JPS60500177A - High-strength, low-carbon duplex steel rods and wires and their manufacturing methods - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] High strength, low carbon duplex steel rods and wires and their manufacturing methods The present invention achieves high strength and high strength by cold drawing dual phase steel. Toward a method of making ductile, low carbon steel wire, bars and rods It is. Here, the term "duplex steel" refers to a dispersed second phase, such as martensa. austenite, painite and/or retained austenite Continuous annealing, batch to obtain a ferrite matrix with A category of steel made by annealing or conventional hot rolling. The second phase is the bar hard, undeformable carbon found in pearlitic rods and wires Unlike the compound phase, it is controlled to be a strong, tough and deformable phase. So This is important because it provides a substantial contribution to strength and Work during punching - i.e. in a suitable and sufficient volume proportion to increase the hardening rate. Must be distributed over 10'lr. To develop a two-phase microstructure Various heat treatment routes can be used to depending on the specific heat treatment used. The preferred heat treatment is an intermediate quenching method. , that is, annealing of two phases α+7 field and ferrite martensitic austenite and /'θ0% martensite before quenching to a straight structure. and quenching. The present invention also provides high strength, high Directed to ductile steel wire and rods.

Steel wire has many known uses such as making cables, chains and springs. It has a purpose for. It's just a matter of making a steel belt and a bead wire for the wire sump. Thin steel cables are also used to connect multiple cables to improve the tensile strength of the wire. Included in the line. In the use of this, +1, etc., the diameter requirement is 0. /Ω7 mm B, 33 mm or more below, strength requirements are relatively small diameter/7.2.2. left m It ranges from a height of 27 mpa to a height of 27 mpa. The smell of all these uses Therefore, it is possible to prepare a steel wire with high tensile strength and good ductility in the required diameter. is important.

The oldest and most common method of making high-strength, high-ductility wire is the Habony technique. Patenting of light steel with toid eutectic structure Depends on the situation. However, this method is complex and expensive.・Different tenting methods The disadvantage is that there is an inherent limit to the maximum wire diameter that can be made at a given strength level. be.

Steel with higher tensile strength and higher ductility than steel wires and bars made by known methods Need for wire and rods and more economical ways to make high strength steel wire and rods There is a need for law. The present invention is based on the practice of tenting P-light steel. Instead of using Martino's alloy with a relatively simple composition? In other words, Cold drawing into wire or rod without intermediate baking or tenting heat treatment give law. Omission of tenting heat treatment in the production of high-strength steel wire The cost of producing high-strength steel wire will soon drop in light of current fuel conditions. There is no one.

Cold drawing process has high initial strength, high ductility, rapid work hardening and good cold deformability. requires a low-alloy steel composition with a given microstructure and morphology. This steel is intermediate Provides desired diameter, tensile strength and ductility without annealing or patenting heat treatments It must be able to be cold drawn as shown.

of certain groups with specially developed chemical compositions to give higher mechanical property values. The steel is conventionally known as high strength low alloy (H8LA) steel. These steels are carbon as a chemical element in an amount reasonably compatible with weldability and ductility. These steels Varying amounts and types of alloy carbide formations to achieve characteristic mechanical properties is added.

However, the high tensile strength and high elongation required in many applications of steel wire and rods properties do not appear to be achievable using H8LA steel.

The factors governing the properties of low carbon steel are mainly its carbon content and microstructure; Next is the remaining alloy.

Generally, low carbon steels include silicon, manganese or a combination of silicon and manganese. size In addition, elements that form carbides, such as pananium, chromium, niobium, and molybdenum, You can also add

Low carbon, characterized by a strong second phase dispersed in a soft ferrite matrix. Duplex microstructured steels meet the requirements for tensile strength, ductility, flexibility and diameter of high-strength steel wires. The groove has the potential to achieve a level of cold deformability that allows cold drawing without intermediate heating. Two. In particular, disclosed in U.S. Patent No. The low carbon, composite ferritic-martensitic steel has high strength and high ductility properties. It is of interest in the present invention because it is composed of an element that has properties and is not expensive. But generally configured As shown, it has a tensile strength of about gλ7mpa, which is higher than that of high-strength steel wire. much lower than the tensile strength required for many applications. The method of the invention comprises at least It is also directed to making high-strength steel wire with a tensile strength of about g, 27 mpa.

The preferred tensile strength range is g2'7mpa-λ2g7mpa, but: It is possible to achieve strength of 27 mpa or higher.

