CN110396647B

CN110396647B - Low-alloy steel with high electromagnetic performance and high strength, production process and application thereof

Info

Publication number: CN110396647B
Application number: CN201910779478.1A
Authority: CN
Inventors: 许加陆; 徐和平; 黄国俊; 沈艳; 来永彪; 屈志东
Original assignee: Zenith Steel Group Co Ltd
Current assignee: Zenith Steel Group Co Ltd
Priority date: 2019-08-22
Filing date: 2019-08-22
Publication date: 2020-09-08
Anticipated expiration: 2039-08-22
Also published as: CN110396647A

Abstract

The invention discloses a low alloy steel with high electromagnetic property and high strength, and a production process and application thereof, wherein the steel material comprises the following chemical components, by weight, 0.01-0.03% of C, 0.10-0.20% of Si, 0.60-0.90% of Mn, 0.003-0.013% of AL, 0.010-0.030% of Ti, less than or equal to 0.10% of Cr, less than or equal to 0.015% of Cu and Ni, and the balance of Fe. The coercive force Hc (A/m) of the low alloy steel is less than or equal to 72, the maximum magnetic permeability mu m (H/m) is more than or equal to 0.0088, the tensile strength Rm (MPa) is more than or equal to 350, the yield strength Rel (MPa) is more than or equal to 210, the electromagnetism is equal to the strength of the electromagnetic pure iron, and the strength is 2 times of the strength of the electromagnetic pure iron. The prepared continuous casting billet is continuously rolled to obtain the steel with higher electromagnetic performance and strength requirements, and the steel is widely used for claw poles of generators in industries such as automobiles, engineering machinery and the like.

Description

Low-alloy steel with high electromagnetic performance and high strength, production process and application thereof

Technical Field

The invention relates to the field of low-alloy structural steel in the steel industry, in particular to high-electromagnetic-property high-strength low-alloy steel and a production process and application thereof.

Background

With the rapid development of the industries of automobiles and engineering machinery, particularly in the 5G era, the gradual application of intelligent and unmanned technologies, the vehicles of the automobiles and the engineering machinery vehicles have higher and higher requirements on the electric energy, the electromagnetic performance and the strength of the steel for the claw pole of the generator are required to be higher and higher, and the higher the purity is, the better the magnetism is in soft magnetic performance. The traditional electromagnetic pure iron (with the purity of 99.6-99.8%) has high electromagnetic performance, but the strength is extremely low, the claw pole material of the generator manufactured by the traditional electromagnetic pure iron can deform under the high-speed rotation state, so that the clamping shell of the generator fails, and the production cost of steel is high. At present, in the prior art, the performance requirements of an automobile generator rotor on claw pole steel are generally based on the electromagnetic performance of an automobile generator, and the mechanical performance of claw poles is often neglected. In an attempt to solve the mechanical properties, the skilled person will find that adjusting the alloying elements therein can improve the mechanical properties, but can also significantly reduce the electromagnetic properties of the material.

Therefore, there is a need for a material that has high strength while maintaining high electromagnetic performance. The high electromagnetic property and high strength low alloy steel are mainly applied to producing the magnetic poles of the generator claw pole and the like, the claw pole is a key component of the engine, and the electromagnetic property of the high electromagnetic property directly influences the waveform of induced alternating current electromotive force and the power generation capacity of the alternating current generator. The optimization of steel components of the claw pole is an urgent problem to be solved by integrating the electromagnetic performance and mechanical performance requirements of the claw pole generator of the automobile.

Disclosure of Invention

The invention provides a high-electromagnetic-performance high-strength low-alloy steel, which not only ensures that the steel has higher electromagnetic performance, but also ensures that the steel has higher performance through component design, and meets the claw pole requirement of a high-speed generator.

The low alloy steel comprises C, Si, Mn, Cr, Cu, Ni, AL, Ti, S, P and Fe.

Further, the low alloy steel comprises the following chemical components in percentage by weight:

C 0.01-0.03％,

Si 0.10-0.20％,

Mn 0.60-0.90％,

AL 0.003-0.013％,

Ti 0.010-0.030％,

Cr 0-0.10％，

Cu 0-0.10％，

Ni 0-0.10％

S 0-0.015％，

P 0-0.015％。

the balance being Fe.

