Non-quenched and tempered steel for automobile parts and production process thereof

Abstract

The invention discloses non-quenched and tempered steel for automobile parts and a production process thereof. The non-quenched and tempered steel comprises less than or equal to 0.20% of Ni, 0.010-0.025% of Ti, 0.012-0.025% of Nb and 0.013-0.019% of N. The process comprises converter smelting, LF refining, RH vacuum treatment, continuous casting and rolling. According to the non-quenched and tempered steel, through reasonable design of components, trace elements such as Ni, Nb, Ti and N are added to refine grains and improve the strength and toughness of the material; refining is carried outthrough a narrow component control technology, soft reduction is used in the continuous casting process, reasonable parameters are adopted to reduce the low-power defects of a casting blank, and the density of the material can be improved; and the structure is uniform through a high-temperature diffusion process in the rolling process, the grains are refined through a controlled cooling and controlled rolling technology, the strength is improved, and finally the comprehensive performance of the material is greatly improved.

Description

technical field

[0001] The invention belongs to the field of metallurgy and relates to a non-quenched and tempered steel for auto parts and a production process thereof. Background technique

[0002] Non-quenched and tempered steel was first developed by West Germany in the early 1970s. The so-called non-quenched and tempered steel is to add trace elements (Nb, V, Ti, N, etc.) The carbon (nitride) compound dispersed and precipitated in the pearlite is the strengthening phase, so that it can obtain the mechanical properties of the combined steel after quenching and tempering treatment without quenching and tempering treatment after rolling. Since the required strength and toughness can be obtained only by controlling the rolling process and the cooling rate after rolling, and the cutting performance is improved by adding appropriate S, the quenching and tempering process is omitted, energy is saved, and quenching is eliminated. Due to deformation, cracking and the increased s...

Examples

Embodiment 1

[0043] 120t converter process

[0044] 1. End point of converter: C content 0.12%, P content 0.009%, tapping temperature 1642°C.

[0045] 2. After 1 minute and 30 seconds of converter tapping, according to the residual alloy composition content, and after calculation, add the corresponding amount of ferroalloy, 700 kg of refining slag, and 450 kg of lime.

[0046] 3. After the converter is tapped, the molten steel is hoisted to the argon station, and then fed into the Al line for 380 meters at the argon station.

[0047] LF refining furnace process

[0048] 1200m of nitrogen-manganese wire is fed after LF, 50Kg of aluminum particles and 100Kg of SiC are used for diffusion deoxidation of steel slag during LF refining, the manganese content of LF furnace is controlled to 1.29% before tapping, and then aluminum wire is fed, ferro-titanium is added, and when LF is discharged Sampling and testing showed that the aluminum content in molten steel was 0.024%, the titanium content wa...

Embodiment 2

[0057] Converter process

[0058] 1. End point of converter: C content 0.13%, P content 0.008%, tapping temperature 1619℃. After the converter is tapped, the molten steel is hoisted to the argon station, and then 370 meters of Al wire is fed into the argon station, and the others are the same as in embodiment 1.

[0059] LF refining furnace process

[0060] Feed 1180m of nitrogen-manganese wire after entering LF, control the manganese content to 1.28% before tapping the LF furnace, then feed the aluminum wire, add ferro-titanium, and take samples for testing when the LF exits, the aluminum content in the molten steel is 0.023%, the titanium content is 0.022%, the sulfur Content 0.056%, other is with embodiment 1.

[0061] RH vacuum treatment process

[0062] The RH circulation time is 34min, of which the high vacuum (≤1.33mbar) time is 17min, the RH lifting gas uses nitrogen throughout the whole process, and the last 12min uses low vacuum (100Mpa), and feeds 260m of MnN wir...

Embodiment 3

[0068] Converter process

[0069] 1. End point of converter: C content 0.08%, P content 0.013%, tapping temperature 1633°C. After the converter is tapped, the molten steel is hoisted to the argon station, and then 400 meters of Al wire is fed into the argon station, and the others are the same as in embodiment 1.

