摘要:
A method of producing non-oriented electrical steel sheets having excellent magnetic properties which comprehends heating a steel at the low temperature for hot rolling, thereby to minimize re-solution of AlN particles when a slab is cooled, so that coarsening of AlN particles is facilitated during annealing the hot rolled sheet; and coiling at low temperatures for controlling the amount of scale generation. De-scaling is perfectly accomplished after the hot rolling, and the hot rolled sheet is annealed in a non-annealing atmosphere, thereby to control the oxidation and the nitriding to a minimum during annealing the hot rolled sheet, and the annealing conditions of the hot rolled sheet are specified for proper coarsening of the cohesion, taking into consideration the magnetic properties and the economics.
摘要:
This invention is to save the energy by heating a slab at high temperature for producing non-oriented electrical steel sheets having excellent magnetic properties uniform over the full length thereof, without carrying out a long soaking, for which a continuously cast slab having a specified chemical composition is heated at a high temperature, and a heat cycle is then defined such that the slab is passed twice nearly around precipitation noses, thereby to coarse the AIN precipitates over the full length of the slab, and the slab is annealed under a specified condition after the hot rolling so that AlN is coarsened and the ferrite grains recrystallize and grow.
摘要:
The present invention is to produce non-oriented silicon steel sheets having excellent magnetic properties in dependence upon a hot direct rolling, wherein the slab is directly sent to the direct rolling without maintaining the heat and soaking, whereby others than AlN precipitated during hot rolling check the precipitation of AlN, and a delay time is taken between the roughing and the finish rolling so that precipitating nuclei of AlN are introduced into the steel, and uniform and coarse AlN precipitation is formed by a subsequent annealing treatment, thereby to enable to provide uniform and satisfied ferrite grain growth at the recrystallization annealing.
摘要:
For enabling the making of non-oriented magnetic steel strips by direct rolling, the amounts of AlN and MnS which precipitate on the way of the direct rolling are decreased to such a level that they do not affect the magnetic properties by regulting the Al and S amounts, and further unavoidable precipitating nitrides are precipitated coarsely as BN. With regard to the steel composition, the amount of C, Si and P are not only regulated, but also the amounts of Mn, Al, S and N are regulated from the above standpoint, and a proper amount of B is added if required. In addition, in regard to treatment conditions, in order to secure necessary finishing and coiling temperatures, the lower limit of the slab temperature at the starting time of the direct rolling is specified. Moreover, to promote refining of ferrite, the upper limit of the finishing temperature is specified, and also to prevent non-uniform recrystallization after coiling, the upper limit of the coiling temperature is specified. Furthermore, to secure satisfied magnetic properties, the annealing of the hot rolled strip is performed under specific conditions determined by a soaking temperature and a soaking time. In addition, to secure the magnetic properties of the cold rolled strip, the strip is finally continuously annealed at determined temperatures.
摘要:
A high strength steel, including about 0.05 to about 0.25% of C, less than about 0.5% of Si, about 0.5 to about 3.0% of Mn, not more than about 0.06% of P, not more than about 0.01% of S, about 0.50 to about 3.0% of Sol. Al, not more than about 0.02% of N, about 0.1 to about 0.8% of Mo, about 0.02 to about 0.40% of Ti, and the balance of iron and unavoidable impurities, wherein the steel has a structure formed of at least three phases including a bainite phase, and a retained austenite phase in addition to a ferrite phase having a composite carbide containing Ti and Mo dispersed and precipitated therein, wherein the total volume of the ferrite phase and the bainite phase is not smaller than 80%, the volume of the bainite phase is about 5% to about 60%, and the volume of the retained austenite phase is about 3 to about 20%.
摘要:
A cold-rolled steel sheet or a zinc or zinc alloy layer coated steel sheet containing 0.0010 to 0.01 wt % of C and having a steel composition containing one or two kinds of 0.005 to 0.08 wt % of Nb and 0.01 to 0.07 wt % of Ti in the ranges given by {(12/93)Nb+(12/48)Ti*} .gtoreq.0.0005, 0.ltoreq.C-{(12/93)Nb+(12/48)Ti*}.ltoreq.0.0015, and Ti*=Ti-{(48/32)S+(48/14)N } , in which a bake hardenability BH f the steel sheet at 170.degree. C..times.20 min after 2% tensile prestrain is 10 to 35 MPa and the BH (MPa) and a yield strength YP (MPa) of the steel sheet satisfy the ranges given by BH.gtoreq.exp(-0.115.multidot.YP+23.0) and 0.67.multidot.BH+160.ltoreq.YP.ltoreq.-0.8.multidot.BH+280.
