MICRO-ALLOYED MANGANESE-BORON STEEL

Abstract

A micro-alloyed manganese-boron steel includes about 0.25 to 0.4 wt. % carbon, about 0.5 to 2.7 wt. % manganese, about 0.001 to 0.005 wt. % boron, about 0.1 to 0.8 wt. % silicon, about 0.1 to 0.6 wt. % chromium, molybdenum and nickel, and about 0.01 to 0.06 wt. % aluminum, niobium and titanium. The balance is iron, and the steel is a micro-alloyed material for hot stamping of automotive parts.

Description

TECHNICAL FIELD

The disclosure relates to a manganese-boron steel micro-alloyed with one or more additives, and optionally coated, for hot stamping and a method of producing and using the same.

BACKGROUND

The requirements for high security, low weight, and good fuel economy have become increasingly important in automotive manufacturing. To meet all of these requirements, high strength steels have become increasingly popular in vehicle body manufacturing to improve crash behavior and at the same time lower the weight of the vehicle. The high strength steels may be produced at room temperature by cold stamping or at high temperatures at which the material is austenized. The latter process called hot stamping is a non-isothermal forming process for sheet metal, where forming and quenching take place in the same step. In comparison to components manufactured by the cold stamping process, hot stamping is capable of providing components having minimum springback, reduced sheet thickness, and superior mechanical properties such as high strength. A variety of press hardening steel grades have been developed for the hot stamping process.

SUMMARY

In at least one embodiment, a micro-alloyed manganese-boron steel is disclosed. The micro-alloyed manganese-boron steel includes about 0.25 to 0.4 wt. % carbon, about 0.5 to 2.7 wt. % manganese, about 0.001 to 0.005 wt. % boron, about 0.1 to 0.8 wt. % silicon, about 0.1 to 0.6 wt. % chromium, molybdenum, and nickel, and about 0.01 to 0.06 wt. % aluminum, niobium, and titanium, the balance being iron and the steel being a micro-alloyed material for hot stamping of automotive parts. The steel may further include up to about 0.01 wt. % sulfur, vanadium, or both. The steel may further include up to about 0.01 wt. % nitrogen. The steel may also include up to about 0.03 wt. % phosphorus. The steel may be coated with an aluminum silicon coating. The coating may be AlSi10Fe3 coating.

In an alternative embodiment, a hot stamping method is disclosed. The method includes forming a hot stamped automotive component from a micro-alloyed manganese-boron steel blank comprising about 0.25 to 0.4 wt. % carbon, about 0.5 to 2.7 wt. % manganese, about 0.001 to 0.005 wt. % boron, about 0.1 to 0.8 wt. % silicon, about 0.1 to 0.6 wt. % chromium, molybdenum, and nickel, about 0.01 to 0.06 wt. % aluminum, niobium, and titanium, and a balance of iron, by hot stamping such that the component reaches a minimum yield strength of 1400 MPa at the end of the hot stamping process. The micro-alloyed manganese-boron steel blank may also include up to about 0.01 wt. % nitrogen. The blank may further include up to about 0.01 wt. % sulfur, vanadium, or both and/or up to about 0.03 wt. % phosphorus. At the end of the quenching operation, and prior to baking in a paint oven, the hot stamped component may have a minimum tensile strength of about 1800 MPa. At the end of the quenching operation, and prior to baking in a paint oven, the hot stamped component may have a minimum total elongation of about 6%. The micro-alloyed manganese-boron steel may be coated with an aluminum silicon coating. The method may also include exposing the hot stamped component to elevated temperatures in a paint baking over to increase yield strength beyond the 1400 MPa. The end of the hot stamping operation includes releasing the component after quenching operation.

