Stainless steel coil surface defect grinding process

Abstract

The invention discloses a stainless steel coil surface defect grinding process which is characterized in that a grinding machine adopts six grinding heads, the six grinding heads are consistent in structure, each grinding head comprises a tension roller, a working roller, a grinding belt, a supporting roller, a first guide roller and a second guide roller, and grinding materials on the grinding belts are made of fused alumina zirconia materials; the grinding belt is tensioned on the tension roller and the working roller, the supporting roller is located below the working roller, and a gap allowing a stainless steel coil to pass through is formed between the grinding belt on the working roller and the supporting roller; the area where the tension roller, the working roller, the grinding belt and the supporting roller are located is a grinding area, and the first guide roller is located in front of the grinding area and makes contact with the upper surface of a stainless steel coil entering the grinding machine; the second guide roller is located behind the grinding area and makes contact with the upper surface of the stainless steel coil entering the grinding machine. And by adopting a high-strength grinding mode, the feeding and discharging times can be reduced, the grinding quality can be improved, the energy consumption can be reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel coil processing, and in particular to a stainless steel coil surface defect grinding process. Background Art

[0002] The process flow of stainless steel coil grinding line is: uncoiling → straightening → front scissors → welding machine → grinding machine → rear scissors → winding, such as Figure 1 The grinder has 6 grinding heads, each of which adopts a top grinding method to grind the upper surface of the stainless steel coil. The abrasive on the grinding belt in each grinding head is made of ceramic material. The first grinding depth of the stainless steel coil by the grinder is usually 20-30 μm, while the depth of the surface defects of the stainless steel coil is usually 60-70 μm. Generally, defects occur on both sides. In order to eliminate the upper and lower surface defects of the stainless steel coil, the material needs to be loaded and unloaded at least 6 times for 300 series steel, and at least 8 times for 400 series steel. Frequent loading and unloading can easily affect the grinding accuracy, and the reliability and consistency of grinding are difficult to guarantee. In addition, the grinding efficiency is low, the energy consumption is large, and the cost is greatly increased. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a stainless steel coil surface defect grinding process with high-intensity grinding ability, thereby reducing the number of loading and unloading times.

[0004] In view of the problem of frequent loading and unloading of stainless steel coils in current grinding lines, the present invention provides a high-intensity grinding method, which can effectively reduce the loading and unloading times of stainless steel coils, shorten processing time, improve grinding efficiency, and reduce energy consumption and costs.

[0005] The specific plan is as follows: The surface defect grinding process of a stainless steel coil described in the present invention has the same process flow as the original one, namely: uncoiling → straightening → front scissors → welding machine → grinder → rear scissors → winding; the grinding head of the grinder is also the same, and 6 grinding heads are also used, namely: No. 1 grinding head, No. 2 grinding head, No. 3 grinding head, No. 4 grinding head, No. 5 grinding head and No. 6 grinding head.

[0006] The structures of the six grinding heads on the grinding machine are consistent, including: tension roller, working roller, grinding belt, support roller, first guide roller and second guide roller. The grinding belt is tensioned on the tension roller and the working roller. The support roller is located below the working roller, and there is a gap between the grinding belt and the support roller on the working roller for the stainless steel coil to pass through. The area where the tension roller, working roller, grinding belt and support roller are located is the grinding area. The first guide roller is located in front of the grinding area and contacts the upper surface of the stainless steel coil entering the grinding machine. The second guide roller is located behind the grinding area and contacts the upper surface of the stainless steel coil entering the grinding machine. The difference is that the abrasive on the grinding belt is made of zirconium corundum. The abrasive made of zirconium corundum has high grinding ability and can grind up to 35-40μm at a time. Compared with abrasives such as zirconium dioxide and ceramics, which can grind up only 20-30μm at a time, the grinding ability has been significantly improved.

