51results about How to "High uniform elongation" patented technology

The invention discloses ultralow yield ratio 980 MPa-grade cold rolling two-phase steel and a manufacturing method of the ultralow yield ratio 980 MPa-grade cold rolling two-phase steel, and belongs to the technical field of two-phase steel. Chemical components of the steel comprise, by weight, 0.13-0.18% of C, 0.3-0.6% of Si, 1.7-2.4% of Mn, 0.03-0.06% of Als, 0-0.05% of Nb, 0.3-0.5% of Cr and the balance Fe and inevitable impurities. In composition design, the composite strengthening way mainly comprising phase transformation strengthening and combining solid solution strengthening, refined crystalline strengthening, phase change strengthening and precipitation strengthening is adopted, the cold rolling two-phase steel plate can be used as an automobile anti-collision part, a structural part and an inner plate material. The steel has the advantages that DP980 has the ultralow yield ratio YS/TS which is smaller than 0.50, good ductility A50 which is larger than or equal to 14%, the high n value, the small mechanical property fluctuation range, the low process sensitivity and other property characteristics, can reduce springback after stamping and is beneficial to follow-up deep processing of the automobile industry.

The invention discloses an X70 large deformation resisting pipeline steel and a manufacturing method. The steel comprises chemical components including, by mass percent, 0.04%-0.09% of C, 0.15%-0.55% of Si, 1.45%-1.75% of Mn, 0.04%-0.10% of Nb, 0.02%-0.08% of V, 0.01%-0.03% of Ti, 0%-0.20% of Cu, 0.15%-0.55% of Ni, 0%-0.15% of Mo, 0.15%-0.45% of Cr, 0.025%-0.045% of Al, 0.0002%-0.011% of N, smaller than or equal to 0.015% of P, smaller than or equal to 0.005% of S, and the balance Fe and other inevitable impurity elements. Production of the X70 large deformation resisting pipeline steel comprises the following process routes of material preparing, converter or electric furnace smelting, furnace exterior refining, casting, slab reheating, controlled rolling and controlled cooling, and after two-phase region quenching, tempering is conducted or the tempering technology is not adopted. Compared with the prior art, the X70 large deformation resisting pipeline steel and the manufacturing method have the beneficial effects that the yield ratio is lower, the uniform ductility is higher, tenacity matching is better, the steel plate and copper plate performance difference is small, the structure uniformity in the thickness direction is high, and the strip-shaped level is low.

The invention discloses a high-strength thick-wall welded steel pipe for a deep sea pipeline and a production method thereof. The steel pipe plate contains the following components in percentage by mass: 0.03-0.07% of C, 0.10-0.40% of Si, 1.20-1.60% of Mn, less than or equal to 0.012% of P, less than or equal to 0.0015% of S, 0.10-0.35% of Ni, 0.10-0.35% of Cr, less than or equal to 0.35% of Cu, 0.10-0.35% of Mo, 0.01-0.06% of Nb, 0.01-0.06% of V, 0.005-0.025% of Ti, 0.01-0.06% of Al, 0.0020-0.0060% of N, 0.0005-0.0035% of Ca, 1.5-4.0% of Ti/N and the balance of Fe and inevitable impurities. The steel pipe disclosed by the invention has high plasticity and corrosion resistance and can be used for conveying the deep sea oil gas in a complicated working condition of deep sea service.

A method and apparatus for joining materials having primarily ferritic properties is described. The method includes joining the ferritic materials using a welding process and a weld material having a primarily austenitic microstructure. The resulting weldment enhances the properties of yield ratio, uniform elongation, toughness and tearing resistance thereby producing superior strain capacity. High strain capacity produces a structure that accommodates high axial loading. The weldment can also accommodate larger than conventional weld flaws while maintaining sufficient strength, tearing resistance, and fracture toughness under high axial loading.

The invention discloses a continuous casting type large-wall-thickness hot-rolled steel plate for deep sea pipelines and a production method thereof, and belongs to the technical field of pipeline steel. The hot-rolled steel plate is composed of, by weight, 0.03-0.06% of C, 0.15-0.30% of Si, 1.20-1.35% of Mn, smaller than or equal to 0.010% of P, smaller than or equal to 0.0012% of S, 0.01-0.05% of Alt, 0.03-0.05% of Nb, 0.00-0.05% of V, 0.005-0.016% of Ti, 0.25-0.40% of Ni, 0.00-0.30% of Cr, 0.00-0.20% of Cu, 0.00-0.15% of Mo and the balance Fe and inevitable impurity elements. Continuous castings with the thickness being 400 mm are adopted for producing the steel plate with the thickness being 41-48 mm. The steel plate and the production method thereof have the advantages that good metallographic structures are obtained, the Charpy impact toughness at -20 DEG C, the drop hammer toughness at -20 DEG C, the low yield ratio, the high uniform elongation rate, the anti-fracture toughness property CTOD, the A solution acid resistance HIC and SSCC, and the like of the large-wall-thickness hot-rolled steel plate for the deep sea pipelines are realized, and therefore the construction requirement of conveying pipelines of oil and gas fields of deep seas can be met.

