CN115466903A - A kind of high-strength special steel and its production process - Google Patents

Abstract

The invention provides a high-strength special steel and a production process thereof, and the production process is used for producing the high-strength special steel and comprises the following steps: s1, converter bottom blowing smelting, namely performing slag splashing treatment on the slag of the previous converter, leaving the final slag in the converter, adding the raw materials into the converter for smelting, performing converter bottom blowing by arranging an oxygen lance in the converter body during smelting, starting to add lime and light-burned dolomite after oxygen blowing, pouring the smelted molten iron into the converter for tapping, adding sufficient silicomanganese alloy during pouring tapping, and performing slag washing by using synthetic slag; s2, continuously casting and rolling steel, wherein during hot continuous rolling, the continuously cast plate blank is reheated to 1230-1250 ℃ for not less than 110min; the final rolling temperature range of the hot continuous rolling is 880-920 ℃; after hot continuous rolling, the steel is rapidly cooled to 670-700 ℃ and 630-660 ℃ respectively by adopting a front section cooling mode for carrying out grading control.

Description

A kind of high-strength special steel and its production process

technical field

The invention relates to the field of special steel, in particular to a high-strength special steel and a production process thereof.

Background technique

Special steel, special steel is also called alloy steel, adding one or several alloying elements in an appropriate amount to carbon steel to change the structure of the steel, so that the steel has various special properties.

In converter smelting specific steel types, the single slag method is a converter smelting method for low-phosphorus steel with the shortest overall cycle and the lowest equipment requirements among all smelting modes. However, due to the traditional understanding of its lack of dephosphorization ability and low dephosphorization efficiency, it is usually not considered as a smelting method for low-phosphorus special steel. Even if there is an attempt to smelt low-phosphorus special steel with single slag, slag There are problems such as a significant increase in volume consumption, a significant increase in the blowing rate at the end point, and poor smelting stability.

With the continuous development of productivity, the demand for the use of special steel alloys for industrial use continues to increase, and the existing special steel alloys have gradually been unable to meet the use needs of the market.

Contents of the invention

Therefore, aiming at the above problems, the present invention proposes a high-strength special steel and its production process.

For realizing above-mentioned technical problem, the solution that the present invention takes is: a kind of high-strength special steel, a kind of high-strength special steel, comprises the following components by weight percentage:

Carbon: 0.05-0.07%, silicon: 0.1-0.2%, manganese: 1.58-2.25%, phosphorus: 0.003-0.005%, chromium: 0.45-0.55%, nickel: 5.5-9.5%, copper: 0 . 4-0.5%, titanium: 2.0-4.0%, tungsten 1.3-2.7%, and the rest are Fe and uncontrollable impurity elements.

As a further improvement of the present invention: include the following components by weight percentage:

Carbon: 0.06%, silicon: 0.15%, manganese: 2.13%, phosphorus: 0.004%, chromium: 0.50%, nickel: 6.3%, copper: 0.45%, titanium: 3.0%, tungsten 2.1%, the rest is Fe and uncontrollable impurity elements.

The present invention also provides a production process for high-strength special steel, the production process is used to produce the above-mentioned high-strength special steel, comprising the following steps:

S1: Converter bottom blowing smelting

After the slag from the previous furnace has been treated by slag splashing, all the final slag is left in the converter, and then the raw materials are added into the furnace to prepare for smelting. After oxygen blowing, lime and lightly burned dolomite are added, and the smelted molten iron is tapped in the furnace. During the tapping process, a sufficient amount of silicon-manganese alloy is added, and synthetic slag is used for slag washing;

S2: continuous casting and rolling

During hot continuous rolling, the slab after continuous casting shall be reheated to 1230°C~1250°C, and the time in the furnace shall not be less than 110min; After rolling, adopt the front-end cooling method to rapidly cool to 670°C~700°C coiling and 630°C~660°C coiling respectively for graded control;

During the pickling and cold rolling process, the cold rolling reduction rate is controlled at 58% to 80%;

S3: heat treatment

The special steel is obtained by annealing and tempering the steel.

As a further improvement of the present invention: in step S1, the bottom blowing of the converter by setting an oxygen lance in the furnace body also includes:

In the stage of blowing, lower the position of the oxygen lance to 1100~1300mm, light the gun and start blowing for 80s~110s.

