CN-122007149-A - Production method for homogenizing SAE6150 structure of alloy tool steel

Abstract

The invention belongs to the technical field of steel rolling, and particularly relates to a control cooling method for homogenizing an alloy tool steel SAE6150 structure, which comprises the following production process routes of molten iron pretreatment, a converter, an LF furnace, continuous casting, continuous rolling, billet cleaning, heating, rolling, controlled cooling and finishing; the rolling is carried out at an initial rolling temperature of 930-980 ℃, a finish rolling inlet temperature of 880-950 ℃, a sizing inlet temperature of 850-920 ℃ and a wire laying temperature of 890-930 ℃, the water bath cooling mode is adopted, the wire rod is fed into a water tank after being laid, the wire rod is cooled to 600-700 ℃ at a cooling speed of 10-15 ℃ per second and fed into a heat preservation cover, the heat preservation cover is completely closed, the cover outlet temperature is 450-600 ℃, and the cooling bed is used for air cooling. The method has the advantages that the cooling technology combining water bath cooling and slow cooling is adopted, and only ferrite and pearlite tissues are obtained in the tissues obtained after the wire rod is cooled, so that the defect of poor same-circle performance of the wire rod is reduced.

Inventors

• HAN LITAO
• LI XU
• GAO HANG
• CHE AN
• MA LIGUO
• GUO DAYONG
• CHANG HONGWEI
• LI KAI
• WANG HONGLIANG
• YANG HUI

Assignees

• 鞍钢股份有限公司

Dates

Publication Date

20260512

Application Date

20260304

Claims (7)

1. 1. A production method for homogenizing an alloy tool steel SAE6150 structure is characterized in that the production process route of the alloy tool steel SAE6150 comprises molten iron pretreatment, a converter, an LF furnace, continuous casting, continuous rolling, billet cleaning, heating, rolling, controlled cooling and finishing; Rolling: The initial rolling temperature is 930-980 ℃, the finish rolling inlet temperature is 880-950 ℃, the reduced sizing inlet temperature is 850-920 ℃, and the spinning temperature is 890-930 ℃; and (3) cooling control: the water bath cooling mode is that the wire rods are fed into a water tank after spinning, the temperature of cooling water in the water tank is 80-100 ℃, the wire rods are cooled to 600-700 ℃ at a cooling speed of 10-15 ℃ and discharged out of the water tank, the wire rods enter a heat preservation cover, the heat preservation cover is completely closed, the cooling speed in the cover is 0.5-1.0 ℃ per second, the temperature of discharged cover is 450-600 ℃, and the cooling bed is air cooled.
2. 2. The production method of the alloy tool steel SAE6150 tissue homogenization, which is characterized by comprising the steps of continuous casting, wherein the superheat degree of a tundish is controlled to be 20-30 ℃, the constant pull rate of a continuous casting billet is controlled to be 0.55+/-0.02 m/min, protection casting, electromagnetic stirring of a crystallizer, the electromagnetic stirring voltage of the crystallizer is 100-200V, the current intensity is 300-500A, and the frequency is 3-8 Hz.
3. 3. The production method of the alloy tool steel SAE6150 structure homogenization treatment according to claim 2, wherein the section size of the continuous casting billet is (250-350) mm× (350-450) mm.
4. 4. The production method of the alloy tool steel SAE6150 with uniform structure according to claim 1 is characterized in that LF refining is performed by adopting micro-positive pressure operation, controlling electrode heating time to be 20-30 min, adjusting components twice, adding 0.5-0.8 kg/t aluminum powder for deoxidization operation during coarse adjustment, and controlling C, si, mn, cr, V content in steel according to a target during fine adjustment.
5. 5. The production method of the alloy tool steel SAE6150 structure homogenization according to claim 1, wherein the alloy tool steel SAE6150 comprises the following chemical components in percentage by weight: 0.50-0.60% of C, 0.20-0.50% of Si, 0.60-1.00% of Mn, 0.90-1.20% of Cr, 0.15-0.30% of V, and the balance of Fe and residual elements.
6. 6. The method for producing the alloy tool steel SAE6150 with uniform microstructure according to claim 5, wherein the microstructure of the alloy tool steel SAE6150 comprises pearlite, ferrite and a small amount of bainite, wherein the pearlite content is 92% -94% by area, and the rest is ferrite and bainite below 0.2%.
7. 7. The production method of the alloy tool steel SAE6150 with uniform structure according to claim 1, wherein the alloy tool steel SAE6150 is a steel wire rod of Bu 5.5-Bu 25 mm.

