阅读说明：本技术 一种双相不锈钢轧制工艺方案 (Double-phase stainless steel rolling process scheme ) 是由 王保勤 张智应 任斌应 魏建宏 王朝辉 龙艳兵 薛建康 高海龙 闫志勇 王建国 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种双相不锈钢轧制工艺方案,所述双相不锈钢轧制工艺步骤为：制坯、轧制、退火酸洗和矫直,所述制坯过程中铁素体钢材与奥氏体钢材各占50％,进行混合加热,所述轧制工艺采用热轧制,加热温度为1200-1300℃,终轧制温度为950-1050℃,热矫直温度为700-750℃,热矫直终了温度为550-600℃,且轧制过程中不锈钢面朝上,单面轧制。本发明通过对双相不锈钢轧制过程中冷却进行阶段性冷却,提高了双相不锈钢的性能和强度,使得双相不锈钢性能能够符合实际使用需要。(The invention discloses a duplex stainless steel rolling process scheme, which comprises the following steps: the method comprises the following steps of blank making, rolling, annealing, pickling and straightening, wherein the proportion of a ferrite steel material and an austenite steel material in the blank making process is respectively 50%, the blank making process is carried out by mixing and heating, the rolling process adopts hot rolling, the heating temperature is 1200-1300 ℃, the final rolling temperature is 950-1050 ℃, the hot straightening temperature is 700-750 ℃, the final hot straightening temperature is 550-600 ℃, and the surface of stainless steel faces upwards in the rolling process and is rolled on one side. According to the invention, the performance and the strength of the duplex stainless steel are improved by cooling the duplex stainless steel in a rolling process in a staged manner, so that the performance of the duplex stainless steel can meet the actual use requirement.)

1. A duplex stainless steel rolling process scheme is characterized in that: the rolling process of the duplex stainless steel comprises the following steps: blank making, rolling, annealing, pickling and straightening, wherein each of a ferrite steel material and an austenite steel material accounts for 50% in the blank making process, and mixing and heating are carried out;

the rolling process adopts hot rolling, the heating temperature is 1200-1300 ℃, the final rolling temperature is 950-1050 ℃, the hot straightening temperature is 700-750 ℃, the final hot straightening temperature is 550-600 ℃, and the stainless steel faces upwards during the rolling process and is rolled on one side.

2. The duplex stainless steel rolling process according to claim 1, wherein: in the hot rolling process, the initial rolling temperature is 1150-;

and rapidly cooling to the temperature of 700-750 ℃ by using high-pressure water of a rolling mill main machine, carrying out water spray cooling after straightening, carrying out air cooling by running a roller way when the temperature of the stainless steel plate is 600 ℃ at 550-750 ℃, and then carrying out stacking cooling.

3. The duplex stainless steel rolling process according to claim 1, wherein: the annealing and pickling process comprises the following steps:

after the rolling of the bidirectional stainless steel plate is finished, the annealing temperature is controlled to be between 1000-1150 ℃, the temperature of the solution annealing is not lower than 1050 ℃, and then the gas cooling or water cooling quenching is carried out immediately.

4. The duplex stainless steel rolling process according to claim 1, wherein: the straightening process is divided into a rolling straightening stage and a cooling straightening stage;

the rolling straightening stage adopts a thermal straightening process, and the rolled duplex stainless steel plate passes through a thermal straightening roller way to straighten the edge of the duplex stainless steel plate;

and in the cooling and straightening stage, straightening is carried out by adopting a local heating process, and straightening is carried out on the surface and the edge of the duplex stainless steel plate again by locally heating the edge of the duplex stainless steel plate at the heating temperature of 600-650 ℃.

5. The duplex stainless steel rolling process according to claim 1, wherein: after the rolling process is finished, cooling the rolled duplex stainless steel plate by adopting two-stage cooling;

the rapid cooling can avoid the isothermal decomposition of the unconverted austenite, and ensure that the required two-phase structure and performance are obtained. For example 0.08% C-1.4% Mn steel, from 800 ℃; the mechanical properties of heating to water cooling are as follows: σ 0.2 ═ 365PMa, σ b ═ 700MPa, σ 0.2/σ b ═ 0.52, eu ═ 18%, et ═ 21%, using a two-stage cooling process, i.e. at 800 ℃; after heating, air cooling to 600 ℃;

then water cooling is carried out, and the properties are as follows: the yield strength of the dual-phase steel is reduced by two-stage cooling, and the ductility is improved by 280MPa for σ 0.2, 600MPa for σ b, 0.47 for σ 0.2/σ b, 21 for eu and 29 for et.

