Method for simulating stainless steel and carbon steel composite rolling

Abstract

The invention relates to a method for simulating stainless steel and carbon steel composite rolling, and belongs to the technical field of composite rolling in the metallurgical industry. According to the technical scheme, stainless steel and carbon steel are machined into cylinders with the same diameter, and the carbon steel, the stainless steel and the carbon steel are combined together in an up-and-down arrangement mode; and mounting the assembly on a thermal simulation testing machine, vacuumizing, introducing argon for protection, heating to a test temperature according to a heating schedule, carrying out compression deformation, compressing two sections of carbon steel and one section of stainless steel together, carrying out air cooling, and taking out a sample. The method has the beneficial effects that a composite rolling process can be simulated on a thermal simulation testing machine, the structure bonding condition of a transition layer is observed by utilizing a scanning electron microscope, and the shearing strength is measured by utilizing an electronic tensile testing machine, so that the bonding condition of stainless steel and carbon steel after rolling is intuitively reflected.

Description

Technical Field

[0001] The invention relates to a method for simulating composite rolling of stainless steel and carbon steel, belonging to the technical field of composite rolling in the metallurgical industry. Background Art

[0002] In order to improve the corrosion resistance of carbon steel products, cladding stainless steel sheets on carbon steel is the current mainstream technology. In order to study the organizational properties of the bonding layer during composite rolling of stainless steel and carbon steel, provide technical support for production, and avoid waste of resources caused by improper production, it is necessary to develop a method to simulate the composite rolling of stainless steel and carbon steel, simulate the composite rolling process, and comprehensively evaluate the organization and bonding strength of the bonding layer. Summary of the invention

[0003] The purpose of the present invention is to provide a method for simulating the composite rolling of stainless steel and carbon steel, which can simulate the composite rolling process on a thermal simulation testing machine, observe the bonding of the transition layer structure using a scanning electron microscope, and measure the shear strength using an electronic tensile testing machine to intuitively reflect the bonding condition of stainless steel and carbon steel after rolling, thereby solving the problems existing in the background technology.

[0004] The technical solution of the present invention is: A method for simulating stainless steel and carbon steel composite rolling is performed according to the following steps: ①Simulated rolling assembly: First, stainless steel and carbon steel are processed into cylinders with the same diameter, with stainless steel as one section and carbon steel as two sections. Then, carbon steel, stainless steel, and carbon steel are assembled together in an upper and lower arrangement. ② Simulate high temperature rolling process: install the above-mentioned billet on the thermal simulation test machine, evacuate the vacuum, introduce argon protection, heat it to the test temperature according to the heating system, perform compression deformation, compress two sections of carbon steel and one section of stainless steel together, and then take out the sample after air cooling; ③ Observation of transition layer structure: Cut the sample after compression deformation into metallographic samples from the middle, and observe the grain bonding of the transition layer and the diffusion of Cr atoms after grinding and corrosion; ④ Transition layer bonding strength test: The compressed and deformed sample is processed into a cylinder of a certain diameter and installed on an electronic tensile testing machine. The sample is subjected to a shear test at a constant rate to reflect the bonding condition of stainless steel and carbon steel after rolling through the shear strength.

[0005] In the step ①, the length of the carbon steel is 5mm-15mm, and the length of the stainless steel is 3mm-7mmmm.

[0006] The diameter of the carbon steel and stainless steel is 10 mm.

[0007] In the step ②, the heating system is: heating to a certain temperature at a constant speed and then keeping the temperature, keeping the temperature for a period of time, cooling to a certain temperature at a constant speed, and after a period of equalization, compressing and deforming at a constant strain rate.

[0008] The heating system is as follows: heating to 1150-1250°C at a rate of 4.5-5.5°C / s for insulation, after insulation time of 160-200s, cooling to 1050-1150°C at a rate of 4.5-5.5°C / s, averaging temperature for 4-6s, and cooling at a rate of 0.4-0.6s. -1 The compression deformation is carried out at a strain rate of .

[0009] In the step ③, the bonding of the transition layer grains is observed under a scanning electron microscope at a magnification of 2000-5000, and the diffusion of Cr atoms is line scanned in the bonding layer using an energy spectrometer to observe changes in the peak value of the spectrum line.

[0010] In step ④, the size of the transition layer bonding test specimen is: 8mm in diameter, 5mm-15mm in length, and the shear test stress rate is 3N / (mm 2 s -1 )-15N / (mm 2 s -1 ).