Therefore, it is desirable to provide an improved method of making high strength, high ductility steel wires and bars and Making steel wire or I″i rods with increased tensile strength, ductility and flexibility in diameter is the object of the present invention.

Another object of the invention is to subject the duplex steel composition to intermediate annealing or pachinting heat treatment. High strength, high ductility steel wire including a cold drawing step to the required strength and ductility without giving you a way to make wires or rods, thereby giving you complete flexibility in the selection of wire diameters. It is to give sex.

・Intermediate and tenting methods used in current methods of making q-light steel wire Provides a method of making high strength, high ductility steel wire or rod that eliminates steps, thereby The complexity, cost and energy of making high-strength steel wires and rods initially combined with Based on the selection of structure and treatment of the microstructure through appropriate heat treatment, the final steel wire Flexible, taking into account a wide range of diameters, strength and ductility properties in rods or rods. It is another object of the present invention to provide a method of making high strength steel wires and bars.

Yet another object of the invention is to provide a high The objective is to provide a high strength, high ductility steel wire or bar.

Other objects and advantages of the present invention will become apparent from the following description including the accompanying drawings. cormorant.

In general, the present invention relates to high strength, high ductility, low carbon steel wires or bars, and methods of making the same. directed towards. This method reduces low carbon duplex steel to the desired diameter in a single multi-pass operation. Including cold drawing. This steel consists of a matrix of soft ferrite dispersed in Composite microstructure consisting essentially of a strong secondary phase and a reduction in cross-sectional area of up to approximately 99.9% It is characterized by a microstructural morphology with sufficient cold deformability to permit small amounts of deformation.

One of the preferred embodiments of the invention is a suitable composite as shown, for example, in FIG. duplex characterized by a ferrite-martensitic microstructure high strength, high ductility, low carbon steel rods or wires made from steel compositions; This is the way to make it. This method uses composite ferritic-martensitic steel in one multi-layer process. Including cold drawing to the desired diameter Ic in the iPS operation. Composite ferrite-marten In high-strength steels with site microstructure, the strong, deformable second phase is mainly austenite, but may also contain pineite and preserved austenite. I can do it. Strong second phase dispersed in a soft ductile ferrite matrix Martensite provides strength in this composite, while ferrite gives ductility.

Figure 1 shows a typical low carbon two-phase ferrite-martensite microstructure before cold drawing. It is an optical micrograph showing a fine structure.

FIG. 2 shows a dislocated flake (+ath) containing a strong second phase in a duplex steel according to the present invention. This is a transmission electron micrograph of martensite.

FIG. 3 shows a cold drawing schedule and diagram for a duplex microstructured steel according to the present invention. Typical ratios of drawing schedules for gilite steels according to the tenting method 2 is a graph illustrating a comparison.

In accordance with the present invention, the high strength, high ductility steel wire or rod is made of ferrite A low carbon steel characterized by a composite microstructure consisting essentially of a strong secondary phase dispersed throughout Made by cold drawing the composition to the desired diameter in a single multi-gas operation. Ru. The starting steel composition before cold drawing was rated at 99% during cold drawing. Cross-sectional area up to M a composite microstructure and morphology sufficient to provide a level of cold deformability that allows reduction in Must have.

The method of the present invention is based on the intermediate heat treatment used in known methods for making pearlitic steel wire. or provide an advantage over known methods in eliminating the tenting step, thereby Reduce process complexity, cost and energy consumption.

Furthermore, the method of the present invention can be used in a wide range of applications in the tenting method. Can make any rod & wire diameter size. In the i9 tenting method , there is an inherent limit to the maximum wire diameter that can be made at a given strength level. .

In FIG. 3, the difference between the method of the present invention and the Tsukutenting method is shown. The continuous line is , cold drawing schedule and various diameters of low carbon composite steel wire according to the present invention. It shows the tensile strength that can be achieved. 4. The broken line indicates the patenting method including intermediate heat treatment. The drawing schedule for the GLITE steel wire is shown below. pearlite steel wire In drawing, the method of the present invention achieves large tensile strengths that can be achieved with various diameters. Intermediate heat treatment is required to achieve this. These intermediate heat treatments create high-strength steel wire. increases the complexity and expense of the The method according to the invention does not involve an intermediate heat treatment and This represents a significant improvement over known methods.