Technical Field

The invention relates to the technical field of duplex stainless steel production, in particular to a duplex stainless steel rolling process scheme.

Background

Duplex stainless steel, which means stainless steel with ferrite and austenite accounting for about 50% each, generally less phases are required to reach 30% at minimum. Under the condition of low C content, the Cr content is 18-28%, and the Ni content is 3-10%. Some steels also contain Mo, Cu, Nb, Ti, N and other alloy elements, and the steels have the characteristics of austenite and ferrite stainless steels, and compared with ferrite, the steels have higher plasticity and toughness, no room temperature brittleness, obviously improved intergranular corrosion resistance and welding performance, and simultaneously keep the characteristics of the ferrite stainless steel, such as 475 ℃ brittleness, high heat conductivity coefficient, superplasticity and the like. Compared with austenitic stainless steel, the strength is high, and the intergranular corrosion resistance and the chloride stress corrosion resistance are obviously improved. The duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.

Through mass search, the prior art is found to be CN102744517B, and the manufacturing method of the duplex stainless steel hollow sandwich structural member belongs to the field of material processing. Firstly, a cold rolling method is adopted to prepare duplex stainless steel superplastic plates with different cold rolling deformation, and the range of the cold rolling deformation is 40-90%. The multi-layer duplex stainless steel superplastic plates with different cold rolling deformation are processed into the hollow sandwich structural member according to the common superplastic forming/diffusion connection method. Under the condition of the same diffusion bonding temperature, the cold rolling deformation is different, the tissue change rule of each duplex stainless steel superplastic plate is different, and the surface chemical activation of the duplex stainless steel plate can be improved by utilizing the difference of the interface tissue change of the two duplex stainless steel superplastic plates, so that the purpose of improving the superplastic forming/diffusion bonding performance of the duplex stainless steel plate is achieved. The method has wide application prospect in the aspect of manufacturing the lightweight hollow sandwich structural member.

In conclusion, in the rolling and cooling process of the existing duplex stainless steel, a single cooling mode is mostly adopted, and the quality of the finished duplex stainless steel product can be greatly influenced by the cooling effect, so that the quality and the strength of the duplex stainless steel can not meet the actual use standard.

Disclosure of Invention

The invention aims to provide a duplex stainless steel rolling process scheme to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a duplex stainless steel rolling process scheme comprises the following steps: blank making, rolling, annealing, pickling and straightening, wherein each of a ferrite steel material and an austenite steel material accounts for 50% in the blank making process, and mixing and heating are carried out;

the rolling process adopts hot rolling, the heating temperature is 1200-1300 ℃, the final rolling temperature is 950-1050 ℃, the hot straightening temperature is 700-750 ℃, the final hot straightening temperature is 550-600 ℃, and the stainless steel faces upwards during the rolling process and is rolled on one side.

Preferably, in the hot rolling process, the rolling temperature is 1150-1200 ℃, the stainless steel surface faces downwards, and the steel is rapidly rolled to the thickness of a finished product;

and rapidly cooling to the temperature of 700-750 ℃ by using high-pressure water of a rolling mill main machine, carrying out water spray cooling after straightening, carrying out air cooling by running a roller way when the temperature of the stainless steel plate is 600 ℃ at 550-750 ℃, and then carrying out stacking cooling.

Preferably, the annealing and pickling process comprises the following steps:

after the rolling of the bidirectional stainless steel plate is finished, the annealing temperature is controlled to be between 1000-1150 ℃, the temperature of the solution annealing is not lower than 1050 ℃, and then the gas cooling or water cooling quenching is carried out immediately.

Preferably, the straightening process is divided into a rolling straightening stage and a cooling straightening stage;

the rolling straightening stage adopts a thermal straightening process, and the rolled duplex stainless steel plate passes through a thermal straightening roller way to straighten the edge of the duplex stainless steel plate;

and in the cooling and straightening stage, straightening is carried out by adopting a local heating process, and straightening is carried out on the surface and the edge of the duplex stainless steel plate again by locally heating the edge of the duplex stainless steel plate at the heating temperature of 600-650 ℃.

