two-phase region, and then rapid cooling treatment is carried out. The steel bar satisfies mechanical performances of: a tensile strength of 1200-1800MPa, an elongation rate higher than 10%, and a yield strength ratio no higher than 0.9. The relaxation performance of the steel bar satisfies that: when initial stress is 70% of a nominal tensile strength, a stress relaxation rate of 1000h is no higher than 2%.

The invention discloses a 1400MPa grade delayed fracture resistant high-strength bolt steel and a manufacturing method. The high-strength bolt steel has a relatively high Cu element content, and the Cu element can play a role of precipitation strengthening in the steel, and can also promote passivation film formation. When Cu element precipitates and Cu element segregates, it can induce the precipitation of Mo, V, Nb and other elemental carbides, enhance its hydrogen trapping effect, and at the same time prevent crack propagation, so that the tensile strength of the finished bolt is not less than 1400MPa. The reduction of area is not less than 40%, and it has excellent resistance to delayed fracture. The bolt steel does not add rare earth elements, and at the same time strictly controls the addition of other microalloying elements, on the one hand, the production cost is reduced, and on the other hand, the relatively simple process is conducive to mass production.

The invention relates to a delayed-fracture-resistant high-strength bolt alloy material and a manufacturing method of bolts. The bolt alloy material comprises, by weight, 0.2%-0.5% of C, 0.05%-0.5% of Si, 0.03%-0.08% of Mn, 0.01%-0.02% of P, 0.02%-0.04% of S, 0.1%-0.16% of Cu, 0.24%-0.32% of Co, 0.22%-0.28% of Ni, 0.08%-0.24% of Al, 0.12%-0.26% of Ti, 0.14%-0.29% of Mo, 0.1%-0.15% of V, 0.08%-0.14% of Sm, 0.04%-0.06% of Te, 0.08%-0.14% of neodymium iron boron and the balance Fe and impurity elements. The bolt alloy material is high in strength and good in delayed fracture resistance.