[0007] High-intensity grinding mainly depends on the cutting force of the grinding belt. The abrasives on the grinding belts currently used are all made of ceramic materials, which are obtained by forming and high-temperature sintering after the aluminum and zirconium synthetic compounds are formed. The grain size is small, usually in the micron or submicron level, and the grinding depth is small. The maximum single grinding depth is about 20 to 30 μm, and the grinding ability is poor. Some grinding belts also use zirconium dioxide, and the maximum single grinding depth of zirconium dioxide is about 20 to 30 μm, and the grinding ability is also relatively poor. The present invention replaces the abrasive on the grinding belt with zirconium corundum material. Zirconium corundum is obtained by electric melting, cooling crystallization, and crushing. The grains are coarse and the Mohs hardness is 9.4. The cutting ability of one feeding, that is, the grinding ability is increased to 35 to 40 μm, and the grinding ability is strong.

[0008] The particle size of the zirconium corundum abrasive in the present invention is preferably 40 mesh.

[0009] by Figure 1 and Figure 2 From the direction shown in Figure 1 The left-hand direction is defined as "left", Figure 1 The right-hand direction is defined as "right", then Figure 2 The left-hand direction is also "left", Figure 2 The right-hand side direction is also "right", so the moving direction of the unfolded stainless steel coil is from right to left. The grinding belt in the grinding head rotates clockwise, which means that the grinding direction of the grinding head is the same as the moving direction of the stainless steel coil entering the grinder. The grinding belt in the grinding head rotates counterclockwise, which means that the grinding direction of the grinding head is opposite to the moving direction of the stainless steel coil entering the grinder.

[0010] Taking into account that the counterclockwise grinding cutting force of the grinding head is stronger than the clockwise grinding cutting force, and combined with the grinding requirements, when the grinder grinds the stainless steel coil, the grinding direction of each grinding head is set as follows: the grinding direction of grinding head No. 3, grinding head No. 4, grinding head No. 5, and grinding head No. 6 are the same as the movement direction of the stainless steel coil entering the grinder, and the grinding direction of grinding head No. 1 and grinding head No. 2 are opposite to the movement direction of the stainless steel coil entering the grinder.

[0011] The grinder feeds and grinds the front side of the unfolded stainless steel coil n times to grind away the surface defects on the front side of the stainless steel coil; the grinder feeds and grinds the back side of the unfolded stainless steel coil n times to grind away the surface defects on the back side of the stainless steel coil; n is 2 to 3 times; The stainless steel coil after being unrolled is first fed and ground, and the grinding amount after being ground by the six grinding heads in the grinder is the first grinding depth ap1, and ap1 is 35-40 μm; The stainless steel coil after unwinding is fed and ground for the second time, and the grinding amount after grinding by the six grinding heads in the grinder is the second grinding depth ap2, and ap2 is 25-30 μm; The stainless steel coil after being unrolled is fed and ground for the third time, and the grinding amount after being ground by the six grinding heads in the grinder is the third grinding depth ap3, and ap3 is 10-15 μm.

[0012] The increase of grinding cutting force leads to an increase of the motor current driving the grinding belt. In order to withstand high pressure support, the support roller of the present invention is made of chromium-molybdenum-iron material, and a chrome-plated layer is plated on the surface of the support roller to further improve the hardness and wear resistance of the support roller, so as to prevent the occurrence of defects such as indentation and friction marks caused by insufficient hardness and wear resistance of the support roller due to large vibration. The thickness of the chrome-plated layer is 0.05-0.1mm.

[0013] Furthermore, in the aforementioned stainless steel coil surface defect grinding process, the moving speed of the stainless steel coil set by the grinder during grinding is 5 to 20 m / min; the rotation speed of the grinding belt in each grinding head in the grinder during grinding is 1200±50 rpm / min; the grinding angle of the stainless steel coil set by the grinder during grinding is 10 to 13°.

[0014] When the stainless steel coil is loaded into the grinder, the tension of the stainless steel coil is maintained by the first guide roller and the second guide roller. The acute angle formed between the stainless steel coil in contact with the first guide roller and the horizontal plane is the grinding angle. The grinding angle is adjusted according to the type of steel. The grinding angle of 300 series stainless steel is 13°, and the grinding angle of 400 series stainless steel is 10°.

[0015] The increase in grinding cutting force leads to an increase in the load of the motor driving the grinding belt. In order to control heat, the motor brake in the grinding machine of the present invention adopts a pneumatic brake to prevent overheating and fire.