In a yet different embodiment, a hot stamped component is disclosed. The component includes a micro-alloyed manganese-boron steel including about 0.25 to 0.4 wt. % carbon, about 0.5 to 2.7 wt. % manganese, about 0.001 to 0.005 wt. % boron, about 0.1 to 0.8 wt. % silicon, about 0.1 to 0.6 wt. % chromium, molybdenum, and nickel, and about 0.01 to 0.06 wt. % aluminum, niobium, and titanium, the balance being iron, and has a minimum yield strength of at least 1400 MPa. The component may be a body in white automotive part. The component may be a side beam. The component, at an end of hot stamping, has a minimum tensile strength of about 1800 MPa. The component, at the end of the hot stamping process, at an end of hot stamping, has a minimum total elongation of about 6%. The micro-alloyed manganese-boron steel may be coated with an aluminum silicon coating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary schematic view of a hot stamping system and process in accordance with one or more embodiments;

FIG. 2 depicts a schematic perspective side view of an exemplary hot stamping press incorporated in the hot stamping system depicted in FIG. 1;

FIG. 3 shows an example automotive component produced from the steel disclosed herein by a hot stamping process such as the hot stamping process of FIG. 1.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

Except where expressly indicated, all numerical quantities in this description indicating dimensions or material properties are to be understood as modified by the word “about” in describing the broadest scope of the present disclosure.

The first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation. Unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.

Reference is being made in detail to compositions, embodiments, and methods of the present invention known to the inventors. However, it should be understood that disclosed embodiments are merely exemplary of the present invention which may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, rather merely as representative bases for teaching one skilled in the art to variously employ the present invention.

The description of a group or class of materials as suitable for a given purpose in connection with one or more embodiments of the present invention implies that mixtures of any two or more of the members of the group or class are suitable. Description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description, and does not necessarily preclude chemical interactions among constituents of the mixture once mixed. The first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation. Unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.

Hot stamping, also called hot forming or press hardening, is a process of forming metal while the metal is very hot, usually in excess of 900° C., and subsequently quenching the formed metal in a closed die. Hot stamping may be direct or indirect. The hot stamping process converts low-tensile-strength metal to a very high-strength metal of about 150 to 230 kilo pounds per square inch (KSI). During a typical hot stamping process, schematically depicted in FIG. 1, a press-hardenable material is heated as a blank 10 to about 900 to 950° C. to an austenite state in the first stage of the press line or hot stamping system 22. The first stage lasts for about 4 to 10 minutes inside of a continuous-feed furnace 12. A robot transfer system 14 subsequently transfers the austenized blank 10 to a press 16 having a die arrangement 18. The transfer usually takes less than 3s. A part 20 is formed in the die arrangement 18 from the blank 10 while the material is very hot. The blanks 10 are stamped and cooled down under pressure for a specific amount of time according to the sheet thickness after drawing depth is reached. During this period, the formed part 20, further also referred to as a component 20, is quickly cooled or quenched by being held in a closed die cavity having a water cooling system. Quenching is provided at a cooling speed of 50 to 100° C./s for a few seconds at the bottom of the stroke, which is when the material's grain structure is converted from the austenitic state to a martensitic state. Finally, the component 20 leaves the hot-stamping line at about 150° C.

Typically, the component 20 has relatively high mechanical properties: tensile strength of about 1,400 to 1,600 MPa (200 to 230 KSI) or higher and a yield strength of about 1,000 and 1,200 MPa (145 to 175 KSI) or higher. The component 20 may be further treated and/or processed, for example incorporated in the body in white (BIW), provided with one or more coatings, baked in a paint oven, or the like.

The hot stamping process provides numerous advantages over other high-strength steel and advanced high-strength steel forming methods such as cold stamping. One of the advantages is providing stress-relieving capability which resolves problems such as springback and warping typically associated with other high-strength steel forming methods. Additionally, hot stamping allows the forming of complex parts in a single-step die and in only one stroke. Thus, multi-component assemblies can be redesigned and formed as one component, eliminating downstream joining processes such as welding and eliminating the need for additional parts. This may, in turn, reduce overall mass of the formed parts.

Hot stamped parts 20 have found broad application in automotive industry. Typically, hot stamping is best-suited to form components which are required to be both lightweight and strong at the same time. Exemplary automotive components formed by hot stamping include body pillars, rockers, roof rails, bumpers, door intrusion beams, carrier understructure, mounting plates, front tunnels, front and rear bumpers, reinforcement members, side rails, and other auto parts that are required to be strong enough to withstand a large load with minimal intrusion into the passenger compartment during a rollover and impact. Hot stamping thus enables producing such components meeting structural performance requirements while adding as little weight to a vehicle as possible.

