End socket machining method capable of reducing ferrite content

Abstract

The invention discloses an end socket processing method capable of reducing ferrite content, which comprises the following steps: S10, blanking; s20, primary cold stamping is carried out, the seal head is formed preliminarily, the seal head formed preliminarily comprises a concave part and a plain piece part located on the periphery of the concave part, and the plain piece part is of a circular ring structure; s30, acid pickling is conducted; s40, solution treatment is conducted, specifically, the end socket subjected to acid pickling is fixed to a solution tool, the solution tool is put into a heating furnace to be heated, and then the solution tool is put into a cooling water pool to be cooled; s50, secondary cold stamping is carried out; s60, plasma beveling is carried out; and S70, spinning forming is conducted, specifically, the flat sheet part is spun into a straight edge through a spinning machine. According to the machining method, the stamping depth each time is reduced, the content of ferrite can be effectively reduced, after the first-time cold stamping, solution treatment is adopted, phase change is accelerated, the austenite generation amount is increased, and the content of ferrite is reduced, so that the content of ferrite in the end socket is further reduced, the machining requirement that ferrite is smaller than or equal to 12% can be met, machining is easy, and the machining cost is reduced. And the production efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of end cap processing, and in particular to an end cap processing method capable of reducing ferrite content. Background Art

[0002] Stainless steel head is a kind of high-quality pipe and tank connector, which is commonly used in petroleum, chemical, pharmaceutical and other industries. The excessive ferrite content of stainless steel head is a common problem. There are two main reasons for the excessive ferrite content. One is the poor surface quality of the plate and too many sundries; the other is excessive cold working or improper temperature control during the head processing. In actual production, in order to avoid excessive cold working and cracking, many manufacturers use multiple cold stamping to process the head, that is, first stamp the head to about 60% of the target depth through a cold stamping, and then stamp the head to the target depth through a second cold stamping. Through multiple stamping, the increase in ferrite is reduced. Through the above processing method, the processed head can basically meet the national standard GB25198 for the processing requirements of head ferrite ≤15%, but for higher requirements, such as ferrite ≤12%, it is usually not met. However, the hot stamping process is used to stamp the head, which requires large investment in hot stamping equipment, high mold prices, low production efficiency, and the core technology is usually controlled by foreign countries, making production difficult and costly.

[0003] Based on this, it is necessary to propose a new processing method for the head to reduce the ferrite content of the head. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in the prior art, the traditional processing technology cannot meet the processing requirement of ferrite ≤ 12%. Based on this, the present invention provides a head processing method that can reduce the ferrite content.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a head processing method capable of reducing the ferrite content, comprising the following steps:

[0006] S10: Cutting the stainless steel sheet into discs;

[0007] S20: a cold stamping operation, wherein a stamping machine is used to stamp the disc to preliminarily form a head. The preliminarily formed head comprises a concave portion and a flat portion located around the concave portion, and the flat portion is in a circular ring structure.

[0008] S30: Pickling: evenly apply the pickling liquid on the surface of the head to remove the oxide layer, oil and rust;

[0009] S40: solution treatment, fixing the pickled heads on the solution fixture, putting the solution fixture into a heating furnace for heating, and then putting it into a cooling water pool for cooling, the solution fixture includes a support plate and a support cylinder fixedly mounted on the support plate, the heads are stacked on top of the support cylinder, and the flat sheet parts between each two adjacent heads are padded with isolation blocks;

[0010] S50: secondary cold stamping, stamping the head after solution treatment to the target depth;

[0011] S60: plasma beveling to remove the excess of the flat sheet portion;

[0012] S70: Spinning, spinning the flat sheet portion into a straight edge by a spinning machine.

[0013] Further, in step S40, a plurality of isolation blocks are disposed between each two adjacent flat sheet portions, and the plurality of isolation blocks are evenly disposed along the circumference of the flat sheet portion.

[0014] Furthermore, the isolation block is an arc block, the support tube is a hollow cylindrical structure, the inner diameter of the arc block is the same as the inner diameter of the support tube, and when installed, the inner and outer arc side walls of the arc block are coplanar with the inner and outer side walls of the support tube.

[0015] Furthermore, the material of the isolation block is the same as that of the end cap.

[0016] Furthermore, in step S40, an isolation block is provided between the flat sheet portion of the bottommost end cover and the support tube.

[0017] Furthermore, the solid solution tooling also includes a lifting plate and a sling, there are more than three slings, and they are evenly arranged along the circumference of the support tube, the lower end of the sling is fixedly connected to the outer wall of the support tube, the upper end of the sling is fixedly connected to the lifting plate, and the lifting plate is used to connect to the crane.

[0018] Furthermore, the stamping depth of the first cold stamping is controlled within the range of 600±10 mm, and the second cold stamping is stamped to a target depth of 630±10 mm.