[0070] LF refining furnace process

[0071] Feed 1240m of nitrogen-manganese wire after entering LF, control the manganese content of 1.31% before tapping the LF furnace, then feed the aluminum wire, add ferro-titanium, and take samples for testing when the LF exits, the aluminum content in the molten steel is 0.025%, the titanium content is 0.023%, the sulfur Content 0.053%, other is with embodiment 1.

[0072] RH vacuum treatment process

[0073] The RH circulation time is 34min30S, of which the high vacuum (≤1.33mbar) time is 17min, the RH lifting gas uses nitrogen throughout the whole process, and the last 12min uses low vacuum (100Mpa), and after the RH trea...

technical field

[0001] The invention belongs to the field of metallurgy and relates to a non-quenched and tempered steel for auto parts and a production process thereof. Background technique

[0002] Non-quenched and tempered steel was first developed by West Germany in the early 1970s. The so-called non-quenched and tempered steel is to add trace elements (Nb, V, Ti, N, etc.) The carbon (nitride) compound dispersed and precipitated in the pearlite is the strengthening phase, so that it can obtain the mechanical properties of the combined steel after quenching and tempering treatment without quenching and tempering treatment after rolling. Since the required strength and toughness can be obtained only by controlling the rolling process and the cooling rate after rolling, and the cutting performance is improved by adding appropriate S, the quenching and tempering process is omitted, energy is saved, and quenching is eliminated. Due to deformation, cracking and the increased s...

Examples

Embodiment 1

[0043] 120t converter process

[0044] 1. End point of converter: C content 0.12%, P content 0.009%, tapping temperature 1642°C.

[0045] 2. After 1 minute and 30 seconds of converter tapping, according to the residual alloy composition content, and after calculation, add the corresponding amount of ferroalloy, 700 kg of refining slag, and 450 kg of lime.

[0046] 3. After the converter is tapped, the molten steel is hoisted to the argon station, and then fed into the Al line for 380 meters at the argon station.

[0047] LF refining furnace process

[0048] 1200m of nitrogen-manganese wire is fed after LF, 50Kg of aluminum particles and 100Kg of SiC are used for diffusion deoxidation of steel slag during LF refining, the manganese content of LF furnace is controlled to 1.29% before tapping, and then aluminum wire is fed, ferro-titanium is added, and when LF is discharged Sampling and testing showed that the aluminum content in molten steel was 0.024%, the titanium content wa...

Embodiment 2

[0057] Converter process

[0058] 1. End point of converter: C content 0.13%, P content 0.008%, tapping temperature 1619℃. After the converter is tapped, the molten steel is hoisted to the argon station, and then 370 meters of Al wire is fed into the argon station, and the others are the same as in embodiment 1.

[0059] LF refining furnace process

[0060] Feed 1180m of nitrogen-manganese wire after entering LF, control the manganese content to 1.28% before tapping the LF furnace, then feed the aluminum wire, add ferro-titanium, and take samples for testing when the LF exits, the aluminum content in the molten steel is 0.023%, the titanium content is 0.022%, the sulfur Content 0.056%, other is with embodiment 1.

[0061] RH vacuum treatment process

[0062] The RH circulation time is 34min, of which the high vacuum (≤1.33mbar) time is 17min, the RH lifting gas uses nitrogen throughout the whole process, and the last 12min uses low vacuum (100Mpa), and feeds 260m of MnN wir...

Embodiment 3

[0068] Converter process

[0069] 1. End point of converter: C content 0.08%, P content 0.013%, tapping temperature 1633°C. After the converter is tapped, the molten steel is hoisted to the argon station, and then 400 meters of Al wire is fed into the argon station, and the others are the same as in embodiment 1.

[0070] LF refining furnace process

[0071] Feed 1240m of nitrogen-manganese wire after entering LF, control the manganese content of 1.31% before tapping the LF furnace, then feed the aluminum wire, add ferro-titanium, and take samples for testing when the LF exits, the aluminum content in the molten steel is 0.025%, the titanium content is 0.023%, the sulfur Content 0.053%, other is with embodiment 1.

[0072] RH vacuum treatment process

[0073] The RH circulation time is 34min30S, of which the high vacuum (≤1.33mbar) time is 17min, the RH lifting gas uses nitrogen throughout the whole process, and the last 12min uses low vacuum (100Mpa), and after the RH trea...

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