Yet, to provide high quality hot stamped parts, a suitable material needs to be used. A plethora of various steel grades for hot stamping has been developed. For example, Usibor® 1500, Ductibor® steel grades, and the like. Manganese-boron steel grades such as 22MnB5 have also become common in hot stamping.

Manganese-boron steels are tempered boron-alloy steels. They usually feature good formability and good strength after heat treatment. The desirable strength of the manganese-born steel grades is at last partially due to their content of carbon and manganese, and a low content of boron, which is typically not more than a few thousandths of a percent. Example manganese-boron steels and their compositions are listed in FIG. 1 below. Weight percent of individual elements is based on an overall weight of the material, the balance being iron.

TABLE 1
Chemical composition of example manganese-boron steels
Steel	C	B	Cr	Mn	Si max	P max	S max
grade	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]
8MnCrB3	0.06-0.11	0.0008-0.0040	0.25-0.5	0.7-1.00	0.4	0.025	0.025
17MnB3	0.15-0.18	0.0008-0.0045	0.15-0.35	0.6-0.8	0.4	0.025	0.025
20MnB5	0.17-0.23	0.0008-0.0050	—	1.1-1.4	0.4	0.025	0.025
22MnB5	0.19-0.26	0.0008-0.0050	0.15-0.35	1.1-1.4	0.4	0.025	0.025
30MnB5	0.27-0.33	0.0008-0.0050	—	1.15-1.45	0.4	0.025	0.025
37MnB5	0.34-0.40	0.0008-0.0050	0.15-0.35	0.8-1.1	0.4	0.025	0.025
38MnB5	0.36-0.42	0.0008-0.0050	—	1.15-1.45	0.4	0.025	0.025

To further improve mechanical properties of certain steel grades, the material may be electrically galvanized, hot-dip galvanized, galvannealed, or coated, for example with aluminum silicon coating.

Another technique to increase at least some mechanical properties of steel is micro-alloying. A micro-alloyed steel is a type of a low-carbon alloy steel containing small amounts of alloying elements or additives, such as 0.05-0.15 wt. %, based on the total weight of the steel material, besides about 0.06 or lower-0.12 wt. % carbon and up to 0.2 wt. % manganese. The elements used for microalloying may be niobium, vanadium, titanium, molybdenum, zirconium, boron, rare-earth metals, or a combination thereof. Each element, its amount, and overall composition of the steel may influence different properties of the steel.

The micro-alloyed steels derive their strength from precipitation hardening. The elements are used to refine the grain microstructure of the steel grade, facilitate precipitation hardening, or both. Specifically, the micro-alloying elements combine with carbon and/or nitrogen and precipitate to strengthen the ferrite phase. Usually, the micro-alloyed steels have a good weldability and notch toughness, which may be further improved by reducing the carbon content. Other beneficial properties typically include good fatigue life and wear resistance which may be superior to heat-treated steels. As the micro-alloyed steels are not quenched and tempered, they are not susceptible to quench cracking and do not require straightening or stress relieving.

Despite existence of available steel grades, a need remains for a steel material suitable for the hot stamping process which would have very high strength levels of up to about 2000 MPa tensile strength. Yet, it would be desirable that such material may be used in a conventional hot stamping process, for example when applying a production hot stamping schedule for press hardening of PHS1500 AlSi10Fe3 coated steel grade, while meeting the following target mechanical properties: minimum yield strength of about 1400 MPa, minimum tensile strength of about 1800 MPa, and minimum elongation of about 6% total elongation after die quenching and preferably before the paint baking process. For example, a steel grade 36MnB5 or 36MnB5 coated with AlSi10Fe3, which are currently being used, do not meet the target properties.

Thus, there remains a need for a manganese-boron steel grade to meet the target mechanical properties prior to the paint baking process, without relying on the effect of the paint baking process during the hot stamping processing and post-processing. Additionally, using steel grades such as 36MnB5 may impose additional constraints on the hot stamping parameters such as die temperature below 100° C., increase of die dwell time, increase of the die contact pressure, and/or other adjustments to the process and equipment which may result in overall increased capital investments associated with the production of the hot stamped parts with materials such as 36MnB5.

In one or more embodiments, a manganese-boron alloy steel overcoming one or more problems described above is disclosed. The manganese-boron alloy steel may include the following elements or additives listed in Table 2. Weight percent of individual elements is based on an overall weight of the material, the balance being iron. Incidental elements commonly found in steelmaking practice are acceptable, as long as they do not so adversely affect the steel that it cannot meet the target mechanical properties.

TABLE 2
The manganese-boron alloy steel composition in weight percent
	element
	C
	[wt.	Mn	Si	Cr	Mo	Ni	S
amount	%]	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]
Min	0.25	0.5	0.1	0.1	0.1	0.1	0.0
Max	0.40	2.7	0.8	0.6	0.6	0.6	0.01
	element
	Al
	[wt.	Nb	Ti	V	N	P	B
amount	%]	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]	[wt. %]
Min	0.01	0.01	0.01	0.0	0.0	0.0	0.001
Max	0.06	0.06	0.06	0.01	0.01	0.03	0.005

The carbon content of the steel may be from about 0.25 to 0.4 wt. %, 0.8 to 3.5 wt. %, or 0.3 to 3.2 wt. %. Lower amount than about 0.25 wt. % may result in insufficient tensile strength of the steel. The amount of carbon above about 0.4 wt. % may, on the other hand, negatively influence elongation.

Manganese may be present in the amount of about 0.5 to 2.7 wt. %, 1 to 2.5 wt. %, or 1.5 to 2 wt. %. Boron may be present in the amount of 0.001 to 0.005 wt. %, 0.002 to 0.005 wt. %, or 0.003 to 0.004 wt. %. Manganese may be added together with sulfur as manganese sulfide inclusions.

The microalloying elements such as sulfur, vanadium, and nitrogen may be present in the amount of 0.0 to 0.01 wt. %, 0.0025 to 0.008 wt. %, or 0.005 to 0.0075 wt. %. The content of chromium, molybdenum, and nickel may be from 0.1 to 0.6 wt. %, 0.2 to 0.5 wt. %, or 0.3 to 0.4 wt. %. The content of aluminum, niobium, and titanium may be from 0.01 to 0.06 wt. %, 0.02 to 0.05 wt. %, or 0.03 to 0.04 wt. %. The amount of silicon may be 0.1 to 0.8 wt. %, 0.2 to 0.6 wt. %, or 0.4 to 0.5 wt. %. The content of phosphorus may be 0.0 to 0.3 wt. %, 0.05 to 0.2 wt. %, or 0.075 to 0.1 wt. %. Vanadium, nitrogen, and phosphorus may or may not be present.

The disclosed steel may comprise the components in Table 2. Alternatively, the disclosed steel may consist of or consist essentially of the elements listed in Table 2.

The focus of the disclosure is to form a manganese-boron steel, micro-alloyed with addition of different proportions of chemical elements listed in Table 2 such that the alloyed steel may be stamped into an automotive component or part 20 by a hot stamping process such that the part 20 has a minimum yield strength of at least about 1400 MPa, about 1400 MPa, or 1400 MPa, minimum tensile strength of at least about 1800 MPa, about 1800 MPa, or 1800 MPa, and minimum elongation of at least about 6%, about 6%, or 6% total elongation right after, or at the end of, a die quenching operation of the hot stamping process without any contribution of the paint baking process. The paint baking process may follow the hot stamping process immediately, shortly, or eventually after the hot stamping process is finished.

Without limiting the disclosure to a single theory, it is anticipated that both the composition and the thermal processing results in a material capable of meeting the target values listed above. The yield strength of the formed alloyed steel meets the target prior to paint baking, and the contribution of precipitation strengthening and dislocation density components to the material yield strength through the effect of the paint baking process is thus only optional and could serve as an additional mechanism, further increasing the yield strength of the material, but is not a necessity. Additional advantages of the disclosed steel grade may be elimination of the mentioned constraints on the hot stamping parameters as well as financial savings.