[0016] The grinder is equipped with a self-circulating coolant system and a coolant wiper. For the convenience of description, the present invention simply refers to the self-circulating coolant system as the cooling system. In order to better wash the metal chips and cool the grinding part of the stainless steel coil, the present invention makes the following adjustments to the groove depth, groove width, tooth width and hardness of each working roll: The groove depth of the working rollers in the two grinding heads, namely the No. 1 grinding head and the No. 2 grinding head, are both 12±0.2mm, the groove width is 23±0.2mm, the tooth width is 17±0.2mm, and the hardness is 75~80HS; the groove depth of the working rollers in the four grinding heads, namely the No. 3 grinding head, the No. 4 grinding head, the No. 5 grinding head and the No. 6 grinding head, are both 12±0.2mm, the groove width is 15±0.2mm, the tooth width is 14±0.2mm, and the hardness is 60~65HS.

[0017] In order to absorb the heat generated during grinding and flush the ground metal chips, the spraying speed of the coolant in the cooling system during grinding is 800±10L / min.

[0018] The cooling system of the grinder is a self-circulating closed system. Each filter bag is immersed in a cooling tank. Its main function is to isolate metal chips. When the cooling system is working, the coolant is pumped from each filter bag through a pump. The coolant is sprayed toward the grinding area and then flows back to the cooling tank together with the metal chips. In actual use, as the grinding time increases, the metal chips in the cooling tank increase. When there are too many metal chips, they will be adsorbed on the surface of each filter bag, which will affect the supply of coolant, and then affect the cooling and flushing effect of the metal chips during grinding. It is easy to cause a fire due to the excessive grinding heat and the lack of effective cooling.

[0019] In order to keep the surface of each filter bag clean, the present invention provides an anti-adsorption device at each filter bag in the cooling system of the grinder to prevent impurities in the coolant from being adsorbed on each filter bag.

[0020] The structure of the anti-adsorption device described in the present invention is as follows: a compressed air branch pipe is arranged between each pair of adjacent filter bags, and the inlet of each compressed air branch pipe is connected to the compressed air main pipe; when the anti-adsorption device is working, compressed air is continuously introduced into the compressed air main pipe, and each compressed air is branched to each compressed air branch pipe, and is blown outward through the outlet of each compressed air branch pipe to form a vortex in the coolant.

[0021] Wherein, the pressure of the compressed air is 0.4-0.8Mpa; and the diameter of each compressed air branch pipe is 25mm.

[0022] The beneficial effects of the present invention are as follows: the use of high-intensity grinding method can reduce the number of loading and unloading times, which can not only improve the reliability and consistency of grinding, improve the grinding quality, but also reduce energy consumption (consumption of electricity, compressed air, etc.) and auxiliary consumption (consumption of coolant), reduce energy waste, and can also improve production efficiency, reduce costs, and enhance production potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the process flow of the grinding line for stainless steel coils.

[0024] Figure 2 It is a working principle diagram of a grinding head in a stainless steel coil surface defect grinding process described in the present invention.

[0025] Figure 3 It is a partial structural schematic diagram of a working roll in a stainless steel coil surface defect grinding process described in the present invention.

[0026] Figure 4 It is a structural schematic diagram of an anti-adsorption device being arranged at each filter bag in a stainless steel coil surface defect grinding process described in the present invention.

[0027] in: 1. Uncoiling; 2. Cooling system; 3. Front scissors; 4. Welding machine; 5. Grinding machine; 6. Rear scissors; 7. Rewinding; 8. Grinding head No. 1; 9. Grinding head No. 2; 10. Grinding head No. 3; 11. Grinding head No. 4; 12. Grinding head No. 5; 13. Grinding head No. 6; 14. Tension roller; 15. Working roller; 16. Grinding belt; 17. Support roller; 18. First guide roller; 19. Second guide roller; 20. Strip steel; 21. Groove; 22. Teeth; 23. Filter bag; 24. Compressed air branch pipe; 25. Compressed air main pipe. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0029] The present invention provides a stainless steel coil surface defect grinding process, such as Figure 1 As shown, the process flow is: uncoiling 1→straightening 2→front scissors 3→welding machine 4→grinder 5→rear scissors 6→coiling 7.