Provided is a low yield ratio, high strength and high uniform elongation steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. In particular, the steel plate contains 0.06% to 0.12% C, 0.01% to 1.0% Si, 1.2% to 3.0% Mn, 0.015% or less P, 0.005% or less S, 0.08% or less Al, 0.005% to 0.07% Nb, 0.005% to 0.025% Ti, 0.010% or less N, and 0.005% or less O on a mass basis, the remainder being Fe and unavoidable impurities. The low yield ratio, high strength and high uniform elongation steel plate has a metallographic microstructure that is a two-phase microstructure consisting of bainite and M-A constituent, the area fraction of the M-A constituent being 3% to 20%, the equivalent circle diameter of the M-A constituent being 3.0 μm or less.

The invention discloses ultra-fine grain martensite ferrite dual-phase steel with two-peak ferrite grains distributed and a production process of the ultra-fine grain martensite ferrite dual-phase steel. After billet steel is obtained through smelting, casting, forging and hot rolling, the billet steel is subjected to heat treatment which comprises the following working procedures of homogenizing annealing, normalizing, warm rolling and continuous annealing, and continuous annealing comprises three stages that firstly, the billet steel is heated to the temperature of Ac1 at the speed of 40 DEG C/s-80 DEG C/s, secondly, the billet steel continues to be heated to 740 DEG C-800 DEG C at the speed of 1 DEG C/s-5 DEG C/s, and thirdly, quenching is carried out. By means of the process, austenite grains are refined, the ferrite gains are distributed in a two-peak size manner, the uniform elongation of the steel is greatly increased when the steel is pulled at the room temperature, and the yield ratio is smaller than 0.5.

A high strength galvanized steel sheet is provided comprising steel containing C: 0.06% or more and 0.20% or less, Si: less than 0.50%, Mn: 0.5% or more and less than 2.0%, P: 0.05% or less, S: 0.02% or less, Al: 0.60% or more and 2.00% or less, N: less than 0.004%, Cr: 0.10% or more and 0.40% or less and B: 0.003% or less, satisfying the relationships 0.8≦Mn_eq≦2.0 and Mn_eq+1.3[% Al]≧2.8, and a microstructure containing a ferrite phase and a second phase whose volume fraction is 15% or less, the second phase having a martensite phase whose volume fraction is 3% or more, a retained austenite phase whose volume fraction is 3% or more and a sum of the volume fractions of a pearlite phase and a bainite phase being equal to or less than the volume fraction of the martensite phase and the volume fraction of the retained austenite phase.

A high-strength steel sheet has a chemical composition consisting of, in mass percent, C: 0.10 to 0.24%, Mn: 3.50 to 12.00%, Si: 0.005 to 5.00%, Al: 0.005 to 5.00%, P: 0.15% or less, S: 0.030% or less, N: 0.020% or less, O: 0.010% or less, Cr: 0 to 5.00%, Mo: 0 to 5.00%, Ni: 0 to 5.00%, Cu: 0 to 5.00%, Nb: 0 to 0.50%, Ti: 0 to 0.50%, W: 0 to 0.50%, B: 0 to 0.010%, Ca: 0 to 0.05%, Mg: 0 to 0.05%, Zr: 0 to 0.05%, REM: 0 to 0.05%, Sb: 0 to 0.50%, Sn: 0 to 0.50%, As: 0 to 0.05%, and V: 0 to 2.0%, with the balance: Fe and impurities, and a steel micro-structure at a ¼ sheet-thickness position includes, in area percent, retained austenite: 10.0 to 55.0%, high temperature tempered martensite: 30.0 to 75.0%, and low temperature tempered martensite: 15.0 to 60.0%, with the balance including fresh martensite: 0 to 10.0%, pearlite: 0 to 5.0%, and bainite: 0 to 5.0%.

A steel sheet according to an aspect of the present invention includes a predetermined chemical composition; in which a metallographic structure in a ¼ t portion contains residual austenite of 4 volume % to 70 volume %; [Mn]_γ/[Mn]_ave>1.5 is satisfied in the ¼ t portion; f_γs/f_γ≤0.30 and [C]×[Mn]≥0.15 are satisfied in the ¼ t portion.

The invention discloses cold-rolled hot-dip galvanized steel. The cold-rolled hot-dip galvanized steel comprises the following chemical elements of, in percentage ration by mass, 0.06%-0.14% of C, 1.3%-2.4% of Mn, 0.1%-1.0% of Si, and the balance Fe and inevitable impurities; and the microstructure of the cold-rolled hot-dip galvanized steel is ferrite + martensite + bainite + retained austenite.In addition, the invention further discloses a manufacturing method of the above cold-rolled hot-dip galvanized steel. The manufacturing method comprises the steps that (1) smelting and casting are carried out; (2) hot rolling is carried out; (3) acid pickling is carried out; (4) cold rolling is carried out; (5) hot galvanizing recrystallization annealing is carried out, specifically, a cold-rolled sheet is heated to the soaking temperature T1 for thermal insulation for a period of time; and then the soaked steel plate is cooled to the intermediate temperature T2 at the first cooling speed andthen cooled to T3 at the second cooling speed, thermal insulation is carried out for a period of time, then the temperature is increased to the zinc pool temperature T4 for thermal insulation for a period of time, wherein the cooling speed is less than the second cooling speed, T2 is larger than or equal to 640 DEG C and less than or equal to T1, and T3 is larger than Ms and less than or equal toT4; and (6) cooling is carried out to the room temperature.

