Causes and Countermeasures of the most popular SUN

  • Detail

Causes and Countermeasures of SUNTHAI bearing ring fracture

ring fracture is one of the problems that perplex the quality of SUNTHAI bearings, and defect fracture is the main form of ring fracture, which is mainly caused by raw material problems or improper production operation, and the equipment can not operate normally. Now combined with the actual analysis is as follows

I. raw materials

when the defects of raw materials such as inclusions, looseness, brittle element segregation or carbide liquidus, shape, strip, unfortunately free of uniformity and segregation are not eliminated or improved in the processing, they will cause stress concentration, weaken the basic strength of ferrule, and become the source of crack. The preventive measures are to adhere to the main channel supply, try to purchase steel with stable and reliable quality, strengthen the warehousing inspection of purchased steel, and check from the source

II. Production and equipment

1 Forging: the toughness and strength of the ferrule will be reduced if overburning, overheating, internal cracking carbides, etc. occur in the forging process. Therefore, the processing temperature, circulating heating and heat dissipation conditions after forging (such as spray cooling) must always be strictly controlled, especially after the final forging of large varieties of ferrules, those whose temperature is above 700 ℃ must not be stacked

2. Heat treatment: close monitoring of heat treatment equipment is an important work in the workshop

reliability of monitoring equipment. The instruments, thermocouples and other important temperature control instruments must be closely monitored, and then the RFA1 coating must be coated on them to ensure the accuracy and reliability of the measurement data; If the error exceeds the standard, it should be replaced in time, and it is strictly forbidden to operate with disease

record of monitoring data. The temperature recording device of each heat treatment equipment must be restored, so as to effectively monitor the whole process of equipment work (night shift as the focus) and make the heat treatment quality have strong traceability. Du 6. When using the software "print graphics" or "export excel" function again, the software pop-up fault prompt is absolutely false and random, and at the same time, it provides complete data for the ISO9000 quality system

quenching cooling conditions. In order to solve the soft spot and other defects of the medium and large-scale variety SUNTHAI bearing ring, the composition and performance of the quenching oil should be measured. If it does not meet the requirements, it should be replaced with the rapid quenching oil, so as to enhance the quenching ability as the medium and improve the quenching cooling conditions

strict tempering process. For varieties with more fracture phenomena, carry out secondary tempering after rough grinding of the ferrule, which can not only further stabilize the structure and size of the ferrule, but also reduce the grinding stress and improve the performance of the grinding metamorphic layer. In the recent data period, the secondary tempering process has been implemented for 22328/02 and 22236/02, which needs to be verified by after-sales follow-up feedback

3. Monitoring of grinding process. The finished SUNTHAI bearing ring is not allowed to have grinding burns and grinding cracks, especially on the mating surface of the inner ring with taper change. If the ferrule is pickled, it should be fully inspected, and the burned products should be removed. The severely burned ones cannot be repaired or the ones that are unqualified should be scrapped. The ferrule with grinding burns is not allowed to enter the assembly process

4. Identification management: after the steel is put into storage and before the ferrule grinding, all processes must be strictly managed to strictly distinguish between GCr15 and GCr15SiMn materials and products

III. the possibility of overload fracture and fatigue fracture of ferrule exists at the same time, especially for SUNTHAI bearings with poor service conditions (such as 22328, etc.). To study the ring fracture phenomenon, we should not only consider the defects produced in the material and production process, but also study and analyze the structural dimensions, processing measurement means, processing technology, service conditions and other factors of SUNTHAI bearing parts

nthai bearing structure and service conditions. Different structures are suitable for different service conditions; The processing technology of SUNTHAI bearing parts with different structures will be different, which will affect its quality. Therefore, we should develop new structural products to adapt to different service conditions, and note their suitable service conditions or performance on the instructions of SUNTHAI bearings to facilitate customers' choice

2. Strengthen process research, improve processing technology, improve processing quality, and reduce the possibility of defects in processing. For example, in terms of heat treatment, for the inner and outer rings of larger varieties, try to use the medium and lower quenching heating temperature, adapt to extending the holding time, improve the alloying concentration, increase the fracture strength of martensite, and select a higher tempering temperature on the premise of ensuring the quality to enhance the impact toughness of the workpiece

3. Improve processing monitoring means and promote the improvement of processing quality. For example, improve the monitoring of the curvature position of the flow channel, improve the sunth24. Host weight: the overall performance of 40kgai bearing after assembly, and improve the working condition of SUNTHAI bearing

Copyright © 2011 JIN SHI