741 results about "Hydrogen embrittlement" patented technology

The present invention relates to a method of baking treatment of steel product parts using a high frequency or ultra-high frequency for preventing delayed fracture from occurring due to diffusive hydrogen occluded in steel parts, for example, screws, bolts and the like, or for heating surface layers of the steel parts to generate a difference in temperature between the surface layers and interiors of the steel parts, thereby causing distortion in lattices, wherein the surface layers of the steel parts are rapidly heated to 100 to 300° C. with a high frequency or ultra-high frequency at 10 KHz or higher to remove the diffusive hydrogen which is involved in hydrogen embrittlement, or to transfer an existing state to non-diffusive hydrogen which is not involved in the hydrogen embrittlement.

The present invention provides an ultra-high strength steel sheet having excellent hydrogen embrittlement resistance, which includes: 0.06 to 0.6% of C; 0.5 to 3% of Si+Al; 0.5 to 3% of Mn; 0.15% or lower of P; and 0.02% or lower of S in terms of mass percentage, and also includes 3% or higher of residual austenite structure, 30% or higher of bainitic ferrite structure, and preferably 50% or lower of polygonal ferrite in terms of an areal ratio to the entire structure, wherein a mean grain size of bainite blocks is smaller than 20 μm as determined by comparing observations of the same region of the bainitic ferrite structure by EBSP (electron back scatter diffraction pattern) and SEM.

The purpose of the present invention is to provide a high strength thin steel sheet that has high hydrogen embrittlement resisting property. In order to achieve the above purpose, a high strength thin steel sheet having high hydrogen embrittlement resisting property comprises: C: 0.10 to 0.25%; Si: 1.0 to 3.0%; Mn: 1.0 to 3.5%; P: 0.15% or less; S: 0.02% or less; and Al: 1.5% or less (higher than 0%) in terms of percentage by weight, with balance of iron and inevitable impurities; and the metal structure comprises: residual austenite; 1% by area or more in proportion to the entire structure; bainitic ferrite and martensite: 80% or more in total; and ferrite and pearlite: 9% or less (may be 0%) in total, while the mean axis ratio (major axis/minor axis) of said residual austenite grains is 5 or higher, and the steel has tensile strength of 1180 MPa or higher.

The invention relates to an ultrahigh-strength thin steel sheet excellent in the hydrogen embrittlement resistance, the steel sheet including, by weight %, 0.10 to 0.60% of C, 1.0 to 3.0% of Si, 1.0 to 3.5% of Mn, 0.15% or less of P, 0.02% or less of S, 1.5% or less of Al, 0.003 to 2.0% of Cr, and a balance including iron and inevitable impurities; in which grains of residual austenite have an average axis ratio (major axis/minor axis) of 5 or more, the grains of the residual austenite have an average minor axis length of 1 μm or less, and the grains of the residual austenite have a nearest-neighbor distance between the grains of 1 μm or less.

The present invention provides a method of hot pressing using hot rolled and cold rolled steel sheet or Al-based plated steel sheet or Zn-based plated steel sheet enabling a strength of at least 1200 MPa to be obtained after high temperature forming and with extremely little possibility of hydrogen embrittlement and such hot pressed parts, that is, a method of hot pressing a high strength automobile parts comprising using steel sheet containing as steel compositions by wt % C:0.05 to 0.5% or steel sheet plated mainly with Al or Zn to produce automobile members by hot pressing during which making the heating temperature before pressing Ac₃ or more to 1100° C. or less, making the hydrogen concentration in the heating atmosphere 6 vol % or less, and making the dew point 10° C. or less and such hot pressed parts.

The present invention provides a high strength steel used for spring steel that has excellent hydrogen embrittlement resistance. The high strength steel which spring steel having excellent hydrogen embrittlement resistance comprises 0.20 to 0.60% of C, 1.0 to 3.0% of Si, 1.0 to 3.5% of Mn, higher than 0% and not higher than 1.5% of Al, 0.15% or less P, 0.02% or less S, and balance of iron and inevitable impurities and the structure includes: 1% or more residual austenite; 80% or more in total of bainitic ferrite and martensite; and 10% or less (may be 0%) in total content of ferrite and pearlite in the proportion of area to the entire structure, and also the mean axis ratio (major axis/minor axis) of the residual austenite grains is 5 or higher and the steel tensile strength is 1860 MPa or higher.