[0030] When stainless steel coils are pickled, the coils are generally less than 30 tons, and manual inspection is carried out online. In order to prevent omissions in manual inspection, SDD is assisted to cooperate with the strip surface defect inspection to ensure that the surface quality of the strip meets customer requirements. The inspector will record the inspection results of each coil in the MES system, and the record content includes coil number, specification, steel type, surface quality, etc. For strips with defects such as steelmaking cracks, hot rolling line defects, scratches caused by scraping equipment, rough plate surface, plate surface stripes, etc. found by manual or SDD inspection, the inspector will go to the grinding production line for surface defect grinding according to the inspection benchmark. Because there are many stainless steel coils that need to be ground, the stainless steel coils that need to be ground are first stored in the warehouse and given a location code. The grinding line also has an MES system. The operator of the grinding line goes to the warehouse to find the coil number of the MES system and uses the crane to lift the stainless steel coil to the surface defect grinding production line. The number of loading and unloading is determined according to the quality.

[0031] The above process flow is a mature process flow on the market. The improvement of the present invention lies in the grinder 5. The rest of the unwinding 1, straightening 2, front scissors 3, welding machine 4, rear scissors 6 and winding 7 maintain the original process unchanged.

[0032] The grinder 5 described in the present invention adopts 6 grinding heads, each of which adopts a top grinding method for grinding the upper surface of the stainless steel coil. For the convenience of description, the 6 grinding heads are defined as: No. 1 grinding head 8, No. 2 grinding head 9, No. 3 grinding head 10, No. 4 grinding head 11, No. 5 grinding head 12 and No. 6 grinding head 13.

[0033] The structures of the six grinding heads on the grinding machine 5 are all the same. Figure 2 As shown, they all include: a tension roller 14, a working roller 15, a grinding belt 16, a support roller 17, a first guide roller 18 and a second guide roller 19. The grinding belt 16 is stretched on the tension roller 14 and the working roller 15. The support roller 17 is located below the working roller 15. There is a gap between the grinding belt 16 and the support roller 17 on the working roller 15 for the stainless steel coil to pass through. The gap is where the grinding belt 16 grinds the unfolded stainless steel coil. The unfolded stainless steel coil is called strip steel 20. The area where the tension roller 14, the working roller 15, the grinding belt 16 and the support roller 17 are located is the grinding area. The first guide roller 18 is located in front of the grinding area and contacts the upper surface of the strip steel 20 entering the grinder 5; the second guide roller 19 is located behind the grinding area and contacts the upper surface of the strip steel 20 entering the grinder 5. The abrasive on the grinding belt 16 is made of zirconium corundum.

[0034] The present invention replaces the ceramic abrasive on the original grinding belt 16 with zirconium corundum abrasive, which is obtained by electric melting, cooling crystallization, and crushing. The grains are coarse, the Mohs hardness is 9.4, and the single grinding capacity is increased to 35-40 μm. Compared with the ceramic abrasive and zirconium dioxide with a single grinding depth of about 20-30 μm, the grinding capacity of zirconium corundum abrasive is stronger. In this embodiment, the particle size of the zirconium corundum abrasive is preferably 40 meshes.

[0035] Considering that the counterclockwise grinding cutting force of the grinding head is stronger than the clockwise grinding cutting force, and combined with the grinding requirements, a more preferred solution is to set the grinding direction of each grinding head as follows when the grinder 5 grinds the strip steel 20: The grinding directions of the No. 1 grinding head 8 and the No. 2 grinding head 9 are opposite to the movement direction of the steel strip 20 entering the grinder 5, that is, they rotate counterclockwise. Since the counterclockwise direction mainly has strong grinding and cutting ability, but heavy grinding marks, the stainless steel surface is not beautiful, and it is not conducive to subsequent processing, the grinding directions of the No. 3 grinding head 10, the No. 4 grinding head 11, the No. 5 grinding head 12 and the No. 6 grinding head 13 are all the same as the movement direction of the steel strip 20 entering the grinder 5, that is, they all rotate clockwise; the clockwise direction mainly grinds the grinding marks to obtain good glossiness.

