Processing technology of high-strength and low-magnetic-permeability stainless steel profiles

Abstract

The invention discloses a high-strength and low-magnetic-permeability stainless steel profile processing process, comprising the following steps: S1: continuously drawing a round wire / round bar, with the total area reduction rate controlled within the range of 5-22%; S2: performing a solid solution treatment on the round wire / round bar before rolling, continuously heating in a furnace, with a furnace temperature of 800±10°C, a speed of 0.5±0.1m / min, a furnace time of 18min, and filling the furnace tube with argon gas, with a total gas flow rate of 60-100NL / min and an oxygen content of less than 0.5%; S3: performing a solid solution treatment on the round wire / round bar before rolling, and continuously heating the round wire / round bar in a furnace, with a furnace temperature of 800±10°C, a speed of 0.5±0.1m / min, a furnace time of 18min, and filling the furnace tube with argon gas, with a total gas flow rate of 60-100NL / min and an oxygen content of less than 0.5%. Two pairs of rollers are used to flat-roll the flat wire / stock, with the area reduction controlled within the range of 5-12%. S4: The flat wire / stock is flat-rolled with four rollers to trim the edges, with the area reduction controlled within the range of 3-6%. S5: The flat wire / stock is flat-rolled with four rollers to reduce the thickness, with the area reduction controlled within the range of 3-10%. S6: The flat wire / stock is cold-rolled with four rollers to form the final product. Solution treatment before rolling ensures that the round wire / bar is hardened evenly and its magnetism is eliminated, leaving the soft round wire / bar easier to flatten later.

Description

Technical Field

[0001] The invention relates to the technical field of special-shaped material processing, in particular to a processing technology of high-strength and low-magnetic-permeability stainless steel special-shaped materials. Background Art

[0002] The processing of high-strength, low-permeability rod and wire uses processes such as multi-pass wire drawing and high-temperature demagnetization to increase surface hardness and reduce magnetic permeability. The main process steps are demagnetization through continuous bright heat treatment to obtain ultra-low magnetic permeability base material; film treatment and drying are carried out, and demagnetization coating is applied at the same time, and then it is dried in an online drying furnace; multiple drawing passes are used to form rods of corresponding diameters; quenching and aging treatment is carried out in a box-type heat treatment furnace, and the semi-finished products are straightened in a straightening machine and ground on a coreless grinder to produce finished products; if this process is used directly to make high-strength flat wire, since round wire / round rods are continuously drawn into flat wires / flat materials, multiple direct drawing passes will cause non-uniform deformation of the rod and wire surface, resulting in different hardness on the cross section of the flat wire / flat material. Therefore, when processing high-strength, low-permeability special-shaped materials, how to ensure uniform deformation of the round wire / round rod surface is the key to processing high-strength, low-permeability special-shaped materials. Summary of the Invention

[0003] The purpose of the present invention is to solve the above technical problems and provide a high-strength and low-magnetic-permeability stainless steel profile processing technology. Through reasonable process steps and control of the area reduction rate of each pass, the round wire / round rod is uniformly deformed to obtain high-strength and low-magnetic-permeability profiles.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: a high-strength and low-magnetic-permeability stainless steel profile processing technology, comprising the following steps:

[0005] S1: Continuously draw the round wire / rod, with the total area reduction rate controlled within the range of 5-22%;

[0006] S2: before rolling, the round wire / round bar is subjected to solution treatment and continuously heated in a furnace at a temperature of 800±10°C, a speed of 0.5±0.1 m / min, and a furnace time of 18 min. The furnace tube is filled with argon gas at a total flow rate of 60-100 NL / min and an oxygen content of <0.5%;

[0007] S3: The round wire / round bar is flat-rolled by two pairs of rollers to form flat wire / flat material, and the area reduction rate is controlled within the range of 5-12%;

[0008] S4: Four-roller flat rolling for flat wire / flat material, with the surface reduction rate controlled within the range of 3-6%;

[0009] S5: Four-roll flat rolling for flat wire / flat material to reduce thickness, and the area reduction rate is controlled within the range of 3-10%;

[0010] S6: The flat wire / flat material is subjected to four-roll forming cold rolling to form the final product.

[0011] Before the final rolling, the round wire / round bar is thoroughly solid-solution treated to make the hardened round wire / round bar soft (annealed state), so that the round wire / round bar can be hardened evenly and the magnetism of the round wire / round bar can be eliminated. The soft round wire / round bar is convenient for subsequent flattening. The round wire / round bar is then rolled into flat wire / flat material (free rolling) by a two-roll rolling mill. The flat wire / flat material is flattened by a double-roll rolling mill, and the flat wire / flat material is edged by four rollers. The minimum edge-cutting amount is controlled to control the area reduction rate within the range of 3-6%, ensuring that the four fillets are within the target range, which can not only deform the section and strengthen the surface, but also prevent uneven deformation caused by transition edge-cutting. During rolling, the thickness is reduced, and the width is only sufficient to ensure that the side edges and arc shapes meet the shape requirements. The flat wire / flat material is trimmed again, and the minimum trimming amount is controlled to keep the area reduction rate within the range of 3-10%. The four fillets are ensured to be within the target range. This can not only deform the cross section and strengthen the surface, but also prevent uneven deformation caused by excessive trimming. The final rolling is achieved by drawing or precision rolling to obtain the finished product size. Through thorough solution annealing before hardening, the upper and lower deformations are followed throughout the deformation process, and the edge deformation is only to ensure the shape. In addition, the hardening can be extended from the middle to the surrounding areas, so that the round wire / round bar is uniformly deformed to obtain high-strength and low-permeability profiles.

[0012] In order to deform the cross section and strengthen the surface, and prevent uneven deformation caused by transitional edge trimming, a further preferred technical solution is that after step S5, steps S4 and S5 are repeated in sequence: for flat wire / flat material, the four-roll flat rolling edge trimming is carried out, and the surface reduction rate is controlled within the range of 3-6%; for flat wire / flat material, the four-roll flat rolling thickness reduction is carried out, and the surface reduction rate is controlled within the range of 3-10%.

[0013] In order to make the wire meet the deformation requirements through process parameters during the hot rolling process, a further preferred technical solution is that in step S3, heating is carried out in a tubular resistance heating furnace at a heating temperature of 880-940°C, argon protection is used during the heating process, the furnace time is 5-10 minutes, and then rolling is carried out on a flat roll mill at a rolling speed of 4-7 m / min.

[0014] In order to make the wire meet the deformation requirements through process parameters during the hot rolling process, a further preferred technical solution is that in step S4, the heating temperature is 840-900°C, argon protection is used during the heating process, the furnace time is 3-8 minutes, and then rolling is carried out on a four-roll mill at a rolling speed of 4-7 m / min.

[0015] In order to make the wire meet the deformation requirements through process parameters during the hot rolling process, a further preferred technical solution is that in step S5, the heating temperature is 840-900°C, argon protection is used during the heating process, the furnace time is 3-8 minutes, and then rolling is carried out on a four-roll mill at a rolling speed of 4-7 m / min.

[0016] Compared with the prior art, the beneficial effects of the present invention are: by solution treatment before rolling, the hardened round wire / round bar is made soft (annealed state), so that the round wire / round bar can be hardened evenly and the magnetism of the round wire / round bar can be eliminated. The soft round wire / round bar is convenient for subsequent flattening, and then the round wire / round bar is rolled into flat wire / flat material through a two-roll rolling mill. Moreover, by heating in a tubular resistance heating furnace before each flattening, the magnetism can be eliminated and the flattening is facilitated. There is no need to carry out the subsequent demagnetization process step, and the demagnetization process step is advanced. By combining demagnetization and flattening, the rolling effect is improved and the subsequent demagnetization step is reduced. At the same time, the minimum edge trimming amount is controlled in the rolling step to ensure that the four fillets are within the target range, which can deform the cross section and strengthen the surface, and prevent uneven deformation caused by excessive edge trimming. The upper and lower deformations are followed in the entire deformation, and the edge deformation is only to ensure the shape needs; and the hardening can be extended from the middle to the surrounding area, so that the round wire / round bar is uniformly deformed to obtain high-strength and low-magnetic-permeability profiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a process flow chart of the high-strength and low-magnetic-permeability stainless steel profile processing according to the present invention;

[0018] Figure 2 This is a schematic diagram of the hardness detection position of the high-strength and low-magnetic-permeability special-shaped material of the present invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] Example 1

[0021] The processing technology of high-strength and low-magnetic-permeability stainless steel profiles includes the following steps:

[0022] S1: Continuously draw the round wire / rod, with the total area reduction rate controlled within the range of 5-22%;

[0023] S2: before rolling, the round wire / round bar is subjected to solution treatment and continuously heated in a furnace at a temperature of 800±10°C, a speed of 0.5±0.1 m / min, and a furnace time of 18 min. The furnace tube is filled with argon gas at a total flow rate of 60-100 NL / min and an oxygen content of <0.5%;

[0024] S3: The round wire / round bar is flat-rolled by two pairs of rollers to form a flat wire / flat stock, which is then heated in a tubular resistance heating furnace at a temperature of 880-940°C. Argon is used as a protection during the heating process, and the furnace time is 5-10 minutes. The flat-roll mill is then used for rolling at a speed of 4-7 m / min, and the area reduction rate is controlled within the range of 5-12%.

[0025] S4: The flat wire / flat material is flat-rolled with four rollers to trim the edges. The flat wire / flat material is heated in a tubular resistance heating furnace at a temperature of 840-900°C. Argon is used as a protection during the heating process. The furnace time is 3-8 minutes. The flat wire / flat material is then rolled on a four-roll mill at a speed of 4-7 m / min. The area reduction rate is controlled within the range of 3-6%.

[0026] S5: The flat wire / flat material is subjected to four-roll flat rolling to reduce the thickness. The flat wire / flat material is heated in a tubular resistance heating furnace at a temperature of 840-900°C. Argon is used as a protection during the heating process. The furnace time is 3-8 minutes. The flat wire / flat material is then rolled on a four-roll mill at a rolling speed of 4-7 m / min. The area reduction rate is controlled within the range of 3-10%.

[0027] S6: The flat wire / flat material is subjected to four-roll forming cold rolling to form the final product.

[0028] Example 2

[0029] like Figure 1 As shown, the high strength and low magnetic permeability stainless steel profile processing technology includes the following steps:

[0030] S1: Continuously draw the round wire / rod, and control the total area reduction rate within 20%;

[0031] S2: before rolling, the round wire / round bar is subjected to solution treatment and continuously heated in a furnace at a temperature of 800°C, a speed of 0.5 m / min, and a furnace time of 18 min. The furnace tube is filled with argon gas at a total flow rate of 80 NL / min and an oxygen content of <0.5%;

[0032] S3: The round wire / bar is flat-rolled by two pairs of rollers to form flat wire / flat stock, which is heated in a tubular resistance heating furnace at a temperature of 900°C under argon protection for 8 minutes. The flat-roll mill is then used for rolling at a speed of 5 m / min, with the area reduction controlled within 4%.

[0033] S4: The flat wire / flat stock is flat-rolled with four rollers to trim the edges. The flat wire / flat stock is heated in a tubular resistance heating furnace at a temperature of 880°C. Argon is used as a protection during the heating process. The furnace time is 6 minutes. The flat wire / flat stock is then rolled on a four-roll mill at a speed of 5 m / min. The area reduction is controlled within 5%.