The method produces steel wires and bars with a wide range of tensile strengths, ductilities and diameters. be able to. The final properties of a steel wire or bar at a given diameter are Due to the combination of construction, properties of the starting steel and the amount of reduction in cross-sectional area during the cold drawing process Therefore, it can be determined. The microstructure of steel can be easily manipulated through appropriate heat treatment. , the properties of the drawn wire are adjusted to meet the required performance specifications of the desired application. Wear. Alloying elements such as silicon, aluminum, manganese, and carbide-forming elements For example, the selection of molybdenum, niobium, vananium, etc. depends on the desired microstructure and properties. determined by. This means a wide range of alloys, including many simple and low cost alloys. Gold can be used as long as they can be heat treated into the desired two-phase microstructure. Wear.

One preferred composite microstructure is a ferrite-martensitic microstructure.

Another preferred microstructure is a composite ferrite-painite microstructure. two In some cases, a strong second phase, i.e. martensite or painite, is singed. Dispersed in a ductile ferrite matrix.

In one preferred embodiment of the process of the present invention, the starting steel composition comprises iron, about O, OS~0. Mainly from /3 hereditary carbon, and about 0 to 3.0' double hereditary silicon. It consists of In another preferred embodiment, the starting steel composition is iron, about O,OS~0 ．． /S double hereditary carbon, about /~triple hereditary silicon and about 0.0S~0.75wt Consists primarily of hereditary Pananoum. In two preferred embodiments, the steel composition is heat treated to create a composite ferrite-martensitic microstructure with fibrous morphology. Form. Briefly, the preferred method is to austenitize the steel composition and Quenching the composition converts austenite to n/00% martensite and annealing the resulting steel for a sufficient time to give the desired austenite to ferrite ratio. heating to annealing temperature and rapidly quenching the austenitic ferrite composition. Convert stenite to martensite and create composite ferrite with fibrous structure - The resulting duplex steel characterized by a martensitic microstructure can be produced in a single multi-gas operation. Each step involves cold drawing to the desired diameter.

More specifically, the starting steel composition is heated to a temperature above the critical temperature for austenite to form. Heated to T1. The temperature range for T1 is approximately 1050°C to //70oC be. This composition almost and completely austenitizes the steel at this temperature. kept for a sufficient period of time. The resulting composition contained almost 100% malt austenite. quenched to convert it into nusite. The composition then has two phases (α17) range It is heated again to the annealing temperature T2 at . α+7 temperature range is approximately gOOoC ~ 1 000cc. The composition is heated to this temperature, the martensitic steel composition is ferritic. and austenite for a sufficient period of time to convert to the desired volume ratio of austenite and austenite. the last roast Upon insertion, austenite converts to martensite, a soft or ductile phase. resulting in a strong second martensitic phase dispersed within the ellitic matrix.

The steel composition at this point consists of fine, isotropic particles in a ductile ferrite matrix. It is characterized by its unique microstructure, which is acicular martensite. this minute The structure is the result of a combination of two heat treatments and the presence of silicon in the amounts mentioned above. . This unique microstructure maximizes the ductility potential of the soft ferrite phase and also By making full use of the strong martensitic phase as a load-bearing component in the microstructure. Ru. Steel can be cold drawn to the desired wire or rod diameter in a single multi-thread operation This is due to the microstructure as well as the morphology of the steel composition. gy).

The composite microstructure and textural morphology is approximately up to 9 mm when the composition is cold drawn. As long as the material is made with sufficient cold deformability to permit a reduction in the cross-sectional area of the Any duplex stainless steel can be used. In particular, two-phase ferrite-martensa steels have a greater bond strength than commercially available high-strength, low-alloy steels, including micro-alloyed, fine-grained steels. It has a sustained yielding behavior, higher ultimate tensile strength and better ductility. In addition, blowjob The high tensile-yield ratio and high 'strain hardening rate in martensitic dual-phase steels are , provides excellent cold deformability.

The exact temperature T1 at which the steel composition is heated in the first austenitizing stage is It is not critical as long as the temperature is above that at which complete austenitization occurs. The composition is free Accuracy in the second heating stage, which is converted into two phases: elliptic and austenite. The temperature T2I″i depends on the desired volume ratio of ferrite and austenite, while The volume ratio depends on the desired volume ratio of ferrite to martensite. In general, The desired volume ratio of light to martensite determines the desired final volume ratio for the steel wire or rod. Depends on the characteristics. Generally, 10-4t in ferrite-martensitic microstructure o The volume ratio of martensite increases the cross-sectional area, the diameter or permit cold drawing of the steel composition at a temperature of at least approximately 27 mpa. will yield steel wire and rods with a tensile strength of . Normally, g27mpa = 24g? Tensile strength in the range of mpa is obtained, but above 273 A mpa You can also get the above.