[0036] The grinder feeds and grinds the front side of the unfolded steel strip 20 n times to grind away the surface defects on the front side of the steel strip 20; the grinder feeds and grinds the back side of the unfolded steel strip 20 n times to grind away the surface defects on the back side of the steel strip 20; n is 2 to 3 times. The number of grinding times is determined according to the specific stainless steel grade. For example, a surface of the 300 series only needs to be grinded twice to grind away the surface defects on the surface, while a surface of the 400 series needs to be grinded three times to grind away the surface defects on the surface, as shown in Table 1. The process of grinding away the surface defects on the front and back sides of the steel strip 20 belongs to the category of rough processing, and then multiple processes such as semi-finishing, finishing, polishing, etc. are selected for superimposed processing according to actual processing requirements.

[0037] The strip steel 20 is first fed and ground, and the grinding amount after being ground by the six grinding heads in the grinder is the first grinding depth ap1, and ap1 is 35-40 μm; The strip steel 20 is fed and ground for the second time, and the grinding amount after grinding by the six grinding heads in the grinding machine is the second grinding depth ap2, and ap2 is 25-30 μm; The strip steel 20 is fed and ground for the third time, and the grinding amount after being ground by the six grinding heads in the grinder is the third grinding depth ap3, and ap3 is 10-15 μm.

[0038] The increase of grinding cutting force leads to the increase of the motor current driving the grinding belt 16. In order to withstand high pressure support, the support roller 17 of the present invention is made of chromium-molybdenum-iron material, and a chrome-plated layer is plated on the surface of the support roller 17 to further improve the hardness and wear resistance of the support roller 17, so as to prevent the occurrence of defects such as indentation and friction marks caused by insufficient hardness and wear resistance of the support roller 17 due to large vibration. The thickness of the chrome-plated layer is preferably 0.05-0.1 mm.

[0039] The moving speed of the steel strip 20 set by the grinder 5 during grinding is 5-20 m / min. The grinding depth is generally measured at a moving speed of 5 m / min for the steel strip 20. The grinding depths corresponding to different moving speeds of the steel strip 20 are also different. The greater the moving speed of the steel strip 20, the smaller the grinding depth. The rotation speed of the grinding belt in each grinding head of the grinder 5 during grinding is 1200±50 rpm / min.

[0040] When the steel strip 20 is loaded into the grinder 5, the tension of the steel strip 20 is maintained by the first guide roller 18 and the second guide roller 19. The acute angle formed between the steel strip 20 in contact with the first guide roller 18 and the horizontal plane is the grinding angle α. The grinding angle α is adjusted according to the type of steel. The grinding angle α of the steel strip 20 set by the grinder 5 during grinding is 10 to 13°.

[0041] Table 1. Grinding parameters of two stainless steel grades Stainless steel grades 300 series 400 series Grinding Angle 13° 10° Grinding times and grinding depth Load the material on the front side twice: the grinding depth of the first loading is 40 microns; the grinding depth of the second loading is 30 microns. Load the material on the back side twice: the grinding depth of the first loading is 40 microns; the grinding depth of the second loading is 30 microns. Load the material on the front side 3 times: the grinding depth of the first loading is 35 microns; the grinding depth of the second loading is 25 microns; the grinding depth of the third loading is 10 microns. Load the material on the back side 3 times: the grinding depth of the first loading is 35 microns; the grinding depth of the second loading is 25 microns; the grinding depth of the third loading is 10 microns. Strip moving speed (m / min) 5 5 Grinding belt rotation speed 1200 1200 The increase of grinding cutting force leads to an increase of the load of the motor driving the grinding belt 16. In order to control heat, the motor brake in the grinding machine 5 of the present invention adopts a pneumatic brake to prevent overheating and fire.

