CN101293255A

CN101293255A - Method for producing economic thermal forming martensite steel plate

Info

Publication number: CN101293255A
Application number: CNA2008101150513A
Authority: CN
Inventors: 董瀚; 时捷; 惠卫军; 王毛球
Original assignee: Central Iron and Steel Research Institute
Current assignee: Central Iron and Steel Research Institute
Priority date: 2008-06-17
Filing date: 2008-06-17
Publication date: 2008-10-29

Abstract

A production method of an economical type hot forming martensitic steel plate belongs to the technical field of the preparation of a steel plate. The technique is as follows: continuous casting is heated to 1050-1250 DEG C; 3-20 times of rolling are carried out at the recrystallization temperature of steel ranging from 900 to 1150 DEG C, so as to thin austenite crystal, improve the quality of the steel plate and reduce the thickness of the steel plate; the final rolling temperature is controlled at the tempreture between 750 to 900 DEG C to ensure the size of final crystal grains; the coiling temperature of the steel plate is kept at 600-700 DEG C to ensure that the steel plate has comparatively low hardness. The production method has the advantages of saving production flow and reducing production cost.

Description

Method for producing economic thermal forming martensite steel plate

Technical field

The invention belongs to the steel plate preparing technical field, a kind of method for producing economic thermal forming martensite steel plate particularly is provided, being suitable for the thickness specification is 1.0-10mm, the thermal forming martensite steel plate of tensile strength more than 1300MPa.

Background technology

Along with the raising of automobile lightweight and security, require automobile structure to have superhigh intensity with steel.The strength level of traditional ferritic steel, pearlitic steel and bainitic steel all is lower than 1.0GPa, can't meet the demands.The thermal forming martensite steel technology prepares auto parts intensity and will reach more than the 1.3GPa, has become one of most important automobile technology of preparing.

The performance requirement of thermal forming martensite steel plate and traditional hot rolled steel plate have bigger different, and this is because the thermal forming martensite steel technical process determines.Conventional steel plates is divided into two kinds usually, and a kind of is low performance steel plate such as Q235, Q345,16Mn etc., and they are straight carbon steels, and smelting, continuous casting and rolling mill practice do not have strict control requirement; Another kind is quality plate such as pipe line steels such as X70, X80, X100, TRIP steel, DP steel etc., and they mainly are low-carbon micro steel-alloys, directly obtains serviceability by controlled rolling and control cooling, especially reaches the intensity of design.It is obviously different that thermal forming martensite steel and above-mentioned steel plate have, and mainly show: 1, the final serviceability of steel plate is not that as-rolled condition determines, but by in thermoforming process heating and process for cooling determined; 2, the chemical composition of steel is generally middle carbon, and contains higher alloying component, has certain quenching degree to guarantee steel plate.For this reason, easily cause problems such as surface of steel plate oxidation and decarburization, steel plate hardness height, lack of homogeneity, rolling deformation drag be big.

Thermal forming martensite steel product production technology need experience processes such as shearing blanking, high temperature heating, drop stamping moulding and control cooling.This possesses following feature with regard to the steel plate that requires as-rolled condition: 1, the steel plate of as-rolled condition has rationalization, with reduction steel plate hardness, thereby guarantees to shear the blanking performance; 2, the excellent metallurgical quality and the good steel plate uniformity are to guarantee the function admirable of part; 3, favorable surface quality, the especially control of skin decarburization layer are to guarantee the mechanical property of part; 4, good and economic and be easy to industrial production.

At present, external thermoforming steel plate adopts 22MnB5 usually, and its final products are cold rolled annealed processing, and the steel plate of thinner specification is also in cold rolling basic upper surface plating Si-Al processing, further to prevent the oxidation in the heating process.Along with the capacity of equipment of hot continuous rolling unit further develops, hot continuous rolling can directly be produced the steel plate that the thickness specification is 1.0mm, replaces cold-rolling process to reduce the production cost of steel by a relatively large margin as producing hot rolling.

Summary of the invention

The object of the invention is to provide a kind of method for producing economic thermal forming martensite steel plate; directly adopt hot continuous rolling process to produce the steel plate that is adapted to the thermal forming martensite steel product, technological process comprises: commentaries on classics () stove+refining+protection casting+continuous casting+hot continuous rolling+batch.Utilize prior art to obtain the continuous casting billet of high-cleanness, high and high evenness, be rolled the control of technology and coiler plate technology then, make steel plate can satisfy of the requirement of thermal forming martensite steel product, save production procedure, lowered production cost than the traditional mode of production route with steel plate.