The following examples serve to more clearly illustrate the method of the invention and the results obtained by this method. properties of steel wire and rods and selection of alloy, tensile strength, ductility and diameter. This demonstrates the versatility of the method in that it allows for

Example/ High-strength, high-ductility steel wire is used to replace bead wire used in the manufacture of automobile wire. It was created to meet the requirements of

The bead wire has an elongation of s, a tensile strength of 1 g AO mpa, and a tensile strength of 1 g AO mpa. A proportional limit of 11mlt is required. bead The wire passed a torsion test that required a 3g twist in the axial direction with a length of 203 m + w. It must have a diameter of approximately 0.9'1 mm and have sufficient ductility to do so. iron , θ, 7-weight hereditary element, - heavy hereditary silicon, and 0. / From the heavy hereditary pananoum The steel rod of Naotomo Goto, which has the main composition, is austenitized, and approximately 100% % martensitic composition. This rod is then connected to two phases. Reheated to qsoOC temperature in α+7 range and rapidly quenched to about 3o body Composite ferrite L-martensa of martensite with a volume coefficient and ferrite with a volume coefficient of 70 created a fine structure. This needle-like ferrite-martensitic microstructure The acicular character is shown in the optical micrograph of FIG. The heat-treated rod is then lubricated. o, q g passes through a conical die with an area reduction of about 3 g per 7 passes. Cold drawn to full diameter. 112 similar to the traditional method! ; Short response at OC After light annealing, a final tensile strength of /902 mpa was achieved. That is, B Meets wire tensile strength requirements. The ductility of this steel wire requires a twist test. It was sufficient to satisfy the requirements.

Example Iron, 0. 6. A steel bar consisting mainly of IM amount % of carbon and λ, 0 weight of hereditary iron. Game It was hot rolled to a diameter of 1. Then use this stick for about 30 minutes //! Heat to 100C, The composition was austenitized. This steel is then quenched in ice-cold salt water to - Almost 700% of stenite was converted to martensite. This bar is next, the structure Temperature of 930oC to convert to about 70% ferrite and 30% austenite. Reheat rapidly. The steel bar is then quenched in water-cooled brine to form austenite. converted to martensite. Finally, this rod is cold drawn to a diameter of 0.7 Amm. Ta. Its tensile strength was μ-bow Ompa. Then, pull it out again to 0, A1mm diameter. The tensile strength was 0 mpa.゛Subsequent cold drawing is λ7! ; A tensile strength of mpa or higher can be achieved.

Cold Blue (, IJ 10'j (no history) FIG, f Submission of translation of written amendment Mr. Manabu Shiga, Commissioner of the Patent Office 1. Indication of patent application PCT/US 821017223, patent applicant 6. List of attached documents Amended scope of claims 1. Fine particles consisting essentially of a strong second phase dispersed in a soft ferrite matrix. Thin structure - and sufficient cold deformability to allow a reduction in cross-sectional area at approximately 99.9% t. Low-carbon, low-alloy duplex steel composition characterized by microstructure and microstructure - High strength, high ductility steel wire, including a step of cold drawing to the desired diameter in a gusset operation. and how to make a stick.

2 The steel composition is characterized by a composite ferrite-martensitic microstructure, and the Ruthensite contains a strong second phase dispersed in a soft ferrite matrix. A method according to claim 1 of the present invention.

3 The steel composition is characterized by a composite ferrite-pineite microstructure, and the pinite ferrite is a soft ferrite, which is characterized by a strong second phase dispersed in the matrix. A method according to the first item in the scope of the request.

4. Iron, about 0.005-0.755% by weight carbon, and about 70-3.0% by weight silicon A steel composition consisting essentially of heating to temperature T1 for a period of time; The obtained austenitized steel composition is quenched to reduce the austenite to 700 % conversion to martensite, The obtained martensitic steel composition is mixed with ferrite and ore. The two phases are heated in the α'-γ range for a sufficient time to convert to the desired volume ratio of stenite. heating to degree T2; The obtained ferritic-austenitic steel composition is quenched to marl the austenite. converting to tensite; and The obtained steel composition is characterized by a composite ferrite-martensitic microstructure. Creates high strength, high ductility steel wire and rods, including a step of cold drawing to the desired diameter Method.