The invention provides a pipeline steel X70 steel plate in low compression ratio, and a production method thereof. The pipeline steel X70 steel plate in low compression ratio is prepared from the following components in weight percent: C is 0.030-0.080%, Mn is 1.55-1.75%, Si is 0.10-0.40%, S is not more than 0.0050%, P is not more than 0.015%, Nb is 0.035-0.060%, Ti is 0.008-0.025%, V is not morethan 0.10%, Alt is 0.020-0.060%, Cr is not more than 0.30%, Mo is not more than 0.20%, and the balance of Fe and unavoidable impurities. In the production method of the steel plate provided by the invention, the X70 pipeline steel with low compression rate and thick specification is produced in batch by adopting laminar subsection cooling process, and the engineering technical requirement is satisfied.

The invention relates to an alloy pipe containing 18-24% of Mn and a manufacturing method thereof. The alloy pipe comprises: 0.002-0.2% of C, 18-24% of Mn, 0-4% of Si, 0-5% of Al, no more than 0.015% of P, no more than 0.01% of S, no more than 0.008% of N, or one or more of 1-6% of Cr, 0.1-0.5% of Cu, 0.01-0.6% of Nb, 0.01-0.1% of Ti and 0.01-0.3% of V, and balance of Fe. The manufacturing method comprises the following steps: casting the raw materials by vacuum melting, carrying out homogenizing annealing and hot-rolling on the casted materials so as to be manufactured into steel plates or bars; carrying out resistance-welding or hot-rolling on the steel plates or balls so as to be manufactured into pipe blanks; carrying out solid solution treatment and ageing treatment on the pipe blanks, wherein the obtained product has a uniform elongation percentage no less than 50% and a yield strength of 300-400MPa; and carrying out dilatational strain of 30% on the pipe blanks, wherein the obtained product has the uniform elongation percentage no less than 20%, the yield strength of 560-760MPa and the yield ratio of 0.62-0.80.

Provided is a low yield ratio, high strength and high toughness steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. The steel plate has a metallographic microstructure that is a three-phase microstructure consisting of bainite, M-A constituent, and quasi-polygonal ferrite, the area fraction of the bainite being 5% to 70%, the area fraction of the M-A constituent being 3% to 20%, the remainder being the quasi-polygonal ferrite, the equivalent circle diameter of the M-A constituent being 3.0 μm or less. The steel plate has a yield ratio of 85% or less and a Charpy impact test absorbed energy of 200 J or more at −30° C. before or after being subjected to strain ageing treatment at a temperature of 250° C. or lower for 30 minutes or less.

The invention discloses X80 large deformation resisting pipeline steel and a manufacturing method. The steel comprises the following chemical components in percentage by mass: 0.04-0.09% of C, 0.15-0.55% of Si, 1.50-1.75% of Mn, 0.04-0.10% of Nb, 0.02-0.08% of V, 0.01-0.03% of Ti, 0.15-0.55% of Cu, 0.15-0.55% of Ni, 0-0.15% of Cr, 0.15-0.45% of Mo, 0.025-0.045% of Al, 0.0002-0.011% of N, P not more than 0.015%, S not more than 0.005%, and the balance of Fe and inevitable impurity elements. The manufacturing method adopts the process route of: material preparation-converter or electric furnace smelting-furnace external refining-casting-plate blank reheating-control rolling-control cooling; and the tempering process is adopted or not adopted after two-phase area quenching. Compared with the prior art, the steel has such advantages as lower yield ratio, higher uniform ductility, better toughness matching, low identical plate performance difference of steel plates, high thickness direction structure uniformity and low belt-shaped grade.

There is provided a steel material having a chemical composition consisting, by mass percent, of C: 0.6-1.8%, Si: 0.05-1.00%, Mn: >25.0-45.0%, Al: 0.003-0.06%, P: ≦0.03%, S: ≦0.03%, Cu: 0.5-3.0%, N: ≦0.10%, V: 0-2.0%, Cr: 0-3.0%, Mo: 0-3.0%, Ni: 0-1.5%, Nb: 0-0.5%, Ta: 0-0.5%, Ti: 0-0.5%, Zr: 0-0.5%, Ca: 0-0.005%, Mg: 0-0.005%, REM: 0-0.01%, B: 0-0.015%, the balance: Fe and impurities, and satisfying [0.6<C−0.18V<1.44], wherein a metal micro-structure is consisting of an austenite single phase, a yield strength is 241 MPa or higher, and a uniform elongation is 40% or higher.