As a further improvement of the present invention: start to add lime and lightly burned dolomite after the oxygen blowing, also includes:

The mass of the lime added is 30-40% of the tapping amount of the converter, and the mass of the light-burned dolomite added is 11-15% of the tapping amount of the converter.

As a further improvement of the present invention: said annealing and tempering the steel also includes:

The steel is sequentially subjected to isothermal annealing, general annealing, preheating, quenching, and secondary tempering immediately after quenching.

As a further improvement of the present invention: before the annealing, first heat the steel to 900-960°C and keep it warm for 1-2 hours.

As a further improvement of the present invention: the preheating includes preheating the steel to 800-850°C and maintaining it for 0.5-1 hour.

As a further improvement of the present invention: the isothermal annealing is carried out while cooling to 680-710° C. for 2 hours.

As a further improvement of the present invention: the secondary tempering includes: the first tempering is 510-540 ° C for 1 hour; the second tempering is 550-560 ° C for 1 hour.

By adopting the aforementioned technical scheme, the beneficial effects of the present invention are:

The production process of the high-strength special steel of the present invention leaves all the final slag obtained from the Shanghai slag of the previous furnace in the converter, then adds raw materials for smelting, and performs bottom blowing from the bottom of the furnace, and adds lime after bottom blowing and lightly burned dolomite, thereby effectively reducing the dephosphorization load of raw materials, the carbon content and phosphorus content of molten iron produced by the furnace can be effectively reduced, silicon-manganese alloy is added when the furnace is tapped, and synthetic slag is used for slag washing , and then ensure the purity of molten iron, and then through the control of hot rolling, cold rolling and heat treatment, the special steel produced has the advantages of high strength, small residual stress and strong toughness.

detailed description

The present invention will be further described in conjunction with specific embodiments now.

Embodiment one

The embodiment of the present invention discloses a production process of high-strength special steel, comprising the following steps:

S1: Converter bottom blowing smelting

After the slag from the previous furnace has been treated by slag splashing, all the final slag is left in the converter, and then the raw materials are added into the furnace to prepare for smelting. After oxygen blowing, lime and lightly burned dolomite are added, and the smelted molten iron is tapped in the furnace. During the tapping process, a sufficient amount of silicon-manganese alloy is added, and synthetic slag is used for slag washing;

S2: continuous casting and rolling

During hot continuous rolling, the slab after continuous casting is reheated to 1230°C first, and the time in the furnace is not less than 110min; the temperature range of the final hot rolling is 880°C; Cool to 670°C for coiling and 630°C for coiling for grading control;

During the pickling and cold rolling process, the cold rolling reduction rate is controlled at 58%;

S3: heat treatment

The special steel is obtained by annealing and tempering the steel.

In this embodiment, further, in step S1, the bottom blowing of the converter by setting an oxygen lance in the furnace body also includes:

In the stage of blowing, lower the position of the oxygen lance to 1100mm, lower the gun and ignite and start blowing for 80s.

In the present embodiment, further, starting to add lime and lightly burned dolomite after the oxygen blowing, also includes:

The added mass of lime is 30% of the tapping amount of the converter, and the added mass of light-burned dolomite is 11% of the tapping amount of the converter.

In this embodiment, further, the annealing and tempering of the steel also includes:

The steel is sequentially subjected to isothermal annealing, general annealing, preheating, quenching, and secondary tempering immediately after quenching.

In this embodiment, further, before the annealing, the steel is heated to 900° C. for 1 hour.

In this embodiment, further, the preheating includes preheating the steel to 800°C and maintaining it for 0.5 hours.

In this embodiment, further, the isothermal annealing is carried out while cooling to 680° C. for 2 hours.

In this embodiment, further, the secondary tempering includes: the first tempering is 510 ° C for 1 hour; the second tempering is 550 ° C for 1 hour.

The high-strength special steel produced by the above production process includes the following components by weight percentage: carbon: 0.05%, silicon: 0.1%, manganese: 1.58%, phosphorus: 0.003%, chromium: 0.45%, nickel : 5.5%, copper: 0.4%, titanium: 2.0%; tungsten 1.3%, the rest is Fe and uncontrollable impurity elements.