The invention relates to a deoiling, derusting and rust preventing metal surface treating compound. It is made up of ammonia or amine, organic acid, auxiliary agent, surface active agent, chelating agent. Its pH value is 7-8. The organic acid belongs to food, participating reaction, and has no waste acid and water after using. The treated metal surface appears virgin metal natural color. It will not corrode the metal. And the í‹hydrogen embrittlementíŒ will never happen.

A weld joint having a base material and a weld metal both of an austenitic steel, wherein the weld metal has a chemical composition, in mass %, that C: 0.04% or less, Si: 1.0% or less, Mn: 3% or less, P: 0.02% or less, S: 0.005% or less, Cr: 15 to 25%, Ni: 30% or more, Mo: 10% or less, Nb: 2.5 to 5%, Al: 3.0% or less, Ti: 0.5% or less, and the balance: Fe and inevitable impurities, the contents of Al and Ti satisfying the following: (Ti+Al)>Nb/8. The weld joint is a high strength austenitic steel weld joint which exhibits excellent toughness at a low temperature and excellent resistance to hydrogen embrittlement, which are required for a piping and a vessel for high pressure hydrogen, particularly also in a welded zone.

A cold rolled steel sheet satisfying on the basis of percent by mass the chemical composition of 0.06-0.6% C, 0.1-2% Si, 0.01-3% Al, 1-4% Si+Al, 1-6% Mn, Si/Mn≦0.40, in which there exists 10 or more pieces/100 μm² of Mn—Si composite oxide having Mn—Si atom ratio (Mn/Si) of 0.5 or over and major axis of from 0.01 μm to 5 μm and also having a covering ratio of 10% or below at which the surface of the steel sheet is covered with oxide containing Si as the main component.

Hydrogen embrittlement is prevented in Sm₂Co₁₇-based magnets and R₂Fe₁₄B-based magnets by metal plating the magnet, then carrying out heat treatment, or by forming a metal oxide or metal nitride layer on the metal plating layer or directly on the magnet itself.

The invention discloses products of a Han ecological cycle method from the first to the seventh (HC, HW and HM series products) and relates to a recycled zero-emission metal and nonmetal surface multifunctional cleaning agent with effects of oil removal (used for nonmetals only), rust removal, scale removal, phosphorization, passivation, oxidation resistance and corrosion prevention. The cleaning agent comprises the following main active ingredients in parts by mass: 1.65-111 parts of a nonionic surfactant, 1.25-115 parts of a zwitterionic surfactant, 12.6-152 parts of a complexing agent, 0.2-157 parts of a chelating agent and 2.25-131 parts of aids. The cleaning agent has wide applicability for the concentrated type multiple metals and nonmetals and synchronous multifunctional complexing property, over-corrosion of exterior of the metals is avoided and hydrogen embrittlement of interior of the metals is avoided, the cleaning agent is safe to use, three wastes are not produced, the resources are saved, and the environmental friendliness is achieved.

The invention relates to a preparing process of a nanometer complex alloy co-permeation anticorrosion coating layer, which belongs to the technical field of the metal surface modified or alloying treatment. The preparing process comprises computer analog computation, preliminary treatment of steel members, complex configuration of co-permeation agent, energizing agent, active agent and filling agent, co-permeation processing of steel members and after-treatment of steel members. The preparing process has the advantages that firstly, the computer simulation is adopted to calculate optimal machining conditions, and to reduce the various consumption under the conditions; secondly, partial zinc powder is replaced by aluminum powder as the co-permeation agent, the hardness and the wear resistant property of a co-permeation layer are improved, and the co-permeation cost is reduced; thirdly, nanometer mixed rare earth oxide with low price and good effect is adopted as the energizing agent; fourthly, the co-permeation layer contains no heavy metal cadmium, is environmentally protective and is free from pollution; fifthly, the preparing process has no hydrogen embitterment damage, the processing temperature is low, the time is short, the hydrogen embitterment damage occurring on the co-permeation layer is avoided, and the energy consumption is reduced simultaneously.