[0019] The beneficial effects of the present invention are as follows: the head processing method of the present invention that can reduce the ferrite content is successively cold stamped once and twice, and compared with a direct stamping into place, the depth of each stamping is reduced, and the ferrite content can be effectively reduced. At the same time, after the first cold stamping, a solid solution treatment is used to accelerate the phase change, increase the amount of austenite generated, and reduce the ferrite content. Therefore, the ferrite content in the head is further reduced, and the processing requirement of ferrite ≤12% can be met. It is easy to process, has low production difficulty, and high production efficiency. In addition, by beveling the flat sheet excess, the amount of spinning is reduced, which is also conducive to reducing the ferrite content. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 It is a flow chart of a head processing method capable of reducing ferrite content of the present invention;

[0022] Figure 2 yes Figure 1 The schematic diagram of the installation of the solid solution tooling and the head in the head processing method that can reduce the ferrite content is shown.

[0023] In the figure: 1, recessed portion, 2, flat sheet portion, 3, solid solution tooling, 31, support plate, 32, support cylinder, 33, lifting plate, 34, sling, 4, isolation block. DETAILED DESCRIPTION

[0024] The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, and therefore only shows the components related to the present invention.

[0025] See also Figure 1 The present invention provides a head processing method capable of reducing ferrite content, comprising the following steps:

[0026] Step S10: Cutting: according to the design size, a circle is drawn on the stainless steel plate as the basis for the cutting size. Then the plate is cut to form a disc. Then, the edges and corners of the disc are deburred and polished.

[0027] Step S20: One-time cold stamping, using a punching machine to stamp the disc. Specifically, place the disc on the fixed die below, start the punching machine, and move the movable die on it downward. The convex part in the middle of the movable die gradually squeezes the center of the disc into the concave part in the middle of the fixed die. When finally formed, the middle part of the disc is concave downward, and the four sides of the disc are squeezed and fixed between the edge of the fixed die and the edge of the movable die. At this time, the head is initially formed, and the initially formed head includes a concave portion 1 formed by a downward depression and a flat sheet portion 2 located around the concave portion 1 and fixedly connected to the concave portion 1, and the flat sheet portion 2 is a circular ring structure. The stamping depth of a single cold stamping is controlled within the range of 600±10mm to ensure that the head has good stiffness and rigidity.

[0028] Step S30: pickling, evenly applying the pickling liquid on the surface of the head to remove the oxide layer, oil and rust, and then rinsing it with clean water, thereby improving the surface quality of the head, reducing impurities attached to the surface of the head, and reducing the ferrite content generated during the head processing.

[0029] Step S40: Solution treatment: The pickled end cap is fixed on the solution treatment tool 3, and the solution treatment tool 3 is placed in a heating furnace and heated to 1050° C., and then placed in a cooling water pool for cooling.

[0030] See also Figure 2 In this embodiment, the solid solution fixture 3 includes a support plate 31 and a support tube 32 fixedly mounted on the upper surface of the support plate 31. The support tube 32 is a hollow cylindrical structure. The pickled heads are stacked on the top of the support tube 32, and a plurality of isolation blocks 4 are placed between the flat sheet parts 2 between each two adjacent heads. Under the action of the isolation blocks 4, the heads are isolated, which also ensures that there is a certain gap between each two adjacent flat sheet parts 2. The gap can ensure that when the solid solution fixture 3 is put into water, the cooling water can enter between the heads through the gap, so that the heads can be fully in contact with the cooling water, thereby increasing the cooling rate of the heads. A high cooling rate will accelerate the phase change, increase the amount of austenite generated, and reduce the ferrite content, thereby further reducing the ferrite content in the heads. Furthermore, by setting the above-mentioned solid solution fixture 3, the number of heads that can be loaded into each heating furnace at one time is increased, saving costs and improving efficiency.

[0031] It should be noted that an isolation block 4 is also provided between the flat sheet portion 2 of the bottommost head and the support tube 32 to ensure that cooling water can enter the support tube 32 so as to immerse the bottommost head in the cooling water.

[0032] As a preferred embodiment, the isolation block 4 is an arc-shaped block, and the inner diameter of the arc-shaped block is the same as the inner diameter of the support tube 32. During installation, the inner and outer arc-shaped side walls of the arc-shaped block are ensured to be coplanar with the inner and outer side walls of the support tube 32, respectively, to ensure the consistency of stacking. Moreover, under the action of the gravity of the head itself, the squeezing and fixing effect on the lower head is achieved. At the same time, a plurality of isolation blocks 4 are arranged between each two adjacent flat sheet parts 2, and the plurality of isolation blocks 4 are evenly arranged along the circumference of the flat sheet part 2 to ensure that the force at each location of the flat sheet part 2 is balanced and prevent the flat sheet part 2 from being severely deformed. In addition, the material of the isolation block 4 is the same as that of the head to ensure that the isolation block 4 has the same heat treatment performance during heating and cooling.