Steel plate composition of the present invention is: C:0.12-0.40, Mn:0.05-2.0, Si:0.05-2.30, and P≤0.015, S≤0.005, [O]≤0.0030, [N] 0.002-0.015 surplusly is Fe and inevitable impurity.On the mentioned component basis, can add B:0.0005-0.005, Cr:0.10-1.50, Mo:0.15-0.80, Al:0.015-0.060, Ti:0.02-0.10, Ni:0.20-4.0, Nb:0.02-0.10, V:0.020.25; Ca or Re:0.001-0.002's is a kind of or whole.

Concrete technology is as follows:

Continuous casting billet is heated to 1050-1250 ℃;

It is rolling to carry out the 3-20 passage in 900-1150 ℃ of scope, with refine austenite crystal grain, improve plate quality and reduce steel plate thickness.

The finish to gauge temperature control guarantees the final crystallite dimension of steel between 750-900 ℃.Simultaneously, the reduction of finishing temperature helps improving the problem of steel plate oxidation.But the further reduction of temperature will increase substantially the resistance of deformation of steel plate makes mill load excessive, also will cause steel plate hardness higher simultaneously.

Coiler plate: the coiling temperature 600-700 of steel plate ℃, have lower hardness to guarantee steel plate.

The invention has the advantages that, save production procedure, lowered production cost.

The specific embodiment

Embodiment:

The chemical composition of table 1 steel

	C	Si	Mn	Ni	Cr	P	S	[N]	[O]	B	Ti	Nb
	C	Si	Mn	Ni	Cr	P	S	[N]	[O]	B	Ti	Nb	1	0.13	0.15	1.15	1.02	-	0.008	0.005	0.004	0.0015	0.0031	0.15	-
2	0.28	1.85	1.05	-	1.03	0.012	0.003	0.003	0.0018	-	-	-	1	0.13	0.15	1.15	1.02	-	0.008	0.005	0.004	0.0015	0.0031	0.15	-
2	0.28	1.85	1.05	-	1.03	0.012	0.003	0.003	0.0018	-	-	-	3	0.18	1.20	1.25	-	-	0.008	0.005	0.007	0.0012	-	-	0.03
4	0.40	1.72	0.12	2.01	1.03	0.004	0.002	0.006	0.008	-	-	-	3	0.18	1.20	1.25	-	-	0.008	0.005	0.007	0.0012	-	-	0.03

Table 2 hot rolling technology

	The continuous casting billet heating, ℃	Breaking down temperature ℃	Finishing temperature ℃	Finished product thickness mm	Coiling temperature ℃
	The continuous casting billet heating, ℃	Breaking down temperature ℃	Finishing temperature ℃	Finished product thickness mm	Coiling temperature ℃	1	1150	1100	750	1.5	630
2	1150	1100	880	1.2	640	1	1150	1100	750	1.5	630
2	1150	1100	880	1.2	640	3	1250	1200	900	2.0	600
4	1200	1150	850	1.6	700	3	1250	1200	900	2.0	600

Table 3 steel plate mechanical property and decarburized layer

Claims

1, a kind of method for producing economic thermal forming martensite steel plate is characterized in that, technology is:

(1) continuous casting billet is heated to 1050-1250 ℃;

(2) it is rolling to carry out the 3-20 passage at 900-1150 ℃, with refine austenite crystal grain, improve plate quality and reduce steel plate thickness;

(3) the finish to gauge temperature control guarantees the final crystallite dimension of steel between 750-900 ℃;

(4) the coiling temperature 600-700 of steel plate ℃, has lower hardness to guarantee steel plate.

According to the described preparation method of claim 1, it is characterized in that 2, described steel plate composition is: C:0.12-0.40, Mn:0.05-2.0, Si:0.05-2.30, P≤0.015, S≤0.005, [0]≤0.0030, [N] 0.002-0.015 surplusly is Fe and inevitable impurity; Or on the mentioned component basis, add B:0.0005-0.005, Cr:0.10-1.50, Mo:0.15-0.80, Al:0.015-0.060, Ti:0.02-0.10, Ni:0.20-4.0, Nb:0.02-0.10, V:0.02-0.25, Ca or Re:0.001-0.002's is a kind of or whole.