摘要:
This invention is to provide a steel sheet for 2-piece battery cans, which has excellent formability in DI molding to give thin-walled, side body parts, and, more preferably, a steel sheet for 2-piece battery cans, which, after having been formed into cans, has high mechanical strength and excellent anti-secondary work embrittlement with excellent corrosion resistance. The steel sheet for 2-piece battery cans of the invention contains S and O (where O is the total oxygen content) while satisfying the conditions that S is from 0.005 to 0.015 wt. %, preferably from 0.005 to 0.012 wt. %, that 0 is from 0 to 0.0025 wt. % and that [S/10+O].ltoreq.0.0035 wt. %, preferably [S/10 +0].ltoreq.0.0030 wt. %. More preferably, the steel sheet contains B of from 0.0005 to 0.0015 wt. % while satisfying 0.2.ltoreq.B/N.ltoreq.1.0, or contains either one or both of Cr of being from 0.03 to 0.10 wt. % and Ni of being from 0.01 to 0.10 wt. %, the total of the two being not larger than 0.10 wt. %. The both surfaces of the steel sheet may be plated with Ni or an Fe--Ni alloy in order to ensure more excellent corrosion resistance of the steel sheet.
摘要:
A continuously annealed cold-rolled steel sheet excellent in balance between deep drawability and resistance to secondary-work embrittlement, which consists essentially of: under 0.0030 wt. % carbon, up to 0.05 wt. % silicon, from 0.05 to 0.20 wt. % manganese, up to 0.02 wt. % phosphorus, up to 0.15 wt. % sulfur, from 0.025 to 0.06 wt. % soluble aluminum, up to 0.0030 wt. % nitrogen, from 0.02 to 0.10 wt. % titanium, from 0.0003 to 0.0010 wt. % boron, and the balance being iron and incidental impurities, where a value of an index (X) representing a content rate of titanium to boron, as calculated by specific formulae, is of from 9.2 to 11.2. The above-mentioned continuously annealed cold-rolled steel sheet is manufactured by: carrying out a finishing-rolling in a hot-rolling of a steel slab having the above-mentioned chemical composition so that a reduction rate distribution function (Y) as expressed by another specific formula is satisfied; completing the finishing-rolling at a temperature of from 880.degree. to 920.degree. C.; then coiling the resultant hot-rolled steel strip; then cold-rolling the hot-rolled steel strip at an accumulative reduction rate of at least 70%; and then continuously annealing the resultant cold-rolled steel strip in a temperature region of from 750.degree. C. to an Ac.sub.3 transformation point.
摘要:
A high strength cold rolled steel sheet consists essentially of 0.0040 to 0.01% C, not more than 0.05% Si, 0.1 to 1.0% Mn, 0.01 to 0.05% P, not more than 0.02% S, 0.01 to 0.1% sol.Al, not more than 0.004% N, 0.01 to 0.14% Nb, by weight, and a balance of substantially Fe and inevitable impurities, and having an n value of not less than 0.21 calculated from two points (1% and 10%) of nominal strain determined by the uniaxial tensile test, and a method for manufacturing the cold rolled steel sheet. The high strength cold rolled steel sheet has excellent combined formability, resistance to embrittlement during secondary operation, formability at welded portions, and anti-burring performance, and has a desirable surface appearance and uniformity of material in a coil, and thus can be desirably used for automobile exterior panels.
摘要:
An ultrathin steel foil which is suited for use as an electromagnetic wave shielding material and which is excellent in shielding properties, is provided by cold rolling to be 31% to 90% reduction and anneal at 600.degree. to 950.degree. C. for 1 hour of a steel material having specific chemical composition including C of less than 0.01% and specified grain diameter of between 20 to 80 .mu.m, and thicknesses of between 20 to 100 .mu.m.