5. Claim 4, wherein the cold drawing step comprises a single multi-pass cold drawing step. How to follow.

6. The steel composition is essentially composed of iron, about 0.7% by weight carbon and about -90% by weight of hereditary silicon. A method according to claim 4 comprising:

7. Claim 4, wherein the steel composition comprises about 0.005 to 0.755 wt% vanazium. How to follow.

8. A method according to claim 7, wherein the vanazoum content is about 0.7% by weight.

9 T1 is in the range of about 10 0°C to //70°C, and T2 is in the range of about 00°C to 7 A method according to claim 4 or claim 7 in the range of 000°C.

A method according to claim 4 or claim 7, wherein 10T1 is approximately /150°C.

1] Set the composition to T2, and then quench the martensite with a volume coefficient of 70 to 0. To achieve a ferrite to austenite ratio that results in a microstructure containing A method according to claim 2 and 4 (rl. 7) of heating for a sufficient period of time.

12T2 was heated to about 90°C, and the obtained microstructure was martensitic with a volume coefficient of about 30. 12. A method according to claim 11, comprising:

13 Soft ferrite consists essentially of a strong second phase dispersed in the lithology. cold drawn from a steel composition characterized by a microstructure of at least A high strength, high ductility copper article having a tensile strength of , 2θksi.

14 Claim 1 in which the tensile force is in the range of about 20ksi to 39θksi Goods according to paragraph 3.

15. A steel article according to claim 14, wherein the article is a steel wire.

16. A steel article according to claim 14, wherein the article is a steel bar.

17 The microstructure is a cold-drawn composite ferrite-martensitic microstructure. A high strength, high ductility, low carbon steel article according to claim 15 or 16.

18 The microstructure is a cold-drawn composite ferrite-pineite microstructure. A high strength, high ductility, low carbon steel article according to claim 15 or 16.

19 Iron, about 0.05-0.755% carbon by weight, and about/~triple hereditary silicon? having a tensile strength of at least gλ7 mpa and having a composite steel composition consisting essentially of Cold thinning from a steel composition characterized by a ferritic-martensitic microstructure Drawn, high strength, high ductility, low carbon steel articles.

20 Claims in which the tensile strength is in the range of g -17 to: tA g 7 mpa Goods according to section 19.

21. An article according to claim 20, wherein the article is a steel wire.

22. The article according to claim 20, wherein the article is a steel rod.

23 Carbon content is approximately 0. / weight range, the silicon content is approximately - weight range, and the composite The ferrite-martensite micro S structure contains about 30 volumes of martensite, Tensile strength is about qq, after 9% cross-sectional area reduction, about 2QA Ompa~about 2ri~ &　Ompa, high strength, high ductility, low carbon according to claim 21 or 22 Raw steel articles.

24 Claims containing steel ljl compound parabolite 0.0S to 0.75% by weight of vanadium High strength, high ductility, low carbon steel articles according to Clause 21 or 22.

25 Carbon content is approximately 0. / weight range, the silicon content is about -0 weight range, and the bar The sodium content is approximately 0.7 weight range, and the composite ferrite-martenzite microstructure is The structure contains 30 volumes of martensite, and the tensile strength is approximately 97% after the cross-sectional area is reduced. High strength, high ductility, low carbon according to claim 24, which is about /90.2 mpa Steel articles.

2. A high strength, high ductility, low carbon steel article made by the method of claim 1.

2. A high strength, high ductility, low carbon steel article made by the method of claim 4.

Iron made by the method described in item 4 of the 28M requirement, approximately 0.0S to 0.0S. /3 li amount of carbon, about 7 to 3% silicon and about 0.05 to 75% vanadium by weight. High strength, high ductility, low carbon steel articles consisting essentially of:

Commissioner of the Patent Office 1. Indication of the case PCT/1Js8210I7223, person making the amendment Relationship to the case: Applicant 5. Date of amendment order: October 23, 1982 International search report

Claims (1)