Description

Production method for homogenizing SAE6150 structure of alloy tool steel Technical Field The invention belongs to the technical field of steel rolling, and particularly relates to a production method for homogenizing an alloy tool steel SAE6150 structure. Background The alloy tool steel SAE6150 wire rod is mainly used for manufacturing small hexagonal hand tool products with high precision and high strength. The traditional cooling method of the wire rod in the production process is a Steyr cooling mode, namely, after the rolled piece is subjected to final rolling pass, the wire rod is cooled to 850-950 ℃ by a water tank, is cooled by blowing by a fan after spinning, and then is subjected to heat preservation and slow cooling to finish phase change. Due to uneven lap points and intermediate cooling of wire rod rings in the cooling process of a fan, bainite and martensite structures exist in a tool steel wire rod structure, and the same-circle performance difference is large. The wire rod is easy to break in subsequent transportation and processing, and the stable product quality and the use of downstream users are affected. In the prior art, patent publication No. CN107142417A discloses a carbon tool steel wire rod for files and a preparation method thereof, wherein the chemical components of the wire rod are ,[C]1.26～1.32％、[Si]0.08～0.18％、[Mn]0.20～0.35％、[Cr]0.55～0.70％、[V]0.10～0.25％、[P]≤0.025％、[S]≤0.025％、[Al]≤0.008％, and the balance of Fe and unavoidable impurities in percentage by weight. The rolling process adopts high-temperature heating, high-pressure water dephosphorization, low-spinning and air cooling processes, wherein the high-temperature heating is carried out in an oxidizing atmosphere. The adoption of the air cooling mode also has the problem of uneven cooling. The patent publication No. CN111690801A discloses a production process of an alloy tool steel hot-rolled wire rod for obtaining a full bainitic structure, wherein the heating temperature of a casting blank soaking section is 1200-1250 ℃ in a cogging procedure, the temperature of an intermediate blank high-temperature section is not higher than 1100 ℃ in a heating procedure, rolling is carried out by adopting a finish rolling and MINI unit in a rolling procedure, high-strain rate large deformation rolling of a non-recrystallization region and an (alpha+gamma) two-phase region is realized, the cumulative reduction reaches 55-85%, a great number of crystal defects such as dislocation and deformation bands are generated in the austenitic structure in the deformation process, the generated deformation storage energy is shortened, the phase transformation incubation period is shortened, the phase transformation driving force is increased, high-temperature heating and high-pressure water dephosphorization are adopted in the rolling procedure, the wire laying temperature in the low wire-laying and air cooling procedure is 750-800 ℃, and the Sitel mole controlled cooling is adopted in the rolling procedure. The invention effectively prevents martensite and the mixture of martensite, pearlite and ferrite from being separated out in the rolling and cooling process, obtains a full bainitic structure, avoids the brittle failure of the martensitic structure, and is beneficial to the processing and the use of the wire rod and the improvement of the fatigue performance. But it also has a problem of uneven cooling. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide a production method for homogenizing an alloy tool steel SAE6150 structure, which improves wire rod cooling uniformity by controlling heating temperature, rolling temperature and water bath cooling after wire rod spinning, obtains a more uniform wire rod structure, avoids the generation of bainite and martensite structures and improves performance uniformity. In order to achieve the above purpose, the present invention is realized by the following technical scheme: A production method for homogenizing the structure of alloy tool steel SAE6150 comprises the following steps of molten iron pretreatment, a converter, an LF furnace, continuous casting, continuous rolling, billet cleaning, heating, rolling, controlled cooling and finishing. LF refining: The primary tasks of LF refining are component fine adjustment, temperature control and slag forming operation, and the nitrogen increase of molten steel is controlled by adopting micro-positive pressure operation, large slag amount and heating time limitation. And performing slag forming operation by using lime and fluorite, and controlling the heating time of the electrode to be 20-30 min. And (3) performing component adjustment twice, adding 0.5-0.8 kg/t aluminum powder for deoxidization during rough adjustment, and controlling C, si, mn, cr, V content in steel according to a target during fine adjustment. Continuous casting, wherein the section size of the continuous casting billet is (250-350)