[0011] The beneficial effects of the present invention are as follows: the method of the present invention adopts a thermal simulation testing machine to simulate the composite rolling of stainless steel and carbon steel, and can simulate different heating systems and different compression deformation amounts. After the simulated rolling, a scanning electron microscope can be used to observe the bonding condition of the transition layer structure, and an electronic tensile testing machine can be used to measure the shear strength of the bonding layer, thereby solving the problem of waste of resources caused by improper production and providing data support for production. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of a shear clamping device; Figure 2 is a side view of the upper clamping end; Figure 3 This is the organizational structure diagram of the transition layer obtained in Example 1; Figure 4 This is the Cr atomic diffusion diagram of the transition layer obtained in Example 1; In the figure: upper clamping end 1, lower clamping end 2, large groove 3 at the upper clamping end, small groove 4 at the upper clamping end, large groove 5 at the lower clamping end, small groove 6 at the lower clamping end. DETAILED DESCRIPTION

[0013] The present invention will be further described below by way of examples with reference to the accompanying drawings.

[0014] Refer to the attached Figure 1-4, a method for simulating stainless steel and carbon steel composite rolling, is operated according to the following steps ①Simulated rolling assembly: First, stainless steel and carbon steel are processed into cylinders with the same diameter, with stainless steel as one section and carbon steel as two sections. Then, carbon steel, stainless steel, and carbon steel are assembled together in an upper and lower arrangement. ② Simulate high temperature rolling process: install the above-mentioned billet on the thermal simulation test machine, evacuate the vacuum, introduce argon protection, heat it to the test temperature according to the heating system, perform compression deformation, compress two sections of carbon steel and one section of stainless steel together, and then take out the sample after air cooling; ③ Observation of transition layer structure: Cut the sample after compression deformation into metallographic samples from the middle, and observe the grain bonding of the transition layer and the diffusion of Cr atoms after grinding and corrosion; ④ Transition layer bonding strength test: The compressed and deformed sample is processed into a cylinder of a certain diameter and installed on an electronic tensile testing machine. The sample is subjected to a shear test at a constant rate to reflect the bonding condition of stainless steel and carbon steel after rolling through the shear strength.

[0015] In the step ①, the length of the carbon steel is 5mm-15mm, and the length of the stainless steel is 3mm-7mmmm.

[0016] The diameter of the carbon steel and stainless steel is 10 mm.

[0017] In the step ②, the heating system is: heating to a certain temperature at a constant speed and then keeping the temperature, keeping the temperature for a period of time, cooling to a certain temperature at a constant speed, and after a period of equalization, compressing and deforming at a constant strain rate.

[0018] The heating system is as follows: heating to 1150-1250°C at a rate of 4.5-5.5°C / s for insulation, after insulation time of 160-200s, cooling to 1050-1150°C at a rate of 4.5-5.5°C / s, averaging temperature for 4-6s, and cooling at a rate of 0.4-0.6s. -1 The compression deformation is carried out at a strain rate of .

[0019] In the step ③, the bonding of the transition layer grains is observed under a scanning electron microscope at a magnification of 2000-5000, and the diffusion of Cr atoms is line scanned in the bonding layer using an energy spectrometer to observe changes in the peak value of the spectrum line.

[0020] In step ④, the size of the transition layer bonding test specimen is: 8mm in diameter, 5mm-15mm in length, and the shear test stress rate is 3N / (mm 2 s -1 )-15N / (mm 2 s -1 ).

[0021] In this embodiment, refer to the attached Figure 1-4 First, a shearing clamping device is made: the upper part of the upper clamping end 1 of the shearing clamping device is a square cross-section with a size of 10mm×10mm, and the lower part is a rectangular cross-section with a size of 10mm×5mm. There are a circular upper clamping end large groove 3 and an upper clamping end small groove 4 in the middle of the lower part of the upper clamping end 1; the lower part of the lower clamping end 2 is a square cross-section with a size of 10mm×10mm, and the upper part is a rectangular cross-section with a size of 10mm×5mm. There are a circular lower clamping end large groove 5 and a lower clamping end small groove 6 in the middle of the upper part of the lower clamping end 2. The diameter of the upper clamping end large groove 3 and the lower clamping end large groove 5 are 12mm and the depth is 2mm, the diameter of the upper clamping end small groove 4 is 8mm and the depth is 3mm, and the diameter of the lower clamping end small groove 6 is 8mm.