[Claims] 1. Fine particles consisting essentially of a strong second phase dispersed in a soft ferrite matrix. It has a thin structure and sufficient cold deformability to allow a reduction in cross-sectional area of approximately 9L9%1. Single multi-pass operation of low carbon duplex steel compositions characterized by microstructure and morphology fabricate high-strength, high-ductility steel wire and rods, including a step of cold drawing to the desired diameter. How to do it. 2 The steel composition is characterized by a composite ferrite-martensitic microstructure, and the Ruthensite contains a strong second phase dispersed in a soft ferrite matrix. A method according to claim 1. 3 The steel composition is characterized by a composite ferrite-bainite microstructure and the pine ferrite is a soft ferrite, which is characterized by a strong second phase dispersed in the matrix. A method according to the first item in the scope of the request. 4 Iron, about 00S~0. /S weight hereditary carbon, and about 70 to 30 weight hereditary silicon? A steel composition consisting essentially of heating to a time temperature T1; The obtained austenitized steel composition is quenched to reduce the austenite to 700 converting into martensite, The obtained martensitic steel composition is mixed with ferrite and ore. The two phases are kept at a temperature in the α+γ range for a sufficient time to convert to the desired volume ratio of stenite. heating to T2; The obtained ferritic-austenitic steel composition is quenched i'L to remove austenite. converting to martensite; and The obtained steel composition is characterized by a composite ferrite-martensitic microstructure. Creates high strength, high ductility steel wire and rods, including a step of cold drawing to the desired diameter How? 5. Claim 4, wherein the cold drawing stage comprises a single multi-layer cold drawing stage. How to follow section. 6 The steel composition is iron, about 0. /Essential than double hereditary carbon and about 2 times zero silicon A method according to claim 4 consisting of: 7 The steel composition is approximately 0.05 to 0. Claim 4 containing /3M quantity factor 0 vanadium How to follow section. 8. A method according to claim 7, wherein the vanadium content is approximately 0/wt. 9 T1 is in the range of approximately 10 left θ0C to //70°C, and T2 is approximately go0°C A method according to claim 4 or 7 in the range of ~7000<0>C. A method according to claim 4 or claim 7, wherein 10T1 is approximately /150°C. 11 The steel composition was changed to T2, and the subsequent quenching produced martensite with a volume ratio of 70 to To achieve a ferrite to austenite ratio that results in a microstructure containing A method according to claim 2, 4 or 7, comprising heating for a sufficient period of time. 12T2 is about 950℃, and the obtained microstructure is martensite with a volume coefficient of about 30 A method according to claim 11 comprising: 13 Soft ferrite Consists essentially of a strong second phase dispersed in a matrix at least g cold drawn from a steel composition characterized by a microstructure; High strength, high ductility, low carbon, steel article with a tensile strength of 27 mpa. 14 Tensile strength gλ7 mpa to λA g? Claims within the scope of mpa Articles according to paragraph 13. 15. A steel article according to claim 14, wherein the article is a steel wire. 16. A steel article according to claim 14, wherein the article is a steel bar. 17 The microstructure is a cold-drawn composite ferrite-martensitic microstructure. A high strength, high ductility, low carbon steel article according to claim 15 or 16. 18 The microstructure is a cold-drawn composite ferrite-pineite microstructure. A high strength, high ductility, low carbon steel article according to claim 15 or 16. 19 Iron, about 0θ5-〇, /S weight hereditary, and about / ~ triple hereditary silicon having a steel composition consisting essentially of a tensile strength of at least g:l 7 mpa; A steel composition characterized by a ferrite-25 martensitic microstructure Cold drawn, high strength, high ductility, low carbon steel articles. 20 Tensile strength is gf7~. Claim 1 in the range of 24 g 7 mpa Goods according to section 9. 21. An article according to claim 20, wherein the article is a steel wire. 22. The article according to claim 20, wherein the article is a steel rod. 23 The carbon content is approximately 0.7%, the silicon content is approximately 2% by weight, and the composite film The elite-martensite microstructure contains about 30% by volume of martensite and is Tensile strength is about 2<z o mpa to about 2g after the cross-sectional area is reduced by about 999 High strength, high ductility, low carbon according to claim 21 or 22, which is ompa Steel articles. 24. Claim 21, wherein the steel composition contains about 0θ5-07 Pananum or high strength, high ductility, low carbon steel articles in accordance with paragraph 22. 25 Carbon content is approximately 0. The silicon content is approximately Ωθ hereditary, and the silicon content is approximately Ωθ hereditary. Nanoum content is approximately 0. / heavy inheritance, composite ferrite-martensitic microstructure The structure contains martensite with a 3θ volume coefficient, and the tensile strength is approximately 97% after the cross-sectional area is reduced. High strength, high ductility, low carbon according to claim 24, which is about / 90.2 mpa Raw steel articles.・2. High strength, high ductility, low Carbon steel articles. 27 High strength produced by the method set forth in Claim Plate 4]8 Highly ductile, low carbon steel articles. 28, about 0.05 to 0.15% by weight of iron, made by the method of claim 4. carbon, about 1-3% by weight silicon, and about 0.05-0.15% by weight vanadium. A high strength, high ductility, low carbon steel article consisting essentially of: