CN1814845A - 1000Mpa-grade high-strength hot-rolled anti-bullet steel plate and making method - Google Patents

Abstract

This invention relates to a kind of high strength hot-rolled bulletproof steel of 1000Mpa in the following weight percentage: C 0.17-0.21%, Si 1.5-2.2%, Mn 1.5-2.0%, P<=0.035%, S<=0.010%, Al 0.015-0.060%, N<=0.0060%, Nb 0.010-0.050%, Ti 0.010-0.060%, Ca<=0.0050%, Fe and unavoidable impurities, which is processed in the following steps: a, smelting according to the above mentioned components, casting to form slabs, b, heating the slabs to 1100-1250DEG C, hot-rolling the slabs in the austenitic area and over 80% of them are deformed and the final temperature is 800-900DEG C, d, the final rolled steel is cooled to 650-780DEG C in the speed of 50deg.C/s and air cooled for 6-15 seconds, e, cooling them to 350-450deg.C in the speed over 50deg.C/s, f, rolling them and air cooling them to room temperature.

Description

Grade high-strength hot-rolled armour plate of a kind of 1000Mpa and manufacture method thereof

Technical field

The invention belongs to metal material field, relate in particular to the ferrous alloy that contains C, Si, Mn, Nb, Ti.Be a kind of need not heat treated high-strength hot-rolled armor plate and manufacture method thereof, this steel plate is especially suitable for use as the bullet resistant material of armoured van.

Background technology

Ballproof cash truck and other bullet-proof car, as mobile bank's car, private bullet-proof sedan, alert with shellproof cruiser, anti-riot car, arrange sudden and violent car etc., shellproof be their the most basic requirements.Generally adopt armour plate as the protection critical material for reaching shellproof purpose.

The topmost function of armour plate is to stop the penetration of bullet to steel plate, and the thickness that increases steel plate increases the required energy of bullet penetration steel plate, is a kind of effective ways that improve the steel plate bulletproof performance, but this will increase light weight minimizing vehicle payload capacity.Therefore the thickness of armour plate has the trend of attenuate, and the used armour plate thickness of ballproof cash truck is generally 3.0mm.China's armoured van armour plate must satisfy corresponding protection condition among the GA164-1997 " special-purpose armoured van guard technology condition " at present.

Improve armor plate strength and hardness, the energy that bullet penetration steel plate is consumed is increased, bullet may be broken when hardness surpasses certain value, thereby help the raising of bulletproof performance.The quenching heat treatment that adopts armour plate on the market effectively improves the intensity and the hardness of steel plate more, and intensity is more than 1500Mpa.The thermal treatment bullet proof steel be organized as tempered martensite, the alloying aspect adopts Cr-Mo system to guarantee the hardening capacity of steel plate, adds Ni to improve the toughness of steel plate.

The armour plate palpus process quenching of russian patent RU 2015491 C1 and 140～170 ℃ low-temperaturetempering.

The described armour plate of " naval vessel passes with three national military standards such as armour plate standards " (metallurgical standard and quality 1999,01 (01)) contains alloying elements such as Cr, Mo, Ni.

(the achievement numbering: 0100390052) armor plating is middle carbon Mn-Cr-Ni-Mo low alloy steel in " development of high-performance armor plating " in " CSTAD ".

Superstrength bullet proof steel GK901 among " design of ballproof cash truck collision bumper and manufacturing " (southern metal Sum.135 December2003p 12-13) is a medium carbon low alloy steel, be through thermal treatment.

The patent No. is EP 1152207 A2, and it discloses a kind of bullet proof steel of abrasive austenic high mangaenese steel, carbon content 1.1～1.3%, manganese content 11.5～13.5%.

The armoured van bullet proof steel generally is not more than 3mm, and the armor plate strength high-ductility that adds low-temperaturetempering with quenching is low, and plate shape and cold-forming property are poor, and heat affected zone, welding back intensity reduces ballistic performance and also will decrease; Contained more Cr, alloying elements such as Mo, Ni in the steel are again through treatment production cost height.

Summary of the invention

The object of the present invention is to provide grade high-strength hot-rolled armour plate of a kind of 1000Mpa and manufacture method thereof, can be heat treated, with the armoured van armour plate and the manufacture method thereof of hot rolling direct production, its armour plate performance is even, plate shape is good, have good cold-workability and welding property, production cost is low, tensile strength reaches more than the 1000MPa, and its ballistic performance satisfies GA 164-1997 " special-purpose armoured van guard technology condition " A level ballistic standard.

For achieving the above object, technical scheme of the present invention is that the grade high-strength hot-rolled armour plate of a kind of 1000Mpa, its composition are (weight percents):

C 0.17～0.21％

Si 1.5～2.2％

Mn 1.5～2.0％

P ≤0.035％

S ≤0.010％

Al 0.015～0.060％

N ≤0.0060％

Nb 0.010～0.050％

All the other are Fe and unavoidable impurities.

Also can add in Ti 0.010～0.060%, Ca≤0.0050% one or more in the hot-rolled armor plate of the present invention.

Manufacture method of the present invention, it comprises the steps:

A. press mentioned component and smelt, cast, form slab;

B. heating is heated to 1100～1250 ℃ with slab;

C. hot rolling is rolled in the austenitic area, and rolling reduction is greater than 80%, 800～900 ℃ of finishing temperatures;

D. cooling, the steel plate after the finish to gauge is as cold as 650～780 ℃ with the above speed of cooling of 50 ℃/s, 6～15 seconds of air cooling;

E. cooling again, the cooling rate above with 50 ℃/s is cooled in the temperature range of 350～450C;

Batch, batch the back air cooling to room temperature.

Bullet proof steel must have enough intensity to resist the penetration of bullet, though the armor plate strength high plasticity add low-temperaturetempering of quenching is low, cold-forming property is poor, and welding back intensity reduces.If steel plate has certain plasticity and toughness when having certain intensity, the kinetic energy that utilizes these performances to produce viscous deformation consumption bullet when bullet penetration steel plate can improve the bulletproof performance of steel plate.Can bring out martensitic transformation when residual austenite is subjected to deformation, the intensity that martensitic transformation improves steel plate also will increase the uniformly extension of steel plate, so residual austenite has the ability of high absorption merit, and the steel with residual austenite has good bulletproof performance.

C: be used to guarantee the intensity rank of steel, be the austenitic principal element of stable residual yet, C too low strength does not reach requirement, and C is too high unfavorable to welding property.

Si: playing the solution strengthening effect in steel, and can make carbon enrichment in austenite, is the indispensable element of stable residual austenite, and Si is too low to be weakened the effect that purifies the carbon in the ferrite, and the too high plasticity of steel that makes reduces.

Mn: be the element of solution strengthening, stable austenite, be lower than the undercapacity of 1.5% steel, too high meeting descends the plasticity of steel.

P, S: be the impurity element in the steel, content should be low more good more.

Al: be the deoxidant element in the steel, reduce oxide inclusion, pure steel in the steel, help ferritic separating out, impel carbon enrichment in austenite, the effect of stable austenite is arranged.

Ti, Nb: be effective crystal grain thinning, improve intensity and flexible element, be present in the steel with the form of carbide and carbonitride, add-on is lower than 0.01% DeGrain.

N: exist with nitride and carbonitride form in steel, the titanium that too high N will consume in the steel forms the disadvantageous TiN inclusion of plasticity.

Ca: can change the form of sulfide in the steel, improve the plasticity and the toughness of steel plate.

The explanation of processing condition among the present invention:

Heating temperature is lower than 1100 ℃, and microalloy element Nb, Ti dissolving is insufficient, fails to make full use of the effect of microalloy element, and intensity reduces.Be higher than 1250 ℃ of easy alligatoring of crystal grain, unfavorable to improving steel plate toughness.

Slab carries out roughing in the crystal boundary area again at austenite, by the recrystallize refine austenite crystal grain behind the rolling deformation, the deflection of steel plate is more than 80%, finishing temperature is controlled at 800～900 ℃ in austenite non-recrystallization district, by the rolling deformation of austenite cold zone, the carbonitride precipitation that makes the austenite crystal intragranular form deformation bands and bring out Nb, Ti microalloy element in response to change increases nucleation rate during to ferritic transformation at supercooled austenite, crystal grain thinning, the toughness of raising steel plate.

Steel plate chilling after the finish to gauge (50 ℃/more than the s) is to 650～780 ℃, and in 6～15 seconds of air cooling, a part of supercooled austenite changes ferrite at ferrite area.Cooling when being lower than 650 ℃ steel to be in time of ferrite transformation too short thereby ferrite content is few, the carbon concentration in the austenite low being unfavorable for obtains many residual austenites in room temperature.Cooling temperature is higher than 780 ℃, and steel also is in austenitic state, and obtaining a certain amount of ferrite will increase the air cooling time, is unallowed big production.Because phase transformation needs incubation period, the air cooling time is less than 6 seconds ferrite content very little, and the carbon concentration that is enriched in the austenite is low, is unfavorable for the stable of residual austenite; The air cooling time, ferrite content increased more than 15 seconds, and yield strength is too low, was unfavorable for improving elastoresistance.

Steel plate is quenched in 350～450 ℃ the scope and batches behind the air cooling, batches the back air cooling to room temperature.Steel plate carries out bainitic transformation in this temperature range, and austenitic carbon concentration constantly increases when bainite is separated out.Its martensite point (Ms) of austenite that carbon concentration increases is reduced to below the room temperature, and the austenite that remains to room temperature becomes residual austenite.It is many and remained austenite content reduces, the toughness of unfavorable raising steel plate that the chilling final temperature is higher than 450 ℃ of bainites; The chilling final temperature is lower than 350 ℃ will suppress separating out of bainite, and austenite will change martensite because of the not enough instability of carbon concentration in process of cooling.

Beneficial effect of the present invention

Hot-rolled high-strength armour plate of the present invention, alloy content lacks than the thermal treatment armour, again without thermal treatment, so low cost of manufacture.Though intensity is lower than thermal treatment armour, because of being arranged in the tissue, residual austenite improves the ability that steel plate absorbs merit, and GA 164-1997 " special-purpose armoured van guard technology condition " A level ballistic standard is satisfied in ball firing.

Because of ferrite and residual austenite are arranged in the steel plate of the present invention, the cold-forming property of steel is better than thermal treatment steel plate.Heat affected zone after the steel plate welding is organized as bainite, and intensity does not reduce, so bulletproof performance does not descend.

Description of drawings

Fig. 1, Fig. 2 are photos after the steel gunslinging of the present invention.

Embodiment

Table 1 is the chemical ingredients of test steel, and table 2 is compositions of comparative steel, and steel of the present invention does not contain valuable alloying elements such as Cr, Co, and Mn content is compared much lower with comparative steel.

Table 1

Embodiment	Chemical ingredients (wt%)
												C	Si	Mn	P	S	Al	Nb	Ti	N	Ca
1	0.18	1.55	1.88	0.015	0.0010	0.047	0.037	0.046	0.0025	0.0050
											2	0.19	1.60	1.82	0.025	0.0080	0.025	0.036		0.0048
3	0.20	2.03	1.71	0.021	0.0012	0.044	0.023		0.0038	0.0020
											4	0.17	1.80	1.53	0.022	0.0045	0.036	0.050		0.0048
5	0.21	1.50	2.00	0.018	0.0015	0.029	0.01	0.060	0.0025
											6	0.18	2.20	1.61	0.026	0.0021	0.027	0.035	0.010	0.0041	0.0025
7	0.18	2.01	1.71	0.035	0.0030	0.060	0.040		0.0055
											8	0.17	2.10	1.72	0.016	0.0100	0.023	0.035		0.0037
9	0.19	1.65	1.67	0.020	0.0040	0.060	0.031	0.020	0.0600
											10	0.19	1.71	1.50	0.014	0.0030	0.035	0.035	0.030	0.0035

Table 2 (wt%)

Comparative example	C	Si	Mn	P	S	Cr
							EP 1152207 A2	1.10～1.30	0.25～0.50	11.5～13.5	Max.0.10	Max 0.040	Max 0.50

Test steel through smelting, forging, rolling, the mechanical property of technology controlling and process and gained steel plate when table 3 is rolling, the test of mechanical property is undertaken by the GB6397-86 standard, and residual austenite is used X light diffracting analysis.Data as can be seen from table, reach more than the 1000MPa by the composition of the present invention's design and the steel plate tensile strength of hot rolling technology control, remained austenite content reaches more than 10%, remained austenite content more the bright steel plate of multilist to absorb the ability of merit strong more, elastoresistance also will be good more.

Table 3

Embodiment	Test piece number (Test pc No.)	Finishing temperature (℃)	One cold back temperature (℃)	The air cooling time (s)	Coiling temperature (℃)	Yield strength Rp0.2 (MPa)	Tensile strength Rm (MPa)	Unit elongation A80 (%)	Residual austenite (%)
										1	1-1	865	670	10	405	790	1100	12	26.9
2	1-2	800	650	8	350	805	1075	11	21.2
										3	2-1	900	726	6	430	862	1140	13	10.4
4	2-2	880	700	11	385	815	1080	13	17.8
										5	3-1	900	720	8.5	440	640	1120	13	31.4
6	3-2	820	670	9.5	440	560	1105	14	32.3
										7	4-1	870	710	13	410	545	1095	13	30.2
8	4-2	850	680	9	390	590	1115	13	24.5
										9	5-1	800	660	7	400	780	1040	11	18.6
10	5-2	880	730	10	420	755	1025	12	20.4
										11	6-1	870	710	10	400	800	1055	12	24.5
12	6-2	900	780	8	450	815	1070	11	16.8
										13	7-1	900	760	6	440	885	1140	10	12.4
14	7-2	850	700	10	405	815	1105	12	19.8
										15	8-1	830	670	7	430	885	1135	11	16.5
16	9-1	880	710	15	360	550	1015	15	31.6
										17	10-1	860	700	10	400	775	1070	12	22.1
18	10-2	860	720	12	370	750	1065	12	24.6

Steel plate of the present invention carries out shooting test by GA 164-1997 " special-purpose armoured van guard technology condition " A grade standard and does not all puncture, and Fig. 1, Fig. 2 are the photos after the gunslinging.

Steel of the present invention directly with hot rolling production, without modified thermal treatment, though intensity is lower than thermal treatment steel plate, thereby have the ballistic performance that a certain amount of residual austenite has been improved steel plate in the steel, reach the level of ballistic protection of thermal treatment high tensile steel plate.This steel plate also has good processability, mainly as the armoured van armour plate.

Claims (3)

1. grade high-strength hot-rolled armour plate of 1000Mpa, its composition is (weight percent):

C 0.17～0.21％

Si 1.5～2.2％

Mn 1.5～2.0％

P ≤0.035％

S ≤0.010％

Al 0.015～0.060％

N ≤0.0060％

Nb 0.010～0.050％

All the other are Fe and unavoidable impurities.

2. the grade high-strength hot-rolled armour plate of 1000Mpa as claimed in claim 1 is characterized in that, also can add in Ti 0.010～0.060%, Ca≤0.0050% one or more.

3. the manufacture method of the grade high-strength hot-rolled armour plate of 1000Mpa, it comprises the steps:

A. press mentioned component and smelt, cast, form slab;

B. heating is heated to 1100～1250 ℃ with slab;

C. hot rolling is rolled in the austenitic area, and rolling reduction is greater than 80%, 800～900 ℃ of finishing temperatures;

D. cooling, the steel plate after the finish to gauge is as cold as 650～780 ℃ with the above speed of cooling of 50 ℃/s, 6～15 seconds of air cooling;

E. cooling again is cooled to the above cooling rate of 50 ℃/s in 350～450 ℃ the temperature range;

F. batch, batch the back air cooling to room temperature.

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