The present invention discloses a titanium alloy chemical milling solution and its application milling process, which mainly contains nitric acid and hydrofluoric acid as the main components of mixed acid acidic corrosion solution, sodium lauryl sulfate, ethylene glycol n-butyl ether and/or or urea additives. The surface tension of the solution is maintained at a stable value by using the present invention. The adsorption of ethylene glycol n-butyl ether can reduce the interfacial tension and increase the chemical milling rate. Sodium lauryl sulfate, which improves the fluidity of the solution, can eliminate excessive corrosion of the metal at the root of the chemical milling fillet, and prevent the appearance of "grooves", "slopes" and "ripples". Sodium nitrate prevents the formation of scale of alloying elements on the surface of the chemical milling groove, improves the surface finish of the chemical milling surface and facilitates maintenance of the equipment. Urea can effectively absorb the nitrogen-containing gas produced in the chemical milling process, reduce the volatilization of acid liquid, and avoid pollution to the environment. The invention does not need heating equipment, the amount of hydrogen added is less than 9ppm, the service life of the solution is long, hydrogen embrittlement does not occur, and the process has little influence on the fatigue performance of the material.

The invention discloses a steel surface compact oxide layer scavenging agent, which is composed of mixed acid, oxidizer, surfactant, corrosion inhibitor, anti-rust agent and pure water with the weightpercent of the components as follows: 5-20% of H2SO4, 10-30% of HCl, 0.5-3% of oxalic acid, 0.25-3.5% of oxidizer, 1-3% of surfactant, 0.25-3% of corrosion inhibitor, 1-3% of anti-rust agent and remainder of water; the scavenging agent is colorless transparent, has no pungent smell, has obvious effect in scavenging steel surface compact oxide layer and rust, and is sucked on pure steel surface compact to form a film, the contact between the scavenging agent and metal can be isolated, the over-corrosion of steel and hydrogen embrittlement can be avoided; the invention has low cost, small investment, simplified technique and good effect in steel surface treatment, and needs no temperature control equipment.

The invention provides a hammered steel with good resistant property for hydrogen brittleness and crank made of said hammered steel, said steel comprises following components: C 0.2-0.6% (by weight percent, the same with following ones); Si 0.1-0.4%; Mn 0.7-1.5%; Ni less than 1.0%; Cr 1.2-3.5%; Mo 0.1-0.6%, Al 0.01-0.05%, and mixture containing at least one of Ti, Zr, Hf larger than 0.005%; the average circular degree of foreign material with maximum chord length being larger than 1 um is larger than 0.5; the number of foreign material with maximum chord length being larger than 20 um (100mm2) is less than 100, and the average circular degree is larger than 0.25, and the number of foreign material with maximum chord length being 1-10 um (100mm2) is larger than 100.

Disclosed is a high strength steel sheet having excellent hydrogen embrittlement resistance. The steel sheet has a tensile strength of 1180 MPa or more, and satisfies the following conditions: with respect to an entire metallographic structure thereof, bainite, bainitic ferrite and tempered martensite account for 85 area % or more in total; retained austenite accounts for 1 area % or more; and fresh martensite accounts for 5 area % or less (including 0 area %).

Disclosed herein is a high strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance. The steel wire comprises, by mass, 0.4 to 0.60% of C, 1.7 to 2.5% of Si, 0.1 to 0.4% of Mn, 0.5 to 2.0% of Cr, 0.015% or less of P (exceeding 0%), 0.015% or less of S (exceeding 0%), 0.006% or less of N (exceeding 0%), 0.001 to 0.07% of Al, and the remainder being Fe and unavoidable impurities. The steel wire has a structure wherein prior austenite has an average grain size of 12 μm or less, and retained austenite exists in an amount of 1.0 to 8.0 vol. % with respect to a whole structure of the steel wire. The retained austenite has an average grain size of 300 nm or less and a maximum grain size of 800 nm or less. The steel has a tensile strength of 1,900 MPa or more.

The invention provides a chemical derusting cleaning agent for removing iron rust and other iron compounds on the surface of iron and inside iron components, and a preparation method and application thereof. The chemical derusting cleaning agent consists of the following substances in percentage by weight: 4 to 10 percent of oxalic acid, 0.5 to 1.5 percent of triethanolamine, 3 to 10 percent of phosphoric acid, 0.3 to 1.5 percent of thiourea, 0.2 to 0.6 percent of zinc dihydrogen phosphate or zinc oxide, 0.5 to 2 percent of ethylene diamine tetraacetic acid, 0.5 to 1.2 percent of hexamethylene tetramine, 0.05 to 0.1 percent of sodium dodecyl benzene sulfonate and the balance of water. Chemical derusting cleaning solution prevents over-corrosion and hydrogen embrittlement on a filter matrix through combination effects of a passivator, a corrosion inhibitor, a protective agent and other components in the derusting process, the waste liquor discharge frequency is low, acid mist does not overflow in the cleaning process, and the cleaning agent is environmentally-friendly and harmless to the health of an operator.