[0042] The grinding machine 5 is equipped with a cooling liquid self-circulating system and a cooling liquid wiper. For the convenience of description, the present invention will refer to the cooling liquid self-circulating system as the cooling system 2. In order to better wash the metal chips and the strip steel 20 grinding place for cooling, such as Figure 3 As shown, the present invention defines the parameters of the groove 21 and the tooth 22 in each working roll 15, and the groove depth, groove width, tooth width and hardness are adjusted as follows: The No. 1 grinding head 8 and the No. 2 grinding head 9 have strong grinding and cutting capabilities, so the corresponding metal chips will be slightly coarser. Taking into account the chip removal capacity and the load-bearing support capacity, the groove depth of the working roller 15 in the No. 1 grinding head 8 and the No. 2 grinding head 9 is 12±0.2mm, the groove width is 23±0.2mm, the tooth width is 17±0.2mm, and the hardness is 75~80HS.

[0043] The No. 3 grinding head 10, the No. 4 grinding head 11, the No. 5 grinding head 12 and the No. 6 grinding head 13 are mainly used to grind the grinding marks to obtain good glossiness. The corresponding metal chips produced are much finer than the metal chips produced by the No. 1 grinding head 8 and the No. 2 grinding head 9. Therefore, the groove depth of the working roller 15 in the four grinding heads of No. 3 grinding head 10, No. 4 grinding head 11, No. 5 grinding head 12 and No. 6 grinding head 13 is 12±0.2mm, the groove width is 15±0.2mm, the tooth width is 14±0.2mm, and the hardness is 60~65HS.

[0044] In order to absorb the heat generated during grinding and flush the ground metal chips, the spraying speed of the coolant in the cooling system 2 during grinding is 800±10 L / min.

[0045] The cooling system 2 of the grinder 5 is a self-circulating closed system. Each filter bag 23 is immersed in a cooling tank, and its main function is to isolate metal chips. When the cooling system is working, a pump extracts coolant from each filter bag 23, and the coolant is sprayed toward the grinding area for flushing and then flows back into the cooling tank together with the metal chips. In actual use, as the grinding time increases, more and more metal chips are in the cooling tank. When there are too many metal chips, they will be adsorbed on the surface of each filter bag 23, which is easy to block the liquid suction port, which will affect the supply of coolant, and then affect the cooling and flushing effect of the metal chips during grinding of the grinder 5, and it is easy to cause a fire due to the excessive grinding heat and the lack of effective cooling.

[0046] In order to keep the surface of each filter bag 23 clean, the present invention provides an anti-adsorption device at each filter bag 23 in the cooling system 2 of the grinder 5 to prevent impurities in the coolant from being adsorbed on each filter bag 23 .

[0047] like Figure 4 As shown in the figure, the structure of the anti-adsorption device in this embodiment is as follows: a compressed air branch pipe 24 is provided between each of the two adjacent filter bags 23, and the inlet of each compressed air branch pipe 24 is connected to the compressed air main pipe 25. When the anti-adsorption device is working, compressed air is continuously introduced into the compressed air main pipe 25, and each compressed air is branched to each compressed air branch pipe 24, and is blown outward through the outlet of each compressed air branch pipe 24, forming a vortex in the coolant, so that metal chips are not easily adsorbed on each filter bag 23.

[0048] The pressure of the compressed air is 0.4-0.8 MPa, and the diameter of each compressed air branch pipe 24 is 25 mm. In addition, the compressed air branch pipe 24 and the compressed air main pipe 25 are usually made of PP material.

[0049] The advantages of the present invention are: the use of high-intensity grinding method can reduce the number of loading and unloading times, which can not only improve the reliability and consistency of grinding, improve the grinding quality, but also reduce energy consumption (consumption of electricity, compressed air, etc.) and auxiliary consumption (consumption of coolant), reduce waste, and can also improve production efficiency and enhance production potential.

