Abstract: A hot-rolled steel plate/strip for sulfuric acid dew point corrosion resistance and manufacturing method therefor. In said method, elements such as Sn and Cu remaining in steel scrap are fully utilized to smelt molten steel, and micro-alloy elements such as Cr, Ti, and Sb are selectively added; in a smelting process, basicity of slag, types and melting points of inclusions in steel, and a free oxygen content and an acid-soluble aluminum (Als) content in molten steel are controlled, a cast strip (11) is casted by means of twin-roll strip continuous casting, the cast strip (11) exits from crystallization rolls (8a, 8b) and directly enters a lower closed chamer (10) having a non-oxidizing atmosphere, then enters, in a closed condition, an on-line rolling mill (13) for hot rolling, after rolling, strip steel is cooled by means of gas atomization cooling, and finally the strip steel is wound up.

Abstract: Disclosed in the present invention is complex-phase steel having high hole expansibility. The complex-phase steel has a microstructure of ferrite and bainite. The complex-phase steel having high hole expansibility comprises the following chemical elements in percentage by mass: C: 0.06-0.09%, Si: 0.05-0.5%, Al: 0.02-0.1%, Mn: 1.5-1.8%, Cr: 0.3-0.6%, Nb?0.03%, Ti: 0.05-0.12%, and the balance of Fe and inevitable impurities. In addition, also disclosed in the present invention is a manufacturing method for the foregoing complex-phase steel having high hole expansibility. The method comprises the following steps: (1) smelting and casting; (2) heating; (3) hot-rolling; (4) phosphorous removal; (5) laminar cooling: a relaxation time period is controlled to be 0-8 s, and a laminar cooling rate is 40-70° C./s; (6) coiling; (7) leveling; and (8) pickling. The complex-phase steel having high hole expansibility can simultaneously satisfy the requirements for hole expansibility and good plasticity.

Abstract: A high-strength thin-gauge checkered steel plate/strip and a manufacturing method therefor, wherein residual elements such as Sn and Cu in steel scrap are fully utilized as alloy elements in the smelting of molten steel, and the steel has selectively added micro-alloy elements such as B; during the smelting process, the alkalinity of the slag, the types of inclusion in the steel and the melting point thereof, the content of free oxygen and the content of soluble aluminum (Als) in the molten steel are controlled; and twin-roll thin-strip continuous casting is performed to cast a cast strip (11); after exiting crystallization rollers (8a, 8b), the cast strip (11) directly enters a lower sealed chamber (10) containing a non-oxidizing atmosphere, and enters an online rolling machine (13) in a sealed manner so as to undergo hot rolling, then after rolling, the strip steel is cooled by means of air atomization.

Abstract: Disclosed is a non-oriented electrical steel sheet with low magnetic anisotropy, which comprises the following chemical elements in mass percentage: 0<C?0.005%; Si: 2.0-3.5%; Mn: 0.1-2.0%; at least one of Sn and Sb: 0.003-0.2%; Al: 0.2-1.8%; the balance being Fe and inevitable impurities. Further disclosed is a manufacturing method for the above non-oriented electrical steel sheet with low magnetic anisotropy, which includes the following steps: (1) smelting and casting; (2) hot rolling; (3) normalizing; (4) cold rolling; (5) continuous annealing: rapidly heating a cold-rolled steel sheet from an initial temperature of 350° C.-750° C. to a soaking temperature at a heating rate of 50-800° C./s, and performing soaking and heat preservation; and (6) applying an insulating coating to obtain a finished non-oriented electrical steel sheet. The non-oriented electrical steel sheet is characterized by low iron loss and low magnetic anisotropy at high frequency.

Abstract: A high-strength and high-toughness tube for perforating gun, having a formulation of chemical elements in percentage by mass as follows: C: 0.15%-0.22%, Si: 0.1%-0.4%, Mn: 0.5%-1%, Cr: 0.3%-0.7%, Mo: 0.3%-0.7%, Nb: 0.01%-0.04%, V: 0.1%-0.2%, Ti: 0.02%-0.05%, B: 0.0015%-0.005%, Al: 0.01%-0.05%, Ca: 0.001%-0.004%, N?0.008%, and the balance of Fe and other inevitable impurities. Accordingly, further disclosed is a method for manufacturing a high-strength and high-toughness tube for perforating gun. The high-strength and high-toughness tube for perforating gun of the present invention has high strength, good toughness and uniform circumferential strength, and is suitable for application in the field of petroleum exploration and exploitation.

Abstract: Disclosed is a method for manufacturing stress-relief-annealing-resistant, low-iron-loss grain-oriented silicon steel, the method comprising: carrying out, by means of a pulse laser, scanning grooving on a single surface or two surfaces of a silicon steel sheet after cold rolling, or after decarburizing annealing, or after high temperature annealing or after hot stretching, temper rolling and annealing, and forming several grooves parallel with each other in a rolling direction of the silicon steel sheet, wherein a single pulse time width of the pulse laser is 100 ns or less, and a single pulse peak energy density is 0.

