58results about How to "Excellent resistance to hydrogen embrittlement" patented technology

Disclosed is a hot-dip galvanized steel sheet which comprises a steel sheet part and a deposit formed on the surface of the steel sheet part and has a tensile strength of 770 MPa or higher, wherein the deposit is a zinc layer formed by hot-dip plating or an alloyed zinc layer formed by hot-dip plating, the steel sheet part comprises a soft layer, which is in direct contact with the deposit, and an inner layer, which is the part other than the soft layer, and the thickness (D) of the soft layer is 0.001 to 5% of the thickness (t) of the steel sheet part. In a cross-section along the thickness direction of the steel sheet part, when the hardness of the soft layer measured by a nanoindentation method is expressed by H1 and the representative hardness of the steel sheet part measured by the nanoindentation method is expressed by Ha, then H1 is 5-75% of Ha.

Provided is a steel structure for hydrogen, such as a pressure accumulator for hydrogen or a line pipe for hydrogen, which has a reduced fatigue crack growth rate, and superior hydrogen embrittlement resistance in a high-pressure hydrogen environment compared to conventional steel. The steel structure for hydrogen, which has excellent hydrogen embrittlement resistance in high-pressure hydrogen gas, has a steel composition having either 10-95% bainite by surface area, 10-95% martensite by surface area, or 10-95% pearlite by surface area, with the remainder substantially comprising ferrite.

The present invention provides an ultrahigh strength steel sheet that has high hydrogen embrittlement resisting property and high workability. The ultrahigh strength steel sheet comprises: C: more than 0.25-0.60 wt%, si: 1.0-3.0 wt%, Mn: 1.0-3.5 wt%, P: less than 0.15 wt%, S: less than 0.02 wt%, Al: less than 1.5 wt% (excluding 0%), the residual consists of Fe and unavoidable impurity, has a metallurgical structure after stretch forming process with 3% working rate, which comprises: 1% or more residual austenite; 80% or more in total of bainitic ferrite and martensite; and 9% or less (may be 0%) in total of ferrite and pearlite in terms of proportion of area to the entire structure, wherein the mean axis ratio (major axis / minor axis) of the residual austenite grains is 5 or higher; and the steel sheet has tensile strength of 1180 MPa or higher.

A high-strength cold-rolled steel sheet having a prescribed chemical composition, wherein the structure at a position 1 / 4 of the sheet thickness from the surface is, by volume ratio, 70.0% or more tempered martensite, more than 3.0% but less than 10.0% residual austenite, a total of 25.0% or less of ferrite and bainite, and 5.0% or less of martensite, the structure at a position 25 mum from the surface is, by volume ratio, a total of 70% or more of ferrite and bainite and a total of 30% or less of martensite and tempered martensite, and at the position 25 mum from the surface the average graindiameter of the martensite and the tempered martensite is 5.0 mum or less, the tensile strength is 1310 MPa or greater, the uniform elongation is 5.0% or greater, and the ratio R / t of the 90-degree V-bend limit bend radius R and the thickness t is 5.0 or less.

This hot-dip galvanized steel sheet has a specific chemical composition and a steel structure that is represented as: containing, in terms of area ratio, polygonal ferrite in an amount not more than 10%, upper bainite in an amount not more than 20%, residual austenite in an amount not more than 5%, and martensite in an amount not less than 70%; and a martensite that includes Fe carbides at a number density not less than 1*106 / mm2, that is contained in an amount not less than 50% of the entire amount of martensite, and that has an average effective crystal grain size of not more than 5.0 [mu]m.

Provided is a high-strength bolt having high strength and exceptional hydrogen embrittlement resistance. The bolt according to the present invention has a chemical composition comprising 0.22-0.40% bymass of C, 0.10-1.50% by mass of Si, 0.20% by mass to less than 0.40% by mass of Mn, 0.020% by mass or less of P, 0.020% by mass or less of S, 0.70-1.45% by mass of Cr, 0.005-0.060% by mass of Al, 0.010-0.045% by mass of Ti, 0.0003-0.0040% by mass of B, 0.0015-0.0080% by mass of N, and 0.0020% by mass or less of O, and the remainder comprising Fe and impurities. The chemical composition satisfiesformulae (1) and (2), and the bolt has a tensile strength of 1000-1300 MPa. (1) 0.50 <= C + Si / 10 + Mn / 5 + 5Cr / 22 <= 0.85 (2) Si / Mn > 1.0 Each of the symbols for the elements in formulae (1) and (2)is assigned with the corresponding content content (mass%).

