Defect Analysis of Heat Treatment of Cold Rolled Ribbed Steel Bars
What are the defects analysis of heat treatment of cold rolled ribbed steel bars? Or what are the defect analysis of cold rolled ribbed steel bars after heating treatment? Gongyi Jindi Metallurgical Equipment Co., Ltd is a professional manufacturer of cold rolling mill, cold rolled ribbed steel mill and cold rolled ribbed steel production line. Regarding many defects encountered by many customers in the heat treatment process of cold rolled ribbed steel bars and detailed analysis has been made.
According to the knowledge of the technicians of the cold rolled ribbed steel production line from Jindi Metallurgical Equipment, there are several kinds of defects in the heat treatment process of cold rolled ribbed steel bars, which are quenching, deformation and poor hardness. The specific analysis is as follows:
First, the reasons for quenching crack of cold rolled ribbed steel bars:
1, the shape effect, mainly caused by design factors, such as the rounded corner R is too small, the hole position is not proper set, the section transition is not good.
2, Overheating (overheating), mainly caused by temperature control, high process setting temperature, uneven furnace temperature and other factors.
3, Decarburization, mainly caused by overheating (or over-burning), unheated heating of the air furnace, small machine margin, forging or pre-heat treatment residual decarburization layer and other factors.
4, Improper cooling, mainly due to improper choice of coolant or too cold, should master the quenching medium cooling characteristics or tempering treatment.
Second, the reasons for the insufficient hardness of cold rolled ribbed steel bars:
1, The heat treatment temperature is too high, which is caused by improper process temperature setting or temperature control system error.
2, Over-tempering, which is caused by the tempering temperature setting being too high, the error of temperature control system or the furnace temperature being too high.
3, Improper cooling, because the pre-cooling time is too long, the cooling medium is improperly selected, the quenching medium temperature is getting higher and the cooling performance is degraded.
Third, the reason for the deformation of cold rolled ribbed steel is too poor:
This is mainly due to the surface embossing effect of the martensitic transformation during heat treatment. Moreover, in many conditions of heat treatment, as long as a certain condition changes, the degree of deformation of the cold rolled ribbed steel bar changes greatly.
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