Abstract: Disclosed are an electromagnetic stirring device and a method for a secondary cooling zone during slab continuous casting. The device comprises an electromagnetic stirring device main body comprising a protection housing (3), a phase sequence control assembly, an iron core (4) and an electromagnetic coil (5) for carrying out variable-direction electromagnetic stirring on molten steel by means of three-phase current phase sequence transformation; an opening adjustment assembly comprising an air cylinder (7), a fixed base (8), a movable joint shaft (12) and a silicon steel sheet group insert (13) for adjusting online the opening degree of the closed annular iron core by means of a movable joint structure; and the secondary cooling assembly comprising a cooling water inlet (9) and a cooling water nozzle (10) for cooling the electromagnetic coil and spraying cooling water to a surface of a cast slab (1).

Abstract: A sucker rod steel, a heat treatment process therefor, and a manufacturing method comprising the heat treatment process are provided. The sucker rod steel comprises, in mass percent, the following chemical elements: C: 0.10˜0.20%, Si: 0.40˜0.80%, Mn: 0.20˜0.60%, Mo: 0.36˜0.46%, Cr: 6.15˜7.10%, Al: 0.015˜0.035%, Nb: 0.02˜0.06%, and N: 0.008˜0.015%, with the balance being Fe and other inevitable impurities. The microstructure of the sucker rod steel is tempered martensite and nanoscale precipitates. The grain size is higher than grade 10, the tensile strength is 920˜1320 Mpa, and the AKU2 impact energy is greater than or equal to 180 J.

Abstract: Disclosed is a high-magnetic-induction oriented silicon steel, wherein the chemical elements thereof are, in mass percentage: Si: 2.0-4.0%; C: 0.03-0.07%; Al: 0.015-0.035%; N: 0.003-0.010%; Nb: 0.0010-0.0500%, the balance being Fe and inevitable impurities. The manufacturing method for the high-magnetic-induction oriented silicon steel includes the steps of: (1) smelting and casting; (2) heating a slab; (3) hot rolling; (4) cold rolling; (5) decarbonizing and annealing; (6) nitriding treatment; (7) applying an MgO coating; (8) high temperature annealing; and (9) applying an insulating coating; wherein a high-magnetic-induction oriented silicon steel is obtained by the manufacturing method, having an average primary grain size of 14-22 ?m and a primary grain size variation coefficient of higher than 1.

Abstract: Provided is a 600 MPa grade non-oriented electrical steel sheet with excellent magnetic properties, comprising the following chemical elements in mass percentage: 0<C?0.0035%; Si: 2.0-3.5%; Mn: 0.4-1.2%; P: 0.03-0.2%; Al: 0.4-2.0%; and the balance being Fe and unavoidable impurities. Also provided is a manufacturing method for the 600 MPa grade non-oriented electrical steel as described above, including the following steps: (1) converter smelting, RH refining and casting; (2) hot rolling; (3) normalizing; (4) cold rolling; (5) continuous annealing; and (6) applying an insulation coating to obtain a finished non-oriented electrical steel sheet.

Abstract: Disclosed is a method for manufacturing a cold-rolling strip steel (1) with the strength and hardness thereof varying in a thickness direction, the method comprising the steps: smelting, continuous casting, hot rolling, cold rolling, and continuous annealing. When quenching is performed in the continuous annealing step, an asymmetric quenching and cooling process is performed on both surfaces of the strip steel. In addition, also disclosed is a cold-rolling strip steel (1) with the strength and hardness thereof varying in a thickness direction, which is prepared by the above manufacturing method.

Abstract: Steel for coiled tubing with a low yield ratio and ultra-high strength and a preparation method thereof, wherein the chemical composition of the steel in mass percentage is: C: 0.05-0.16%, Si: 0.1-0.9%, Mn: 1.25-2.5%, P?0.015%, S?0.005%, Cr: 0.51-1.30%, Nb: 0.005-0.019%, V: 0.010-0.079%, Ti: 0.01-0.03%, Mo: 0.10-0.55%, Cu: 0.31-0.60%, Ni: 0.31-0.60%, Ca: 0.0010-0.0040%, Al: 0.01-0.05%, N?0.008%, and the rest being Fe and inevitable impurity elements. The chemical composition combines the technologies of low temperature finishing rolling and low temperature coiling to obtain an MA constituent+bainite+ferrite multiphase structure. The steel has a low yield ratio and ultra-high strength with the following specific properties: yield strength?620 MPa, tensile strength?750 MPa, elongation?11%, and yield ratio?0.83, and is suitable for manufacturing coiled tubing with ultra-high strength having a grade of 110 ksi or higher.

Abstract: A free-cutting and non-quenched and tempered steel, comprising the following chemical elements by mass percentages: C: 0.35-0.45%, Si: 0.45-0.0.65%, Mn: 1.35-1.65%, S: 0.025-0.065%, V: 0.07-0.15%, Ti: 0.01-0.018%, N: 0.012-0.017%, Al: 0.015-0.035%, Ca: 0.0008-0.0025%, with the remaining being iron and other unavoidable impurities, wherein the S and Ca elements satisfy the relationship S/Ca=20-60. A manufacturing method of the free-cutting and non-quenched and tempered steel, comprising the following steps: (1) smelting and refining; (2) casting; (3) rolling; (4) forging; and (5) two-stage cooling.