[0050] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A stainless steel coil surface defect grinding process, the process flow is: uncoiling → straightening → front scissors → welding machine → grinding machine → rear scissors → winding; characterized by: The grinding machine uses 6 grinding heads, namely: grinding head No. 1, grinding head No. 2, grinding head No. 3, grinding head No. 4, grinding head No. 5 and grinding head No. 6; The structures of the six grinding heads on the grinding machine are all the same, and all include: a tension roller, a working roller, a grinding belt, a support roller, a first guide roller and a second guide roller. The abrasive on the grinding belt is made of zirconium corundum; the grinding belt is tensioned on the tension roller and the working roller, the support roller is located below the working roller, and there is a gap between the grinding belt on the working roller and the support roller for the stainless steel coil to pass through after being unfolded; the area where the tension roller, the working roller, the grinding belt and the support roller are located is the grinding area, the first guide roller is located in front of the grinding area and contacts the upper surface of the stainless steel coil entering the grinding machine; the second guide roller is located behind the grinding area and contacts the upper surface of the stainless steel coil entering the grinding machine; When the grinder grinds the unrolled stainless steel coil, the grinding directions of the No. 3 grinding head, the No. 4 grinding head, the No. 5 grinding head and the No. 6 grinding head are all the same as the moving direction of the stainless steel coil entering the grinder, and the grinding directions of the No. 1 grinding head and the No. 2 grinding head are all opposite to the moving direction of the stainless steel coil entering the grinder; The grinder feeds and grinds the front side of the unfolded stainless steel coil n times to grind away the surface defects on the front side of the stainless steel coil; the grinder feeds and grinds the back side of the unfolded stainless steel coil n times to grind away the surface defects on the back side of the stainless steel coil; n is 2 to 3 times; The stainless steel coil after being unrolled is first fed and ground, and the grinding amount after being ground by the six grinding heads in the grinder is the first grinding depth ap1, and ap1 is 35-40 μm; The stainless steel coil after unwinding is fed and ground for the second time, and the grinding amount after grinding by the six grinding heads in the grinder is the second grinding depth ap2, and ap2 is 25-30 μm; The stainless steel coil after being unrolled is fed and ground for the third time, and the grinding amount after being ground by the six grinding heads in the grinder is the third grinding depth ap3, and ap3 is 10-15 μm.

2. A stainless steel coil surface defect grinding process according to claim 1, characterized in that: The particle size of the zirconium corundum abrasive is 40 meshes and the Mohs hardness is 9.

4.

3. The stainless steel coil surface defect grinding process according to claim 1, characterized in that: The support roller is made of chromium-molybdenum-iron, and a chrome-plated layer is plated on the surface of the support roller. The thickness of the chrome-plated layer is 0.05-0.1 mm.

4. A stainless steel coil surface defect grinding process according to claim 1, 2 or 3, characterized in that: The moving speed of the stainless steel coil set by the grinder during grinding is 5 to 20 m / min; the rotation speed of the grinding belt in each grinding head in the grinder during grinding is 1200±50 rpm / min; the grinding angle of the stainless steel coil set by the grinder during grinding is 10 to 13°.

5. A stainless steel coil surface defect grinding process according to claim 4, characterized in that: The motor brake in the grinding machine adopts a pneumatic brake.

6. The stainless steel coil surface defect grinding process according to claim 1, characterized in that: The groove depth of the working rolls in the No. 1 grinding head and the No. 2 grinding head is 12±0.2mm, the groove width is 23±0.2mm, the tooth width is 17±0.2mm, and the hardness is 75-80HS; The groove depth of the working rolls in the four grinding heads, namely, the No. 3 grinding head, the No. 4 grinding head, the No. 5 grinding head and the No. 6 grinding head, are all 12±0.2mm, the groove width is all 15±0.2mm, the tooth width is all 14±0.2mm, and the hardness is all 60-65HS.

7. A stainless steel coil surface defect grinding process according to claim 1 or 6, characterized in that: The spraying rate of the coolant in the grinder during grinding is 800±10 L / min.

8. The stainless steel coil surface defect grinding process according to claim 1, characterized in that: An anti-adsorption device is provided at each filter bag in the cooling system of the grinding machine to prevent impurities in the coolant from being adsorbed on each filter bag; The structure of the anti-adsorption device is as follows: a compressed air branch pipe is arranged between each pair of adjacent filter bags, and the inlet of each compressed air branch pipe is connected to the compressed air main pipe; when the anti-adsorption device is working, compressed air is continuously introduced into the compressed air main pipe, and each compressed air is branched to each compressed air branch pipe, and is blown outward through the outlet of each compressed air branch pipe to form a vortex in the coolant.

9. A stainless steel coil surface defect grinding process according to claim 8, characterized in that: The pressure of the compressed air is 0.4-0.8Mpa; the diameter of each compressed air branch pipe is 25mm.

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