CN112626308A - Production process of high-quality asymmetric flat-bulb steel produced by adding NbN - Google Patents

Abstract

The invention relates to the technical field of asymmetric flat-bulb steel production, in particular to a production process of high-quality asymmetric flat-bulb steel produced by adding NbN, which is used for producing the asymmetric flat-bulb steel by the production processes of material selection, LF refining, auxiliary material addition, soft argon blowing, casting, slow cooling and rolling. According to the production process of the high-quality asymmetric flat-bulb steel produced by adding the NbN, the Nb alloy and the manganese-nitrogen wire are added in the process of smelting AH36 steel, so that when Nb is contained in the steel, due to the dragging effect of a solute, the pinning effect at high temperature and the blocking effect during crystallization are added, the effect of refining grains is further achieved, and Nb and N form NbN precipitated phases in the heating, deformation and cooling phase change of steel rolling, and a good precipitation strengthening effect can be achieved.

Description

Production process of high-quality asymmetric flat-bulb steel produced by adding NbN

Technical Field

The invention relates to the technical field of asymmetric flat-bulb steel production, in particular to a production process of high-quality asymmetric flat-bulb steel produced by adding NbN.

Background

The main problem of asymmetric flat bulb steel production is that due to the asymmetry of the bulb and the web, the inhomogeneity appears in the aspects of microstructure, mechanical property and the like, and the inhomogeneity becomes more obvious along with the improvement of specification and strength. At present, vanadium is mainly used at home and abroad to improve the strength of the flat-bulb steel, the cost is higher, the strengthening effect is general, and the performance stability of the flat-bulb steel is insufficient.

Disclosure of Invention

In order to overcome the defects of high cost, general strengthening effect and poor stability caused by the fact that vanadium is used for improving the strength of the existing asymmetric flat-bulb steel, the invention provides a production process of high-quality asymmetric flat-bulb steel produced by adding NbN, and the asymmetric flat-bulb steel is produced by the production processes of material selection, LF refining, auxiliary material addition, soft argon blowing, casting, slow cooling and rolling.

The technical scheme adopted by the invention for solving the technical problems is as follows: a production process of high-quality asymmetric flat-bulb steel produced by adding NbN comprises the following production steps:

the method comprises the following steps: selecting materials: selecting AH36 steel, Nb alloy and manganese-nitrogen alloy wires;

step two: LF refining: putting AH36 steel into an LF refining furnace for LF refining, adding Nb alloy under the condition of white slag in the LF refining furnace, and finely adjusting to control the adding content to be between 0.012 and 0.020 percent;

step three: adding auxiliary materials: after adding Nb alloy for 10-12 minutes, feeding N element by using a manganese-nitrogen alloy wire to control the content of the N element to be 0.007-0.010%;

step four: soft argon blowing: stopping smelting after finishing the wire feeding in the third step, and performing soft argon blowing operation for 15-17 min;

step five: casting: pouring the molten steel subjected to soft argon blowing in the fourth step into a continuous casting machine for casting, wherein the casting end surface is 165 x 280 mm;

step six: slow cooling: placing the casting blank in the step five into a cold pit, covering the cold pit with a cover, and slowly cooling for 30 hours;

step seven: rolling: and C, rolling and rolling the slowly-cooled blank in the step six to prepare the asymmetric flat-bulb steel.

Further, the white slag condition in the second step is that FeO is less than or equal to 0.50 percent.

The invention has the beneficial effects that the production process of the high-quality asymmetric flat-bulb steel produced by adding NbN is used for producing the asymmetric flat-bulb steel by the production processes of material selection, LF refining, auxiliary material addition, soft argon blowing, casting, slow cooling and rolling, and Nb alloy and manganese nitrogen wire are added in the process of smelting AH36 steel, so that the steel has the function of refining crystal grains due to the dragging of solute when containing Nb components and the pinning effect at high temperature and the blocking effect during crystallization, and Nb and N form NbN precipitated phases in the heating, deformation and cooling phase change of steel rolling, so that a good precipitation strengthening effect can be generated; under the condition of not adjusting other alloy components and elements, the strengthening effect of NbN ensures that the performances of 1, the upper yield strength, the tensile strength, the elongation percentage after fracture and the like of AH36 are similar to those of DH36 and EH36, and 2, the impact absorption energy KV2 is more than or equal to 34J at the temperature of-20 ℃ and the temperature of-40 ℃ of DH36 of steel grades to be higher than or equal to 2.