Abstract: There is provided a production method for on-line improving precipitation strengthening effect of Ti microalloyed hot-rolled high-strength steel, comprising: casting a molten steel with microalloying element Ti added to obtain an ingot; after heating the ingot, subjecting it to rough rolling, finish rolling, laminar cooling and coiling to obtain a hot-rolled coil; after unloading the coil, covering the coil on-line with an insulating enclosure and moving it into a steel coil warehouse along with a transport chain; after a specified period of on-line insulating time, removing the coil from the insulating enclosure, and cooling it to room temperature in air, wherein the microalloying element Ti has a content of ?0.03 wt %; the coiling is performed at a temperature of 500-700° C.; said covering on-line with an insulating enclosure means each hot-rolled coil is individually covered with an independent, closed insulating enclosure unit within 60 minutes after unloading; the on-line insulating time is ?60 minutes.

Abstract: The invention discloses a 780 MPa cold-rolled dual-phase strip steel having a microstructure of fine equiaxed ferrite matrix and martensite islands distributed homogeneously on the ferrite matrix, and comprising the following chemical elements in mass percentage: C: 0.06-0.1%; Si?0.28%; Mn: 1.8-2.3%; Cr: 0.1-0.4%; Mo: not added when Cr?0.3%; Mo=0.3—Cr when Cr<0.3%; Al: 0.015-0.05%; at least one of Nb and Ti elements, wherein Nb+Ti is in the range of 0.02-0.05%; and the balance amounts of Fe and other unavoidable impurities. Correspondingly, the invention also discloses a method for manufacturing the 780 MPa cold-rolled dual-phase strip steel. The 780 MPa cold-rolled dual-phase strip steel has high strength, superior elongation, good phosphating property and small anisotropy in mechanical properties.

Abstract: A hot dipped high manganese steel and a manufacturing method therefor. The high manganese steel comprises a steel base plate and a coating on the surface of the steel base plate. The core of the steel base plate is austenite. The surface layer of the steel base plate is a ferrite fine grain layer. The ferrite fine grain layer comprises an oxide of Al. Furthermore, the steel base plate of the hot dipped high manganese steel comprises, in mass percentages, 10 to 30% of Mn element, 1 to 2% of Al element, and 0.4 to 0.8% of C element. The manufacturing method comprises: 1) manufacturing strip steel; 2) primary annealing and acid washing; 3) secondary annealing and hot dipping.

Abstract: A cold-rolled low-density steel sheet having excellent phosphorability is provided. An iron particle layer is disposed on the surface of the cold-rolled low-density steel sheet, and dispersed iron particles exist in the iron particle layer. The cold-rolled low-density steel sheet comprises 3.0% to 7.0% of element Al by mass percentage.

Abstract: Disclosed are a non-oriented electrical steel sheet with excellent magnetic properties and a manufacturing method thereof, wherein the mass percentage of the chemical components thereof are: C: 0-0.005%; Si: 2.1-3.2%, Mn: 0.2-1.0%, P: 0-0.2%, Al: 0.2-1.6%, N: 0-0.005%, Ti: 0-0.005%, Cu: 0-0.2%, and the balance of Fe and inevitable impurities; and at the same time, (the S content for forming MnS+the S content for forming CuxS)/the S content in the steel is required to be less than or equal to 0.2. The process for manufacturing the non-oriented electrical steel sheet of the present invention is simple and convenient, the chemical components of the steel are easy to control, the manufacturing process is stable, and the technical requirements are easy to realize.

Abstract: Disclosed is a method for manufacturing an equal-strength steel thin-wall welding component with an aluminum or aluminum-alloy plating, wherein the plating comprises an intermetallic compound alloy layer in contact with the base body and a metal alloy layer on the intermetallic compound alloy layer; the plating is not removed or thinned before or during welding; and by presetting a welding gap and using a carbon-manganese-steel welding wire, a welding process and protective gas for welding, the tensile strength of a welding seam of the welding component after hot stamping processing is greater than the tensile strength of a base metal, and the elongation of a welded joint is greater than 4% Further disclosed are a welding wire for welding and an equal-strength steel thin-wall welding component with an aluminum or aluminum-alloy plating.

Abstract: A laser-scribed grain-oriented silicon steel resistant to stress-relief annealing and a manufacturing method therefor. Parallel linear grooves (20) are formed on one or both sides of grain-oriented silicon steel (10) by laser etching. The linear grooves (20) are perpendicular to, or at an angle to, the rolling direction of the steel plate. A maximum height of edge protrusions of the linear grooves (20) does not exceed 5 ?m, and a maximum height of spatters in etch-free regions between adjacent linear grooves (20) does not exceed 5 ?m, and the proportion of an area occupied by spatters in the vicinity of the linear grooves (20) does not exceed 5%. The steel has low manufacturing costs, and the etching effect of the finished steel is retained during a stress-relief annealing process. The steel is suitable for manufacturing of wound iron core transformers.