By adding the elements of Table 2 to the manganese-boron steel, the contribution of solid solution strengthening component is increased while the benefit and the contribution of the grain size component to the material yield strength is maintained. Alloying the elements listed in Table 2 enables the precipitates to be taken into the solution during the heating and soak stages (quenching), remain in the solution during hot working, and precipitate to strengthen the ferrite during cooling. To enable effective precipitation, the growth of the precipitates should not exceed a size at which they would not provide strengthening. Precipitation strengthening may lead to lower ductility and impact resistance. Yet, the precipitation may be used to control the austenitic grain size and ferrite grain size after transformation.

The austenitic grain size may be controlled, for example, by restraining the austenitic grain growth during the soak, using a dispersion such as fine TiN which remains undissolved at the soak temperature, or choosing a precipitate capable of inhibiting the rate of recrystallization of the austenite.

The method of production of the disclosed steel also influences the steel properties. The method may include forming an initial alloying material from the base steel material with the elements or microalloying additives listed above. The base steel material is a manganese-boron steel material. The base steel may be Mn36B5 steel base material. The base steel material includes iron ore and coal. The coal may be cleaned of impurities in a coke oven to yield an almost pure form of carbon.

The method may include heating a mixture of the base steel material and the microalloying additives, melting the mixture, and homogenizing the steel molten material. The melting may be provided in a blast furnace. The method may include processing the steel from the steel molten material in an oxygen converter, an open hearth, an electric arc furnace, a cyclone converter furnace, or a different apparatus. The method may include secondary steelmaking processes such as stirring, ladle furnace, ladle injection, degassing, composition adjustment, oxygen blowing, or the like. The method also includes ingot or continuous casting such that the molten steel material is cast into a cooled mold causing a thin steel shell to solidify. The strand may be cut into desired lengths such as thin strips. The micro-alloyed steel may be subsequently forged by hot-rolling, which helps eliminate cast defects and achieve a desired shape and surface quality. Hot rolling may be followed by cold-rolling in ambient air without an additional heat treatment. The rolled sheets may feature ferritic-pearlitic microstructure which is transformed to fully martensitic structure after or during the hot stamping process.

The steel may be also coated to enhance certain properties such as tolerance of temperatures of up to 800° C. without scaling, delamination, or both, or to increase corrosion resistance. The coating may be, for example, aluminum silicon coating. The coating may be AlSi10Fe3 coating.

The method includes using the steel disclosed herein in the blank 10 of the hot stamping process described above to form one or more hot stamped parts. The one or more hot stamped parts may be a part for automotive applications such as high tensile strength automobile parts 20 meeting or exceeding the target properties named above. The part 20 may be a front bumper, tail bumper, A column, B column, C column, roof frame, floor frame, door panel, door anti-beam, intrusions beams, body pillars, rockers, mounting plates, front tunnels, side rails, reinforcement members, and other parts in BIW, or the like, example of which is shown in FIG. 3.

At the end of the hot stamping cycle, and prior to being exposed to additional high temperatures such as for example in a paint baking oven, the component or part 20 made from the disclosed steel material has a minimum yield strength of at least about 1400 MPa or about 1400 MPa, or 1400, 1410, 1420, 1430, 1440, 1450, 1480, 1500, 1510, 1520, 1550, 1580, 1600 MPa or higher; a minimum tensile strength of at least about 1800 MPa or about 1800, 1810, 1820, 1830, 1840, 1850, 1870, 1890, 1900, 1920, 1940, 1950, 1960, 1980, 2000 MPa, and minimum elongation of at least about 6% or about 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.7, 7.9, 8.0, 8.1, 8.5, 9.0, 9.5. 10, 10.5, 11% or more total elongation.

The end of the hot stamping cycle or operation is the release of the part 20 after quenching such when the part 20 leaves the hot-stamping line at about 150° C. Paint baking is not a part of the hot stamping process, but a subsequent process or operation. The paint baking process may follow the hot stamping process immediately, shortly, or eventually after the hot stamping process is finished. The paint baking may further improve the properties named above by exposing the part 20 to elevated temperatures. The elevated temperatures include temperatures needed to cure one or more coatings such as one or more layers of automotive paint.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosure. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the disclosure.

Claims

1. A micro-alloyed manganese-boron steel comprising:

about 0.25 to 0.4 wt. % carbon;

about 0.5 to 2.7 wt. % manganese;

about 0.001 to 0.005 wt. % boron;

about 0.1 to 0.8 wt. % silicon;

about 0.1 to 0.6 wt. % chromium, molybdenum and nickel; and

about 0.01 to 0.06 wt. % aluminum, niobium and titanium;

the balance being iron, and the steel being a micro-alloyed material for hot stamping of automotive parts.

2. The manganese-boron steel of claim 1, further comprising up to about 0.01 wt. % sulfur, vanadium or both.

3. The manganese-boron steel of claim 1, further comprising up to about 0.01 wt. % nitrogen.

4. The manganese-boron steel of claim 1, further comprising up to about 0.03 wt. % phosphorus.

5. The manganese-boron steel of claim 1, wherein the steel is coated with an aluminum silicon coating.

6. The manganese-boron steel of claim 5, wherein the coating comprises AlSi10Fe3.

7. A hot stamping method comprising:

forming a hot stamped automotive component, from a micro-alloyed manganese-boron steel blank comprising about 0.25 to 0.4 wt. % carbon, about 0.5 to 2.7 wt. % manganese, about 0.001 to 0.005 wt. % boron, about 0.1 to 0.8 wt. % silicon, about 0.1 to 0.6 wt. % chromium, molybdenum and nickel, about 0.01 to 0.06 wt. % aluminum, niobium and titanium, and a balance of iron, by hot stamping such that the component reaches a minimum yield strength of 1400 MPa at an end of hot stamping.

8. The method of claim 7, wherein the micro-alloyed manganese-boron steel blank further comprises up to about 0.01 wt. % nitrogen.

9. The method of claim 7, wherein the micro-alloyed manganese-boron steel blank further comprises up to about 0.01 wt. % sulfur, vanadium, or both and/or up to about 0.03 wt. % phosphorus.

10. The method of claim 7, wherein at an end of a quenching operation, and prior to baking in a paint oven, the hot stamped component has a minimum tensile strength of about 1800 MPa.

11. The method of claim 7, wherein at an end of a quenching operation, and prior to baking in a paint oven, the hot stamped component has minimum total elongation of about 6%.

12. The method of claim 7, further comprising coating the micro-alloyed manganese-boron steel with an aluminum silicon coating.

13. The method of claim 7, further comprising exposing the hot stamped component to elevated temperatures in a paint baking oven to increase yield strength beyond the 1400 MPa.

14. The method of claim 7, wherein the end of the hot stamping includes releasing the component after quenching.

15. A hot stamped component comprising:

a micro-alloyed manganese-boron steel including about 0.25 to 0.4 wt. % carbon, about 0.5 to 2.7 wt. % manganese, about 0.001 to 0.005 wt. % boron, about 0.1 to 0.8 wt. % silicon, about 0.1 to 0.6 wt. % chromium, molybdenum and nickel, and about 0.01 to 0.06 wt. % aluminum, niobium and titanium, the balance being iron, and having a minimum yield strength of at least 1400 MPa.

16. The hot stamped component of claim 15, wherein the component is a body in white automotive part.

17. The hot stamped component of claim 15, wherein the component is a side beam.

18. The hot stamped component of claim 15, wherein the component, at an end of hot stamping, has a minimum tensile strength of about 1800 MPa.

19. The hot stamped component of claim 15, wherein the component, at an end of hot stamping, has a minimum total elongation of about 6%.

20. The hot stamped component of claim 15, wherein the micro-alloyed manganese-boron steel is coated with an aluminum silicon coating.