Detailed Description

A production process of high-quality asymmetric flat-bulb steel produced by adding NbN comprises the following production steps:

the method comprises the following steps: selecting materials: selecting AH36 steel, Nb alloy and manganese-nitrogen alloy wires;

step two: LF refining: putting AH36 steel into an LF refining furnace for LF refining, adding Nb alloy under the condition of white slag in the LF refining furnace, and finely adjusting to control the adding content to be between 0.012 and 0.020 percent;

step three: adding auxiliary materials: after adding Nb alloy for 10-12 minutes, feeding N element by using a manganese-nitrogen alloy wire to control the content of the N element to be 0.007-0.010%; the Nb alloy is added under the condition of white slag to form stable Nb content;

step four: soft argon blowing: stopping smelting after finishing the wire feeding in the third step, and performing soft argon blowing operation for 15-17 min; the manganese-nitrogen alloy wire has the following functions: feeding under the condition of white slag to provide stable N content;

step five: casting: pouring the molten steel subjected to soft argon blowing in the fourth step into a continuous casting machine for casting, wherein the casting end surface is 165 x 280 mm;

step six: slow cooling: placing the casting blank in the step five into a cold pit, covering the cold pit with a cover, and slowly cooling for 30 hours;

step seven: rolling: and C, rolling and rolling the slowly-cooled blank in the step six to prepare the asymmetric flat-bulb steel.

Further, the white slag condition in the second step is that FeO is less than or equal to 0.50 percent.

The first embodiment is as follows: the asymmetric flat-bulb steel is produced by the production processes of material selection, LF refining, auxiliary material addition, soft argon blowing, casting, slow cooling and rolling, and Nb alloy and a manganese nitrogen wire are added in the process of smelting AH36 steel, so that when Nb is contained in the steel, a solute dragging effect is achieved, a pinning effect at high temperature and a blocking effect during crystallization are achieved, a grain refining effect is achieved, and Nb and N form an NbN precipitated phase in the heating, deformation and cooling phase change of rolling, so that a good precipitation strengthening effect can be achieved; under the condition of not adjusting other alloy components and elements, the strengthening effect of NbN ensures that the performances of 1, the upper yield strength, the tensile strength, the elongation percentage after fracture and the like of AH36 are similar to those of DH36 and EH36, and 2, the impact absorption energy KV2 is more than or equal to 34J at the temperature of-20 ℃ and the temperature of-40 ℃ of DH36 of steel grades to be higher than or equal to 2.

The foregoing description is intended to be illustrative rather than limiting, and it will be appreciated by those skilled in the art that many modifications, variations or equivalents may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (2)

1. A production process of high-quality asymmetric flat-bulb steel produced by adding NbN is characterized by comprising the following production steps:

the method comprises the following steps: selecting materials: selecting AH36 steel, Nb alloy and manganese-nitrogen alloy wires;

step two: LF refining: putting AH36 steel into an LF refining furnace for LF refining, adding Nb alloy under the condition of white slag in the LF refining furnace, and finely adjusting to control the adding content to be between 0.012 and 0.020 percent;

step three: adding auxiliary materials: after adding Nb alloy for 10-12 minutes, feeding N element by using a manganese-nitrogen alloy wire to control the content of the N element to be 0.007-0.010%;

step four: soft argon blowing: stopping smelting after finishing the wire feeding in the third step, and performing soft argon blowing operation for 15-17 min;

step five: casting: pouring the molten steel subjected to soft argon blowing in the fourth step into a continuous casting machine for casting, wherein the casting end surface is 165 x 280 mm;

step six: slow cooling: placing the casting blank in the step five into a cold pit, covering the cold pit with a cover, and slowly cooling for 30 hours;

step seven: rolling: and C, rolling and rolling the slowly-cooled blank in the step six to prepare the asymmetric flat-bulb steel.

2. The process according to claim 1, wherein the white slag condition in the second step is FeO < 0.50%.