[0034] S5: The flat wire / flat material is subjected to four-roll flat rolling to reduce the thickness. The flat wire / flat material is heated in a tubular resistance heating furnace at a temperature of 880°C. Argon is used as a protection during the heating process. The furnace time is 6 minutes. The flat wire / flat material is then rolled on a four-roll mill at a rolling speed of 5m / min. The area reduction rate is controlled within 5%.

[0035] Repeat step S4 to flatten the flat wire / flat stock by four-roll flat rolling, heat it in a tubular resistance heating furnace at a temperature of 880°C, use argon protection during the heating process, and keep it in the furnace for 6 minutes. Then roll it on a four-roll mill at a rolling speed of 5m / min, and control the area reduction rate within 5%;

[0036] Repeat step S5 to reduce the thickness of the flat wire / flat material by four-roll flat rolling, heat it in a tubular resistance heating furnace at a temperature of 880°C, use argon protection during the heating process, and keep it in the furnace for 6 minutes, then roll it on a four-roll mill at a rolling speed of 5m / min, and control the area reduction rate within 5%;

[0037] S6: The flat wire / flat material is subjected to four-roll cold rolling to form the final product;

[0038] Take samples of the final product to test the hardness, such as Figure 2 As shown in the figure, the hardness test results of the three test points are within the range of HV280±10, indicating that the flat steel produced by this process has high metal streamline consistency and uniform hardness, which can ensure that the material has high strength while also having extremely low magnetic permeability.

[0039] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. High strength and low magnetic permeability stainless steel profile processing technology, characterized by: The following steps are included: S1: Continuously draw the round wire / rod, with the total area reduction rate controlled within the range of 5-22%; S2: before rolling, the round wire / round bar is subjected to solution treatment and continuously heated in a furnace at a temperature of 800±10°C, a speed of 0.5±0.1 m / min, and a furnace time of 18 min. The furnace tube is filled with argon gas at a total flow rate of 60-100 NL / min and an oxygen content of <0.5%; S3: The round wire / round bar is flat-rolled by two pairs of rollers to form flat wire / flat material, and the area reduction rate is controlled within the range of 5-12%; S4: Four-roller flat rolling for flat wire / flat material, with the surface reduction rate controlled within the range of 3-6%; S5: Four-roll flat rolling for flat wire / flat material to reduce thickness, and the area reduction rate is controlled within the range of 3-10%; S6: The flat wire / flat material is subjected to four-roll forming cold rolling to form the final product.

2. The high-strength and low-magnetic-permeability stainless steel profile processing process according to claim 1, characterized in that: After step S5, steps S4 and S5 are repeated in sequence: the flat wire / flat material is subjected to four-roll flat rolling for edge trimming, and the area reduction rate is controlled within the range of 3-6%; the flat wire / flat material is subjected to four-roll flat rolling for thickness reduction, and the area reduction rate is controlled within the range of 3-10%.

3. The high-strength and low-magnetic-permeability stainless steel profile processing process according to claim 1 or 2, characterized in that: In step S3, heating is performed in a tubular resistance heating furnace at a temperature of 880 to 940° C., argon is used for protection during the heating process, and the furnace time is 5 to 10 minutes. Then, rolling is performed on a flat roll mill at a rolling speed of 4 to 7 m / min.

4. The high-strength and low-magnetic-permeability stainless steel profile processing process according to claim 1 or 2, characterized in that: In step S4, heating is performed in a tubular resistance heating furnace at a temperature of 840 to 900° C. Argon is used for protection during the heating process, and the furnace time is 3 to 8 minutes. Then, rolling is performed on a four-high rolling mill at a rolling speed of 4 to 7 m / min.

5. The high-strength and low-magnetic-permeability stainless steel profile processing process according to claim 1 or 2, characterized in that: In step S5, heating is performed in a tubular resistance heating furnace at a temperature of 840 to 900° C., argon gas is used for protection during the heating process, and the furnace time is 3 to 8 minutes. Then, rolling is performed on a four-high rolling mill at a rolling speed of 4 to 7 m / min.

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