Embodiment two

The embodiment of the present invention discloses a production process of high-strength special steel, comprising the following steps:

S1: Converter bottom blowing smelting

After the slag from the previous furnace has been treated by slag splashing, all the final slag is left in the converter, and then the raw materials are added into the furnace to prepare for smelting. After oxygen blowing, lime and lightly burned dolomite are added, and the smelted molten iron is tapped in the furnace. During the tapping process, a sufficient amount of silicon-manganese alloy is added, and synthetic slag is used for slag washing;

S2: continuous casting and rolling

During hot continuous rolling, the slab after continuous casting is reheated to 1240°C first, and the time in the furnace is not less than 110min; the temperature range of the final hot rolling is 900°C; Cooling to 690°C coiling and 650°C coiling for graded control;

In the process of pickling and cold rolling, the cold rolling reduction rate is controlled at 65%;

S3: heat treatment

The special steel is obtained by annealing and tempering the steel.

In this embodiment, further, in step S1, the bottom blowing of the converter by setting an oxygen lance in the furnace body also includes:

In the stage of blowing, lower the position of the oxygen lance to 1200mm, lower the gun, ignite and start blowing for 100s.

In the present embodiment, further, starting to add lime and lightly burned dolomite after the oxygen blowing, also includes:

The added mass of lime is 35% of the tapping amount of the converter, and the added mass of light-burned dolomite is 13% of the tapping amount of the converter.

In this embodiment, further, the annealing and tempering of the steel also includes:

The steel is sequentially subjected to isothermal annealing, general annealing, preheating, quenching, and secondary tempering immediately after quenching.

In this embodiment, further, before the annealing, the steel is heated to 930° C. for 1 hour.

In this embodiment, further, the preheating includes preheating the steel to 830C and maintaining it for 0.5 hours.

In this embodiment, further, the isothermal annealing is carried out while cooling to 690° C. for 2 hours.

In this embodiment, further, the secondary tempering includes: the first tempering is 530° C. for 1 hour; the second tempering is 555° C. for 1 hour.

The high-strength special steel produced by the above production process includes the following components by weight percentage: carbon: 0.06%, silicon: 0.15%, manganese: 2.13%, phosphorus: 0.004%, chromium: 0.50%, nickel: 6.3% %, copper: 0.45%, titanium: 3.0%, tungsten 2.1%, and the rest are Fe and uncontrollable impurity elements.

Embodiment three

The embodiment of the present invention discloses a production process of high-strength special steel, comprising the following steps:

S1: Converter bottom blowing smelting

After the slag from the previous furnace has been treated by slag splashing, all the final slag is left in the converter, and then the raw materials are added into the furnace to prepare for smelting. After oxygen blowing, lime and lightly burned dolomite are added, and the smelted molten iron is tapped in the furnace. During the tapping process, a sufficient amount of silicon-manganese alloy is added, and synthetic slag is used for slag washing;

S2: continuous casting and rolling

During hot continuous rolling, the slab after continuous casting shall be reheated to 1250°C first, and the time in the furnace shall not be less than 110min; the temperature range of the final hot rolling shall be 920°C; Cooling to 700°C coiling and 660°C coiling for graded control;

In the process of pickling and cold rolling, the reduction rate of cold rolling is controlled at 80%;

S3: heat treatment

The special steel is obtained by annealing and tempering the steel.

In this embodiment, further, in step S1, the bottom blowing of the converter by setting an oxygen lance in the furnace body also includes:

In the stage of blowing, lower the position of the oxygen lance to 1300mm, lower the gun and ignite and start blowing for 110s.

In the present embodiment, further, starting to add lime and lightly burned dolomite after the oxygen blowing, also includes:

The added quality of the lime is 40% of the tapping amount of the converter, and the added quality of the light-burned dolomite is 15% of the tapping amount of the converter.

In this embodiment, further, the annealing and tempering of the steel also includes:

The steel is sequentially subjected to isothermal annealing, general annealing, preheating, quenching, and secondary tempering immediately after quenching.

In this embodiment, further, before the annealing, the steel is heated to 960° C. for 2 hours.