Preferably, after the rolling process is finished, cooling the rolled duplex stainless steel plate by adopting two-stage cooling;

the rapid cooling can avoid the isothermal decomposition of the unconverted austenite, and ensure that the required two-phase structure and performance are obtained. For example 0.08% C-1.4% Mn steel, from 800 ℃; the mechanical properties of heating to water cooling are as follows: σ 0.2 ═ 365PMa, σ b ═ 700MPa, σ 0.2/σ b ═ 0.52, eu ═ 18%, et ═ 21%, using a two-stage cooling process, i.e. at 800 ℃; after heating, air cooling to 600 ℃;

then water cooling is carried out, and the properties are as follows: the yield strength of the dual-phase steel is reduced by two-stage cooling, and the ductility is improved by 280MPa for σ 0.2, 600MPa for σ b, 0.47 for σ 0.2/σ b, 21 for eu and 29 for et.

Compared with the prior art, the invention has the beneficial effects that: the invention adopts a staged cooling mode, ensures the performance of the duplex stainless steel reinforcing steel bar, meets the requirements of customers by using a controlled cooling process scheme to produce the duplex stainless steel reinforcing steel bar, can avoid the isothermal decomposition of unconverted austenite by fast cooling, ensures the required duplex structure and performance, reduces the yield strength of the duplex steel by two-stage cooling, and improves the ductility.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention provides two embodiments:

the first embodiment is as follows:

a duplex stainless steel rolling process scheme comprises the following steps: blank making, rolling, annealing, pickling and straightening, wherein the ferrite steel and the austenite steel respectively account for 50% in the blank making process, and mixing and heating are carried out;

the rolling process adopts hot rolling, the heating temperature is 1200-1300 ℃, the final rolling temperature is 950-1050 ℃, the hot straightening temperature is 700-750 ℃, the final hot straightening temperature is 550-600 ℃, and the stainless steel faces upwards in the rolling process and is rolled on one side.

In the hot rolling process, the initial rolling temperature is 1150-1200 ℃, the stainless steel surface faces downwards, and the steel is quickly rolled to the thickness of a finished product;

and rapidly cooling to the temperature of 700-750 ℃ by using high-pressure water of a rolling mill main machine, carrying out water spray cooling after straightening, carrying out air cooling by running a roller way when the temperature of the stainless steel plate is 600 ℃ at 550-750 ℃, and then carrying out stacking cooling.

After the rolling process is finished, cooling the rolled duplex stainless steel plate by adopting two-stage cooling;

the rapid cooling can avoid the isothermal decomposition of the unconverted austenite, and ensure that the required two-phase structure and performance are obtained. For example 0.08% C-1.4% Mn steel, from 800 ℃; the mechanical properties of heating to water cooling are as follows: σ 0.2 ═ 365PMa, σ b ═ 700MPa, σ 0.2/σ b ═ 0.52, eu ═ 18%, et ═ 21%, using a two-stage cooling process, i.e. at 800 ℃; after heating, air cooling to 600 ℃;

then water cooling is carried out, and the properties are as follows: the yield strength of the dual-phase steel is reduced by two-stage cooling, and the ductility is improved by 280MPa for σ 0.2, 600MPa for σ b, 0.47 for σ 0.2/σ b, 21 for eu and 29 for et.

Example two:

the annealing and pickling process comprises the following steps:

after the rolling of the bidirectional stainless steel plate is finished, the annealing temperature is controlled to be between 1000-1150 ℃, the temperature of the solution annealing is not lower than 1050 ℃, and then the gas cooling or water cooling quenching is carried out immediately.

The straightening process is divided into a rolling straightening stage and a cooling straightening stage;

the rolling straightening stage adopts a thermal straightening process, and the rolled duplex stainless steel plate passes through a thermal straightening roller way to straighten the edge of the duplex stainless steel plate;

and in the cooling and straightening stage, straightening is carried out by adopting a local heating process, the edge of the duplex stainless steel plate is locally heated, the heating temperature is controlled at 600-650 ℃, and the surface and the edge of the duplex stainless steel plate are straightened again.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.