[0022] Select carbon steel and stainless steel with appropriate composition, see the table below, and process the carbon steel into a diameter of 10 mm and a length of 15 mm, and the stainless steel into a diameter of 10 mm and a length of 5 mm. Carbon steel requires 2 sections and stainless steel requires 1 section. After processing, use sandpaper to polish the upper and lower surfaces and sides of the cylinder, wipe each surface with anhydrous ethanol to remove grease and moisture on the surface, and assemble the blank in the form of carbon steel-stainless steel-carbon steel;

[0023] The assembled samples were installed on a thermal simulation test machine, and after vacuuming, argon gas was introduced for protection. The temperature was raised to 1200°C at a rate of 5°C / s for 180s, and then cooled to 1100°C at a rate of 5°C / s. The temperature was averaged for 5s to eliminate the temperature gradient, and then the temperature was kept at 0.5s. -1 The strain rate was 60% compression deformation, and after air cooling, the deformed sample was taken out; The deformed sample was split along the stainless steel and carbon steel in the middle, and the cut middle surface was used as the observation surface. The metallographic sample was inlaid and polished. After grinding, polishing and corrosion, the transition layer composite interface was observed under a scanning electron microscope at a magnification of 2000 times. It was very clear, with only a very small number of oxidized dots scattered around. Figure 3 As shown in the figure, the transition layer is scanned by a scanning electron microscope equipped with an energy spectrometer. The Cr atomic diffusion layer is about 5μm. Figure 4 As shown; The deformed sample was processed into a cylinder with a diameter of 8 mm and a length of 10 mm. The middle of the cylinder was a stainless steel layer. The upper clamping end of the shear clamping device was installed in the upper fixture of the electronic tensile testing machine and clamped. The cylindrical sample was inserted into the bottom of the small groove of the upper clamping end through the small groove of the lower clamping end. The lower clamping end of the shear clamping device was installed in the lower fixture of the electronic tensile testing machine and clamped. The shear test stress rate was constant at 5 N / (mm 2 s -1) A shear test was carried out on the cylindrical sample and the shear strength was 183MPa.

Claims

1. A method for simulating stainless steel and carbon steel composite rolling, characterized in that: Follow the steps below to do this ①Simulated rolling assembly: First, stainless steel and carbon steel are processed into cylinders with the same diameter, with stainless steel as one section and carbon steel as two sections. Then, carbon steel, stainless steel, and carbon steel are assembled together in an upper and lower arrangement. ② Simulate high temperature rolling process: install the above-mentioned billet on the thermal simulation test machine, evacuate the vacuum, introduce argon protection, heat it to the test temperature according to the heating system, perform compression deformation, compress two sections of carbon steel and one section of stainless steel together, and then take out the sample after air cooling; ③ Observation of transition layer structure: Cut the sample after compression deformation into metallographic samples from the middle, and observe the grain bonding of the transition layer and the diffusion of Cr atoms after grinding and corrosion; ④ Transition layer bonding strength test: The compressed and deformed sample is processed into a cylinder of a certain diameter and installed on an electronic tensile testing machine. The sample is subjected to a shear test at a constant rate to reflect the bonding condition of stainless steel and carbon steel after rolling through the shear strength.

2. The method for simulating stainless steel and carbon steel composite rolling according to claim 1, characterized in that: In the step ①, the length of the carbon steel is 5mm-15mm, and the length of the stainless steel is 3mm-7mmmm.

3. The method for simulating stainless steel and carbon steel composite rolling according to claim 2, characterized in that: The diameter of the carbon steel and stainless steel is 10 mm.

4. The method for simulating stainless steel and carbon steel composite rolling according to claim 1, characterized in that: In the step ②, the heating system is: heating to a certain temperature at a constant speed and then keeping the temperature, keeping the temperature for a period of time, cooling to a certain temperature at a constant speed, and after a period of equalization, compressing and deforming at a constant strain rate.

5. The method for simulating stainless steel and carbon steel composite rolling according to claim 4, characterized in that: The heating system is as follows: heating to 1150-1250°C at a rate of 4.5-5.5°C / s for insulation, after insulation time of 160-200s, cooling to 1050-1150°C at a rate of 4.5-5.5°C / s, averaging temperature for 4-6s, and cooling at a rate of 0.4-0.6s. -1 The compression deformation is carried out at a strain rate of .

6. The method for simulating stainless steel and carbon steel composite rolling according to claim 1, characterized in that: In the step ③, the bonding of the transition layer grains is observed at a high magnification of 2000-5000 under a scanning electron microscope, and the diffusion of Cr atoms is line scanned in the bonding layer using an energy spectrometer to observe changes in the peak value of the spectrum line.

7. The method for simulating stainless steel and carbon steel composite rolling according to claim 1, characterized in that: In step ④, the size of the transition layer bonding test specimen is: 8mm in diameter, 5mm-15mm in length, and the shear test stress rate is 3N / (mm 2 s -1 )-15N / (mm 2 s -1 ).

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