Disclosed are an austenitic stainless steel having improved hydrogen embrittlement resistance, and a high-pressure hydrogen gas container. The austenitic stainless steel according to one embodiment ofthe present invention comprises by wt%: 0.1% or less (excluding 0) of C; 1.0% or less (excluding 0) of Si; 2.0% to 7.0% of Mn; 15% to 25% of Cr; 7% to less than 10% of Ni; 0.4% or less (excluding 0)of N, and the balance of Fe and other inevitable impurities, wherein the stacking fault energy (SFE) defined by the following formula (1) is 40-70 mJ / m2.

The present invention addresses the problem of providing, with regard to a high-strength galvanized steel sheet for which hydrogen embrittlement is a concern, a high-strength galvanized steel sheet which has excellent plating appearance and the material of which has excellent hydrogen embrittlement resistance, and a high yield strength suitable for impact-resistant parts of construction materialsand automobiles, and providing a high-strength member, and manufacturing methods therefor. This high-strength galvanized steel sheet comprises: a steel sheet having a prescribed component compositionand a steel structure containing 4-20% residual austenite, 30% or less (including 0%) ferrite, 40% or greater martensite, and 10-50% bainite, and a zinc plating layer on the steel sheet. The amount ofdiffusible hydrogen in the steel is less than 0.20 mass pmm, and the tensile strength is 1100 MPa or greater. The relationship between the tensile strength TS (MPa), the elongation El (%), and the sheet thickness t (mm) satisfies formula (1), and the yield ratio YR is 67% or greater. TS*(El+3-2.5t)>= 13000 (1)

A low alloy steel subjected to thermal treatment after welding, the low alloy steel containing, in mass%, 0.01 to 0.15% C, 3% or less Si, 3% or less Mn, 0.08% or less Al, and one or more element selected from among Ti, V and Nb in a range satisfying equation (1), the remainder being Fe and impurities, wherein the impurities contain 0.01% or less N, 0.05% or less P, 0.03% or less S, and 0.03% or less O. Said low alloy steel exhibits excellent resistance to embrittlement caused by hydrogen such as stress corrosion cracking in a wet hydrogen sulfide environment in a HAZ. Equation (1): 0.1[C(%)]<=[Ti(%)]+[V(%)]+0.5[Nb(%)]<=0.2. (Each element symbol in the equation represents the content (mass%) of each element}.

The present invention provides a hot-dip galvanized steel sheet having a hot-dip galvanized layer on at least one surface of a base material steel sheet of the hot-dip galvanized steel sheet, and a method for producing the same, wherein the base material steel sheet has a predetermined composition so as to The integral rate meter contains: ferrite: 0% to 50%, retained austenite: 0% to 30%, tempered martensite: 5% or more, fresh martensite: 0% to 10%, and pearlite Total with cementite: 0% to 5%, in the case of residual structure, the residual structure is composed of bainite, and the concentration of B atoms at the prior austenite grain boundary is 2.0 atomic% or more, and The average effective crystal grain size is 7.0 μm or less.

Provided is an austenitic stainless steel material having excellent hydrogen embrittlement resistance and high strength. This austenitic stainless steel material has a chemical composition in terms of mass% of no more than 0.100% C, no more than 1.00% Si, no more than 5.00% Mn, 15.00-22.00% Cr, 10.00-21.00% Ni, 1.20-4.50% Mo, no more than 0.050% P, no more than 0.050% S, no more than 0.100% Al, no more than 0.100% N, and 0-0.70% Cu, the remainder comprising Fe and impurities, the austenitic grain size number based on ASTM E112 of the austenitic stainless steel material is 5.0 to less than 8.0, the dislocation cell structure ratio in a cross section perpendicular to the longitudinal direction of the austenitic stainless steel material is 50% to less than 80%, and the number density of deposits having a major axis of 1.0 um or greater is 5.0 / 0.2 mm2 or less.

The invention discloses a hydrogen permeating alloy material and a method for preparing the same, and the alloy comprises the following components by molar percentage: titanium of 23mol%-54mol%, cobalt of 21mol%-39mol% and tantalum, titanium, cobalt and tantalum of which the total content is of 98-100mol%.The manufacturing of the alloy material comprises steps of putting titanium, cobalt and tantalum with a purity of more than 99% into a non-consumable vacuum arc furnace, vacuumizing to a pressure below 3*10 3 Pa, filling in argon of high purity to a pressure of 4*10 Pa, and then smelting. The alloy material of the invention has the hydrogen permeability and excellent hydrogen brittleness resistance ability higher than pure palladium under 573-673K, while the cost of the alloy material isonly about 1 / 100 of that of the pure palladium, thus, the alloy material can be used for hydrogen gas isolation and purification, and can also be used for a catalytic-reformed compact membrane reactor and the like.