[0033] In the present invention, the head is fixed and isolated from each other by the cooperation between the head structure (flat sheet portion 2) and the isolation block 4, without the need to set other fixing structures. The operation is simple and convenient, and the work efficiency is greatly improved.

[0034] The solid solution tooling 3 also includes a lifting plate 33 and a sling 34. There are more than three slings 34, which are evenly arranged along the circumference of the support tube 32. The lower end of the sling 34 is fixedly connected to the outer wall of the support tube 32, and the upper end of the sling 34 is fixedly connected to the lifting plate 33. The lifting plate 33 is used to connect to the crane. In this way, the solid solution tooling 3 carrying the head can be moved into or out of the cooling water pool by lifting the crane.

[0035] Step S50: secondary cold stamping. The end cap may be partially deformed after solution treatment. After surface cleaning, secondary cold stamping is performed until the target depth is 630±10 mm. In this process, the deformation of the end cap caused by high temperature can be corrected.

[0036] Step S60: plasma beveling. The flat sheet 2 is beveled to remove the excess at the end cap port to obtain the reasonable arc length required by the product. In the solution treatment stage, the relatively large flat sheet 2 can ensure that it has a sufficiently large contact area with the isolation block 4, which is conducive to stably installing the end cap on the solution tooling. After the secondary cold stamping, the excess part on the flat sheet 2 is removed, which reduces the amount of spinning in the subsequent process, thereby helping to reduce the ferrite content.

[0037] Step S70: Spinning. The end cap is mounted on a spinning machine, and the flat sheet portion 2 is spun into a straight edge by the extrusion of the inner and outer wheels. Thus, the end cap processing is completed.

[0038] The head processing method capable of reducing the ferrite content of the present invention successively performs one cold stamping and two cold stamping, and compared with one direct stamping, the depth of each stamping is reduced, and the ferrite content can be effectively reduced. At the same time, after the first cold stamping, a solid solution treatment is used to accelerate the phase change, increase the amount of austenite generated, and reduce the ferrite content, thereby further reducing the ferrite content in the head, and the processing requirement of ferrite ≤ 12% can be met. It is easy to process, has low production difficulty, and high production efficiency. In addition, by beveling the excess of the flat sheet part 2, the amount of spinning is reduced, which is also conducive to reducing the ferrite content.

[0039] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the scope of the present invention through the above description. The technical scope of this invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for processing a head capable of reducing ferrite content, comprising the following steps: S10: Cutting the stainless steel sheet into discs; S20: a cold stamping operation, wherein a stamping machine is used to stamp the disc to preliminarily form a head. The preliminarily formed head comprises a concave portion and a flat portion located around the concave portion, and the flat portion is in a circular ring structure. S30: Pickling: evenly apply the pickling liquid on the surface of the head to remove the oxide layer, oil and rust; S40: solution treatment, fixing the pickled heads on the solution fixture, putting the solution fixture into a heating furnace for heating, and then putting it into a cooling water pool for cooling, the solution fixture includes a support plate and a support cylinder fixedly mounted on the support plate, the heads are stacked on top of the support cylinder, and the flat sheet parts between each two adjacent heads are padded with isolation blocks; S50: secondary cold stamping, stamping the head after solution treatment to the target depth; S60: plasma beveling to remove the excess of the flat sheet portion; S70: Spinning, spinning the flat sheet portion into a straight edge by a spinning machine.

2. The head processing method capable of reducing ferrite content according to claim 1, characterized in that: In step S40, a plurality of isolation blocks are disposed between every two adjacent flat sheet portions, and the plurality of isolation blocks are evenly disposed along the circumference of the flat sheet portion.

3. The method for processing a head capable of reducing ferrite content according to claim 2, characterized in that: The isolation block is an arc block, the support tube is a hollow cylindrical structure, the inner diameter of the arc block is the same as the inner diameter of the support tube, and when installed, the inner and outer arc side walls of the arc block are coplanar with the inner and outer side walls of the support tube.

4. The head processing method capable of reducing ferrite content according to claim 1, characterized in that: The material of the isolation block is the same as that of the end cap.

5. The head processing method capable of reducing ferrite content according to claim 1, characterized in that: In step S40, an isolation block is provided between the flat sheet portion of the bottommost end cover and the support tube.

6. The method for processing a head capable of reducing ferrite content according to any one of claims 1 to 5, characterized in that: The solid solution tooling also includes a lifting plate and a sling. There are more than three slings, which are evenly arranged along the circumference of the support tube. The lower end of the sling is fixedly connected to the outer wall of the support tube, and the upper end of the sling is fixedly connected to the lifting plate. The lifting plate is used to connect to the crane.

7. The method for processing a head capable of reducing ferrite content according to claim 1, characterized in that: The stamping depth of the first cold stamping is controlled within the range of 600±10mm, and the second cold stamping is stamped to a target depth of 630±10mm.

Images