摘要:
Blister-resistant steel sheet consists essentially of 0.0005 to 0.003 wt. % C, 0.10 to 2.2 wt. % Mn, 0.6 wt. % or less Si, 0.07 wt. % or less P, 0.025 wt. % or less S, 0.02 to 0.06 wt. % of sol. Al, 0.0035 wt. % or less N, 0.003 wt. % or less O, [(48/14)N+(48/32)S+4.times.(48/12)C] wt. % or less Ti and the balance being Fe and inevitable impurities; and smaller one of either Ti (wt. %) or [(48/14)N+(48/32)S] (wt. %) being [0.002 t.sup.2 +0.003] or more, where t is a thickness (mm) of the steel sheet. Method for producing blister-resistant steel sheet comprises preparing a cold rolled steel sheet having the composition of described above, and continuously annealing or continuous hot dip galvanizing by heating the steel sheet from room temperature to 650.degree.-720.degree. C. at a rate of 20.degree. C. sec or more and further to the soaking temperature above recrystallization temperature at a rate of 1.degree.-5.degree. C./sec.
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 method for manufacturing an ultra-high-strength cold-rolled steel sheet having desirable delayed fracture resistance, which comprises: preparing a material consisting essentially of 0.1 to 0.25 wt. % carbon, up to 1 wt. % silicon, 1 to 2.5 wt. % manganese, up to 0.020 wt. % phosphorus, up to 0.005 wt. % sulfur, 0.01 to 0.05 wt. % soluble aluminum, 0.0010 to 0.0050 wt. % nitrogen, optionally at least one of Nb, Ti or V, optionally at least one of Cu, Ni, B, Cr or Mo, the balance being iron and incidental impurities; subjecting the material to a hot rolling, a pickling and a cold rolling to prepare a cold-rolled steel sheet; and subjecting the cold-rolled steel sheet to a continuous heat treatment which comprises: subjecting the cold-rolled steel sheet to a soaking treatment at a temperature of Ac.sub.3 to 900.degree. C. for 30 seconds to 15 minutes, quenching the cold-rolled steel sheet at a quenching rate of at least 400.degree. C./second from a temperature of at least a lower limit temperature (T.sub.Q) for starting quenching as expressed by the following formula to a temperature of up to 100.degree. C.: T.sub.Q (.degree.C.)=600+800.times.C+(20.times.Si+12.times.Mo+13.times.Cr)-(30.times.Mn+8.times.Cu+7.times.Ni+5000.times.B), wherein C, Si, Mo, Cr, Mn, Cu, Ni and B are respectively weight percents for carbon, silicon, molybdenum, chromium, manganese, copper, nitrogen and boron, and tempering the cold-rolled steel sheet at a temperature of 100.degree. C. to 300.degree. C. for 1 to 15 minutes.
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:
A method for producing a non-oriented electrical steel sheet with precise thickness and homogeneous magnetic property comprising the steps of: making a steel ingot which has: 0.01 wt. % or less C, 0.003 wt. % or less N, 0.01 to 1.0 wt. % Mn, Al and Si satisfying, in wt. %, the formulas of: ##EQU1## provided that (Si %) represents the Si (wt. %) and (Al %) represents Al content (wt. %), and the balance being Fe and inevitable impurities to produce a steel slab; hot-rolling the slab at a finishing temperature of 700.degree. to 900.degree. C. into a steel strip and coiling the hot rolled strip; and cold-rolling the hot-rolled strip into a cold-rolled strip, followed by annealing the cold-rolled strip.
摘要:
For enabling the manufacture of non-oriented steel strips by HDR, the amounts of AlN and MnS which precipitate on the way of HDR are decreased to such a level that they do not affect the magnetic properties by regulating the Al and S contents, and further unavoidable precipitating nitrides are precipitated as coarse BN. With regard to the steel composition, the amounts 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 HDR is specified. Moreover, to secure precipitation of BN and recrystallization of a ferrite structure, the lower limits of the finishing and coiling temperatures are specified. Furthermore, to secure the magnetic properties after cold rolling, the strips are finally continuously annealed at the determined temperature.
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 steel slab containing not more than 0.005 wt % carbon, 1.0 to 4.0 wt % silicon, 0.1 to 1.0 wt % manganese, not more than 0.1 wt % phosphorus, not more than 0.005 wt % sulfur, and 0.1 to 2.0 wt % aluminum is directly sent to a hot rolling step without brief soaking, whereby Al and N are made soluble with respect to species other than AlN inevitably precipitated during hot rolling, and uniform and coarse AlN precipitation is formed by a subsequent annealing treatment in which the hot rolled plate is soaked at a temperature of 800.degree. to 1000.degree. C. for a period of time t defined as exp (-0.018T+19.4) .ltoreq.t.ltoreq.exp (-0.022T+25.4) wherein T is the soaking temperature (.degree.C.) and t is the soaking time (minutes). Uniform and satisfactory ferrite grain growth at the recrystallization annealing is provided thereby.
摘要:
Non-oriented electrical steel sheets having excellent magnetic properties are produced by carrying out a coiling at a low temperature for monitoring the amount of scale generation; de-scaling after hot rolling; and annealing the de-scaled hot rolled sheet in a non-oxidizing atmosphere to thereby minimize the oxidation and nitriding during annealing the hot rolled sheet. By determining a higher heating temperature for hot rolling, a magnetic property (magnetic flux density) is improved, and the hot rolled sheet is subjected to an open coil-annealing and annealing conditions therefor are specified in order to perfectly precipitate re-solute AlN particles by this heating and fully coarsen AlN particles.