Wherein, C: the carbon content of the steel is 0.07-0.17%, the steel is peritectic steel, the surface of a billet is easy to generate longitudinal cracks, the continuous casting production difficulty is increased, and therefore the content of the carbon is limited to 0.01-0.03%. The carbon content is less than 0.01%, the mechanical property is reduced, and the carbon content is more than 0.03%, the electromagnetic property is obviously reduced.

Si: ferrite can be dissolved in steel, so that the strength and hardness of alloy steel can be improved, and the plasticity and toughness of the steel can be reduced. Si is an indispensable deoxidizer in the steel-making process, but Si element causes the electromagnetic properties of steel to be reduced. Therefore, the content of Si must be suppressed to a low level that can be achieved.

Cu, Ni, Cr: such alloying elements, although increasing the strength of the steel, may result in a reduction in the electromagnetic properties of the steel. Therefore, the contents of Cu, Ni and Cr are designed to be 0-0.10%; p, S, Cr, Ni and Cu are residual elements, the elements are residual elements, the lower the control as possible, the better, and the content is infinitely close to 0.

Ti: the element is an element which forms a precipitate and is effective for strengthening and toughening, and can refine crystal grains, so that the internal structure of the steel is compact, the aging sensitivity and the cold brittleness are reduced, the surface structure and the crystal grains of the steel are refined, and the longitudinal cracks on the surface of the continuous casting billet are prevented. Therefore, the Ti content is designed to be 0.010-0.030 percent.

Al: because the steel belongs to the ultra-low carbon alloy steel, a proper amount of AL is added in the tapping and refining processes to reduce the oxygen content in the steel and improve the purity of the molten steel. Therefore, the Al content is designed to be 0.003-0.0130%.

Mn: in the traditional electromagnetic material, impurity elements need to be reduced and controlled, so that the content of Mn element is controlled to be lower, while the content of Mn element designed by the invention is 0.60-0.90%, in the steel grade of the invention, the Mn element containing 0.60-0.90% can be used as a mechanical strengthening element to compensate the strength reduction caused by extremely low C and Si, more importantly, in the steel grade, the Mn element containing 0.60-0.90% can coarsen the crystal grain of the steel, and is beneficial to improving the electromagnetic performance of the steel while improving the mechanical performance.

The invention also provides a preparation method of the high-electromagnetic-property high-strength low-alloy steel, which comprises the following specific steps:

(1) smelting in a converter to realize pre-removing P and primary component adjustment; the molten iron and the scrap steel comprise trace components such as C, Si, Mn, Cr, Cu, Ni, Ti, AL, S, P and the like, and mainly comprise C and Fe;

(2) refining in vacuum;

(3) LF refining;

(4) continuous casting, namely casting a continuous casting blank on a continuous casting machine;

(5) continuous rolling: the continuous casting slab is heated in a steel rolling heating furnace by adopting medium temperature heat of 400-600 ℃, is rolled into round steel of 50mm by high temperature rolling of 1150-plus 1180 ℃ and rolling by a continuous rolling unit so as to obtain coarse ferrite grains, and the grain size of the low alloy steel obtained by hot rolling is grade 5. The steel obtains higher electromagnetic performance.

The low alloy steel with high electromagnetic performance and high strength prepared by the invention is suitable for the claw pole of the generator of vehicles such as automobiles, engineering machinery and the like.

The invention has the beneficial effects that:

the invention relates to a high-electromagnetic-performance high-strength low-alloy steel which is an ultra-low-carbon low-alloy steel developed based on the influence of various elements of steel on electromagnetic performance and ferrite grain control technology. Because the carbon content of the steel is extremely low, and a proper amount of elements Si, Mn, AL and Ti and lower trace element components Cr, Cu, Ni, S, P and the like are added, the steel has higher electromagnetic performance and high strength requirements and meets the requirements of the electromagnetic performance and high-speed rotation of a high-performance generator. According to the invention, through component design, the steel is ensured to have higher electromagnetic performance and higher mechanical property, and the claw pole requirement of the high-speed generator is met. Tests show that the electromagnetic performance of the steel can not only reach the index of the electromagnetic pure iron (DT4A), but also the strength is 2 times of the electromagnetic pure iron, and the requirements of the electromagnetic performance and the strength of the high-speed running generator of the automobile and the engineering machinery are met.