A microwave sintering and heat treatment method for preparing high-performance tungsten-based high-density alloy comprises the following steps: preparing a powder compact by a traditional powder metallurgy method, putting the compact in a microwave high-temperature furnace with atmosphere protection and a vacuum pump, controlling the atmosphere in the furnace chamber to be reducing atmosphere at a heating phase below 1200 DEG C; sintering the product at low vacuum at a high-temperature phase of 1200-1400 DEG C, and vacuumizing the furnace to obtain a high vacuum of 10-2 Pa at a cooling phase after sintering. The obtained alloy has a uniform fine grain structure, and high mechanical properties. The invention adopts low vacuum at the sintering phase, and adopts high vacuum at the cooling phase, which allow the hydrogen content of the alloy to be reduced, and effectively avoid the hydrogen embrittlement phenomenon. Additionally, the tungsten-based high-density alloy is prepared by microwave sintering technology and equipment, which is rapid, high-efficient, simple, and low in cost; the tungsten-based high-density alloy is prepared by microwave sintering-heat treatment technology; theprocess is easy to control; the technology is mature, and is applicable to industrial production.

A hot stamping steel material, which secures good hydrogen embrittlement resistance even when the steel sheet after hot stamping is subjected to processing leading to remaining of stress, such as piercing and which is easily practicable, wherein the steel sheet has the chemical composition of: C: 0.18 to 0.26%; Si: more than 0.02% and not more than 0.05%; Mn: 1.0 to 1.5%; P: 0.03% or less; S: 0.02% or less; Al: 0.001 to 0.5%; N: 0.1% or less; O: 0.001 to 0.02%; Cr: 0 to 2.0%; Mo: 0 to 1.0%; V: 0 to 0.5%; W: 0 to 0.5%; Ni: 0 to 5.0%; B: 0 to 0.01%; Ti: 0 to 0.5%; Nb: 0 to 0.5%; Cu: 0 to 1.0%; and balance: Fe and impurities, in terms of % by mass, the concentration of a Mn-containing inclusion is not less than 0.010% by mass and less than 0.25% by mass, and the number ratio of a Mn oxide to the inclusion having a maximum length of 1.0 to 4.0 μm is 10.0% or more.

The invention discloses a preparation method for producing a diamond cutting line through steel wire magnetization. The method comprises the following steps: carrying out chemical nickel-plating treatment on diamond micro-powder so as to metalize the surface of the diamond micro-powder; removing a brass layer of a copper wire the surface of which is plated by brass in an alkali solution; preplating copper in a cyanide-free alkali copper plating solution; magnetizing the steel wire with pre-plated copper by magnetizing with a sintered neodymium iron boron strong magnet; in the process of sanding and electric-plating, attaching the diamond micro-powder which is dispersed in the solution and the surface is metalized to the surface of the steel wire under a magnetic field and the stirring function, and compositely depositing on the surface of the steel wire together with the copper plated layer; and plating the outermost layer of the steel wire with nickel. The electric-plated diamond cutting line is subjected to thermal treatment so as to demagnetize and eliminate the hydrogen embrittlement. The copper plated layer is adopted in pre-plating, sanding and electric-plating, so that the cost of the plated layer is lowered, the time needed for plating plated layers of the same thickness is also reduced, the production efficiency is improved, and meanwhile the uniform distribution of the diamond micro-powder on the surface of the steel wire is realized in sanding and electric-plating.

A method is provided for coating a steel surface of a workpiece. According to an aspect of the invention, a steel workpiece is subjected to a first embrittlement-relief baking operation to form a protective oxide layer on the steel surface. The protective oxide layer is de-scaled, and the steel surface is activated. A hydrogen barrier coating is deposited on the activated steel surface, and activated. A zinc-nickel alloy is plated on the barrier coating, and subjected to a second embrittlement-relief baking operation. The porous plating is sealed with a conversion coat. The method is especially useful in making low to no hydrogen embrittlement cadmium-replacement steel parts. Also provided is a corrosion resistant coated steel workpiece.