In this embodiment, further, the preheating includes preheating the steel to 850C and maintaining it for 1 hour.

In this embodiment, further, the isothermal annealing is carried out while cooling to 710° C. for 2 hours.

In this embodiment, further, the secondary tempering includes: the first tempering is 540 ° C for 1 hour; the second tempering is 560 ° C for 1 hour.

The high-strength special steel produced by the above production process includes the following components by weight percentage: carbon: 0.07%, silicon: 0.2%, manganese: 2.25%, phosphorus: 0.005%, chromium: 0 . 55%, nickel: 9.5%, copper: 0.5%, titanium: 4.0%, tungsten 2.7%, the rest is Fe and uncontrollable impurity elements.

Modifications and changes made by using this creation all belong to the scope of patents claimed by this creation, and are not limited to those disclosed in the embodiments.

Claims (10)

1. A high-strength special steel, characterized in that: comprising the following components by weight percentage: Carbon: 0.05-0.07%, silicon: 0.1-0.2%, manganese: 1.58-2.25%, phosphorus: 0.003-0.005%, chromium: 0.45-0.55%, nickel: 5.5-9.5%, copper: 0 . 4-0.5%, titanium: 2.0-4.0%, tungsten 1.3-2.7%, and the rest are Fe and uncontrollable impurity elements. 2. The high-strength special steel according to claim 1, characterized in that: it comprises the following components by weight percentage: Carbon: 0.06%, silicon: 0.15%, manganese: 2.13%, phosphorus: 0.004%, chromium: 0.50%, nickel: 6.3%, copper: 0.45%, titanium: 3.0%, tungsten 2.1%, the rest is Fe and uncontrollable impurity elements. 3. A production process of high-strength special steel, said production process is used to produce high-strength special steel as claimed in claim 1 or 2, it is characterized in that: comprise the following steps: S1: Converter bottom blowing smelting After the slag from the previous furnace has been treated by slag splashing, all the final slag is left in the converter, and then the raw materials are added into the furnace to prepare for smelting. After oxygen blowing, lime and lightly burned dolomite are added, and the smelted molten iron is tapped in the furnace. During the tapping process, a sufficient amount of silicon-manganese alloy is added, and synthetic slag is used for slag washing; S2: continuous casting and rolling During hot continuous rolling, the slab after continuous casting shall be reheated to 1230°C~1250°C, and the time in the furnace shall not be less than 110min; After rolling, adopt the front-end cooling method to rapidly cool to 670°C~700°C coiling and 630°C~660°C coiling respectively for graded control; During the pickling and cold rolling process, the cold rolling reduction rate is controlled at 58% to 80%; S3: heat treatment The special steel is obtained by annealing and tempering the steel. 4. The production process of high-strength special steel according to claim 3, characterized in that: in step S1, the bottom blowing of the converter by setting an oxygen lance in the furnace body also includes: In the stage of blowing, lower the position of the oxygen lance to 1100~1300mm, light the gun and start blowing for 80s~110s. 5. The production process of high-strength special steel according to claim 3, characterized in that: adding lime and lightly burned dolomite after the oxygen blowing, further comprising: The mass of the lime added is 30-40% of the tapping amount of the converter, and the mass of the light-burned dolomite added is 11-15% of the tapping amount of the converter. 6. The production process of high-strength special steel according to claim 3, characterized in that: said annealing and tempering the steel also includes: The steel is sequentially subjected to isothermal annealing, general annealing, preheating, quenching, and secondary tempering immediately after quenching. 7. The production process of high-strength special steel according to claim 6, characterized in that: before the annealing, the steel is heated to 900-960°C for 1-2 hours. 8 . The production process of high-strength special steel according to claim 6 , wherein the preheating includes preheating the steel to 800-850° C. and maintaining it for 0.5-1 hour. 9. The production process of high-strength special steel according to claim 6, characterized in that: said isothermal annealing is carried out after cooling to 680-710°C for 2 hours. 10. The production process of high-strength special steel according to claim 6, characterized in that: the secondary tempering includes: the first tempering is 510-540 ° C for 1 hour; the second tempering is 550 ° C Incubate at -560°C for 1 hour.