Detailed Description

According to the chemical composition of the steel in table 1, a conventional low carbon steel preparation method is adopted: converter smelting, vacuum refining, LF refining, and continuous casting to obtain steels having chemical compositions shown in Table 1.

And (3) continuous rolling, namely, feeding the continuous casting blank into a steel rolling heating furnace for heating by adopting medium temperature heat of 400-600 ℃, rolling at the beginning temperature of 1160 ℃, rolling the continuous rolling mill into round steel, and carrying out hot rolling to obtain low alloy steel with the grain size of 5 grade of 50mm round steel.

8-furnace steels were prepared with the chemical composition as given in table 1 below:

table 1: chemical composition of Steel (% by weight)

Serial number	C	Si	Mn	P	S	Cr	Ni	Cu	AL	Ti	Fe
												1	0.02	0.11	0.65	0.010	0.003	0.03	0.03	0.03	0.007	0.015	Surplus
2	0.02	0.15	0.70	0.014	0.001	0.03	0.03	0.03	0.008	0.017	Surplus
												3	0.03	0.13	0.73	0.011	0.002	0.03	0.03	0.03	0.006	0.018	Surplus
4	0.01	0.14	0.68	0.009	0.004	0.03	0.03	0.03	0.009	0.016	Surplus
												5	0.02	0.12	0.75	0.008	0.002	0.03	0.03	0.03	0.005	0.019	Surplus
1*	0.06	0.11	0.65	0.010	0.003	0.03	0.03	0.03	0.007	0.015	Surplus
												2*	0.005	0.15	0.70	0.014	0.001	0.03	0.03	0.03	0.008	0.017	Surplus
3*	0.02	0.13	0.4	0.010	0.003	0.03	0.03	0.03	0.007	0.015	Surplus

The mechanical properties (according to GB/T228 standard) and the electromagnetic properties of the 8-furnace steel are measured by tests and are shown in the following table 2:

table 2: mechanical and electromagnetic properties of steel

Table 3: index of electromagnetic pure iron

Number plate	Coercive force Hc (A/m)	Maximum magnetic permeability mum (H/m)
			DT4A	72	0.0088

Claims

1. The utility model provides a high electromagnetic property and high strength low alloy steel which characterized in that: the low alloy steel comprises C, Si, Mn, Cr, Cu, Ni, AL, Ti, S, P and Fe;

the chemical components by weight percentage are as follows:

C 0.01-0.03 %，

Si 0.10-0.20%，

Mn 0.60-0.90% ，

AL 0.003 -0.013%，

Ti 0.010-0.030%，

Cr、 Cu、Ni≤0.10%，

S 、P≤0.015%，

the balance being Fe;

heating the continuous casting slab with the components at the medium temperature of 400-600 ℃ in a steel rolling heating furnace, rolling at the high temperature of 1130-1180 ℃, rolling by a continuous rolling unit, and rolling into round steel;

the rolled low alloy steel is used in a claw pole of a vehicle generator.

2. The high electromagnetic performance and high strength low alloy steel of claim 1, wherein: the electromagnetic properties of the high electromagnetic property steel are as follows: the coercive force Hc (A/m) is less than or equal to 72, and the maximum magnetic permeability mu m (H/m) is more than or equal to 0.0088; the mechanical properties are as follows: tensile strength Rm (MPa) is more than or equal to 350, and yield strength ReL (MPa) is more than or equal to 210.

3. The method for preparing a high electromagnetic performance and high strength low alloy steel according to claim 1 or 2, characterized in that: the preparation method of the continuous casting slab comprises the following steps:

firstly, smelting in a converter, then carrying out vacuum refining and LF refining, and casting the mixture on a continuous casting machine to form a continuous casting billet.

4. The method of manufacturing a high electromagnetic performance and high strength low alloy steel according to claim 1, wherein: and the initial rolling temperature is 1160 ℃, rolling by a continuous rolling unit, and hot rolling to obtain 50mm round steel, wherein the grain size is 5 grade.